A silicon nanoparticle-based polymeric nano-composite material for glucose sensing

A novel non-enzyme glucose sensing material has been prepared by incorporating ultrasmall (1-3 nm) silicon nanoparticles in polyaniline, a conducting polymer, as a nano-composite material (NCM). When deposited on electrodes, the composite material with three-dimensional loading of the nanoparticles showed a significantly enhanced amperometric response to glucose, compared to the nanoparticles deposited on bare electrodes and electrodes immobilized with the enzyme, glucose oxidase. The linear range of the glucose response of NCM electrodes covered both the hypo- and hyper-glycaemic glucose levels. The sensitivity of the NCM electrodes was 2.5 μA cm^-2 mM^-1. The NCM electrodes' selectivity for glucose against interfering agents was achieved by covering the composite material with a Nafion membrane. The glucose response of Nafion-NCM electrodes was characterized with single 1 μl drops of glucose-solution, showing a sensitivity of 2.2 μA cm ^-2 mM^-1. The NCM electrode's long-term in vitro glucose response appeared to be reasonably stable over a period of 40 days.