Standalone extended gate FET-based multiplexed sensing platform

Reliable biosensing is crucial in demanding fields such as theranostics and drug discovery. Multiplexing can improve biosensing performance and stability by enabling simultaneous multimarker sensing, more accurate differential measurements, and robust measurement statistics. Biosensing platforms based on field-effect transistors (FETs) comprising extended gate (EG) as a disposable cost-effective sensing element and reusable FET transducer are widely used for electrical label-free detection of biological and chemical analytes. EG electrodes can be modified to detect various analytes while allowing for easy integration of many sensing elements within the same chip. Useful features of EG open the possibility for multiplexed analyte sensing with an EG electrode array and a single FET transducer. Current EG FET-based platforms do not include large-scale multiplexing and rely on external modules such as specialized instruments for electrical measurements and bulky reference electrodes. We present the concept of a standalone EG FET platform for multiplexed sensing based on custom-built electronics interfaced with the EG chip comprising a common integrated reference electrode and microfluidic reservoir. Arduino Uno board enables the digital control of the reed relay-based multiplexing module and FET transducer readout circuit. Readout of the sensor signal is performed by sweeping in constant charge mode. Our platform is a practical and versatile laboratory tool adaptable for sensing different analytes.