The present disclosure relates to a sample holder used in automated polymerase chain reaction (PCR) testing of DNA or RNA templates extracted from a biological sample. Moreover, the disclosure relates to thermal cyclers and methods and assemblies for producing and testing the replicated DNA/RNA.
Testing within diagnostic laboratories, for example, may involve extracting and quantifying one or more constituents in a biological sample obtained from a patient, such as from blood serum or blood plasma.
PCR testing, in particular, is a technique used to amplify a targeted DNA or RNA sequence from a few extracted DNA or RNA fragments (hereinafter the “DNA/RNA template”) that have been extracted from the biological sample to billions of copies within a short period of time. For example, PCR testing can be used for identification of DNA/RNA sequences involved in cancer or genetic disorders, such as cystic fibrosis, or for the identification and diagnosis of diseases caused by fungi, bacteria, and viruses.
In such PCR processing, cycles of heating and cooling are repeated many times on a PCR solution containing the extracted DNA/RNA templates, a master mix, possibly and reagent, and possibly water, leading to a large number of (e.g., more than one billion in some cases) exact copies of the originally-extracted DNA/RNA templates. Once the replication has occurred, an optical technique such as fluorescence staining may be used to determine the amount of replicated DNA/RNA that is present and/or analyze sequences thereof.
According to a first aspect, a sample holder is provided. The sample holder includes a body having a top surface and a bottom surface, the body further comprising: an inlet groove formed into the bottom surface; an outlet groove formed into the bottom surface alongside the inlet groove; a detection recess formed into the bottom surface and connected to the inlet groove and the outlet groove; a fill port interconnected to both the inlet groove and the outlet groove; and a cover connected to the bottom surface wherein the cover interfaces with the body to form an inlet channel interconnected to the fill port, a detection region interconnected to the inlet channel, and an outlet channel interconnected to the detection region and the fill port.
According to another aspect, a PCR station assembly is provided. The PCR station assembly includes a base configured to receive a sample holder; a clamp member configured to secure the sample holder to the base; and a temperature-controlling element operable to heat and cool the base in intimate thermal contact with the sample holder. The sample holder can include the configuration defined in claim 1 herein.
In another aspect, a method of operating a PCR testing system is provided. The method includes providing a PCR station comprising a base, a clamp member, and a temperature-controlling element thermally coupled to the base; securing a sample holder between the base and clamp member, the sample holder including an inlet channel interconnected to a fill port, a detection region interconnected to the inlet channel, and an outlet channel interconnected to the detection region and the fill port; inserting a volume of PCR solution into the fill port thus filling the detection region; subjecting the PCR solution to heating and cooling by subjecting the base to cycles of heating and cooling with the temperature-controlling element to replicate tagged DNA/RNA templates to produce tagged replicated DNA/RNA; and after a predetermined number of heating and cooling cycles, measuring fluorescent emissions from the detecting region with an optical interrogation apparatus by exciting the tagged replicated DNA/RNA with a particular wavelength of light.
Still other aspects, features, and advantages of the present disclosure may be readily apparent from the following detailed description by illustrating a number of example embodiments and implementations. The present invention may also be capable of other and different embodiments, and its several details may be modified in various respects. The disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.
The disclosure will be better understood by referring to the detailed description taken in conjunction with the following drawings. The drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. The drawings are not necessarily drawn to scale. Like numerals are used throughout to denote like elements.
The present disclosure is directed at sample holders for use in, for example, PCR testing. In particular, the sample holders can provide a low-cost design that can be used with automated PCR processing for both the amplification phase and detection phases of PCR processing. The sample holder can be intended for a single use, and disposed thereafter. Optionally, the sample holder may be washed and reused.
In another aspect, the sample holder is miniaturized in that the sample holder can perform detection (e.g., fluorescence or other detection) on very small volumes of the PCR solution including the extracted DNA/RNA templates, master mix, and possibly a reagent, such as less than or equal to 20 μL, or even from 5 μL to 20 μL in the detection region.
In another aspect, the PCR station assembly is provided that is configured to hold the sample holder in a defined position for the amplification and detection phases of PCR. During the amplification phase, the PCR solution is subjected to multiple heating and cooling cycles to replicate the DNA/RNA templates. Thereafter, the PCR station assembly holds the sample holder containing the replicated DNA/RNA templates for interrogation by an optical interrogation apparatus, such as a fluorescence detection apparatus.
In view of the foregoing, there is an unmet for simple and cost effective sample holders for PCR testing, and that can process even very small volumes of the PCR solution containing thin a detection region thereof (e.g., ≤20 μL).
These and other aspects and features of embodiments of the disclosure will be described with reference to
Referring now to
The body 102 further comprises an inlet groove 108 formed into the bottom surface 106 and an outlet groove 110 also formed into the bottom surface 106. The outlet groove 110 is positioned alongside the inlet groove 108. The groves 108, 110 may run in parallel and may be formed by molding. The inlet and outlet grooves 108, 100 can have groove depths of from 0.4 mm to 0.7 mm in depth. Grooves 108, 110 can have a variable groove width such as from 0.3 mm to 1.5 mm, for example.
The body 102 further comprises a detection recess 112 formed into the bottom surface 106. The detection recess 112 is sufficiently large for the particular optical interrogation system (e.g., optical interrogation system 340) to be able to measure light emission readings (e.g., fluorescence emission readings) therefrom, for example. The detection recess 112 may have a semi-circle of diameter between about 2 mm to 5 mm, for example. The detection area may be greater than 3.14 mm2. Structurally, the inlet groove 108 leads to and is connected to the detection recess 112 and the outlet groove 110 is connected to and leads away from the detection recess 112. The groves 108, 110, and the detection recess 112 may be of the same depth from the bottom surface 106.
A fill port 114 can be interconnected to both the inlet groove 108 and the outlet groove 110 and provides both a fill and overflow function. The top surface 114S of the fill port 114 may be a planar surface and can be located above the top surface 104 and thus can be sealed with any suitable sealing membrane once the PCR solution 124 is received therein. Sealing may occur prior to insertion of the sample holder 100 in the PCR station assembly 225 (
The sample holder 100 can include a cover 116 connected to and sealed to the bottom surface 106 of the body 102 by any suitable means. The cover 116 can be a thin film cover in some embodiments, such as a generally planar sheet of constant thickness plastic or metal film. The thickness may be between 0.05 mm and 0.5 mm, for example. Other suitable thicknesses and other non-planar configurations of the cover 116 may be used. Depending on the configuration of the optical interrogation apparatus 340 (
The outlet channel 122 is thus interconnected to the reservoir 119 and the included detection region 120 therein and may also be connected to the fill port 114. The cover 116 may be bonded to the body 102 by any suitable means. For example, the cover 116 may be bonded by thermal bonding, ultrasonic welding, adhesive bonding, solvent bonding, or by including a pressure sensitive adhesive layer on the body 102. If a metal layer is used, and additional bonding layer of polymer can be used for thermal bonding.
In some embodiments, sealing of a PCR solution 124 in the reservoir 119 can involve at least one sealing member comprising heat sealing or deformation sealing along the lengths of one or more of the inlet channel 118 and outlet channel 122, or providing a sealing member such as a sealing film 233 sealing the top of the fill port 114, for example. Other sealing means may be used prior to PCR processing, such as deformation of the ports 123, 126, sealing of the ports 123, 126 by adhesive, or sealing with heavy oil (e.g., a mineral oil) in ports 126, 126 or channels 118, 122. If heat sealed, the thermal formed seals can be at two discreet locations along the lengths of the channels 118, 122 at locations that can minimize displacement of the plastic volume and maintain acceptable flatness.
The grooves 108, 110 may be locally modified to allow improved sealing. In some embodiments, more than one sealed area may be provided along each of the channels 118, 122 to provide for a primary and secondary seal for backup. The seals may avoid trapped air in the channels 118, 122. The second seal can be used to contain any displaced solution 124 that has been displaced by the first seal. In some embodiments, the fill port 114 can include one or more funnels connected one or more of the inlet and outlet ports 123, 126. The included cone angle can be less than 120 degrees, for example. The funnels aid in ensuring proper fill with PCR solution 124. The inlet and outlet ports 123, 126 may be located approximately equidistant from the detection area 120 along the length of the body 102 so that they can be easily sealed and both are uninterrupted and uncovered by any part of the PCR station 225 (
In operation, as shown in
In more detail, the inlet channel 118 can comprise an inlet first channel portion 118A and an inlet second channel portion 118B that is wider than the inlet first channel portion 118A, and thus has a larger cross-sectional area. The inlet channel 118 can further comprise an inlet transition portion 118T that allows the inlet first channel portion 118A to generally smoothly transition to the larger inlet second channel portion 118B. The transition portion 118T can allow the PCR solution 124 to expand to the larger area of the inlet second channel portion 118B with less turbulence that might undesirably introduce bubbles in the PCR solution 124.
Likewise, the outlet channel 122 can comprises an outlet first channel portion 122A and an outlet second channel portion 122B that is wider than the outlet first channel portion 122A, and thus of a larger cross-sectional area. The outlet channel 122 can further comprise an outlet transition portion 122T that allows the transition from the larger outlet second channel portion 122B to the smaller outlet first channel portion 122A. The transition portion 122T allows the PCR solution 124 to contract from the larger area outlet second channel portion 122B to minimize the amount of PCR solution 124 in the sample holder 100.
The detection region 120 is a region that contains a volume of the PCR solution within the reservoir 119 that is adapted to contain the PCR solution 124 and replicated DNA/RNA templates after the amplification phase and that viewable by the optical interrogation apparatus 340, as shown in
In the depicted embodiment, the PCR station 225 can include a base 230 and a clamp member 232. The base 230 and clamp member 232 cooperate to form a recess that is appropriately sized to receive and retain, via clamping, the sample holder 100 therein. Any suitable clamp initiator 235, such as a screw or electro-, hydraulic- or pneumatic-actuator may be used to initiate the clamping. The clamping ensures intimate thermal contact of the bottom of the sample holder 100 with the base 230. The base 230 and the clamp member 232 may be made out of a highly thermally-conductive material, such as aluminum, copper, or the like.
The PCR station 225 can include a temperature-controlling element 234. Temperature-controlling element 234 can be a thermoelectric element such as a Peltier device that can rapidly heat and cool the base 230 that is in intimate thermal contact with the sample holder 100. Thus, rapid temperature cycling between heating and cooling can be provided as controlled by drive signals from one or more drivers of a controller 342 (
The PCR station 225 can also include one or more heat sinks 236 coupled thermally to the base 230 and/or possibly to the temperature-controlling element 234. The one or more heat sinks 236 may be coupled to one or more sides or top of the base 230 and/or to the sides and/or bottom of the temperature-controlling element 234. Any suitable construction of the one or more heat sinks 236 may be used. The one or more heat sink may be aluminum or other conductive metal and may include a plurality of fins.
Pocket 230P may include a stop 230S configured to limit the extent of insertion of the sample holder 100 in the pocket 230P. The pocket 230P can include lateral sidewalls 230W that aid in positioning the reservoir 119 of the sample holder 100 relative to the viewing aperture 237. The holding portion 232H can register against lateral sidewalls 230W. Base 230 further can include extenders 230E that extend to the width and length of the temperature-controlling element 234 to maximize thermal contact therewith.
In some embodiments, the base 230 may include a temperature sensor 244 in thermal contact with the base 230, such as by being mounted therein or thereon, such as in a hole formed therein proximate the detection region 120. The temperature sensor 244 may provide feedback information to estimate the temperature of the PCR solution 124 in the detection region 120. The temperature sensor 244 may be a thermocouple or a thermistor, for example, and may be used by the controller 342 to maintain the upper and lower temperatures of the heating and cooling cycles.
Referring now to
Referring now to
The method 400 includes, in 404, securing a sample holder (e.g., 100) between the base and clamp member, the sample holder including an inlet channel (e.g., inlet channel 118) interconnected to a fill port (e.g., fill port 114), a detection region (e.g., detection region 120) interconnected to the inlet channel, and an outlet channel (e.g., outlet channel 122) interconnected to the detection region and the fill port. Securing may be by way of a clamp initiator 235 or other suitable clamping or securement means.
The method 400 includes, in 406, inserting a volume of PCR solution (e.g., PCR solution 124) into the fill port thus filling the detection region. Insertion of the volume may be before or after the insertion of the sample holder 100 in the PCR station assembly 225. Thereafter, the channels 118, 122, ports 123, 126, and/or fill port 114 may be sealed as described herein.
Next, in 408, the PCR solution 124 is subjected to heating and cooling by subjecting the base 230 to cycles of heating and cooling with the temperature-controlling element 234 to replicate the tagged DNA/RNA templates and to produce tagged replicated DNA/RNA. The tagged replicated DNA/RNA are replicates of the tagged DNA/RNA templates extracted by the previously conducted PCR sample processing via known methods.
According to the method, in 410, after a predetermined number of heating and cooling cycles, fluorescent emissions are detected and measured from the detecting region with an optical interrogation apparatus (e.g., interrogation apparatus 340) by exciting the tagged replicated DNA/RNA with a particular wavelength of light. This can be used to monitor the progress of the PCR process. Other wavelengths of light may be used to excite other fluorescent dyes tagged to the tagged replicated DNA along with associated changes to the respective filter 345 (and possibly filter 348) and dichroic mirror 346 in the optical interrogation apparatus 340 for analysis at other wavelengths as are known to those of ordinary skill in the art.
Fast PCR processing can be achieved using the sample holder 100, PCR station assembly 225, and PCR testing system 300 described herein. Further, only a small volume of the PCR solution 124 are needed to carry out the replication and testing. Sealing of the sample holder 100 prior to replication can act as a means of reducing cross contamination.
While the disclosure is susceptible to various modifications and alternative forms, specific apparatus, assembly, system, and method embodiments have been shown by way of example in the drawings and are described in detail herein. It should be understood, however, that it is not intended to limit the invention to the particular apparatus, assemblies, systems, or methods disclosed but, to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.
Filing Document | Filing Date | Country | Kind |
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PCT/US21/70132 | 2/8/2021 | WO |
Number | Date | Country | |
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62989948 | Mar 2020 | US |