Pt-NiCo Nanostructures with Facilitated Electrocatalytic Activities for Sensitive Determination of Intracellular Thiols with Long-Term Stability

A Pt-NiCo nanomaterial has been synthesized for developing the sensitive electrochemical determination of biological thiols that include L-cysteine (CySH), homocysteine (HCySH), and gluthione (GSH) with high sensitivity and long-term stability, in which the Pt nanoparticles are well supported on amorphous NiCo nanofilms. The electrochemical oxidation of thiols has been successfully facilitated on the optimized Pt NiCo nanostructures, that is, two oxidation peaks of CySH have been clearly observed at potentials of +0.06 and +0.45 V. The experimental results demonstrate that the first peak for CySH oxidation may be attributed to a direct oxidation from CySH to L-cystine (CySSCy), whereas the second peak possibly results from a sequential oxidation from CySSCy to cysteic acid (CySO3H), together with a direct oxidation of CySH into CySO3H. The enhanced electrocatalytic activities at the Pt-23-NiCo nanostructures have provided a methodology to determine thiols at a very low potential of 0.0 V with relatively high sensitivity (637 nA mu M cm(-2)), a low detection limit (20 nm), and a broad linear range. The striking analytical performance, together with the characteristic properties of the Pt-NiCo nanomaterial itself, including long-term stability and strong antipoisoning ability, has established a reliable and durable approach for the detection of thiols in liver cancer cells, Hep G2.