Methods and compositions for directed microwave chemistry

Abstract

The present invention concerns a novel means by which chemical preparations can be made. Reactions can be accelerated on special cartridges using microwave energy. The chips contain materials that efficiently absorb microwave energy causing chemical reaction rate increases. The invention is important in many chemical transformations including those used in protein chemistry, in nucleic acid chemistry, in analytical chemistry, and in the polymerase chain reaction.

Description

[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 10 / 234,092 (filed on Sep. 5, 2002), which application is a continuation in part of U.S. patent application Ser. No. 09 / 968,517 (filed on Oct. 2, 2001), which application claims priority to U.S. patent application Ser. No. 60 / 237192 (filed on Oct. 3, 2000, now abandoned), all of which applications are herein incorporated by reference in their entirety.[0002] The present invention relates to the field of microwave chemistry. It also relates to the field of biotechnology, specifically microplate-and array chip-based preparative and analytical chemistry.[0003] Until now, no one has performed chemical transformations as disclosed herein. Devices are used that emit radiofrequency / microwave energy. The energy is directed to a target object, for example, a microarray chip or a microtiter plate that contains one or more material(s) that absorb(s) microwave energy. The microwave-generated heat energy acceler...

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Benefits of technology

[0199] It is a distinct advantage of the present invention that surface microwave heating can be used both for preparative reactions and, in the same location, for subsequent analytical reactions. Described below are innovative ways in which preparative and analytical microwave reactions can be used sequentially.

[0201] It is shown here for the first time that directed microwave heating can dramatically accelerate nucleic acid hybridization. Polymerase chain reaction is one practical application where nucleic acid hybridization is essential (McPherson & Moller, 2000; Newton & Graham, 1994). PCR is a nucleic acid amplification method in which a specific nucleic acid sequence is geometrically amplified through an iterative process involving heating and cooling (FIG. 12). In PCR, high temperatures are used to dissociate strands of double-stranded DNA. Using the invention described, two steps--annealing (hybridization) and dissociation--can be accelerated.

[0202] Rapid PCR methods are desirable because of their convenience and because of the importance of obtaining test results rapidly in critical lifesaving applications such as biodefense testing (Chen, 2003; Fermer et al, 2003; Gloffke, 2003). PCR hybridization reactions are slower in the earlier cycles of amplification due to the low concentration of template (amplified sample) in comparison to the fairly high concentration of added primer. Conventional PCR is carried out in a temperature cycling instrument called a thermal cycler (thermocycler). Thermal cyclers are widely available bulk heating devices (Constans, 2003). Several designs of thermal cyclers are available based for example on; heating and cooling by fluids, heating by electric resistance and cooling by fluid or refrigerant, heating by electric resistance and cooling by semiconductors (Peltier devices), and heating matt black metal surfaces by light followed by air cooling (Newton & Graham, 1994). Thermal cycler-based PCR is relatively slow--an amplification cycle may commonly take 6 minutes (

Problems solved by technology

However, in these cases the microwaves are not directed to heat a surface, but used to heat the bulk solution.

Microwave irradiation causes a temperature increase in the microwave susceptible material, which consequently causes a reaction rate increase of the reactants to form products.

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