Detection of Bacteria by Using Biofunctional Gold Nanomaterials

• Main Authors: Yu-Ting Tseng, 曾于庭
• Other Authors: Chih-Ching Huang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/23317628227712593403

碩士 === 國立臺灣海洋大學 === 生物科技研究所 === 101 === In our article, we demonstrated biofunctional gold nanomaterials could be developed for detection and inhibition of the growth of bacteria, respectively. (1)We developed a simple and convenient method for synthesis of luminescent mannosed-capped gold nanodots (Man–Au NDs). Multivalent interactions between the Man–Au NDs and FimH proteins located on the bacterial pili of Escherichia coli (E. coli) resulted in the formation of aggregated bacterial clusters. Monitoring the luminescence of the Man–Au NDs allowed the detection of E. coli at levels as low as 150 CFU/mL. The Man–Au NDs were also an efficient antibacterial agent, selectively inhibiting the growth of E. coli through Man–Au ND–induced agglutination. Our small-diameter Man–Au NDs, which provided an ultrahigh ligand density (local concentration) of mannose units for antibacterial agent in real samples. (2)We described a novel method for bacterial detection using mass spectrometry and antibody-conjugated gold nanoparticles (AbAu NPs). The AbAu NPs were obtained from as-prepared 5.5 nm Au NPs and bacteria-specific antibodies. After binding of the AbAu NPs to the bacteria, the purified AbAu NPs/bacteria conjugates were deposited on a nitrocellulose membrane (NCM; 0.3 cm×0.3 cm; pore size: 0.45 μm) prior to LDI-MS analysis. The Au ion signals from the Au NPs using LDI were employed to analyze bacteria. Under optimal conditions, this AbAu NPs/NCM probe is highly sensitive [limit of detection ~500 colony forming units (CFU)/mL] and selective toward bacteria E. coli, Staphylococcus aureus (S. aureus), or Salmonella enterica (S. enterica) by using the corresponding Ab–Au NPs. Therefore, this LDI-MS approach provides a simple and cost-effective route for the high-speed analysis of low concentrations of bacteria with ultrahigh sensitivity and selectivity.