Electrochemiluminescence of Ru(bpy)3 2+ in 1-ethyl-3-methylimidazolium Tetrafluoroborate Salt and Its Application in the Fabrication of Biosensor for Thrombin

Abstract

Electrochemiluminescence (ECL) of needle-like structure Ru(bpy)3 2+ (RuND) was investigated in the room temperature ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) medium. The results revealed that strong anodic ECL and moderate cathodic ECL could be obtained in ionic liquid without the need of additional coreactant, which could simplify the process for biosensor fabrication. Several experimental parameters, such as potential range, potential scan direction, and ECL spectrum were studied and the possible ECL mechanisms were proposed. Ferrence exhibited apparent inhibiting effect on ECL signal, based on which a label-free ECL aptasensor was fabricated for the detection of thrombin in EMImBF4. In the range of 1.0 × 10−12 to 1.0 × 10−9 mol l−1, the ECL intensity varied linearly with the logarithmic of thrombin concentration with a detection limit of 0.74 pM. The fabricated ECL sensor showed high sensitivity and good selectivity in the detection of thrombin. The results suggested that ionic liquids are the potential media for the fabrication of ECL sensors.