Development of a glycine-modified iron oxide nanoparticle-electrochemical biosensor for specific detection of <i>Klebsiella pneumoniae</i> DNA

This study presents a simple electrochemical DNA biosensor to accurately detect <i>Klebsiella pneumoniae</i> DNA. The biosensor uses glycine functionalized iron oxide nanoparticles (glycine@Fe₃O₄) to capture <i>Klebsiella pneumoniae</i> DNA. The as-synthesized nanoparticles were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, and transmission electron microscopy, and created a sensitive electrode surface that produced strong electrochemical signals when DNA attached. Electrochemical techniques, including cyclic voltammetry and square wave voltammetry, were used to develop a biosensor for detecting <i>Klebsiella pneumoniae</i> DNA. The biosensor showed limits of detection of 3.27 nM in the 30-90 nM range and 3.94 nM in the 120-270 nM range, with limits of quantification of 3.90 nM and 11.95 nM, respectively. The sensitivity, determined from calibration curves, was 0.1009 μA nM^-1 for the low range and 0.0838 μA nM^-1 for the high range. The biosensor demonstrated high sensitivity and selectivity, effectively distinguishing the analyte from interferents like albumin and folic acid. Molecular docking showed strong DNA binding (-6 kcal mol^-1). Lab tests confirmed detection of <i>Klebsiella pneumoniae</i> antimicrobial resistance genes (SHV, TEM, CTX-M, OXA-1) <i>via</i> PCR-based gel electrophoresis. This easy-to-use non-enzymatic biosensor offers fast, accurate, rapid, sensitive, and specific <i>Klebsiella pneumoniae</i> DNA detection, valuable for point-of-care diagnostics and antimicrobial resistance monitoring.