2D Colloidal Array of Glucose-Conjugative Conductive Microparticles for a Pressure-Mediated Chemiresistive Sensor Platform

A platform is introduced for pressure-mediated chemiresistive glucose sensing based on a 2D array of glucose-conjugating silver nanowire (AgNW)-deposited conductive microparticles (AgCMPs). Glucose-conjugating AgCMPs, as transducers of the sensors, are fabricated by decorating the surface of monodisperse polyurethane elastomeric MPs with AgNWs by layer-by-layer deposition. Then, the AgNWs are covalently bonded to 4-mercaptophenylboronic acid (4-MPBA) to endow them with chemiresistive glucose sensing property against the applied pressure. The 4-MPBA-functionalized AgCMPs are positioned with high accuracy on a hole-patterned stencil film placed between electrodes. Using this sensor system, it is shown that the current induced by the application of constant pressure to the sensor film at a given supply voltage varies linearly with the glucose concentration before and after critical glucose bridging concentration. Notably, the AgCMP-based chemiresistive sensors could detect glucose over a wide concentration range from 0.56 × 10⁻⁶ m to 56 × 10⁻³ m with remarkable sensitivity and selectivity.