The invention relates generally to assay devices and methods, and more particularly to an optical disk assay device, system and methods of use.
In the fields of biological and biochemical testing and analysis, the use of ELISAs (Enzyme-Linked Immunosorbent Assays), are well known. An ELISA is a sensitive immunoassay that uses an enzyme linked to an antibody or antigen and used as a marker for the detection of a specific protein. This link is synonymous with a key and a lock, where, metaphorically speaking, the antibody is a key, and the specific protein holds a lock into which the key fits. Thus, there must be certainty that detection occurs where the key (the antibody) fits. Common test kits are available for many different applications. However, these kits generally only perform a test for a single analyte, and require. specialized test equipment to detect and/or measure the specific protein in question.
Additionally, flow cytometry may be used to measure concentrations of biological solutions. Flow cytometry is the analysis of biological material by detection of the light-absorbing or fluorescing properties of cells or sub-cellular fractions (i.e., chromosomes) passing in a narrow stream through a laser beam. An absorbance or fluorescence profile of the sample is produced. However, flow cytometers are expensive, specialized test instruments, and are therefore not readily available.
It would therefore be desirable to have an inexpensive and easy to use device to detect and measure biological and biochemical material. As will be seen, the invention accomplishes this and overcomes the deficiencies in the prior art in a novel and elegant manner.
FIGS. 1A-D are illustrations of an optical disk according to the invention;
FIGS. 2A-C are illustrations of an optical disk being exposed to binding entities according to the invention;
FIGS. 3A-C are illustrations of an optical disk being exposed to binding entities according to the invention;
FIGS. 4A-B are illustrations of an optical disk being exposed to binding entities according to the invention and a related analysis graph;
FIGS. 5A-B are illustrations of an optical disk having multiple tracks with separate binders being exposed to binding entities according to the invention and a related analysis graph;
FIGS. 7A-D are illustrations of a method and related optical hardware according to the invention; and
The invention is directed to an optically readable device for use in an assay process, where a surface readable by an optical reading device has at least one binder located on the surface for exposure to a medium and the binder is configured to bind to a target entity that may be present in the medium. The optically readable device may be a compact disc (CD), a digital video disc (DVD), a device readable by a raster scanner, or any other optical device that operates to read a surface using optical means. An optical reading device, typically run by a CPU having software for reading an optically readable device, can then run a program to detect empirical data from the presence of one or more target entities bound to the binder.
In one embodiment, the invention is directed to an optically readable device for use in an assay process, that includes a surface readable by an optical reading device; and at least one binder located on the surface for exposure to a medium and configured to bind to a target entity that may be present in the medium. The binder is embedded in the plastic surface, or may be an active amino group embedded in the plastic surface. The invention further includes an identifier configured to bind to a target entity to aid in detecting the presence of any target entities on the surface. The disk surface may include a top layer configured to hold at least one binder, and an inner layer configured to retain optically readable inner surface entities, the device further comprising software code that, when processed by a data processor, enables the data processor to detect the presence of any target entities on the top layer. The surface may include a top layer configured to hold at least one binder and an inner layer configured to retain optically readable inner surface entities, the device further comprising software code that, when processed by a data processor, enables the data processor to detect the presence of any identifiers on the top layer. The invention may be embodied in an optically readable disk, where optically readable code is located on a section of the optical disk, where the code, when read and processed by a data processor, enables the data processor to detect the presence of any target entities on the surface. The surface may include a top layer configured to hold at least one binding entity, and an inner layer configured to retain optically readable surface entities located on the inner layer. In another embodiment, the surface includes a top layer configured to hold at least one binding entity, and an inner layer configured to retain optically readable inner surface entities, the device further comprising software code that, when processed by a data processor, enables the data processor to detect the presence of any target entities on the top layer. The disk may includede optically readable code located on a section of the inner layer in the form of optically readable entities, where the code, when read by an optical reading device and processed by a data processor, enables the data processor to detect the presence of any target entities on the top layer. Again, the surface may include a top layer configured to hold at least one binding group and an inner layer configured to retain optically readable target entities, the optical disk further comprising optically readable code located on a section of the inner layer in the form of optically readable entities, where the code, when read by an optical reading device and processed by a data processor, enables the data processor to detect the presence of any target entities bound to a binding group on the top layer. The top layer may further include active amino groups embedded therein configured to bind to target entities located within the medium. The optically readable code includes code configured to enable an optical reading device to detect errors at positions on the top layer where target entities in the medium bind to the binding entity.
The optically readable disk may include the optically readable code, which may include code configured to enable an optical reading device to detect errors at positions on the top layer where target entities in the medium bind to the binding entity, wherein a processor, when executing the code, is configurable to determine whether a number of read errors is related to the number of target entities located in the medium.
In operation, the system may perform the process of treating an optical disk with a binding entity to a material of interest; exposing the disk to a solution containing the material of interest, such that the material of interest binds to the binding entity; reading the disk in an optical disk reader; and counting the number of read errors caused by the material of interest on the optical disk; wherein the number of read errors is proportional to an amount of the material of interest. Prior to reading the disk, the disk may be exposed to a secondary binding entity to the material of interest, wherein the secondary binding entity carries a substance which will cause a read error. Also, different disk sections may be treated with different binding entities. The method may include measuring the size of a cell by treating an optical disk with an antibody to the cells; exposing the disk to a solution containing the cells, such that the cells bind to the antibody; reading the optical disk in an optical disk reader; and analyzing read errors from the optical disk reader caused by the cells, such that error analysis determines a pattern of the errors and a corresponding size of the cells. The target entity may be a cell or other entity in this example, and the optical disk may be treated with a plurality of antibodies configured to bind different target entities.
Optical reading hardware and related controllers and software are configured to detect the presence of antibodies on the surface using ordinary optical reading devices, such as a CD or DVD reader used in most computers, laptops or other devices. Raster scanners also exist that read optical surfaces, and can be configured to operate according to the novel methods of the invention. Well known error checking software exists that is configured to detect errors on the optical reading surface of a CD or DVD, and, according to the invention, can be adapted to check for the presence of target entities attached to a surface by the antibodies. Those skilled in the art will understand that there is a wealth of optical reading hardware and software and related controller components that exists in the art that can be easily adapted without any undue experimentation. Generally, an optical surface of a CD or DVD player is made up of pits, both long and short, and lands, that define logic 0's and 1's. Error checking software is configured to detect defects on the optical surface that are large enough to distort the reading of the data from the disc. According to the invention, such components and related software is used to detect the presence of target entities on the surface of an optical disc, to quantify the target entities and to make computations related to the quantity, quality and other characteristics of the target entities in the medium being tested and measured. Thus, the target entities, once bound to the disk, can cause errors that the error checking software can detect as errors.
If the target entity is not large enough to be detected as an error, a secondary antibody attached to a more obstructive object, such as beads used on cytometry, so that the error checking software can detect the presence of the target entity on the optical surface. Such antibodies and related beads are well known in the art of cytometry, and will be well understood by those skilled in the art to exist in many varieties, particularly in sizes that can be detected by error testing software according to the invention.
Again, in some applications, the target entity may be too small to be detected by the optical reading device. In this case, a second binder may be connected to an obstructive object that can be detected by the optical reading device. Such an object would be large enough to be detected, such as that known in the art as a bead discussed further below. Thus, when the target entity that is bound to the surface is then exposed to the other binder connected to the bead, an optical reading device can then read the bead as evidence of the existence of the target entity in the medium.
The target may be organic or inorganic chemicals, biological, biomedical, complex or simple. The invention is adaptable to any system where a target entity exists in a medium, and where an antibody can be affixed or otherwise associated with a surface in order to attract and bind to the target entity. The medium may be a fluid, gas, or vapor, and may be a substance sputtered, sprayed or otherwise exposed to the binder. For example, one or more binders can be connected to a surface, and then the surface with the binders can be exposed to a blood sample, where certain blood cells are attracted to the binders on the surface. Once bound to the surface, they may be detectable to error checking software commonly used to check for errors in optical disk surfaces. If they are too small to show up as errors, a second binder attached to a larger entity, such as a bead as discussed below, that can be detected by error software can be exposed to the disk, attaching them to the bound blood cells. Thus, the error checking software can detect the larger entity, or bead, and count the bound cell on the optical surface.
The optical surface can then be scanned or simply read by a compact disc reader that is configured with appropriate error checking software. Such software is well know in the art, and would be easily adapted to an application embodying the invention without any undue experimentation. Typically, error checking software checks the number of errors by percentage or number, records the errors during a checking process, but stops at a point where a certain number of errors are found, rendering the optical surface useless for use in storing data. According to the invention, however, such software can be easily modified to continue checking until all tracks of the optical disc are examined, giving an accurate count of the entities relevant for the test.
Applications may include detection of bacteria or other biological entities in water systems, chlorine content in a pool, different organic and inorganic entities in lakes or water systems, and many other applications.
In one embodiment, the binder is embedded in the plastic surface. In another embodiment, the binder is an active amino group embedded in the plastic surface. The invention may further include an identifier configured to bind to a target entity to aid in detecting the presence of any target entities on the surface. An example is a bead or other obstructive entity that would be detectible by error software run using an optical reading apparatus, which is discussed in more detail below. The surface may include a top layer configured to hold at least one binder, and an inner layer configured to retain optically readable inner surface entities. The device may further include software code that, when processed by a data processor, enables the data processor to detect the presence of any target entities on the top layer. If the binder is embodied on an optically readable disk, the software may be embedded within the optical medium.
The readable surface may be simple, in that it can simply be readable by an optical reading device when there are target entities. For example, the optical reading device may read the presence of target entities present, whether they have any secondary entity bound to it, such as a bead for example. Thus, commonly used reading software can be configured to simply detect and count or otherwise record the presence of target entities in a medium. Such software can be well known error checking software, or can also include any of a number of reading software applications that can be easily coded to detect and record the presence of target entities in a medium. Thus, a disk could be used that does not have optically readable tracks. It could have a background that is simply the land of the disk, whether it is made of silicon or any other material. Thus, a simple disk surface where there is only a land, no pits, and that picks up the binding entity with binders, such as antibodies attached to the disk surface. Then, beads or other obstructions having binders can be exposed to the surface.
The surface of the medium may include a top layer configured to hold at least one binder and an inner layer configured to retain optically readable inner surface entities, the device may thus include software code that, when processed by a data processor, enables the data processor to detect the presence of any identifiers or target entities on the top layer.
In one embodiment, the surface includes a top layer configured to hold at least one binding entity, and an inner layer configured to retain optically readable surface entities located on the inner layer. Alternatively, the surface may include a top layer configured to hold at least one binding entity, and an inner layer configured to retain optically readable inner surface entities, where the device has software code that, when processed by a data processor, enables the data processor to detect the presence of any target entities on the top layer. Those skilled in the art will understand that simple modifications to an optical reading medium can be made to enhance or simplify the testing and measuring process according to the invention. For example, an optical reader may be able to read a surface that is prepared with antibodies and exposed to a medium, whether secondary obstructive entities are used or not used, whether there is an optical surface that is digitally readable by an optical reader or not. The optical reader could simply read the errors occurring on the surface caused alone by the target entities or secondary entities that are used to identify the target entities. The invention, however, is not limited to any particular optical surface configuration, but extends to any optically readable surface that can be used in conjunction with error checking software to detect the presence of the target entities in the medium being tested.
In one embodiment, the invention is directed to a system, device and method for determining the concentration of biochemical or biological entities using an optically readable surface, such as an optical disk. More particularly, an optical disk may be covered with binding entity, such as an antibody to a specific target to be measured. The surface may be treated with a binding entity or agent in a number of ways, including sputtering, spraying, printed or imprinted onto the optical surface. Those skilled in the art will understand that there is a wealth of different types of methods
This may be accomplished, for example, by using well known standard inkjet printer technology to print directly onto the disk using a solution of the binding entity, or other similar method. Those skilled in the art will understand that there are many ways to apply, embed or otherwise bind the binding entity to the optical surface, thus making the optical surface attractive to the target entities that are bound to or otherwise receptive to the binding entities.
In operational use, the disk is exposed to a medium, such as a liquid, vapor or gas, containing the target to be measured, such as a protein. Once introduced into the medium, the target binds to its binding entities, such as antibodies on the disk surface. The disk may then be rinsed or washed to remove any other superfluous material that is not relevant to the testing or measuring. If the bound entities are not large enough to be detected by the error checking software and associated optical reading means, then the disk may subsequently be exposed to a secondary compound such as another antibody, which may be the same or a different antibody as the antibody on the surface, or may be another antibody attached to a bead or other obstructive entity that is readable by the optical reader. The secondary binder will ultimately bind to the target and interfere with normal detection of the digital information on the optical disk.
If the optical surface is an optical disk, such as a CD or DVD, which is then read by an optical reader, there will be a read error at each location of a bound target, since the normal pit that is read by the error checking software that searches for errors on the disk will not be readable. The number of read errors is directly proportional to the number of bound targets, and therefore the concentration of the original solution can be calculated.
Since many commercially available optical readers, such as CD or DVD players, include built-in error detection and correction, a more ideal reader for the invention is a reader that does not perform any such correction, but merely passes the read error information to the control software for counting. Also, the disk may also be covered with different solution on different sections of the disk in order to perform multiple measurements utilizing a single disk. Thus, as described herein, the invention provides an economical and convenient system for biological and biochemical measurement and analysis.
The invention is an improvement over the prior art in that it offers increased sensitivity with respect to measurements such as ELISA, and can also perform multiplex tests i.e. using a single sample to measure multiple analytes. Furthermore, the invention does not require a specialized and expensive optical test instrument, but instead uses a relatively inexpensive optical disk reader, which may come with modern laptop or desktop computers.
According to the invention, the term of binding to “plastic” is intended to be interpreted broadly, for example, the plastic may be that which is used to sandwich laser sensitive material in CD's or DVD's as currently used. It may also include plastics that can be made that have binding groups embedded. For example, predetermined binding groups can be bound chemically (covalently). As another example, embedding active amino groups allows simple chemistry to bind virtually anything to the plate, which in turn may be specific for the analyte to be tested.
Sensitivity and linearity is determined by the sensitivity of the optical disk and the corresponding optical reading device, which may simply measure the number of events. For example, even if a fraction of a 700 mB disk is covered, millions of occurrences of target entities can be detected and measured. Hence concentration limits, on the low end, are only limited by non-specific noise. Therefore, femto molar amounts can be detected. Similarly, the linear range may be large, orders of magnitude, as this only depends on the coverage of the plate, or the number of errors can be made. One possible range may be from mM (moles) to fM, depending on the compounds under scrutiny. This can be very useful if the specific range is not known.
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In another embodiment, the concentration of the number of cells in a solution can be measured. Since human cells are of a significant size, their presence on the disk will in and of themselves cause an error. Therefore, a disk covered with an antibody that attracts a cell, will be able to attract the cells of interest that may be located in a mixture of biological materials, and include the cells of interest. The disk may then be exposed to a solution that contains the mixture of biological materials and will pick up the cells of interest on the surface. Depending on the cells of interest, a stain may be needed in order to clearly identify the cell. The disk may then be identified using error checking software in
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Those skilled in the art will understand that various types of error checking software exists and that this type of functionality can be easily implemented using conventional state of the art error checking software technology. Also, such error checking software is not limited to compact disks (CDs), but can also extend to DVDs (digital video disks) as well as HD-DVDs (high definition digital video disks), where each of these simply have a higher concentration of pits and lands and are more sensitive to defects. In fact, given the future of technology, once the pits and lands become smaller and smaller, the defects become more significant. As a result, it would be easier for the systems configured according to the invention to detect defects on a smaller scale that may not even require any secondary exposure of the error causing entities such as those illustrated in
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As a result, the invention provides a system and method for easily and inexpensively measuring the existence of targets such as proteins, enzymes, cells, or other target media into which the disk is exposed. Afterwards, these targets can be measured, analyzed, and otherwise observed for useful purposes. For example, in a third world situation where expensive equipment is not readily available, such a system according to the invention can be used simply dip a pre-prepared disk into a medium, such as a body of water, to determine whether certain pollutants, bacteria or other harmful entities exist in the water. Also, such a system could also provide an inexpensive and simple process for testing blood samples, urine samples, and other fluid samples where the existence of harmful bacteria, proteins, enzymes, certain types of cells exist. Moreover, given the ability to apply the binders to multiple tracks of the disk, several different types of targets can be measured when exposed to certain environments.
It will be apparent to those skilled in the art that the applicability of such binders to a plastic surface are readily available and widely used in other applications, and can be easily applied to an optical disk using different types of technology, for example, the spray technology used in laser printers or ink jet printers may be used to apply the binders in uniform manner on the disk, whether in a circular manner of application or a horizontal manner of application, depending on the manufacturer ability of the disks with the binder material attached. Also, many types of error inducing entities are widely available in the art. For example, BD™ CBA technology is widely used in the neonatal sepsis studies. There are also many companies that produce beads and related products pre-prepared with antibodies attached. These are used in flow cytometry discussed above. Many products exist, such as beads, that act as error causing entities. These beads are connected to detector bodies, which are connected to the lysate, serum or supernatant. Once these are mixed together, the antibodies are attracted to the beads. In flow cytometry, the beads are detected as a medium flows past a laser, and the targets are counted. According to the invention, an optically readable surface is covered with such antibodies and is exposed to a medium containing target entities. The surface can then be exposed to such beads having antibodies attached, which will attach to the target entities on the optical surface. The optical surface can then be read, perhaps using error detection software, and the presence of target entities can be detected, counted, or otherwise measured. Calculations can also be done to quantify and qualify the presence of the target entities.
Also, once antibodies are attracted to the surface of the disks, the beads having the antibodies connected thereto will be attracted to the targets that are attracted to the disk surface. This would cause the beads to be attracted to the disk, flagging or otherwise indicating that the targets, such as the enzyme, protein, blood cell, or other target entity has been attracted to the binder on the surface of the optical disk. Finally, the disk can be rinsed, dried out, and analyzed in a typical optical reading system, where the bound targets along with their error causing entities, such as beads, can be read as errors in the optical disk.
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Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiments can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.
This application claims priority based on U.S. Provisional Application No. 60/641,173, filed on Jan. 4, 2005.
Number | Date | Country | |
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60641173 | Jan 2005 | US |