Polymerase Chain Reaction on Microchips

The polymerase chain reaction (PCR) provides an in vitro method for rapid enzymatic amplification of fragments of DNA. Microchip-based PCR devices (with reaction volumes from picoliters to microliters) have been realized using various combinations of silicon, glass, and/or plastic materials. Passivation of exposed surfaces in the microreactor is critical for successful PCR. Silicon and plastic surfaces can be passivated by silanization. With surface passivation, PCR can be performed efficiently and economically in chip-based microreactors. The reduced thermal mass of microchips allows for extremely fast temperature ramping. PCR protocols established for benchtop reactors may need to be adjusted accordingly when transferred to microchips. Here, we provide detailed protocols for microchip PCR including procedures for surface passivation and bonding of glass to silicon with ultraviolet curable glue, because both procedures have a major influence on the success or failure of the PCR.