On-chip PCR with free-standing parylene channel

Abstract

We present an on-chip PCR using a free-standing parylene channel with an integrated platinum heater for on-chip temperature cycling. The PCR chip reduces the reagent amount from tens of uL (as required by convention qPCRs) to 550 nL. The on-chip PCR has a higher thermal efficiency than conventional PCR because of its smaller thermal capacity and good heat transfer. The demonstrated chip’s free-standing channel structure reduces the thermal capacitance to 3.25 mJ/oC and shortens the duration of PCR cycles with a thermal time constant of 3 seconds. The transparent parylene channel in visible light range enables direct optical detection. The impermeable parylene channel also prevents solution evaporation. It is shown that the pin-hole free, chemically and biologically inert parylene allows efficient PCR amplification and no additional surface treatment is required. The PCR chip can facilitate the further development of a fully-integrated, portable PCR system.