An Array of Glucose Nanozymes That Can Selectively Detect Glucose in Whole Blood

Achieving sensors that can sensitively and selectively quantify levels of analytes in complex biofluids such as blood remains a significant challenge. To address this, we synthesized an array of isolated carbon nanochannels on a flat gold electrode that function as molecular sieves to prevent protein fouling and eliminate the need for antifouling layers. Utilizing a two-step pulsed technique, a reductive pulse expels negative interferences and fouling molecules followed by an oxidative pulse that oxidizes glucose at the bottom of the channel and on the gold surface. The nanoconfined environment created by the top carbon nanochannel layer (6 nm diameter, 21 nm length confirmed by TEM and SEM), with redox pulses enabled the gold catalytic center to generate hydroxide ions, fostering a higher pH environment favorable for glucose oxidation. The nonenzymatic approach to detecting glucose was shown to give equivalent data directly in whole blood to that achieved by using an enzyme blood glucose meter determined using a Clark Error Grid. This simplified sensor design, suitable for wearable systems, offers a solution for glucose monitoring in complex biofluids with a far greater stability over time.