Affinity peptide-based electrochemical biosensor with 2D-2D nanoarchitecture of nickel-chromium-layered double hydroxide and graphene oxide nanosheets for chirality detection of symmetric dimethylarginine.

The accurate assessment of kidney dysfunction is crucial in clinical practice, necessitating the exploration of reliable biomarkers. However, current methods for measuring SDMA often fall short in terms of sensitivity and specificity. In this study, we employed phage display technology to identify high affinity peptides that specifically bind to SDMA. The selected peptide was subsequently integrated into a novel Ni-Cr layered double hydroxide-graphene oxide (NCL-GO) nanoarchitecture. We characterized the electrochemical properties of the biosensor using cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry, systematically evaluating critical parameters such as limit of detection (LOD), reproducibility, and performance in complex biological matrices including urine. The NCL-GO architecture not only enhances the surface area available for electrochemical reactions but also facilitates rapid electron transfer kinetics which are essential for the accurate quantification of small molecule, SDMA. The electrochemical biosensor exhibited an outstanding limit of detection of 0.1 ng/mL in the 0-1 ng/mL range and 7.2 ng/mL in the 1-100 ng/mL range, demonstrating exceptional sensitivity and specificity for SDMA. Furthermore, the biosensor displayed excellent reproducibility with a relative standard deviation of 4.9%. Notably, it maintained robust chirality sensing capabilities, even in complex biological fluids. These findings suggest that this biosensor could play a pivotal role in early disease diagnosis and therapeutic monitoring, ultimately improving clinical outcomes and advancing biomedical research.