Affinity Capture of Uropathogenic Escherichia coli Using Pigeon Ovalbumin-Bound Fe_(3)O_(4)@Al_(2)O_(3) Magnetic Nanoparticles

摘要

Escherichia coli and Staphylococcus saprophyticus are the most common causes of urinary tract infections, with 80percent of these infections caused by uropathogenic E. coli. Because the P fimbriae of E. coli have specificity toward Gal(alpha1-4)Gal(beta) units, pigeon ovalbumin (POA), whose structure contains terminal Gal(alpha1-4)Gal(beta) moieties, was used as a probe for interaction with P fimbriated E. coli. The functional affinity probes for these bacteria by immobilizing POA-a phosphoprotein-onto the surface of magnetic iron oxide nanoparticles (NPs) coated with alumina (Fe_(3)O_(4)@Al_(2)O_(3)), using the phosphate units of POA as linking groups for the formation of phosphate-alumina complexes. The immobilization process occurred within 30 s when performing the reaction under microwave heating. The magnetic POA-Fe_(3)O_(4)@Al_(2)O_(3) NPs generated using this facile approach exhibited specificity toward P fimbriated E. coli. The bacteria targeted by the affinity probes were characterized by matrix-assisted laser desorption/ionization mass spectrometry. The detection limit toward uropathogenic bacteria when using this approach was approx9.60 X 10~(4) cfu/mL (0.5 mL).