Title: Phage Display-Based Biosensing for Rapid Detection of Neonatal Group B Streptococcal (GBS) Infection
Abstract:
Group B Streptococcus (GBS) is a leading cause of neonatal infection, meningitis, and pneumonia, yet existing diagnostic methods are time-consuming or dependent on specialised laboratories, limiting their use for early screening during pregnancy. To address this challenge, we used M13 phage display to discover peptide probes that can detect GBS with high specificity while discriminating against a broad range of clinically relevant bacteria and fungi. Through a subtractive biopanning strategy, a single phage clone, designated as P17, emerged as the most selective candidate, consistently demonstrating a strong affinity toward GBS while showing negligible interaction with non-target microorganisms. Validation using plate-based binding assays confirmed that P17 strongly favours GBS over all other tested species. To enable direct visual detection, the P17 clone was conjugated with fluorescein isothiocyanate (FITC), producing a fluorescent probe that retained its binding selectivity. When exposed to GBS, FITC-labelled P17 generated a clear and uniform fluorescent signal under microscopy. These findings establish P17 as a highly selective, phage-displayed peptide probe that can be converted into a fluorescent biosensing element without loss of specificity. The ability of this probe to directly label GBS cells underscores its strong potential for translating into rapid, low-cost diagnostic formats, such as lateral flow tests, paper-based devices, and microfluidic point-of-care platforms, designed to support improved maternal and neonatal health outcomes.
