An electromagnetically-driven microfluidic platform with indirect-heating thermo-pneumatic valves

摘要

In this work, we present a microfluidic platform which is capable of carrying out a series of laboratorial operations on a disposable chip. The platform employs coil arrays to transport biological samples attached on magnetic beads through different reaction zones in aqueous solutions. Micromachined thermo-pneumatic valves are adopted as the interfaces between sequential reactions. The self-contained system is composed of a disposable microfluidic reaction (MFR) chip and a fluidic driving/sensing (FDS) module. Various reaction zones with different functionalities are implemented on the MFR chip. Arrays of coils and micro-machined heater/sensing chips are integrated into the FDS module. Also, novel indirect-heating thermo-pneumatic valves (IH-TPVs), which are monolithically integrated into the disposable MFR chip, are proposed and characterized. With an applied voltage of 3.2 V, the IH-TPV effectively isolates two adjacent reaction zones, while its temperature elevation is sufficiently low for biological samples and reagents. By employing the proposed approach, we design and implement a miniaturized biochip system which carries out the processes of DNA extraction, purification and amplification from whole blood sample. The dimension of the fully-integrated system is 72 mm x 54 mm x 1 mm, and the system could be fully operated with a 12 V DC power supply. DNA extraction and purification from human whole blood followed by PCR amplification for the 122 bp segment is successfully performed by using the system.