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43. Bioconjugates of Glucose Oxidase and Gold Nanorods Based on Electrostatic Interaction with Enhanced Thermostability

Author

Ma Zhanfang and Ding Teng

Subjects
Gold nanorods, Enzyme thermostability, Glucose oxidase, Polyelectrolytes, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Abstract Bioconjugates made up of an enzyme and gold nanorods (GNRs) were fabricated by electrostatic interactions (layer-by-layer method, LBL) between anionic glucose oxidase (GOD) and positively charged GNRs. The assembled processes were monitored by UV–Vis spectra, zeta potential measurements, and transmission electron microscopy. The enzyme activity assays of the obtained bioconjugates display a relatively enhanced thermostability behavior in contrast with that of free enzyme. Free GOD in solution only retains about 22% of its relative activity at 90 °C. Unexpectedly, the immobilized GOD on GNRs still retains about 39.3% activity after the same treatment. This work will be of significance for the biologic enhancement using other kinds of anisotropic nanostructure and suggests a new way of enhancing enzyme thermostability using anisotropic metal nanomaterials.

Published
2009
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45. Antibacterial performance of polymer quaternary ammonium salt–capped silver nanoparticles onBacillus subtilisin water

Author

Minghao Sui, Ma Zhanfang, Bojie Yuan, Jingyu Wang, and Hongwei Li

Subjects
chemistry.chemical_classification, biology, General Chemical Engineering, Respiratory chain, 02 engineering and technology, General Chemistry, Bacillus subtilis, 010402 general chemistry, 021001 nanoscience & nanotechnology, biology.organism_classification, Antimicrobial, 01 natural sciences, Chloride, Silver nanoparticle, 0104 chemical sciences, Cell wall, chemistry.chemical_compound, chemistry, medicine, Humic acid, Ammonium, 0210 nano-technology, medicine.drug, Nuclear chemistry
Abstract

In this study, we prepared polymer quaternary ammonium salt–capped silver nanoparticles (PQAS–AgNPs) and investigated their antimicrobial activities. The antimicrobial effectiveness of PQAS–AgNPs on Bacillus subtilis (B. subtilis), and the effect of dose, pH, chloride ion and humic acid (HA) were studied. It was found that PQAS–AgNPs revealed excellent antimicrobial activity to B. subtilis, compared with polyvinylpyrrolidone-capped silver nanoparticles (PVP-AgNPs), which was the reference antimicrobial material. The positive surface, the antimicrobial activity of PQAS, and the synergistic antibacterial effect between PQAS and AgNPs contributed to the significant antibacterial superiority of PQAS–AgNPs. This study demonstrated that the impact of the dose of the material was positive and the microbiocidal efficacy of PQAS–AgNPs was stronger at lower pH. In addition, the antibacterial performance of PQAS–AgNPs decreased in the presence of Cl− and HA. Finally, in combination with the results of FCM and adenosine triphosphate (ATP) content, it was found that PQAS–AgNPs destroyed the respiratory chain of bacterial cells, reduced the synthesis of ATP, and destroyed the cell wall and cell membrane function.

Published
2019

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