Hierarchical Gold-Galinstan nanodendrites modified disposable immunosensor for the Label-free detection of KIM-1 by antibody immobilization on Staphylococcal protein a

In this work, we developed a novel Gold (Au)-Galinstan (Ga-In-Sn) nanodendrites modified label-free paper-based electrochemical immunosensor to detect one of the most prominent renal injury biomarkers known as Kidney injury molecule-1 (KIM-1). The Au-Galnstan dendritic nanostructure was obtained by a simple galvanic replacement method supported by polyethylene glycol (PEG) assisted co-reduction, where pH played an essential role in developing the dendritic morphology. Various physicochemical characterizations confirmed the successful formation of the nanodendrites in-depth. The large surface area, excellent synergistic charge transfer kinetics, and catalytic properties of the Au-Galinstan nanodendrites (Nds) modified paper electrode facilitated the oriented immobilization of the anti-KIM-1 antibodies involving Staphylococcal protein A (SPA). Under optimized conditions, the proposed immunosensor obtained an adequately low limit of detection (LOD) of 64 pg ml⁻¹ in a wide linear range (0.1 ng ml⁻¹ –1000 ng ml⁻¹). The highly stable and easily reproducible sensor selectively identified KIM-1 in the presence of interferents. The high recovery rate obtained by the sensor in KIM-1 spiked human serum confirmed its applicability in a real clinical sample. Hence, the proposed immunosensor introduces an emerging platform to provide a simple, cost-effective, stable, and reliable detection of kidney injury-related markers.