Rapid quantitative detection of capsaicinoids in serum based on an electrochemical immunosensor with a dual-signal amplification strategy

In this paper, a dual-signal amplified electrochemical immunosensor for quantitative detection of capsaicinoids in serum was reported, which could be used to study the pharmacological properties of capsaicinoids. To improve the sensitivity of the immunosensor, the glassy carbon electrode was modified with Prussian blue-gold nanocomposites (PB-AuNPs) and thionine (TH). PB-AuNPs provided better electrical conductivity. At the same time, TH enhanced the stability of electron transfer, leading to superior electrochemical performance. Meanwhile, an excellent anti-capsaicinoids antibody (Ab) was used to ensure the sensitivity and specificity of the electrochemical immunosensor. The prepared immunosensor was tested using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimal conditions, the proposed immunosensor displayed a wide linear range from 0.01 to 1000 ng/mL with a detection limit of 0.01 ng/mL and showed good recoveries (85.12–104.25%) and high stability. Additionally, the immunosensor was successfully applied to monitor capsaicinoids in real serum samples.