A cost-effective and sensitive Au/6-mercaptohexanol/CNBr modified immunosensor approach for adiponectin analysis

The scheme of the immobilization procedures of the constructed biosensor. [Display omitted] •The biosensor has low detection limit, ultra wide detection range for adiponectin.•This biosensor allows the successful analysis of adiponectin.•This biosensor’s modification strategy ispracticable and easy to use.•The built biosensor includes advantages such as cheapness, miniaturized flexibility. This research aimed to develop a method for analyzing adiponectin using a label-free impedimetric indium tin oxide-polyethylene terephthalate (ITO-PET) immunosensing system. A simple and stable process to design a bioelectrode modified with gold (Au)/6-mercaptohexanol (6-MH)/cyanogen bromide (CNBr)/anti-adiponectin and its biocompatibility with adiponectin was investigated. The immunosensor performance, optimization tests, and immobilization steps were all monitored and analyzed using Electrochemical Impedance spectroscopy (EIS) and cyclic voltammetry (CV). Scanning Electron microscopy (SEM) examined the surface morphology of this biosensor during its immobilization process. Testing the developed biosensor with real human serum samples allowed for an evaluation of its clinical performance. The proposed immunosensor demonstrated high repeatability, reproducibility (RSD%: 4.37 %), long storage stability, and reusability (preserving 85 % of activity in the third regeneration step), along with a low limit of detection for adiponectin antigen and a wide range of linear values. The sensor suggested a linear detection range of 0.25 pg/mL to 500 pg/mL. The limit of detection (LOD) was found to be 0.20 pg/mL, and the limit of quantification (LOQ) was determined to be 0.66 pg/mL. It appears that the biosensor decorated with Au/6-MH/CNBr could be a good choice for the selective determination of adiponectin protein, according to the statistical data.