Fluorescent Nanoparticles for Multiplexed Bacteria Monitoring

Abstract

Rapid, sensitive, and selective detection of pathogenic bacteria is extremely important for proper containment, diagnosis, and treatment of diseases like foodborne illness, sepsis, and bioterrorism. Most current bacterial detection methods are time-consuming and laborious and can detect only one bacterial pathogen at a time. We have developed a method for sensitive, multiplexed monitoring of bacterial pathogens within 30 min using multicolored FRET (fluorescence resonance energy transfer) silica NPs (nanoparticles). By varying the ratio of three tandem dyes coencapsulated into the NPs, we have synthesized NPs that emit unique colors upon excitation with a single wavelength. When these NPs were conjugated to monoclonal antibodies specific for the pathogenic bacteria species Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus, and then incubated with small concentrations of the bacteria, simultaneous and sensitive detection of the multiple bacterial targets was achieved.

Applications of Nanomedicine in Antibacterial Medical Therapeutics and Diagnostics~!2009-08-26~!2009-11-25~!2010-02-24~!

“…The three bacterial species were incubated for 30 min along with the three-antibody labeled NPs and when viewed under a confocal microscope it was observed that bacteria were covered with their specifically colored NPs corresponding to their antigen present on the surface of the bacteria. The study highlights the potential of such a multiplexed diagnostic system, which is able to quickly and accurately identify a particular bacteria, such a system could be applicable for commercial use and for diagnostic purposes in regards to human health and livestock [40].…”

“…Results observed showed that it was possible to detect a single bacterium within 20 minutes and was confirmed by plate-counting method [39]. Wang [40] also showed the dye-doped silica NPs could be used as a method of monitoring pathogenic bacteria, with high sensitivity and short amount of incubation time. In their study they employed multicolored FRET (fluorescence resonance energy transfer) silica NPs, which employs the use of using a ratio of three dyes encapsulated in the silica NPs to produce unique colors upon excitation.…”

Bioconjugated silica nanoparticles: Development and applications

“…These antibody-NPs were incubated with small concentrations of the bacteria. After the incubation and washing steps, simultaneous and sensitive detection of the multiple bacterial targets was achieved [68] (Fig. 5(c)).…”

Synthesis of Ru(bpy)3 -doped Silica Nanoparticle and Its Application in Fluorescent Immunoassay

“…To conjugate with SA [11], the nanoparticles were coated with BSA first. 1.0mg nanoparticles ultrasonic dispersed in 1.0mL of 0.1M phosphate buffer(pH 7.0) was mixed with 4.0mg of BSA and 0.3 mL of 1% (v/v) glutaraldehyde, stirred for 24 h at 4℃.…”