A disposable on-chip microvalve and pump for programmable microfluidics.

In this work, a low-cost PDMS micro-pump and -valve have been designed and developed to control multiple reagents for enzyme-linked immunosorbent assay (ELISA) on a programmable lab-on-a-chip (LOC) platform. The micro pump and valves were precisely controlled by selectively pressurizing the PDMS channels and chamber to actuate the multiple reagents in a controlled manner. Selective pressurizing of the PDMS structures was initiated by a simple system that maneuvered a single roller bar operated by a programmed microprocessor. The performance of the micro-pump was fully characterized and a minimum fluid volume of 1 μL was controlled. Also, the on-chip microvalves were programmed to flow the multiple reagents to automatically process the multi-step ELISA procedures. By applying the proposed platform, 19.40 pg ml-1 cardiac troponin T (cTnT) was successfully detected on the LOC device by using multiple programmed valves as multiple steps of the enzyme-linked sandwich immunoassay. As a result, the developed micro-pump and -valve, which were successfully applied to actuate a series of solutions in a controlled manner, can be widely applied to lab-on-a-chip based bioassays.