This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2008-174927, filed Jul. 3, 2008, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a method of detecting a nucleic acid sample by a nucleic acid sample detection device having nucleic acid probes immobilized thereon, and in particular, to a method of detecting a plurality of nucleic acid samples at one time.
2. Description of the Related Art
With the development of molecular biology in recent years, many disease genes have been identified, which has made the identification of diseases by genetic diagnosis possible. Tailor-made medicines are now being realized which, on the basis of results on genetic diagnosis, provide optimum treatment to individual patients.
As the effectiveness of genetic diagnosis increases, the number of samples handled in the clinical field increases drastically, so examination arrays and examination methods for examining a lot of nucleic acid samples simultaneously are strongly desired, and some have already been realized (Jpn. Pat. Appln. KOKAI Publication No. 2005-345243).
However, when a lot of nucleic acid samples are simultaneously examined, there arise problems such as mix-up of samples and contamination. Genetic diagnosis is often preclinical diagnosis, and based on the diagnostic results, preventive therapy is conducted frequently, so acquisition of accurate diagnostic results is essential.
The object of the present invention is to provide a detection method that can prevent false detection by mix-up of samples and contamination among samples and is endowed with high safety and reliability required in the clinical field.
The present invention provides, as a first embodiment, a method of detecting a plurality of nucleic acid samples, wherein 1st to nth (n: a natural number of 2 or more) nucleic acid samples are detected on a nucleic acid sample detection device including 1st to nth positive control immobilization region.
Further, the present invention provides, as a second embodiment, a method of detecting a plurality of nucleic acid samples, wherein 1st to nth (n: a natural number of 2 or more) nucleic acid samples are detected on a nucleic acid sample detection device including 1st to nth positive control immobilization regions and 1st to nth negative control immobilization regions.
Further, the present invention provides, as a third embodiment, a method of detecting a plurality of nucleic acid samples, wherein 1st to nth (n: a natural number of 2 or more) nucleic acid samples are detected on a nucleic acid sample detection device including 1st to nth positive control immobilization regions and 1st to nth negative control immobilization regions, wherein each negative control immobilization region is composed of 1 immobilization region.
The present invention provides, as a fourth embodiment, a method of detecting a plurality of nucleic acid samples, wherein 1st to nth (n: a natural number of 2 or more) nucleic acid samples are detected on a nucleic acid sample detection device including 1st to nth positive control immobilization regions and 1st to nth negative control immobilization regions, by using 1st to nth nucleic acid sample discrimination reagents containing 1st to nth positive control judgment reagents and 1st to nth negative control judgment reagents.
The present invention provides, as a fifth embodiment, a method of detecting a plurality of nucleic acids, wherein 1st to nth (n: a natural number of 2 or more) nucleic acid samples are detected on a nucleic acid sample detection device including 1st to nth positive control immobilization regions and 1st to nth negative control immobilization regions, by using 1st to nth nucleic acid sample discrimination reagents containing 1st to nth positive control judgment reagents and 1st to nth negative control judgment reagents, wherein the negative control judgment reagents have the function as a linker.
According to the present invention, there can be realized a detection method that can prevent false detection by mix-up of samples and contamination among samples and is endowed with high safety and reliability required in the clinical field.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
Hereinafter, (1) a nucleic acid sample detection device, (2) detection technique, (3) nucleic acid sample, and (4) detection procedures are described.
The nucleic acid sample detection device in this embodiment is characterized by comprising, for example, a substrate, a plurality of nucleic acid probe immobilization regions formed on the substrate, and a frame for dividing the nucleic acid probe immobilization regions. The frame forms at least one well, each well constitutes one examination lane for detecting 1 nucleic acid sample, and a nucleic acid probe immobilization region on which a nucleic acid probe as a subject of examination is immobilized (hereinafter referred to as detection nucleic acid probe immobilization region) is formed in each well.
Materials used for the substrate and frame are not particularly limited and may be any materials known by those skilled in the art. The materials that can be used herein include, for example, inorganic insulating materials such as glass, quartz glass, silicon, alumina, sapphire, forsterite, silicon carbide, silicon oxide, and silicon nitride. Other examples of the materials that can be used herein include organic materials such as polyethylene, ethylene, polypropylene, polyisobutylene, polyethylene terephthalate, unsaturated polyester, fluoroplastic, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyvinyl alcohol, polyvinyl acetal, acrylic resin, polyacrylonitrile, polystyrene, acetal resin, polycarbonate, polyamide, phenol resin, urea resin, epoxy resin, melamine resin, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer, silicone resin, polyphenylene oxide, and polysulfone. The shape of the substrate is not particularly limited and may be flat or uneven or may be porous.
The nucleic acid probe immobilization region is composed of a detection nucleic acid probe immobilization region, a positive control immobilization region and a negative control immobilization region.
The “detection nucleic acid probe immobilization region” is a region for detecting the presence or absence of a target nucleic acid sequence to be examined. For example, when the presence or absence of a certain disease gene is examined, the presence of absence of the disease gene in a nucleic acid sample can be judged by previously immobilizing a nucleic acid probe having a sequence complementary to the disease gene. By arranging a plurality of detection nucleic acid probe immobilization regions and immobilizing, on each region, a nucleic acid probe containing a different nucleotide sequence, a plurality of detection items can be simultaneously examined. The “nucleic acid probe having a sequence complementary to the disease gene” refers to a nucleic acid probe having a sequence complementary to at least a part of the disease gene.
The “positive control immobilization region” is a region for confirming the presence or absence of mix-up of nucleic acid samples. This “positive control immobilization region” is not present in conventional nucleic acid sample detection devices, and therefore, even if a certain nucleic acid sample is mistaken for another nucleic acid sample in detecting a plurality of nucleic acid samples simultaneously, this fact cannot be confirmed in the conventional detection devices. On the other hand, the nucleic acid sample detection device in this embodiment can confirm the presence or absence of mix-up of nucleic acid samples by the “positive control immobilization region” and can thus serve as a nucleic acid sample detection device endowed with high safety and reliability without mix-up of nucleic acid samples.
The “negative control immobilization region” is a region for confirming the presence or absence of contamination. This “negative control immobilization region” is not present in conventional nucleic acid sample detection devices, and therefore, even if a certain nucleic acid sample is contaminated with another nucleic acid sample in detecting a plurality of nucleic acid samples simultaneously, this fact cannot be confirmed in the conventional detection devices. On the other hand, the nucleic acid sample detection device in this embodiment can confirm the presence or absence of contamination with another nucleic acid sample by the “negative control immobilization region” and can thus serve as a nucleic acid sample detection device endowed with high safety and reliability without contamination.
The material for the nucleic acid probe immobilized on the nucleic acid probe immobilization region is not particularly limited and may be any material known by those skilled in the art. For example, DNA, RNA, PNA, a nucleic acid of methylphosphonate skeleton, other nucleic acid analogues, and chimeric nucleic acids thereof can be used. The length of the probe used is not particularly limited. For example, the probe is 8 to 200 bases in length, preferably 10 to 100 bases, more preferably 12 to 50 bases.
The method of immobilizing nucleic acid probes to prepare the nucleic acid probe immobilization region is not particularly limited, and any method known by those skilled in the art can be used in immobilization. The nucleic acid probe can be immobilized, for example, by physical adsorption, chemical adsorption, hydrophobic bonding, embedding, or covalent bonding. Specifically, a condensing agent such as carbodiimide can be used in covalently bonding a probe to a substrate via an amino group introduced into the end of the probe. Alternatively, by coating a substrate with an anionic organic substance, a nucleic acid probe can be immobilized on the substrate via ionic bonding. When biotin is introduced into the end of a probe, the probe can also be immobilized via biotin-avidin bonding. Further, a probe can be strongly immobilized by introducing a thiol group into the end of the probe and then forming S—S between the thiol group and a thiol-containing substance coated on a substrate. In these cases, the surface of a substrate can be previously modified with a molecule having a functional group to facilitate immobilization. For reducing the steric hindrance between the surface of the substrate and the probe, a spacer is desirably interposed between the probe and the terminal functional group. The spacer molecule is not particularly limited and may be for example an alkane skeleton, an alkyne skeleton, an alkene skeleton, an ethylene glycol skeleton or a nucleic acid chain. Its molecular structure may be either a linear chain or a branched chain. The length of the spacer is not particularly limited, but is preferably 10 to 500, more preferably 20 to 200, even more preferably 50 to 100, in terms of the number of carbon-carbon bonds.
When an immobilization device called a DNA spotter or a DNA arrayer is used in immobilization of the nucleic acid probe on a substrate, the probe can relatively easily be immobilized. In this case, a spotter of an ink jet system or an electrostatic system is preferably used to prevent the surface of the substrate from being damaged. It is also possible to directly synthesize the nucleic acid chain on the surface of the substrate.
The process of immobilizing nucleic acid probes to form the nucleic acid probe immobilization region is carried out preferably before bonding a substrate to a frame, but even after bonding, nucleic acid probes can be immobilized. The nucleic acid sample detection device in this embodiment is not necessarily provided in the state where nucleic acid probes have been immobilized on the nucleic acid probe immobilization region, and the device may be provided as a substrate on which nucleic acid probes are not immobilized. In this case, desired nucleic acid probes are immobilized on the substrate as described above so that the substrate can be used as the nucleic acid sample detection device.
The shape of a well formed by a frame is also not particularly limited and may be circular, rectangular or polygonal. The nucleic acid detection substrate in this embodiment would be easily prepared by preparing a frame with wells having no bottom and then bonding the frame to a substrate on which the nucleic acid probe immobilization region has been formed for use. For bonding the frame to the substrate, a strong bonding method such as adhesive bonding or pressure bonding to prevent liquid leakage is desired, and a silicon packing can also be used in bonding.
The nucleic acid detection substrate in this embodiment does not always have to be provided in the state where the substrate on which the nucleic acid probe immobilization region has been formed and the frame are integrated into one body, and the nucleic acid detection substrate may be provided in the state where both the substrate and the frame are separate. In this case, the substrate and the frame are bonded as described above for use as the nucleic acid detection substrate.
The nucleic acid sample detection device in this embodiment is provided with a plurality of wells formed by the frame in order to detect a plurality of nucleic acid samples. The number of wells is not particularly limited, and is preferably 3 or more and less than 100, more preferably 4 or more and 50 or less, still more preferably 5 or more and 20 or less. These wells are formed on the same device but are not always formed on 1 substrate. All wells may be formed on 1 substrate, or a plurality of wells may be formed on a plurality of substrates. For example, a plurality of nucleic acid samples may be detected simultaneously by preparing a plurality of substrates each having 1 well formed thereon. In this case, 1 nucleic acid sample is detected with 1 substrate.
The present invention includes all detection techniques known to those skilled in the art, and should not be construed as restrictive with respect to detection techniques. For example, detection by the fluorescence intensity of a fluorescent dye, detection by a radioisotope, detection by an electrochemical response of an intercalator molecule, and detection by a change in electrostatic capacity can be used. Particularly, as typical detection techniques, there are detection by fluorescence and electrochemical detection. In detection by fluorescence, detection results can be visually recognized, thus preventing erroneous judgment of the results. In electrochemical detection, on the other hand, only current values are used in examination, and thus the device can be downsized, the examination cost can be reduced, and the examination time can be shortened. In the case of electrochemical detection, each of the nucleic acid probe immobilization regions is constituted as an electrode, and each nucleic acid probe is immobilized on the electrode.
In the case of fluorescence detection, the nucleic acid sample is previously labeled with a fluorescent substance. For example, a primer labeled with a fluorescent substance is used to amplify the target nucleic acid by PCR. The target nucleic acid that formed a hybrid chain with a nucleic probe remains in the nucleic acid probe immobilization region even after washing and thus gives fluorescence light. The fluorescent substance used may be an arbitrary fluorescent substance known in the art, and for example, FITC, Cy3, Cy5 or rhodamine is used. The emission of the fluorescent substance can be detected with a fluorescence detector. The presence or absence of the target nucleic acid corresponding to each nucleic acid probe can be determined from the amount of the obtained fluorescence.
For preventing the unspecific adsorption of nucleic acids or fluorescent dyes onto the nucleic acid probe immobilization region in the fluorescence detection method, the surface of the nucleic acid probe immobilization region is desirably coated with lipids, surfactants, albumins or nucleic acids, such as mercaptoethanol, mercaptohexanol, mercaptoheptanol, mercaptoethylene glycol, mercaptooligoethylene glycol, mercaptopolyethylene glycol, mercaptans such an alkane thiol having a C30 to C50 chain, and stearylamines.
In the case of electrochemical detection, on the other hand, an electrochemically active molecule is used. The electrochemically active molecule refers to a molecule which binds to a hybrid chain and emits an electron upon application of an electric potential. An arbitrary electrochemically active molecule known in the art may be used. Examples of the electrochemically active molecule that can be used include Hoechst 33258 (registered trademark) (available from CALBIOCHEM), Acridine Orange, quinacrine, daumonycin, a metallo-intercalator, a bis-intercalator such as bisacridine, a tris-intercalator or a poly-intercalator. Particularly, Hoechst 33258 (registered trademark) is preferably used. Hoechst 33258 (registered trademark) is a molecule composed of a chemical substance p-(5-(5-(4-methylpiperazin-1-yl)benzimidazol-2-yl) benzimidazol-2-yl) phenol. Moreover, these intercalators may be modified with an electrochemically active metal complex such as ferrocene (dicyclopentadienyl iron) or viologen. The concentration of the molecule is selected appropriately, and is generally in the range of from 1 ng/ml to 1000 ng/ml. At this time, a buffer solution having an ionic strength ranging from 0.01 to 5 and a pH ranging from 5 to 10 can be used.
The molecule recognizes the hybrid chain and intercalates it. Upon application of a potential, the redox reaction of the molecule occurs to release an electron therefrom, thus bringing about passage of a current. Thereupon, the potential may be swept at a constant rate or applied by pulsation, or a constant potential may be applied. The potential sweeping rate is in the range of 10 to 1000 mV/sec. For measurement, the electricity and voltage may be regulated by using a device such as a potentiostat, a digital multimeter and a function generator. A current derived from the molecule flows in the electrode, and the presence or absence of the target nucleic acid corresponding to each nucleic acid probe can be determined by measuring the current value.
For preventing the unspecific adsorption of nucleic acids or intercalators onto the nucleic acid probe immobilization region (electrode) in the electrochemical detection method, the surface of the electrode is desirably coated with lipids, surfactants, albumins or nucleic acids, such as mercaptoethanol, mercaptohexanol, mercaptoheptanol, mercaptoethylene glycol, mercaptooligoethylene glycol, mercaptopolyethylene glycol, mercaptans such as an alkane thiol having a C30 to C50 chain, and stearylamines.
The nucleic acid sample detected by the nucleic acid sample detection device in this embodiment is not especially limited, and may be a nucleic acid sample extracted from a sample such as blood, serum, leukocyte, urine, feces, semen, salivary juice, tissue, cultivated cell, phlegm, food, soil, drainage, waste water, air, and the like, or a nucleic acid sample obtained by amplification treatment after extraction. The detection method in this embodiment can be used to detect, for example, virus infections caused by viruses such as hepatitis virus (A, B, C, D, E, F, and G types), HIV, influenza virus (A, B, C, D, E, and F), herpes group virus, adenovirus, human polyoma virus, human papilloma virus, human parvovirus, mumps virus, human rotavirus, enterovirus, Japanese encephalitis virus, smallpox virus, coronavirus, SARS, dengue fever virus, rubella viruses, and HTLV, infections caused by microorganisms such as yellow staphylococcus, hemolytic streptococcus, pathogenic Escherichia coli, enteritis vibrio, Helicobacter pylori, campylobacter, cholera bacterium, dysentery bacterium, salmonella, anthrax, yersinia, gonococcus, listeria, leptospire, legionalla bacterium, spirochete, pneumonia mycoplasma, rickettsia, chlamydia, malaria, dysentery amoebas, and pathogenetic fungus as well as parasite and fungus.
The detection method in this embodiment can also be used in genotyping of microorganisms causing the infections mentioned above. For example, the detection method can be used in detecting genotypes of the HCV virus, that is, 1a, 1b, 2a, 2b, 3a and 3b and genotypes of human papillomavirus, that is, 16, 18, 31, 33, 35, 39, 45, 51, 52, 53, 54, 56, 58, 59, 66, 68 and 69 which are related to malignant transformation and 6, 11, 34, 40, 42, 43, 44 and 70 which are not related to malignant transformation. Drug resistance genes can also be detected, and examples include drug resistance genes of the tubercle bacillus, AIDS virus, and microorganisms causing respiratory infections. The detection method in this embodiment can also be used in examining hereditary diseases, neoplastic diseases such as retinoblastoma, virus tumor, familial colonic polyposis, hereditary nonpolyposis colon cancer, neurofibromatosis, familial chest cancer, xeroderma pigmentosum, brain cancer, oral cancer, esophageal cancer, stomach cancer, colon cancer, liver cancer, pancreatic cancer, lung cancer, thyroid tumor, mammary gland tumor, urinary tumor, virilia tumor, muliebria tumor, skin tumor, osteosarcoma, osteochondrosarcoma, leukemia, lymphoma, and solid tumor. The detection method can be adopted to all fields to which the gene check is necessary; in a food check, quarantine, medicine check, legal medicine, agriculture, stock raising, fishery, and forestry, etc. as well as in medical treatment. In addition, the detection of restriction fragment length polymorphism (RFLP), single nucleotide polymorphisms (SNPs), and the micro satellite array, etc. is also possible. The detection method can also be used for analyzing unknown nucleotide sequences.
For detection of nucleic acids contained in samples, a nucleic acid component is extracted from the samples thereby obtaining nucleic acid samples. There is no particular limitation to the extraction method, and a liquid-liquid extraction such as a phenol/chloroform method or a solid-liquid extraction using a carrier may also be used. A commercially available nucleic acid extraction method such as a QIAamp method (produced by QIAGEN) or Sumi Test (produced by Sumitomo Metal Industries, Ltd.) can also be utilized. These samples are pipetted onto a microtiter plate or the like and subjected to gene detection. When a microtiter plate retaining a hydrophobic membrane, for example, is used in gene extraction, a detection operation can be started more easily. The extracted nucleic acid is preferably dissolved in a suitable solution.
The hybridization reaction between the nucleic acid and a probe immobilized on a probe immobilization region is carried out in a buffer solution as a reaction solution having an ionic strength ranging from 0.01 to 5 and a pH ranging from 5 to 10. Dextran sulfate, salmon sperm DNA, bovine thymus DNA, EDTA and surfactants may be added as hybridization accelerators to the reaction solution. Further, a salt concentration regulator, a positive control reagent, etc. may also be added. According to necessity, a nucleic acid amplification reaction may be carried out as a pretreatment. The nucleic acid amplification reaction includes, but is not limited to, PCR, LAMP, and ICAN. Then, the extracted nucleic acid is added to the reaction solution and thermally denatured at 90° C. or more. Contacting the nucleic acid-containing reaction solution with a probe immobilization electrode may be carried out immediately after the denaturation or after rapid cooling to 0° C. During the reaction, the reaction rate can be increased by an operation such as stirring or shaking. The reaction may be performed at a temperature ranging from 10 to 90° C. for the period of about one minute to overnight. After the hybridization reaction, the probe immobilization region is washed. In washing, a buffer solution having an ion strength ranging from 0.01 to 5 and a pH ranging from 5 to 10 is used. At this time, a nucleic acid sample discrimination reagent is added to the nucleic acid-containing reaction solution. The composition of the nucleic acid sample discrimination reagent depends on whether the immobilized probe is a positive control nucleic acid probe or a negative control nucleic acid probe.
After washing, the presence or absence of hybridization is detected. The detection techniques are not particularly limited, and detection by the fluorescence intensity of a fluorescent dye, detection by a radioisotope, detection by an electrochemical response of an intercalator molecule, detection by a change in electrostatic capacity, or the like, can be used as described above.
According to the detection method in this embodiment, samples derived from different analytes are used in the respective reaction wells formed on the substrate, and nucleic acid chains in the samples can be simultaneously detected.
The nucleic acid reaction and nucleic acid detection can be automated. Variations in measurement result, which are attributable to handling, etc., can be reduced by automation. The automated examination apparatus can include a temperature regulation system for regulating the reaction temperature in an extraction reaction, an amplification reaction, a hybridization reaction and a washing reaction. A Peltier element, an electrothermal heater, etc. may be utilized in the temperature regulating system. The automated examination apparatus can also include a solution-sending system for sending a solution of each reagent. In the solution-sending system, a pump, a pipe, a flow-rate monitor, a degassing mechanism, a gas/liquid detection monitor, or the like, can be used. The automated examination apparatus can also include a detection system for detecting a double-stranded nucleic acid and a single-stranded nucleic acid. Although the detection system varies depending on the detection method, a laser irradiation device and CCD camera can be used in the fluorescence detection method. A two- or three-electrode current/voltage regulating device can be used in the current detection method. The automated examination apparatus can also include a signal processing system for performing automatic judgment based on an obtained signal. Using a database, a threshold value, etc. previously incorporated in a computer, a sample nucleic acid can be sequenced, or the presence or absence of a target nucleic acid can be judged on the basis of an obtained signal. The automated apparatus can deal with a plurality of nucleic acid sample detection devices at one time. One apparatus may also perform the entire process, or a plurality of apparatuses may share the process.
Hereinafter, embodiments of the present invention are described with reference to the drawings. The embodiments shown below are set forth for illustrative purposes for describing the constitution of the invention in detail. Therefore, the invention should not be construed as restrictive on the basis of the following description of embodiments. The scope of the invention encompasses all embodiments which are within the scope of the invention as defined by the appended claims, and include a wide variety of alterations and modifications thereof.
1st to nth wells 121-n are provided with injection ports 151-n (also referred to hereinafter as 1st to nth injection ports 151-n) for injection of 1st to nth nucleic acid samples respectively. The 1st well 121 is a well for detecting the first nucleic acid sample, and the kth (k: a natural number of 2 or more) well 12k is a well for detecting the kth nucleic acid sample.
The 1st well 121 includes a detection nucleic acid probe immobilization region 131 for detecting the 1st nucleic acid sample (also referred to hereinafter as the 1st detection nucleic acid probe immobilization region 131) and a positive control immobilization region 141 for discriminating the 1st nucleic acid sample (also referred to hereinafter as the 1st positive control immobilization region 141), while the k (k: a natural number of 2 to n) well 12k includes a nucleic acid probe immobilization region 13k for detecting the kth nucleic acid sample (also referred to hereinafter as the kth detection nucleic acid probe immobilization region 13k) and a positive control immobilization region 14k for discriminating the kth nucleic acid sample (also referred to hereinafter as the kth positive control immobilization region 14k). The nucleic acid sample detection device 11 constituted as described can detect the 1st to nth (n: a natural number of 2 or more) nucleic acid samples.
A nucleic acid sample detection device 11 capable of detecting 1st to 4th (n=4) nucleic acid samples (nucleic acid samples S1 to S4), for example, is shown in
Discrimination nucleic acid probes different from one another are immobilized on the “positive control immobilization regions” respectively. For example, a nucleic acid probe C1 constituting the 1st positive control is immobilized on the 1st positive control immobilization region 141, a nucleic acid probe C2 constituting the 2nd positive control is immobilized on the 2nd positive control immobilization region 142, a nucleic acid probe C3 constituting the 3rd positive control is immobilized on the 3rd positive control immobilization region 143, and a nucleic acid probe C4 constituting the 4th positive control is immobilized on the 4th positive control immobilization region 144.
In the “detection nucleic acid probe immobilization region”, one or more nucleic acid probes complementary to target sequences to be detected are immobilized on mutually independent regions, respectively. For example, when there are 2 or more target sequences to be detected, the detection nucleic acid probe immobilization region is provided with 2 or more independent immobilization regions, and on each of the immobilization regions, a nucleic acid probe complementary to one of the target sequences is immobilized.
1st to nth (n: a natural number of 2 or more) nucleic acid sample discrimination reagents are added to the 1st to nth nucleic acid samples, respectively. The 1st nucleic acid sample discrimination reagent contains a “1st positive control nucleic acid” having a sequence complementary to a nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141. The kth (k: a natural number of 2 or more) nucleic acid sample discrimination reagent contains a kth positive control nucleic acid having a sequence complementary to a nucleic acid probe C(k) immobilized on the kth positive control immobilization region 14k. The 1st to nth nucleic acid samples to which the 1st to nth nucleic acid sample discrimination reagents including the above components were added respectively are injected respectively via the 1st to nth injection ports 151-n disposed in the 1st to nth wells, thereby causing hybridization reactions in the 1st to nth positive control immobilization regions 14n-1, and by detecting the reactions, it can be confirmed that there was no mix-up of the 1st to nth nucleic acid samples.
In
The 1st nucleic acid sample discrimination reagent (reagent 1) contains a nucleic acid T1 having a sequence complementary to the nucleic acid probe C1 immobilized on the 1st positive control (PC) immobilization reagent 141 (
The 1st to 4th nucleic acid samples (samples S1 to S4) to which the 1st to 4th nucleic acid sample discrimination reagents (reagents 1 to 4) were added are injected into the 1st to 4th wells 141 to 144, respectively. The samples are injected via the 1st to 4th injection ports 151 to 154 disposed respectively in the 1st to 4th wells 141 to 144. For example, when the 1st nucleic acid sample to which the 1st nucleic acid sample discrimination reagent (reagent 1) was added is injected into the 1st well 121, a nucleic acid T1 contained in the reagent 1 hybridizes with the nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141 (
The 1st negative control immobilization region 321 is composed of (n-1) immobilization regions on which the nucleic acid probes C2 to Cn immobilized on the 2nd to nth positive control immobilization regions have been immobilized respectively and independently, and the kth (k: a natural number of 2 to n) negative control immobilization region 32k is composed of (n-1) immobilization regions on which the nucleic acid probes C1 to Cn immobilized on the 1st to nth positive control immobilization regions, excluding the nucleic acid probe C(k) immobilized on the kth positive control immobilization region, have been immobilized respectively and independently.
A nucleic acid sample detection device 31 capable of detecting 1st to 4th (n=4) nucleic acid samples, for example, is shown in
Similarly to the first embodiment, the 1st to 4th nucleic acid samples (samples S1 to S4) to which the 1st to 4th nucleic acid sample discrimination reagents (reagents 1 to 4) were added are injected into the 1st to 4th wells 121 to 124 respectively. The samples are injected respectively via the 1st to 4th injection ports 151 to 154 disposed in the 1st to 4th wells 121 to 124. For example, when the 1st nucleic acid sample to which the 1st nucleic acid sample discrimination reagent (reagent 1) was added is injected into the 1st well 121, a nucleic acid T1 contained in the reagent 1 hybridizes with the nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141 (
On the other hand, when a signal is detected from the 1st negative control immobilization region 321, the contamination of the sample with another nucleic acid sample can be detected. For example, when the 1st nucleic acid sample (sample S1) has been contaminated with the 2nd nucleic acid sample (sample S2) to which the 2nd nucleic acid sample discrimination reagent (reagent 2) was added (
The nucleic acid sample detection device 51 in the third embodiment is characterized in that a plurality of negative control immobilization regions arranged in each well in the second embodiment are constituted as one immobilization region.
The 1st negative control immobilization region is composed of one immobilization region on which nucleic acid probes having the same sequences as in the nucleic acid probes C2 to C(n) immobilized on the 2nd to nth positive control immobilization regions have been immobilized together, and the kth (k: a natural number of 2 to n) negative control immobilization region is composed of one immobilization region on which nucleic acid probes having the same sequences as in the nucleic acid probes immobilized on the 1st to nth positive control immobilization regions, excluding the nucleic acid probe C(k) immobilized on the kth positive control immobilization region, have been immobilized together.
A nucleic acid sample detection device 51 capable of detecting 1st to 4th (n=4) nucleic acid samples for example is shown in
When a plurality of negative controls are arranged in one region, the arrangement includes, for example, an arrangement in which plural types of nucleic acid probes constituting negative controls are immobilized in parallel (
As the downsizing of an examination substrate advances at present, probe immobilization spots thereon tend to be micronized. A significant increase in the number of samples is also estimated. The increase in the number of samples leads to an increase in the number of negative controls, but when a large number of negative controls are mixed and arranged in parallel on a micronized region estimated to be realized in the future (
In the third embodiment, similarly to the second embodiment, the 1st to 4th nucleic acid samples (samples S1 to S4) to which the 1st to 4th nucleic acid sample discrimination reagents (reagents 1 to 4) were added are injected into the 1st to 4th wells 121 to 124 respectively. The samples are injected via 1st to 4th injection ports 151 to 154 disposed in the 1st to 4th wells 121 to 124. For example, when the 1st nucleic acid sample to which the 1st nucleic acid sample discrimination reagent (reagent 1) was added is injected into the 1st well 121, a nucleic acid T1 contained in the reagent 1 hybridizes with the nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141 (
When a signal is detected from the 1st negative control immobilization region 321, contamination with another nucleic acid sample can be detected. For example, when the 1st nucleic acid sample (sample S1) has been contaminated with the 2nd nucleic acid sample (sample S2) to which the 2nd nucleic acid sample discrimination reagent (reagent 2) was added (
The third embodiment, similarly to the second embodiment, can detect not only mix-up of nucleic acid samples but also contamination, thus providing a safer and highly reliable detection method. In the third embodiment, the nucleic acid probes immobilized on the negative control immobilization region have been immobilized together on one region so that even if the number of nucleic acid samples increase, it is not necessary to increase the number of the negative control immobilization regions. Accordingly, the majority of the detection substrate area can be allotted to examination items, and even in detection for many examination items, a large number of nucleic acid samples can be simultaneously examined on a small detection substrate.
The basic structure of this device is the same as in the first to third embodiments. That is, the nucleic acid sample detection device 81 includes 1st to nth wells 121-n provided respectively with injection ports 151-n for injecting 1st to nth nucleic acid samples.
The 1st well 121 contains a 1st detection nucleic acid probe immobilization region 131 for detecting the 1st nucleic acid sample, a 1st positive control immobilization reagent 141 for discriminating the 1st nucleic acid sample, and a 1st negative control immobilization region 321 for detecting contamination with a nucleic acid sample other than the 1st nucleic acid sample, and the kth (k: a natural number of 2 to n) well 12k contains a kth detection nucleic acid probe immobilization regions 13k for detecting the kth nucleic acid sample, a kth positive control immobilization reagent 14k for discriminating the kth nucleic acid sample, and a kth negative control immobilization region 32k for detecting contamination with a nucleic acid sample other than the kth nucleic acid sample.
A 1st positive control judgment reagent and a 1st negative control judgment reagent are added to the 1st nucleic acid sample. The 1st positive control judgment reagent is the same as the 1st nucleic acid sample discrimination reagent described in the first to third embodiments, and contains the “1st positive control nucleic acid”, that is, a nucleic acid T1 having a sequence complimentary to a nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141. On the other hand, the 1st negative control judgment reagent contains nucleic acids U2 to U(n) having sequences complementary to nucleic acid probes H2 to H(n) immobilized on the 2nd to nth negative control immobilization regions 322-n, respectively.
Similarly, a kth positive control judgment reagent and a kth negative control judgment reagent are added to the kth nucleic acid sample. The kth positive control judgment reagent contains a nucleic acid T(k) having a sequence complementary to a nucleic acid probe C(k) immobilized on the kth positive control immobilization region 14k. On the other hand, the kth negative control judgment reagent contains nucleic acids U1 to U(n) having sequences complementary to nucleic acid probes H1 to H(n) immobilized on the 1st to nth negative control immobilization regions 322-n, respectively, excluding a nucleic acid U(k) having a sequence complementary to a nucleic acid probe H(k) immobilized on the kth (n: a natural number of 2 to n) negative control immobilization region 32k.
Using the 1st to nth positive control judgment reagents and the 1st to nth negative control judgment reagents, the nucleic acid probes immobilized on each negative control immobilization reagent can be limited to 1 type. The positive control judgment reagent and the negative control judgment reagent may be independent reagents, or may be prepared all together as a “nucleic acid sample discrimination reagent”. The “nucleic acid sample discrimination reagent” may contain an arbitrary additive, for example, a salt concentration regulation buffer and the like.
A nucleic acid sample detection device 81 capable of detecting 1st to 4th (n=4) nucleic acid samples (nucleic acid samples S1 to S4), for example, is shown in
Discrimination nucleic acid probes C1 to C4 that are different from one another are immobilized on the “positive control immobilization region”. For example, a nucleic acid probe C1 constituting the 1st positive control is immobilized on the 1st positive control immobilization region 141, a nucleic acid probe C2 constituting the 2nd positive control is immobilized on the 2nd positive control immobilization region 142, a nucleic acid probe C3 constituting the 3rd positive control is immobilized on the 3rd positive control immobilization region 143, and a nucleic acid probe C4 constituting the 4th positive control is immobilized on the 4th positive control immobilization region 144.
Discrimination nucleic acid probes H1 to H4, differing from the nucleic acid probes C1 to C4 immobilized on the “positive control immobilization region”, are immobilized on the “negative control immobilization region”. For example, a nucleic acid probe H1 constituting the 1st negative control is immobilized on the 1st negative control immobilization region 141, a nucleic acid probe H2 constituting the 2nd negative control is immobilized on the 2nd negative control immobilization region 142, a nucleic acid probe H3 constituting the 3rd negative control is immobilized on the 3rd negative control immobilization region 143, and a nucleic acid probe H4 constituting the 4th positive control is immobilized on the 4th negative control immobilization region 144.
The 1st to 4th positive control judgment reagents (reagents 1A to 4A) are the same as the 1st to 4th nucleic acid sample discrimination reagents described in the first to third embodiments.
Now, the 1st to 4th negative control judgment reagents (reagents 1B to 4B) are described.
First, the 1st negative control judgment reagent (reagent 1B) is a reagent added to the 1st nucleic acid sample. The reagent 1B is a reagent containing 3 nucleic acids U2, U3 and U4, that is, a “nucleic acid U2” having a sequence complementary to the nucleic acid probe H2 immobilized on the 2nd negative control (NC) immobilization region 322, a “nucleic acid U3” having a sequence complementary to the nucleic acid probe H3 immobilized on the 3rd negative control (NC) immobilization region 323, and a “nucleic acid U4” having a sequence complementary to the nucleic acid probe H4 immobilized on the 4th negative control (NC) immobilization region 324.
The 1st negative control judgment reagent (reagent 1B), together with the 1st positive control judgment reagent (reagent 1A), is added to the 1st nucleic acid sample (sample S1). The reagents 1A and 1B may be independent reagents or may be prepared all together as, for example, a “nucleic acid sample discrimination reagent 1E”.
Next, the 2nd negative control judgment reagent (reagent 2B) is a reagent added to the 1st nucleic acid sample. The reagent 2B is a reagent containing 3 nucleic acids U1, U3 and U4, that is, a “nucleic acid U1” having a sequence complementary to the nucleic acid probe H1 immobilized on the 1st negative control (NC) immobilization region 321, the “nucleic acid U3” having a sequence complementary to the nucleic acid probe H3 immobilized on the 3rd negative control (NC) immobilization region 323, and the “nucleic acid U4” having a sequence complementary to the nucleic acid probe H4 immobilized on the 4th negative control (NC) immobilization region 324.
The 2nd negative control judgment reagent (reagent 2B), together with the 2nd positive control judgment reagent (reagent 2A), is added to the 2nd nucleic acid sample (sample S2). The reagents 2A and 2B may be independent reagents or may be prepared all together as, for example, a “nucleic acid sample discrimination reagent 2E”.
Subsequently, the 3rd negative control judgment reagent (reagent 3B) is a reagent added to the 1st nucleic acid sample. The reagent 3B is a reagent containing 3 nucleic acids U1, U2 and U4, that is, the “nucleic acid U1” having a sequence complementary to the nucleic acid probe H1 immobilized on the 1st negative control (NC) immobilization region 321, the “nucleic acid U2” having a sequence complementary to the nucleic acid probe H2 immobilized on the 2nd negative control (NC) immobilization region 322, and the “nucleic acid U4” having a sequence complementary to the nucleic acid probe H4 immobilized on the 4th negative control (NC) immobilization region 324.
The 3rd negative control judgment reagent (reagent 3B), together with the 3rd positive control judgment reagent (reagent 3A), is added to the 3rd nucleic acid sample (sample S3). The reagents 3A and 3B may be independent reagents or may be prepared all together as, for example, a “nucleic acid sample discrimination reagent 3E”.
Finally, the 4th negative control judgment reagent (reagent 4B) is a reagent added to the 1st nucleic acid sample. The reagent 4B is a reagent containing 3 nucleic acids U1, U2 and U3, that is, the “nucleic acid U1” having a sequence complementary to the nucleic acid probe H1 immobilized on the 1st negative control (NC) immobilization region 321, the “nucleic acid U2” having a sequence complementary to the nucleic acid probe H2 immobilized on the 2nd negative control (NC) immobilization region 322, and the “nucleic acid U3” having a sequence complementary to the nucleic acid probe H3 immobilized on the 3rd negative control (NC) immobilization region 323.
The 4th negative control judgment reagent (reagent 4B), together with the 4th positive control judgment reagent (reagent 4A), is added to the 4th nucleic acid sample (sample S4). The reagents 4A and 4B may be independent reagents or may be prepared all together as, for example, a “nucleic acid sample discrimination reagent 4E”.
The 2nd nucleic acid sample (sample S1) to which the reagents 1A and 1B were added is injected via an injection port 151 into well 121. At this time, the nucleic acid T1 contained in the reagent 1A hybridizes with the nucleic acid probe C1 immobilized on the positive control immobilization region 141, and a signal derived from the hybrid chain is detected (
Similarly, the 1st nucleic acid sample (sample S2) to which the reagents 2A and 2B were added is injected via an injection port 152 into well 122. At this time, the nucleic acid T2 contained in the reagent 2A hybridizes with the nucleic acid probe C2 immobilized on the positive control immobilization region 142, and a signal derived from the hybrid chain is detected (
Now, the case where the 1st nucleic acid sample (sample S1) was contaminated with the 2nd nucleic acid sample (sample S2) is described (
The feature of the fourth embodiment lies in that negative control judgment reagents are newly prepared, and the number of the nucleic acid probes immobilized on each of the 1st to nth negative control immobilization regions is limited to 1 type. In the fourth embodiment, the number of the nucleic acid probes immobilized on each of the negative control immobilization regions is always 1 type, even if the number of nucleic acid samples increases. Accordingly, a change in design of the negative control immobilization region accompanying an increase or decrease in the number of nucleic acid samples is not necessary, and a device for detecting a lot of nucleic acid probes can be easily and rapidly provided.
The nucleic acid sample detection device 81 shown in
First, the 1st to 4th negative control judgment reagents (reagents 1B to 4B) are described.
The 1st negative control judgment reagent (reagent 1B) is a reagent added to the 1st nucleic acid sample. The reagent 1B is a reagent containing nucleic acids V2, V3 and V4. The nucleic acid V2 has, at one end, a sequence complementary to a nucleic acid probe H2 immobilized on the 2nd negative control immobilization region 322, and at the other end, a sequence complementary to a “nucleic acid T2” hybridizing with a nucleic acid probe C2 immobilized on the 2nd positive control immobilization region 142. The nucleic acid V3 has, at one end, a sequence complementary to a nucleic acid probe H3 immobilized on the 3rd negative control immobilization region 323, and at the other end, a sequence complementary to a “nucleic acid T3” hybridizing with a nucleic acid probe C3 immobilized on the 3rd positive control immobilization region 143. The nucleic acid V4 has, at one end, a sequence complementary to a nucleic acid probe H4 immobilized on the 4th negative control immobilization region 324, and at the other end, a sequence complementary to a “nucleic acid T4” hybridizing with a nucleic acid probe C4 immobilized on the 4th positive control immobilization region 144.
The 1st negative control judgment reagent (reagent 1B), together with the 1st positive control judgment reagent (reagent 1A), is added to the 1st nucleic acid sample (sample S1). The reagents 1A and 1B may be independent reagents or may be prepared altogether as, for example, the “nucleic acid sample discrimination reagent 1E”.
Then, the 2nd negative control judgment reagent (reagent 2B) is a reagent added to the 2nd nucleic acid sample. The reagent 2B is a reagent containing nucleic acids V1, V3 and V4. The nucleic acid V1 has, at one end, a sequence complementary to a nucleic acid probe H1 immobilized on the 1st negative control immobilization region 321, and at the other end, a sequence complementary to a “nucleic acid T1” hybridizing with a nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141. The nucleic acid V3 has, at one end, a sequence complementary to the nucleic acid probe H3 immobilized on the 3rd negative control immobilization region 323, and at the other end, a sequence complementary to the “nucleic acid T3” hybridizing with the nucleic acid probe C3 immobilized on the 3rd positive control immobilization region 143. The nucleic acid V4 has, at one end, a sequence complementary to the nucleic acid probe H4 immobilized on the 4th negative control immobilization region 324, and at the other end, a sequence complementary to the “nucleic acid T4” hybridizing with the nucleic acid probe C4 immobilized on the 4th positive control immobilization region 144.
The 2nd negative control judgment reagent (reagent 2B), together with the 2nd positive control judgment reagent (reagent 2A), is added to the 2nd nucleic acid sample (sample S2). The reagents 2A and 2B may be independent reagents or may be prepared altogether as, for example, the “nucleic acid sample discrimination reagent 2E”.
Then, the 3rd negative control judgment reagent (reagent 3B) is a reagent added to the 3rd nucleic acid sample. The reagent 3B is a reagent containing nucleic acids V1, V2 and V4. The nucleic acid V1 has, at one end, a sequence complementary to the nucleic acid probe H1 immobilized on the 1st negative control immobilization region 321, and at the other end, a sequence complementary to the “nucleic acid T1” hybridizing with the nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141. The nucleic acid V2 has, at one end, a sequence complementary to the nucleic acid probe H2 immobilized on the 2nd negative control immobilization region 322, and at the other end, a sequence complementary to the “nucleic acid T2” hybridizing with the nucleic acid probe C2 immobilized on the 2nd positive control immobilization region 142. The nucleic acid V4 has, at one end, a sequence complementary to the nucleic acid probe H4 immobilized on the 4th negative control immobilization region 324, and at the other end, a sequence complementary to the “nucleic acid T4” hybridizing with the nucleic acid probe C4 immobilized on the 4th positive control immobilization region 144.
The 3rd negative control judgment reagent (reagent 3B), together with the 3rd positive control judgment reagent (reagent 3A), is added to the 3rd nucleic acid sample (sample S3). The reagents 3A and 3B may be independent reagents or may be prepared altogether as, for example, the “nucleic acid sample discrimination reagent 3E”.
Finally, the 4th negative control judgment reagent (reagent 4B) is a reagent added to the 4th nucleic acid sample. The reagent 4B is a reagent containing nucleic acids V1, V2 and V3. The nucleic acid V1 has, at one end, a sequence complementary to the nucleic acid probe H1 immobilized on the 1st negative control immobilization region 321, and at the other end, a sequence complementary to the “nucleic acid T1” hybridizing with the nucleic acid probe C1 immobilized on the 1st positive control immobilization region 141. The nucleic acid V2 has, at one end, a sequence complementary to the nucleic acid probe H2 immobilized on the 2nd negative control immobilization region 322, and at the other end, a sequence complementary to the “nucleic acid T2” hybridizing with the nucleic acid probe C2 immobilized on the 2nd positive control immobilization region 142. The nucleic acid V3 has, at one end, a sequence complementary to the nucleic acid probe H3 immobilized on the 3rd negative control immobilization region 323, and at the other end, a sequence complementary to the “nucleic acid T3” hybridizing with the nucleic acid probe C3 immobilized on the 3rd positive control immobilization region 143.
The 4th negative control judgment reagent (reagent 4B), together with the 4th positive control judgment reagent (reagent 4A), is added to the 4th nucleic acid sample (sample S4). The reagents 4A and 4B may be independent reagents or may be prepared altogether as, for example, the “nucleic acid sample discrimination reagent 4E”.
Now, the detection mechanism in the fifth embodiment is described.
The 1st nucleic acid sample (sample S1) to which the reagents 1A and 1B were added is injected via an injection port 151 into well 121. At this time, the nucleic acid T1 contained in the reagent 1A hybridizes with the nucleic acid probe C1 immobilized on the positive control immobilization region 141, and a signal derived from the hybrid chain is detected (
Similarly, the 2nd nucleic acid sample (sample S2) to which the reagents 2A and 2B were added is injected via an injection port 152 into well 122. At this time, the nucleic acid T2 contained in the reagent 2A hybridizes with the nucleic acid probe C2 immobilized on the positive control immobilization region 142, and a signal derived from the hybrid chain is detected (
Now, the case where the 1st nucleic acid sample (sample S1) was contaminated with the 2nd nucleic acid sample (sample S2) is described (
As the reagent 1B, there is a reagent wherein nucleic acids V2, V3 and V4 contained in the reagent 1B are prepared as mutually independent nucleic acids (
As the number of nucleic acid samples increases, the types of nucleic acids contained in the negative control judgment reagent also increase. When the nucleic acid reagents are tandemly joined (
A nucleic acid sample detection kit used in each of the first to fifth embodiments can be provided. The nucleic acid detection kit contains both the nucleic acid sample detection device used in each of the first to fifth embodiments and the 1st to nth (n: a natural number of 2 or more) nucleic acid sample discrimination reagents. On the detection nucleic acid probe immobilization region in the nucleic acid sample detection device, a nucleic acid probe having a sequence complementary to a specific disease gene to be examined has been immobilized, and a plurality of nucleic acid samples are treated with the nucleic acid sample discrimination reagents contained in the kit and then injected into the nucleic acid sample detection device, whereby examination results can be obtained simultaneously and rapidly.
In the nucleic acid sample detection device contained in the kit, examination lanes each detecting one nucleic acid sample may be formed integrally on one substrate, or each examination lane may be formed in an independent substrate. Alternatively, 2 substrates each containing 4 examination lanes may be prepared for detecting 8 nucleic acid samples, or 3 substrates each containing 3 examination lanes may be prepared for detecting 9 nucleic acid samples.
The 1st to nth nucleic acid discrimination reagents may be composed respectively of the mutually independent 1st to nth positive control judgment reagents and the 1st to nth negative control judgment reagents, in which arbitrary additives such as a salt concentration regulation buffer may be present as reagents.
The basic structure of the nucleic acid sample detection device used in this example is shown in
Also, in this example, a nucleic acid sample detection device capable of electrochemical detection was used. That is, a plurality of nuclei acid probe immobilization regions formed in each well have gold electrodes respectively by which an electric signal derived from a double-stranded nucleic acid formed on each immobilization region can be detected. The electric signal can be obtained by using an intercalator binding specifically to the double-stranded nucleic acid. In this example, Hoechst 33258 (registered trademark) was used as the intercalator.
The sequences of nucleic acid probes C1 to C4 immobilized respectively on the positive control immobilization regions 141-4 are as follows:
The sequences of nucleic acid probes D1 to D4 immobilized on each of the detection nucleic acid probe immobilization regions 131-4 are as follows:
The sequences of nucleic acids T1 to T4 contained in the positive control judgment reagents (reagents 1 to 4) are as follows:
Reagent 1: (Nucleic acid T1 (sequence complementary to C1) is contained)
Reagent 2: (Nucleic acid T2 (sequence complementary to C2) is contained)
Reagent 3: (Nucleic acid T3 (sequence complementary to C3) is contained)
Reagent 4: (Nucleic acid T4 (sequence complementary to C4) is contained)
The sequences of 1st to 4th nucleic acid samples (samples S1 to S4) to be detected contain the following sequences:
Sample S1: (Sequence complementary to the detection nucleic acid probe D1 is contained)
Sample S2: (Sequence complementary to the detection nucleic acid probe D2 is contained)
Sample S3: (Sequence complementary to the detection nucleic acid probe D3 is contained)
Sample S4: (Sequence complementary to the detection nucleic acid probe D4 is contained)
The positive control judgment reagents (reagents 1 to 4) together with a salt concentration regulation buffer were added to the 1st to 4th nucleic acid samples (samples S1 to S4) respectively. Then, the samples S1 to S4 were injected via injection ports into the 1st to 4th wells, respectively. After injection, the samples hybridize with nucleic acid probes at 45° C. for 10 minutes, and then a washing buffer was injected into each well, followed by a washing reaction at 30° C. for 10 minutes, to remove unspecifically adsorbed nucleic acid. And then an intercalator molecule (50 μM Hoechst 33258 (registered trademark)) into each well, and apply a voltage to each electrode, and measure the oxidation current of the intercalator molecule. Thereafter, whether the reaction had occurred in the positive control immobilization regions in the 1st to 4th wells was determined, and whether the reaction had occurred in the detection nucleic acid probe immobilization regions in the 1st to 4th wells was also determined. Whether the reaction had occurred or not was determined by comparing the current with each electrodes. A graph showing the measurement result of current values is shown in
For simulation of mix-up of samples, the S1 and S2 were intentionally exchanged with each other and then subjected to detection in the same manner. A graph showing the measurement result of current values is shown in
When a nucleic acid formed a double strand, a current value not lower than a predetermined threshold value is detected by the nucleic acid sample detection device capable of electrochemical detection used in this example; on the other hand, when no double strand was formed, a current value not higher than the threshold value is detected. The reason why a small current value was detected is attributable to unspecifically adsorbed nucleic acid that was not completely removed in the washing reaction.
Referring to
Thus, nucleic acid sequences contained in the nucleic acid samples could be identified from the current values obtained from the detection nucleic acid probe immobilization regions D1 to D4. That is, in the nucleic acid sample S1, 82 nA was detected by the nucleic acid probe D1, and it could be confirmed that a sequence complementary to the nucleic acid probe D1 was contained in the nucleic acid sample S1. In the nucleic acid sample S2, 62 nA was detected by the nucleic acid probe D2, and it could be confirmed that a sequence complementary to the nucleic acid probe D2 was contained in the nucleic acid sample S2. In the nucleic acid sample S3, 73 nA was detected by the nucleic acid probe D3, and it could be confirmed that a sequence complementary to the nucleic acid probe D3 was contained in the nucleic acid sample S3. In the nucleic acid sample S4, 66 nA was detected by the nucleic acid probe D4, and it could be confirmed that a sequence complementary to the nucleic acid probe D4 was contained in the nucleic acid sample S4.
Referring to
In addition, it can be confirmed that there was no mix-up of the nucleic acid samples S3 and S4, and the correct examination result could be obtained. That is, in the nucleic acid sample S3, 66 nA was detected by the nucleic acid probe D3, and it could be confirmed that a sequence complementary to the nucleic acid probe D3 was contained in the nucleic acid sample S3. Further, in the nucleic acid sample S4, 73 nA was detected by the nucleic acid probe D4, and it could be confirmed that a sequence complementary to the nucleic acid probe D4 was contained in the nucleic acid sample S4.
The basic structure of the nucleic acid sample detection device used in this example is shown in
Nucleic acid probes and judgment reagents are as shown in Example 1. In Example 2, negative control immobilization regions 321-4 are used. Nucleic acid probes C1 to C4 immobilized on the negative control immobilization regions 321-4 are the same as the nucleic acid probes C1 to C4 immobilized on the positive control immobilization regions 141-4.
The sequences of 1st to 4th nucleic acid samples (samples S1 to S4) to be detected contain the following sequences:
Sample S1: (Sequence complementary to the detection nucleic acid probe D1 is contained)
Sample S2: (Sequence complementary to the detection nucleic acid probe D2 is contained)
Sample S3: (Sequence complementary to the detection nucleic acid probe D3 is contained)
Sample S4: (Sequence complementary to the detection nucleic acid probe D4 is contained)
The positive control judgment reagents (reagents 1 to 4) together with a salt concentration regulation buffer were added to the 1st to 4th nucleic acid samples (samples S1 to S4) respectively. Then, the samples S1 to S4 were injected via injection ports into the 1st to 4th wells, where a sample (S1+S2) in which S1 and S2 had been intentionally mixed was injected into the 1st well to simulate contamination of the sample. After injection, the samples were subjected to hybridization reaction at 45° C. for 10 minutes, and then a washing buffer was injected into each well, followed by a washing reaction at 30C for 10 minutes, to remove unspecifically adsorbed nucleic acid. And then an intercalator molecule (50 μM Hoechst 33258 (registered trademark)) into each well, and apply a voltage to each electrode, and measure the oxidation current of the intercalator molecule. Thereafter, whether the reaction had occurred in the positive control immobilization regions in the 1st to 4th wells was determined, and whether the reaction had occurred in the detection nucleic acid probe immobilization regions in the 1st to 4th wells was also determined. Whether the reaction had occurred or not was determined in the same manner as in Example 1 by comparing the current with each electrodes. A graph showing the measurement result of current values is shown in
When a nucleic acid formed a double strand, a current value not lower than a predetermined threshold value is detected by the nucleic acid sample detection device capable of electrochemical detection used in this example similar to Example 1; on the other hand, when no double strand was formed, a current value not higher than the threshold value is detected.
Referring to
In the 1st well, current values not lower than the threshold value were obtained from the negative control probes (NCP), and it could be correctly confirmed that there was contamination with another nucleic acid sample.
In addition, it could be confirmed that there was no mix-up of the nucleic acid samples S2, S3 and S4, and the correct examination result could be obtained. That is, in the nucleic acid sample S2, 72 nA was detected by the nucleic acid probe D2, and it could be confirmed that a sequence complementary to the nucleic acid probe D2 was contained in the nucleic acid sample S2. In the nucleic acid sample S3, 69 nA was detected by the nucleic acid probe D3, and it could be confirmed that a sequence complementary to the nucleic acid probe D3 was contained in the nucleic acid sample S3. In the nucleic acid sample S4, 72 nA was detected by the nucleic acid probe D4, and it could be confirmed that a sequence complementary to the nucleic acid probe D4 was contained in the nucleic acid sample S4.
The basic structure of the nucleic acid sample detection device used in this example is shown in
Nucleic acid probes and judgment reagents are as shown in Example 1. In Example 3, negative control immobilization regions 321-4 are used. Nucleic acid probes C1 to C4 immobilized on each of the negative control immobilization regions 321-4 are the same as nucleic acid probes C1 to C4 immobilized on each of the positive control immobilization regions 141-4.
The sequences of 1st to 4th nucleic acid samples (samples S1 to S4) to be detected contain the following sequences:
Sample S1: (Sequence complementary to the detection nucleic acid probe D1 is contained)
Sample S2: (Sequence complementary to the detection nucleic acid probe D2 is contained)
Sample S3: (Sequence complementary to the detection nucleic acid probe D3 is contained)
Sample S4: (Sequence complementary to the detection nucleic acid probe D4 is contained)
The positive control judgment reagents (reagents 1 to 4) together with a salt concentration regulation buffer were added to the 1st to 4th nucleic acid samples (samples S1 to S4) respectively. Then, the samples S1 to S4 were injected via injection ports into the 1st to 4th wells, where S3 and S4 were intentionally exchanged and injected for simulation of mix-up of the samples. After injection, the samples were subjected to a hybridization reaction at 45° C. for 10 minutes, and then a washing buffer was injected into each well, followed by a washing reaction at 30° C. for 10 minutes, to remove unspecifically adsorbed nucleic acid. And then an intercalator molecule (50 μM Hoechst 33258 (registered trademark)) into each well, and apply a voltage to each electrode, and measure the oxidation current of the intercalator molecule. Thereafter, whether the reaction had occurred in the positive control immobilization regions in the 1st to 4th wells was determined, and whether the reaction had occurred in the detection nucleic acid probe immobilization regions in the 1st to 4th wells was also determined. Whether the reaction had occurred or not was determined in the same manner as in Example 1 by comparing the current with each electrodes. A graph showing the measurement result of current values is shown in
Each symbol shown in
When a nucleic acid formed a double strand, a current value not lower than a predetermined threshold value is detected by the nucleic acid sample detection device capable of electrochemical detection used in this example similar to Examples 1 and 2; on the other hand, when no double strand was formed, a current value not higher than the threshold value is detected.
Referring to
In the 3rd and 4th wells, current values not lower than the threshold value were obtained from the negative control probes (NCP), and from this result, it was also found that the mix-up of the nucleic acid samples could be correctly confirmed.
In addition, it could be confirmed that there was no contamination of the nucleic acid samples S1 and S2, and the correct examination result could be obtained. That is, in the nucleic acid sample S1, 65 nA was detected by the nucleic acid probe D1, and it could be confirmed that a sequence complementary to the nucleic acid probe D1 was contained in the nucleic acid sample S1. In the nucleic acid sample S2, 72 nA was detected by the nucleic acid probe D2, and it could be confirmed that a sequence complementary to the nucleic acid probe D2 was contained in the nucleic acid sample S2.
In this example, not only the positive control judgment reagents 1A to 4A used in Examples 1 to 3 but also negative control judgment reagents 1B to 4B are used to detect mix-up of samples and contamination.
The basic structure of the nucleic acid sample detection device used in this example is as shown in
The sequences of nucleic acid probes C1 to C4 immobilized on the positive control immobilization regions 141-4 are as follows (the same as in Example 1):
The sequences of nucleic acid probes H1 to H4 immobilized on the negative control immobilization region 321-4 are as follows:
The sequences of nucleic acid probes D1 to D4 immobilized on the detection nucleic acid probe immobilization region 131-4 are as follows (the same as in Example 1):
The sequences of nucleic acids T1 to T4 contained in the positive control judgment reagents (reagents 1A to 4A) are as follows:
Reagent 1A: (Nucleic acid T1 (sequence complementary to C1) is contained)
Reagent 2A: (Nucleic acid T2 (sequence complementary to C2) is contained)
Reagent 3A: (Nucleic acid T3 (sequence complementary to C3) is contained)
Reagent 4A: (Nucleic acid T4 (sequence complementary to C4) is contained)
The sequences of nucleic acids V1 to V4 contained in the negative control judgment reagents (reagents 1B to 4B) are as follows:
Reagent 1B: (Nucleic acid U1 (sequence complementary to H1) is contained)
Reagent 2B: (Nucleic acid U2 (sequence complementary to H2) is contained)
Reagent 3B: (Nucleic acid U3 (sequence complementary to H3) is contained)
Reagent 4B: (Nucleic acid U4 (sequence complementary to H4) is contained)
The sequences of 1st to 4th nucleic acid samples (samples S1 to S4) to be detected contain the following sequences:
Sample S1: (Sequence complementary to the detection nucleic acid probe D1 is contained)
Sample S2: (Sequence complementary to the detection nucleic acid probe D2 is contained)
Sample S3: (Sequence complementary to the detection nucleic acid probe D3 is contained)
Sample S4: (Sequence complementary to the detection nucleic acid probe D4 is contained)
The positive control judgment reagents (reagents 1A to 4A) and the negative control judgment reagents (reagents 1B to 4B) together with a salt concentration regulation buffer were added to the 1st to 4th nucleic acid samples (samples S1 to S4) respectively. Then, the samples S1 to S4 were injected via injection ports into the 1st to 4th wells. After injection, the samples were subjected to a hybridization reaction at 45° C. for 10 minutes, and then a washing buffer was injected into each well, followed by washing reaction at 30° C. for 10 minutes, to remove unspecifically adsorbed nucleic acid. And then an intercalator molecule (50 μM Hoechst 33258 (registered trademark)) into each well, and apply a voltage to each electrode, and measure the oxidation current of the intercalator molecule. Thereafter, whether the reaction had occurred in the positive control immobilization regions in the 1st to 4th wells was determined, and whether the reaction had occurred in the detection nucleic acid probe immobilization regions in the 1st to 4th wells was also determined. Whether the reaction had occurred or not was determined in the same manner as in Example 1 by comparing the current with each electrodes. A graph showing the measurement result of current values is shown in
For simulation of mix-up of samples, the S1 and S2 were intentionally exchanged with each other and then subjected to detection in the same manner. A graph showing the measurement result of current values is shown in
Each symbol shown in
When a nucleic acid formed a double strand, a current value not lower than a predetermined threshold value is detected by the nucleic acid sample detection device capable of electrochemical detection used in this example, similarly to Examples 1 to 3; on the other hand, when no double strand was formed, a current value not higher than the threshold value is detected.
Referring to
In all the 4 wells, a current value not lower than the threshold value was not obtained from the negative control probes (NCP), and from this result, it could also be confirmed that there was no contamination with another nucleic acid sample.
Then, nucleic acid sequences contained in the nucleic acid samples could be identified from the current values obtained from the detection nucleic acid probe immobilization regions D1 to D4. That is, in the nucleic acid sample S1, 56 nA was detected by the nucleic acid probe D1, and it could be confirmed that a sequence complementary to the nucleic acid probe D1 was contained in the nucleic acid sample S1. In the nucleic acid sample S2, 67 nA was detected by the nucleic acid probe D2, and it could be confirmed that a sequence complementary to the nucleic acid probe D2 was contained in the nucleic acid sample S2. In the nucleic acid sample S3, 56 nA was detected by the nucleic acid probe D3, and it could be confirmed that a sequence complementary to the nucleic acid probe D3 was contained in the nucleic acid sample S3. In the nucleic acid sample S4, 72 nA was detected by the nucleic acid probe D4, and it could be confirmed that a sequence complementary to the nucleic acid probe D4 was contained in the nucleic acid sample S4.
Referring to
In addition, it could be confirmed that there was no mix-up of the nucleic acid samples S3 and S4, and the correct examination result could be obtained. That is, in the nucleic acid sample S3, 62 nA was detected by the nucleic acid probe D3, and it could be confirmed that a sequence complementary to the nucleic acid probe D3 was contained in the nucleic acid sample S3. In the nucleic acid sample S4, 71 nA was detected by the nucleic acid probe D4, and it could be confirmed that a sequence complementary to the nucleic acid probe D4 was contained in the nucleic acid sample S4.
In this example, not only the positive control judgment reagents 1A to 4A used in Examples 1 to 4 but also negative control judgment reagents 1B to 4B are used to detect mix-up of samples and contamination.
The basic structure of the nucleic acid sample detection device used in this example is as shown in
The sequences of nucleic acid probes C1 to C4 immobilized on the positive control immobilization region 141-4 are as follows (the same as in Example 1):
The sequences of nucleic acid probes H1 to H4 immobilized on the negative control immobilization region 321-4 are as follows:
The sequences of nucleic acid probes D1 to D4 immobilized on the detection nucleic acid probe immobilization regions 131-4 are as follows (the same as in Example 1):
The sequences of nucleic acids T1 to T4 contained in the positive control judgment reagents (reagents 1A to 4A) are as follows:
Reagent 1A: (Nucleic acid T1 (sequence complementary to C1) is contained)
Reagent 2A: (Nucleic acid T2 (sequence complementary to C2) is contained)
Reagent 3A: (Nucleic acid T3 (sequence complementary to C3) is contained)
Reagent 4A: (Nucleic acid T4 (sequence complementary to C4) is contained)
The sequences of nucleic acids V1 to V4 contained in the negative control judgment reagents (reagents 1B to 4B) are as follows:
Reagent 1B: (Nucleic acid V1 (sequence complementary to H1+sequence complementary to T1) is contained)
Reagent 2B: (Nucleic acid V2 (sequence complementary to H2+sequence complementary to T2) is contained)
Reagent 3B: (Nucleic acid V3 (sequence complementary to H3+sequence complementary to T3) is contained)
Reagent 4B: (Nucleic acid V4 (sequence complementary to H4+sequence complementary to T4) is contained)
The sequences of 1st to 4th nucleic acid samples (samples S1 to S4) to be detected contain the following sequences:
Sample S1: (Sequence complementary to the detection nucleic acid probe D1 is contained)
Sample S2: (Sequence complementary to the detection nucleic acid probe D2 is contained)
Sample S3: (Sequence complementary to the detection nucleic acid probe D3 is contained)
Sample S4: (Sequence complementary to the detection nucleic acid probe D4 is contained)
The positive control judgment reagents (reagents 1A to 4A) and the negative control judgment reagents (reagents 1B to 4B) together with a salt concentration regulation buffer were added to the 1st to 4th nucleic acid samples (samples S1 to S4), respectively. Then, the samples S1 to S4 were injected via injection ports into the 1st to 4th wells, where a sample (S3+S4) in which the S3 and S4 had been intentionally mixed was injected into the 3rd well to simulate contamination of the sample. After injection, the samples were subjected to a hybridization reaction at 45° C. for 10 minutes, and then a washing buffer was injected into each well, followed by a washing reaction at 30° C. for 10 minutes, to remove unspecifically adsorbed nucleic acid. And then an intercalator molecule (50 μM Hoechst 33258 (registered trademark)) into each well, and apply a voltage to each electrode, and measure the oxidation current of the intercalator molecule. Thereafter, whether the reaction had occurred in the positive control immobilization regions in the 1st to 4th wells was determined, and whether the reaction had occurred in the detection nucleic acid probe immobilization regions in the 1st to 4th wells was also determined. Whether the reaction had occurred or not was determined in the same manner as in Example 1 by comparing the current with each electrodes. A graph showing the measurement result of current values is shown in
Each symbol shown in
When a nucleic acid formed a double strand, a current value not lower than a predetermined threshold value is detected by the nucleic acid sample detection device capable of electrochemical detection used in this example similar to Examples 1 to 4; on the other hand, when no double strand was formed, a current value not higher than the threshold value is detected.
Referring to
In the 3rd well, a current value not lower than the threshold value was obtained from the negative control probe (NCP), and it was found that contamination with another nucleic acid sample could be correctly confirmed.
In addition, it could be confirmed that there was no mix-up of the nucleic acid samples S1, S2 and S4, and the correct examination result could be obtained. That is, in the nucleic acid sample S1, 63 nA was detected by the nucleic acid probe D1, and it could be confirmed that a sequence complementary to the nucleic acid probe D1 was contained in the nucleic acid sample S1. In the nucleic acid sample S2, 72 nA was detected by the nucleic acid probe D2, and it could be confirmed that a sequence complementary to the nucleic acid probe D2 was contained in the nucleic acid sample S2. In the nucleic acid sample S4, 62 nA was detected by the nucleic acid probe D4, and it could be confirmed that a sequence complementary to the nucleic acid probe D4 was contained in the nucleic acid sample S4.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
Number | Date | Country | Kind |
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2008-174927 | Jul 2008 | JP | national |