Speaker: Sara Neshani, ECpE Graduate Student
Advisor: Nathan Neihart
Title: System Design of a Low-Cost Sensitive Differential Capacitive Bridge Readout Interface for Real-Time Field Deployable Sensing of MC-LR
Abstract: The ongoing development of Internet of Things brings about growing demand for real-time field deployable biosensors. Moreover, fast, low cost and easy to operate biosensors are required for frequent medical and environment monitoring applications. Motivated by this, there has been a surge in the development of new transducers targeting a wide range of biosensing applications for protein, DNA, etc…. Label-free capacitive biosensors are among the most popular prototypes for the above mentioned point of care biosensing applications. One great challenge however, is for most diagnostic and monitoring applications the detection target concentrations of interest are generally small, ranging from / to /, giving rise to a small response signal for the transducer. In this regrad, expensive and complicated lab grade analysis needs to be utilized for determining certain toxin concentrations in water. A bridge based differential read-out interface for capacitive bio-functionalized electrodes detecting MC-LR toxin in water, is introduced in this work to replace the lab instrumentation. A comprehensive study of the design tradeoffs between overall sensor system complexity and performance in low-cost (< $10), real-time electrode-solution interfacial capacitance sensing targeting 8-bit resolution will be presented along with practical discrete characterization. The characterization results verify, with the designed less complicated and low cost read-out board, 8-bit resolution is achievable even with 1% full scale capacitive change for the transducer.