Quantum Capacitive Lactate Dehydrogenase Label-Free Biosensor Based on One-Step Biointerface Preparation

Quantum capacitive biosensor based on the nanoscale BSA/graphene layer integrated Indium tin oxide (ITO) three-electrodes was firstly demonstrated. Lactate dehydrogenase (LDH), a ubiquitously expressed pivotal enzyme in biological systems, plays a central role in energy metabolism and concurrently serves as a significant biomarker for cellular injury. In this work, a one-step modification method based on the graphene (Gr)/heatdenatured bovine serum albumin (dBSA) complex was applied to immobilize LDH antibodies as the electrochemical nanosensing biointerface. Electrochemical capacitance was continuously recorded to quantify LDH in complex biological sample with the sensitivity of 1 ng/mL, which was one orders of magnitude lower than existing detection methods.