Detecting errors and attacks in microfluidics using on-chip valve-based pneumatic logic

Many microfluidic biochips contain pneumatically-actuated on-chip valves and pumps for manipulating small volumes of fluids.  These microfluidic valves and pumps are typically controlled by pneumatic signals (pressure and vacuum) provided by off-chip computer-controlled electronic valves.  While the electronic portions of this control system (the computer and electronic valves) can be monitored for errors and attacks using traditional techniques, the pneumatic portions (the pneumatic lines connecting the electronic valves to the biochip and the on-chip pneumatic channels and valves) are vulnerable to attacks and errors that are currently difficult or impossible to detect.  In this talk, I will share our recent work developing strategies for detecting errors and attacks in real time in microfluidic chips using on-chip, valve-based pneumatic logic.  These pneumatic “circuits” use monolithic membrane valves like transistors to perform complex computations on-chip.  We show that a pneumatic “parity bit” calculated on-chip using pneumatic logic can be used to not only detect valve actuation errors but also enable the chip to gracefully recover from such errors.  We also demonstrate pneumatic logic checksums and other on-chip techniques for detecting attacks and errors.  As microfluidic biochips grow more complex and find more important applications in day-to-day life, pneumatic logic should play a major role in protecting these chips from accidental errors and intentional attacks.