Wien Oscillator Using Organic Enzyme‐Chemiresistors for Fused Measurement of Glucose and Lactate

Abstract

Total body sensor networks for physiological (diagnostic biosensors) and biomechanical (force and motion) systems require data fusion through several algorithms. A novel, device-level method of sensor data fusion is presented. This biomimetic concept is demonstrated through the development of glucose and lactate sensitive chemiresistors in a biologically responsive Wien bridge oscillator circuit. Biocompatible and bioresponsive polymers suitable for integration of molecular recognition and transduction yield stimuli-responsive chemiresistors. The analyte-responsive chemiresistors are electroconductive hydrogels that separately incorporate the enzymes glucose oxidase and/or lactate oxidase that are conjugated with single-walled carbon nanotubes (SWCNTs) and embedded in a percolating network of conductive polymer (polypyrrole). The input of the system is the chemical potential of the analytes, glucose and lactate, acting through the biological activity of immobilized enzymes, and the output of the system is a single sinusoidal wave from which the concentrations of glucose and lactate can be deconvoluted from the amplitude and DC offset, respectively. This engineered system, based on soft bioelectronic circuit elements, aims to offer simultaneous, real-time analyte biosensing at a biomolecular level in a move toward biologically responsive circuits and eventually, bioanalytical systems suitable for indwelling in human tissue for extended periods of time.