Chitosan-stabilized gold nanoparticles supported on silica/titania magnetic xerogel applied as antibacterial system
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The sol-gel method is an excellent choice to produce composite materials with enhanced performance by efficiently combining the individual features of their components. In this work, chitosan-stabilized gold nanoparticles (ChAuNPs) were immobilized onto a SiO2/TiO2 magnetic xerogel, which was synthesized through hetero-condensation of silica and titania precursors in the presence of magnetite particles covered with a silica shell. This system allies the antimicrobial capacity of ChAuNP, the surface reactivity of titania, porous structure of silica, and magnetic response of the magnetite particles. The magnetite phase was characterized by X-ray diffraction and the shape and size of the particles were observed by scanning and transmission electron microscopy. ChAuNPs were obtained in spherical shape with size below 10 nm, as characterized by UV–Vis spectroscopy and transmission electron microscopy. SiO2/TiO2 magnetic xerogel containing the ChAuNP was also characterized by thermogravimetric and textural analysis, transmission electron microscopy, and magnetism. The ChAuNP-SiO2/TiO2 magnetic xerogel is mesoporous with facile magnetic recovering and its performance as antimicrobial agent was assessed against the pathogen E. coli. The ChAuNP-SiO2/TiO2 magnetic xerogel presented inhibitory effect against the tested bacteria, even with such low gold content. After the magnetic recovering, the material was reused and maintained its antibacterial activity.
Magnetic composite embedding magnetite particles in silica/titania network.
Adhesion of chitosan-stabilized gold nanoparticles to silica/titania surface.
Porous and high surface area material containing gold nanoparticles as antimicrobial agent.
Efficient and reusable antimicrobial system against E. coli bacteria.
KeywordsCore shell Magnetic composite Spherical metal nanoparticles Hybrid structure SiO2/TiO2 mixed oxide
We thank CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), FAPERGS (Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul), and CAPES (Coordenação de Aperfeiçoamento Pessoal de Nível Superior) for financial support and grants. We also thank CNANO (Centro de Nanociência e Nanotecnologia) and CMM (Centro de Microscopia e Microanálise) of UFRGS (Universidade Federal do Rio Grande do Sul).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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