Using biofunctionalized nanoparticles to probe pathogenic bacteria.
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.
Ho
Kun-Chan
KC
Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan.
Tsai
Pei-Jane
PJ
Lin
Ya-Shiuan
YS
Chen
Yu-Chie
YC
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
D001426:Bacterial Proteins; D007074:Immunoglobulin G; D006046:Gold