Browsing by Author "Liu, Jr-Chi"

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Affinity capture of uropathogenic Escherichia coli using pigeon ovalbumin-bound Fe(3)O(4)@Al(2)O(3) magnetic nanoparticles
(2008-07-15)
Liu, Jr-Chi
;
Tsai, Pei-Jane
;
Lee, Yuan C.
;
Chen, Yu-Chie
;
應用化學系
Escherichia coli and Staphylococcus saprophyticus are the most common causes of urinary tract infections, with 80% of these infections caused by uropathogenic E. coli. Because the P fimbriae of E. coli have specificity toward Gal(alpha 1-4)Gal beta units, pigeon ovalbumin (POA), whose structure contains terminal Gal(alpha 1-4)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 similar to 9.60 x 10(4) cfu/mL (0.5 mL).
Affinity capture of uropathogenic Escherichia coli using pigeon ovalbumin-bound Fe3O4@Al2O3 magnetic nanoparticles
(2008-07-15)
Liu, Jr-Chi
;
Tsai, Pei-Jane
;
Lee, Yuan C.
;
Chen, Yu-Chie
;
應用化學系
Escherichia coli and Staphylococcus saprophyticus are the most common causes of urinary tract infections, with 80% of these infections caused by uropathogenic E. coli. Because the P fimbriae of E. coli have specificity toward Gal(alpha 1-4)Gal beta units, pigeon ovalbumin (POA), whose structure contains terminal Gal(alpha 1-4)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 (Fe3O4@Al2O3), 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-Fe3O4@Al2O3 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 similar to 9.60 x 10(4) cfu/mL (0.5 mL).
Identification of Pseudomonas aeruginosa using functional magnetic nanoparticle-based affinity capture combined with MALDI MS analysis
(2009)
Liu, Jr-Chi
;
Chen, Wei-Jen
;
Li, Chen-Wei
;
Mong, Kwok-Kong Tony
;
Tsai, Pei-Jane
PA-IL is a galactophilic lectin that is found on the outer membrane of Pseudomonas aeruginosa. Pigeon ovalbumin (POA), a phosphoprotein, contains high levels of terminal Gala(1 -> 4) Gal units. Thus, magnetic nanoparticles with immobilized POA can be used as affinity probes for P. aeruginosa, functioning via the recognition of galactophilic PA-IL. We fabricated POA-bound nanoparticles (NPs) by immobilizing POA onto the surface of core/shell magnetic iron oxide/alumina NPs via metal phosphate chelation. We then used the generated NPs to probe target bacteria from complex samples. The trapped bacterial cells were characterized based on their mass peak profiles obtained from MALDI MS analyses. In addition, we confirmed the determination of P. aeruginosa using a proteomic strategy: combining the resultant MALDI MS/MS spectra of its tryptic digest with protein database searching. The feasibility of using this approach to rapidly characterize P. aeruginosa from clinical samples without the need to perform culturing steps was also demonstrated.