Strategy of Dimercaptothiol as Self-assembled Monolayers Enhance the Sensitivity of SPR Immunosensor for Detection of Salbutamol

Abstract

The formation of self-assembled monolayers (SAMs) is a normal method for the immobilization of biorecognition elements immobilized on SPR sensors. With this method, mercaptopropionic acid (MPA) with carboxylic and thiol group is the most commonly used. Dimercaptosuccinic acid (DMSA) having two carboxylics and two thiol groups is a classical antidote for heavy metal ions. In this paper, DMSA was first used to form SAMs to connect the antigen on the chip of a surface plasmon resonance (SPR) immunosensor for detection of salbutamol (SAL), and the results were compared with a traditional (MPA)-SPR sensor. Dihydrolipoic acid(DHLA)-SPR showed that the recognition efficiency of antigen and antibody of DMSA-SPR immunosensor was 170.1% at room temperature with the linear range of 5 -150 ng/mL. The recovery rate of this sensor applied to SAL detection in pork reached 94.9 -108.0% and the limit of quantification (LOQ) was 5 ng/mL. The results were in good correlation with the analysis results of ultra-high phase liquid chromatographytandem mass spectrometry (UPLC-MS/MS) analysis. This novel DMSA-SPR immunosensor provides insight into a new idea and method for improving the sensitivity of SPR immunosensors and can be widely used in the detection of other small molecules.

Current Advances in Immunoassays for the Detection of β2-Agonists

“…The β 2 -agonist in the sample bound to the antibody and inhibited it from binding to the β 2 -agonist mobilized on the sensor chip surface and consequently induced an increase in the refractive index at the SPR sensor surface. SPR sensor has been built to detect salbutamol in swine urine with LOD of 5 ng/mL [80]. Suherman et al [81] fabricated SPR sensors with covalently immobilized β-albuterolvistion on Au chips for detection of ractopamine and salbutamol, respectively.…”

Facile electrochemical affinity measurements of small and large molecules

“…Other techniques include stability shi assays, mobility shi assays or spectroscopic ones. 5 Among these BLI and SPR are established label-free techniques that can easily detect a large molecule binding to a functionalized surface, 6,7 but detecting the binding of small molecules is more challenging and requires advanced and costly instruments, 8,9 clearly indicating the need for more straightforward affordable techniques. Among the assay methods in drug discovery, electrochemical methods are not usually mentioned.…”