A novel single-use SU-8 microvalve for pressure-driven microfluidic applications

A novel microfluidic single-use valve for fluid injection and extraction in pressure-driven applications is presented in this paper. The device consists of a thin SU-8 membrane crossed by a resistor that withstands a mechanical stress induced by a pressure difference. When the resistor heats up the membrane, the SU-8 fracture strength drastically decreases causing the valve activation. This device has been designed, fabricated using inexpensive SU-8 and printed circuit board technologies and finally characterized. The hybrid thermal–mechanical microvalve operation principle has been demonstrated and experimental results have shown the device characteristics and performance. Specifically, this design was functional at pressures of 0.8 MPa and opened in less than 3.2 s with an applied power of 280 mW. The simple fabrication process and the absence of moving mechanical parts have made the valve suitable for large-scale integration in lab-on-chip microfluidic platforms