Microdevices for high-throughput screening of biomolecules

Abstract

Methods and devices for the parallel, in vitro screening of biomolecular activity using miniaturized microfabricated devices are provided. The biomolecules that can be immobilized on the surface of the devices of the present invention include proteins, polypeptides, nucleic acids, polysaccharides, phospholipids, and related unnatural polymers of biological relevance. These devices are useful in high-throughput drug screening and clinical diagnostics and are preferably used for the parallel screening of families of related proteins.

Description

[0001]This application is a continuation of co-pending application Ser. No. 09 / 115,397, filed Jul. 14, 1998, which is incorporated herein by reference in its entirety for all purposes and the specific purposes disclosed throughout this application.BACKGROUND OF THE INVENTION[0002]A vast number of new drug targets are now being identified using a combination of genomics, bioinformaties, genetics, and high-throughput (HTP) biochemistry. Genomics provides information on the genetic composition and the activity of an organism's genes. Bioinformatics uses computer algorithms to recognize and predict structural patterns in DNA and proteins, defining families of related genes and proteins. The information gained from the combination of these approaches is expected to boost the number of drug targets, usually proteins, from the current 500 to over 10,000 in the coming decade.[0003]The number of chemical compounds available for screening as potential drugs is also growing dramatically due to...

AI Technical Summary

Benefits of technology

[0014]The present invention is directed to a device and methods of use of the device that satisfy the need for parallel, in vitro, high-throughput screening of functionally or structurally related protein targets against potential drug compounds in a manner that minimizes reagent volumes and protein inactivation problems.

Problems solved by technology

However, although increases in well numbers per plate are desirable for high throughput efficiency, the use of volumes smaller than 1 microliter in the well format generates significant problems with evaporation, dispensing times, protein inactivation, and assay adaptation.

Maintaining microscopic volumes in open systems is therefore very difficult.

However, the interaction of drug compounds with proteins other than the desired targets is a serious problem related to this approach which leads to a high rate of false positive results.

Microfluidic networks prevent evaporation but, due to the large surface to volume ratio, result in significant protein inactivation.

Drug screening of soluble targets against solid-phase synthesized drug components is intrinsically limited.

The surfaces required for solid state organic synthesis are chemically diverse and often cause the inactivation or non-specific binding of proteins, leading to a high rate of false-positive results.

Furthermore, the chemical diversity of drug compounds is limited by the combinatorial synthesis approach that is used to generate the compounds at the interface.

Another major disadvantage of this approach stems from the limited accessibility of the binding site of the soluble target protein to the immobilized drug candidates.

DNA microarray technology is not immediately transferable to protein screening microdevices.

Their underlying chemistry and materials are not readily transferable to protein assays.

Often, a compound that effectively interferes with the activity of one family member also interferes with other members of the same family.

Using standard technology to discover such additional interactions requires a tremendous effort in time and costs and as a consequence is simply not done.

However, cross-reactivity of a drug with related proteins can be the cause of low efficacy or even side effects in patients.

For instance, AZT, a major treatment for AIDS, blocks not only viral polymerases, but also human polymerases, causing deleterious side effects.

Cross-reactivity with closely related proteins is also a problem with nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin.

However, the same drugs also strongly inhibit a related enzyme, cyclooxygenase-1, that is responsible for keeping the stomach lining and kidneys healthy, leading to common side-effects including stomach irritation.

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