Recently, various attempts have been made to develop non-enzymatic glucose sensor platforms. Their sensing performance is typically determined by how effectively the degree of glucose conjugation with metals, metal oxides, and carbon materials transduces into readable output signals, such as surface-enhanced Raman scattering, surface plasmon resonance, electrochemical, and colorimetric signals. In metal-based nonenzymatic glucose sensors, glucose is electrochemically oxidized at the electrode surface by metallic catalysts. The concentration of glucose detected is determined from the glucose oxidation current. However, other compounds in blood, including amino acids, uric acids, and ascorbic acids, may also adhere and saturate the electrode surface, thereby deteriorating the selectivity and sensitivity. For successful non-invasive application, it is essential to have a technology that can detect even low concentration in body fluids such as tears, sweat, and saliva. In particular, to achieve high sensitivity as well as selectivity for glucose, an advanced transducer system consisting of an integrated structure sensing matrix and glucose-specific chemical conjugation moiety should be developed. Herein, we introduce a platform for pressure-mediated chemiresistive glucose sensing based on a two-dimensional (2D) array of glucose-conjugating silver nanowire (AgNW)-deposited conductive microparticles (AgCMPs). Glucose-conjugating AgCMPs, as transducers of the sensors, were fabricated by decorating the surface of monodisperse polyurethane elastomeric MPs with AgNWs by layer-by-layer deposition. Then, the AgNWs were 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 were positioned with high accuracy on a hole-patterned stencil film placed between electrodes. Using this sensor system, we figured out that the current induced by the application of a constant pressure to the sensor film at a given supply voltage varied linearly with the glucose concentration before and after critical glucose bridging concentration. Notably, our AgCMP-based chemiresistive sensors could detect glucose over a wide concentration range from 0.56 μM to 56 mM with remarkable sensitivity and selectivity.

Two-dimensional colloidal array of glucose-conjugative conductive microparticles for a pressure-mediated chemiresistive sensor platform

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.