Trench field-effect transistors integrated in a microfluidic channel and design considerations for charge detection

Field-effect transistors (FETs) combined with a microfluidic system allow for the electrical detection of charged materials moving in a microfluidic channel. Here, we demonstrate trench-shaped silicon FETs with the combination of a microfluidic channel that can be used for simultaneous electrical and optical detection of charged fluorescent beads. The n-channel silicon trench FETs have a maximum transconductance of 1.83 x 10(-5) S at near-zero gate bias voltage, which is beneficial for the high sensitivity of electrical detection. The optical transparency and physical robustness of the integrated microfluidic channel are achieved by a polydimethylsiloxane (PDMS)/glass hybrid cover combining the good sealing characteristics of PDMS, and the thin and flat properties of glass. Device evaluation methodologies and measurement approaches are also presented demonstrating a synchronized time-lapse imaging and electronic detection of bead transport. The proposed device and design consideration could advance the promise of electronic sensing to measure potential differences induced by charged analytes. Published under an exclusive license by AIP Publishing.

Automated summary

This study demonstrated trench-shaped silicon FETs with a microfluidic channel for simultaneous electrical and optical detection of charged fluorescent beads. The integration of PDMS and glass materials provided optical transparency and physical robustness to the microfluidic channel. The study also presented device evaluation methodologies and demonstrated synchronized time-lapse imaging and electronic detection of bead transport.