Label-free sugar detection using phenylboronic acid-functionalized piezoresistive microcantilevers

By appropriate surface functionalization using a thiolated phenylboronic acid derivative, gold-coated piezoresistive microcantilevers responsive to analytes having vicinal cis-diols were fashioned. A reference, uncoated cantilever permitted reliable subtraction of background signal (i.e., differential measurement). Experiments carried out in static mode under flow conditions, using the monosaccharide D-(-)-fructose as a test analyte in aqueous buffer, showed that the measured stationary-state surface stress was linear in analyte concentration over the 0-25 mM range, allowing this sugar to be readily detected at physiologically meaningful concentrations and at neutral pH. This approach offers a simple, reagentless, and flexible format for polyol screening that does not require aqueous alkaline solutions, suggesting potential applications in biomass process monitoring and glucose assay.