Monitoring of bovine serum albumin using ultrasensitive electrochemiluminescence biosensors based on multilayer CdTe quantum dots modified indium tin oxide electrodes

Abstract

A novel method for the determination of bovine serum albumin (BSA) is proposed based on the electrochemiluminescence (ECL) of BSA with CdTe quantum dots (QDs) films. Thioglycolic acid (TGA) is used to cap CdTe colloidal solutions to obtain stable water-soluble QDs and intensive anodic ECL emission with a peak value starting from +1.2 V (vs.Ag/AgCl) in a carbonate bicarbonate buffer solution (pH 9.32) at an indium tin oxide (ITO) electrode. The ITO glass is modified with CdTe QDs by the layer-by-layer (LbL) self-assembly technique, which is immobilized into a homemade ECL flow chip and used as a receptor of the ECL sensor. The ECL intensity is correlated linearly with the concentration of BSA over the range of 1.0 × 10⁻⁹–1.0 × 10⁻⁶ g mL⁻¹ and 1.0 × 10⁻⁶–1.0 × 10⁻⁵ g mL⁻¹, and the detection limit is 5.48 × 10⁻¹⁰ g mL⁻¹. The relative standard deviation is 1.62% for 4.0 × 10⁻⁷ g mL⁻¹ BSA (n = 11). This simple and sensitive method reveals good reproducibility for ECL analysis. It puts forward a new efficient ECL method for the determination of BSA and opens new avenues for the application of QDs in ECL biosensors.