title: Using biofunctionalized nanoparticles to probe pathogenic bacteria.
abstract: In this paper, we report a method for fabricating biofunctionalized nanoparticles by attaching human immunoglobulin (IgG) onto their surfaces through either electrostatic interactions or covalent binding. We found that these IgG-presenting nanoparticles can bind selectively to the cell walls of pathogens that contain IgG-binding sites based on the investigation of transmission electron microscopy images. Our results demonstrate that such Au-IgG nanoparticles may serve as useful nanoscale probes for exploring the interactions between IgG and pathogens. Furthermore, the IgG-presenting magnetic nanoparticles have been employed as effective affinity probes for selectively concentrating traces of target bacteria from sample solutions. The trapped bacteria were then characterized by using matrix-assisted laser desorption/ionization mass spectrometry. The lowest cell concentration we detected for both Staphylococcus saprophyticus and Staphylococcus aureus in aqueous sample solutions (0.5 mL) was approximately 3 x 10(5) cfu/mL, while the detectable cell concentration for S. saprophyticus in a urine sample was approximately 3 x 10(7) cfu/mL.
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan.
authors.forename: Kun-Chan
authors.initials: KC
authors.lastname: Ho
authors.forename: Pei-Jane
authors.initials: PJ
authors.lastname: Tsai
authors.forename: Ya-Shiuan
authors.initials: YS
authors.lastname: Lin
authors.forename: Yu-Chie
authors.initials: YC
authors.lastname: Chen
mesh_terms: D001426:Bacterial Proteins / Q000276:immunology*; D001665:Binding Sites; D006046:Gold / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D018189:Immunomagnetic Separation / Q000379:methods*; D049329:Nanostructures; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013211:Staphylococcus aureus / Q000737:chemistry / Q000302:isolation & purification* / Q000472:pathogenicity; D014556:Urine / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D007074:Immunoglobulin G; D006046:Gold