A Universal Approach to Enhance Glucose Biosensor Performance by Building Blocks of Au Nanoparticles

Glucose biosensors play a critical role in clinically examining the blood sugar level to assess whether the pancreas performs normally to release insulin. However, the sensitivity of state-of-the-art glucose biosensors is still insufficient to ensure a reliable non-invasive examination of blood sugar level in the low-concentration glucose-containing-samples such as interstitial fluids, perspiration, and saliva. Here, a facile method is reported on to improve glucose sensitivity of electrochemical reaction based biosensors by modifying the electrode with building blocks of ion-sputtering-coated 3.4 nm gold (Au) nanoparticles. High-resolution transmission electron microscopy studies in combination with electrochemical characterizations reveal that the improvement of glucose biosensor performance resulted from better charge transfer during the electrochemical reaction process, which is attributed to the modification of electrodes with catalytically active Au nanoparticles. The glucose sensitivity is demonstrated to be more than doubled in the flexible glucose biosensors with the modification of various electrodes (e.g., Au, conductive carbon). The Au-electrode-based glucose biosensors after modification with Au nanoparticles yield a sensitivity of 216.9 mu A mm(-1) along with a detection limit of 1 x 10(-6) m. This study paves a practicable way to develop more sensitive glucose biosensors by the modification of electrodes with building blocks of Au nanoparticles toward non-invasive blood-glucose monitoring applications.