Research on a molecularly imprinted electrochemical sensor based on a graphene quantum dot-gold nanoparticle composite for the determination of 17β-estradiol

Abstract

In this study, a molecularly imprinted electrochemical sensor (MIECS) was constructed based on the combination of graphene quantum dots-gold nanoparticles (GQDs-AuNPs), molecular imprinting polymer (MIP), and electrochemical technology for the ultra-sensitive detection of 17β-estradiol (E₂). GQDs-AuNPs were synthesized and modified on the surface of glassy carbon electrodes (GCE). Safranine T was used as the functional monomer and E₂ was the template molecule for self-assembly and electropolymerization, thus generating an MIP film on the electrode surface. By elution, a large number of recognition sites for E₂ were left in the polymer matrix. Before and after the combination with the target, there is an obvious change in the peak current signal, which enables the quantitative detection of E₂ to be achieved. Under the optimized conditions, the concentration of E₂ showed a good linear relationship with the peak current of the sensor in the range of 1 × 10⁻⁵–1 × 10⁻¹⁴ M, and the detection limit was 2.2 fM. The molecularly imprinted electrochemical sensor based on GQDs-AuNPs established in this study offers the features of simplicity of operation, low experimental cost, and high sensitivity. This method successfully detected E₂ in milk, urine, and human serum, demonstrating its potential for broad application in clinical practice.