Assay imaging apparatus and methods

Abstract

A method of conducting an assay on a plurality of samples is provided. The method includes the steps of performing an assay at each sample site in a sample array having greater than 100 sample sites simultaneously illuminating each sample site using one or more LEDs, and simultaneously imaging each of the sample sites to produce imaging data pertinent to the optical effect of each site. Each assay provides an optical effect.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority from U.S. provisional patent application Ser. No. 60 / 434,988, entitled “Chip Temperature Cycling,” filed Dec. 20, 2002; U.S. provisional patent application Ser. No. 60 / 461,559, entitled “Immobilized Probe Nanotiter Array,” filed Apr. 9, 2003; U.S. provisional patent application 60 / 528,461, entitled “Improved Selective Ligation and Amplification Assay” filed Dec. 10, 2003; and U.S. provisional patent application Ser. No. 60 / 461,556, entitled “High-Density Microfluidic Thermal Cycling with Stackability,” filed Apr. 9, 2003. Each of these patent applications described in this paragraph is hereby incorporated by reference, in its entirety.FIELD OF THE INVENTION[0002]The present invention relates to devices and methods for assaying samples in nanoliter volumes, potentially for achieving high throughput screening and for other purposes where the ability to assay low-volume samples at high densities is desired.BA...

AI Technical Summary

Benefits of technology

[0046]In related embodiments of the invention, the array may include a hydrophobic surface surrounding the openings of each sample site. The sample sites may include a hydrophilic surface that attracts the at least one of sample and reagent. The sheet may have a pair of opposed surfaces and a thickness, and the sample sites include a plurality of through-holes running through the thickness between the surfaces. The sample sites may include a plurality of closed-ended wells. At least one cover of which is light transmissive may be coated with a hydrophobic layer to prevent fogging. The array may include a recessed opening at each sample site, the recess preventing fluid in each sample site from coming into contact with a cover to which each such sample site is proximate. The system may further include one of a UV curable sealent and a grease for sealing the opening. The frame and the covers may be coupled together to form the case by at least one of an epoxy or other adhesive. The frame may be, or in

Problems solved by technology

One primary challenge for bio-defense and diagnostic applications is the early detection of infections, which typically requires increasing assay sensitivity.

1) The cost of the assays and amount of sample needed are often too prohibitive to run large numbers of assays against a patient sample.

2) The assays amplify but do not concentrate nucleic acids. For example, if there are 10 copies of SARS RNA in a patient sample, performing assays against 20 viral sequences involves a significant risk of obtaining a false negative test result.

3) Multiplexing numerous assays is quite difficult due to the need to harmonize reaction conditions and separate results into different optical channels. A typical problem in PCR multiplexing is the competition between the many primers.

4) Screening for potential bio-terrorism agents tend to be done only at the state and federal level, and not at the clinic or local level. That is because even with an assay that was 99.9% accurate, the numerous false positives that would occur with widespread screening would result in unreasonable expense as well as economic and political disruption. Thus, there is a need for a great increase in the reliability of such tests.

One problem that has been observed with this approach is that when the array is immersed in a sample liquid to load the through-holes, the dried probes and reagents can dissolve and float away out of the sample wells tha

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