An affinity peptide-incorporated electrochemical biosensor for the detection of neutrophil gelatinase-associated lipocalin

In this study, we demonstrate a novel affinity peptide-incorporated electrochemical biosensor for the detection of acute kidney injury and the diabetic biomarker neutrophil gelatinase-associated lipocalin (NGAL). Biopanning of the M13 phage display library over immobilized NGAL led to the rapid identification of unique affinity peptide with an amino acid sequence of DRWVARDPASIF, and the peptide-displayed phage particles were found to be specific affinities for NGAL. To address the development of peptide-based electrochemical sensor, a series of synthetic peptides away from phage particles was rationally designed, chemically synthesized, and immobilized to a gold sensor layer. Among five synthetic peptide derivatives tested, NGAL BP1 was selected as most promising recognition receptor, and its binding affinity was monitored by SWV and EIS. Using EIS, the limit of detection (LOD) was 1.74 ng/mL, while SWV had a LOD of 3.93 ng/mL. The detection performance of the peptide-incorporated sensor was comparable to commercially available ELISA NGAL detection kits. In addition, the validation of the peptide sensor was also confirmed with plasma from patients, and it was observed that the sensitivity of the peptide sensor showed a statistically significant difference. Our results show that the phage and peptide sensor system could detect NGAL with high sensitivity and selectivity, and this suggests its potential use as a biosensing platform for monitoring NGAL in a miniaturized electrochemical biosensor.