Browsing by Author "Tsai, Pei-Jane"

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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).
Functional Fe3O4/TiO2 core/shell magnetic nanoparticles as photokilling agents for pathogenic bacteria
(2008-04-01)
Chen, Wei-Jen
;
Tsai, Pei-Jane
;
Chen, Yu-Chie
;
應用化學系
;
應用化學系分子科學碩博班
A photokilling approach for pathogenic bacteria is demonstrated using a new type of magnetic nanoprobe as the photokilling agent. In addition to their magnetic property, the nanoprobes have other features including a photocatalytic property and the capacity to target bacteria. The nanoprobes comprise iron oxide/titania (Fe3O4@TiO2) core/shell magnetic nanoparticles. As dopamine molecules can self-assemble onto the surface of the titania substrate, dopamine is used as the linker to immobilize succinic anhydride onto the surfaces of the Fe3O4@TiO2 nanoparticles. This is followed by the immobilization of IgG via amide bonding. We demonstrate that the IgG-Fe3O4@TiO2 magnetic nanoparticles not only have the capacity to target several pathogenic bacteria, but they also can effectively inhibit the cell growth of the bacteria targeted by the nanoparticles under irradiation of a low-power UV lamp within a short period. Staphylococcus saprophyticus, Streptococcus pyogenes, and antibiotic-resistant bacterial strains, such as multiantibiotic-resistant S. pyogenes and methicillin-resistant Staphylococcus aureus (MRSA), are used to demonstrate the feasibility of this approach.
Functional gold nanoparticles as photothermal agents for selective-killing of pathogenic bacteria
(2007-12-01)
Huang, Wei-Chieh
;
Tsai, Pei-Jane
;
Chen, Yu-Chie
;
應用數學系
;
應用化學系分子科學碩博班
Aims: Our aim was to demonstrate that functional gold nanoparticles can be used as photothermal agents for the selective killing of pathogenic bacteria. Materials & methods: Gold nanoparticles with polygonal shapes, capable of absorbing near infrared (NIR) light, were generated through a photochemical reaction. Vancomycin, which can bind with the terminal D-Ala-D-Ala moieties of the peptide units of pathogen cell walls, was immobilized on the surface of the gold nanoparticles. The vancomycin-bound gold nanoparticles were used as the photothermal agents for the inhibition of pathogenic bacteria growth, under irradiation of NIR light (808 nm). Results & discussion: We have demonstrated that vancomycin-bound gold nanoparticles are capable of selective-binding onto the cell walls of pathogenic bacteria. A large portion (> 99%) of bacteria targeted by the gold nanoparticles was destroyed under illumination by NIR light within 5 min owing to suffering from heating. Conclusions: This photothermal approach is effective for the inhibition of pathogenic bacteria cell growth, including Gram-positive bacteria, Gram-negative bacteria and antibiotic-resistant bacteria.
Functional Nanoparticle-Based Proteomic Strategies for Characterization of Pathogenic Bacteria
(2008-12-15)
Chen, Wei-Jen
;
Tsai, Pei-Jane
;
Chen, Yu-Chie
;
應用化學系
;
Department of Applied Chemistry
Although matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) can be employed to rapidly characterize pathogenic bacteria, bacterial cultures are generally required to obtain sufficient quantities of the bacterial cells prior to MALDI MS analysis. If this time-consuming step could be eliminated, the length of time required for identification of bacterial strains would be greatly reduced. In this paper, we propose an effective means of rapidly identifying bacteria-one that does not require bacterial culturing-using functional nanoparticle-based proteomic strategies that are characterized by extremely short analysis time. In this approach, we used titania-coated magnetic iron oxide nanoparticles (Fe(3)O(4)@TiO(2) NPs) as affinity probes to concentrate the target bacteria. The magnetic properties of the Fe(3)O(4)@TiO(2) NPs allow the conjugated target species to be rapidly isolated from the sample solutions under a magnetic field. Taking advantage of the absorption of the magnetic Fe(3)O(4) NPs in the microwave region of the electromagnetic spectrum, we performed the tryptic digestion of the captured bacteria under microwave heating for only 1-1.5 min prior to MALDI MS analysis. We identified the resulting biomarker ions by combining their MS/MS analysis results with protein database searches. Using this technique, we identified potential biomarker ions representing five Gram-negative bacteria: Escherichia coli O157:H7, uropathogenic E. coli, Shigella sonnei, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Finally, we demonstrated the practical feasibility of using this approach to rapidly characterize bacteria in clinical samples.
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.
Multifunctional Fe(3)O(4)@Au Nanoeggs as Photothermal Agents for Selective Killing of Nosocomial and Antibiotic-Resistant Bacteria
(2009-01-01)
Huang, Wei-Chieh
;
Tsai, Pei-Jane
;
Chen, Yu-Chie
;
應用化學系
;
Department of Applied Chemistry
Multifunctional Fe3O4@Au Nanoeggs as Photothermal Agents for Selective Killing of Nosocomial and Antibiotic-Resistant Bacteria
(2009-01-01)
Huang, Wei-Chieh
;
Tsai, Pei-Jane
;
Chen, Yu-Chie
;
應用化學系
;
Department of Applied Chemistry
Nitrilotriacetic acid-coated magnetic nanoparticles as affinity probes for enrichment of histidine-tagged proteins and phosphorylated peptides
(2007-10-01)
Li, Yi-Cheng
;
Lin, Ya-Shiuan
;
Tsai, Pei-Jane
;
Chen, Cheng-Tai
;
Chen, Wei-Yu
We herein demonstrate superparamagnetic Fe3O4 nanoparticles coated with nitrilotriacetic acid derivative (NTA) that can bind with different immobilized metal ions are capable of probing diverse target species. Immobilized Ni(II) on the surfaces of the NTA-magnetic nanoparticles have the capability of selectively trapping histidine (His)tagged proteins such as a mutated streptopain tagged with 6x His, i.e., C192S (MW similar to 42 kDa), from cell lysates. Enrichment was achieved by vigorously mixing the sample solution and the nanoparticles by pipetting in and out of a sample vial for only 30 s. After enrichment, the probe-target species could be readily isolated by magnetic separation. We also characterized the proteins enriched on the affinity probes using on-probe tryptic digestion under microwave irradiation for only 2 min, followed by matrix-assisted laser desorption/ionization mass spectrometry analysis. Using this enrichment and tryptic digestion, the target species can be rapidly enriched and characterized, reducing the time required for carrying out the complete analysis to less than 10 min. Furthermore, when either Zr(IV) or Ga (III) ions are immobilized on the surfaces of the NTA-magnetic nanoparticles, the nanoparticles have the capability of selectively enriching phosphorylated peptides from tryptic digests of alpha-, beta-caseins, and diluted milk. The detection limit for the tryptic digests of alpha- and,beta-caseins is similar to 50 finol.
Rapid enrichment of phosphopeptides and phosphoproteins from complex samples using magnetic particles coated with alumina as the concentrating probes for MALDI MS analysis
(2007-01-05)
Chen, Cheng-Tai
;
Chen, Wei-Yu
;
Tsai, Pei-Jane
;
Chien, Kun-Yi
;
Yu, Jau-Song
In this study, we used nanocomposite magnetic particles coated with alumina as the affinity probes to selectively concentrate phosphorylated peptides and proteins from a low volume of sample solution. Tryptic digest products of phosphoproteins including alpha- and beta-caseins, human protein phosphatase inhibitor 1, nonfat milk, egg white, and a cell lysate were used as the samples to demonstrate the feasibility of this approach. In only 30 and 90 s, phosphopeptides and phosphoproteins sufficient for characterization by MALDI-MS were enriched by the particles, respectively. Proteins trapped on the particles could be directly digested on the particles. The same particles in the digest solution were employed for enrichment of phosphopeptides. We estimated the required time for performing the enrichment of phosphopeptides from complex samples and characterization by MALDI MS was within 5 min. A small volume (50 mu L) and a low concentration (5 x 10(-10) M) of tryptic digest product of a phosphoprotein sample could be dramatically enriched and characterized using this approach.