A sensitive determination of albumin in urine by molecularly imprinted electrochemical biosensor based on dual-signal strategy

Abstract

The detection of albumin in urine is of great significance for the early diagnosis and treatment of diseases. Herein, a molecularly imprinted electrochemical biosensor was designed for the detection of human serum albumin (HSA) in urine based on dual-signal strategy. The gold electrode (GE) was orderly modified by Au nanoparticles (AuNPs), polythionine-methylene blue (PTH-MB) and molecularly imprinted polymers (MIPs). The MIPs were synthesized through electro-polymerization, which utilized HSA as the template, and employed o-phenylenediamine (o-PD) and hydroquinone (HQ) as the functional monomers. The biosensor showed dual-signals at 0.20 V and −0.22 V corresponding to Fe(CN)63−/4− and PTH-MB, respectively. When HSA was captured on the MIPs, the dual-signal simultaneously decreased. Both of the current signals of the substrate probe PTH-MB (ΔIsubstrate) and the solution probe [Fe(CN)6]3-/4-(ΔIprobe) were converted before and after the incubation of target HSA. The sum of the signal conversions ΔID (ΔIsubstrate+ΔIprobe) was utilized to quantify the target amount. Under the optimal conditions, the proposed biosensor exhibited a linear regression equation in the concentration range from 1.0×10-10 to 1.0×10-4 g L-1, with a low detection limit of 3.0×10-11 g L-1 (S/N=3). Furthermore, the prepared biosensor was employed for the determination of albumin in urine with satisfied selectivity and reproducibility.