Material properties are strongly dependent on material structure. The large diversity and complexity of material structures provide significant opportunities to improve the properties of the materials, expanding their applications. Here, we discuss the fabrication of a multifunctional silver film prepared by controlling the nucleation and growth of silver particles. Silver films with high hydrophobicity and antibacterial activity were fabricated by adopting an electrochemical approach. The dependence of the hydrophobic and antibacterial properties on the size and shape of the silver particles was first investigated. Small-sized silver particles exhibited a high antibacterial rate, while a porous silver film composed of dendritic particles showed a significant hydrophobic activity. By regulating the reaction time, current density, and silver salt concentration, a silver film with a contact angle of 150.9° and an antibacterial rate of 54.7% was synthesized. This study demonstrates that finding a compromise between different material structures is a suitable way to fabricate multifunctional devices.
Microbial silver nanoparticles have been known to have bactericidal effects but the antimicrobial mechanism has not been clearly revealed. The use of microorganisms in the synthesis of nanoparticles emerges as an ecofriendly and exciting approach. Here we report on the extracellular synthesis method for the preparation of silver nanoparticles in water using the extract of Agaricus bisporus, a naturally occurring edible mushroom, as reducing and protecting agents. The silver nanoparticles were characterised by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and X-Ray diffraction (XRD) analysis. The synthesised silver nanoparticles showed antibacterial activity against the multi-drug resistant Gram positive and Gram negative bacterial pathogens. 相似文献
The biosynthesis of silver nanoparticles (AgNps) has a wide range of applications, and here we develop a rapid synthesis using the leaf extract of Ipomea carnea. We demonstrated that 100?mL of a 1?mM silver nitrate solution was reduced to AgNps by 500?µL of I. carnea extract in 5?min and that one or more of the chemical constituents present in the extract acted as the reducing agent. Surface plasmon resonance peaks were observed from 410 to 440?nm for AgNps synthesised using the plant extract, and the peaks showed a characteristic blue shift with variation of pH from 2 to 8. Particle size analysis revealed the size of the AgNps to be from 30 to 130?nm, which was also confirmed by dynamic light scattering, atomic force microscopy and transmission electron microscopy. Additionally, the antibacterial effects of the AgNps were evaluated against selected human pathogens such as Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Klebsiella pneumoniae, Aeromonas hydrophila, Salmonella typhi, Proteus vulgaris and Pseudomonas aeruginosa. Finally, the AgNps were impregnated with a cellulose acetate membrane to form an antimycobacterial membrane. Antimycobacterial activity against a non-pathogenic Mycobacterium smegmatis showed that the AgNp-embedded membrane system has a zone of inhibition of 14?mm. 相似文献
This study investigates the ability of cellulose filter paper coated with silver nanoparticles to remove Escherichia coli from drinking water. The cellulose filter paper was coated with silver nanoparticles by a chemical reduction method using two different ratios of sodium borohydride and silver nitrate. In consideration of drinking-water quality standards and non-carcinogenic health risks, the optimum sodium borohydride:silver nitrate ratio for coating the cellulose filter paper was determined by comparing the silver in the effluent after E. coli removal. For both ratios, 100% E. coli removal was realised. In terms of the silver in the effluent, only the first two lowest concentrations for both ratios of sodium borohydride and silver nitrate were compliant with the drinking-water quality standards, demonstrating hazard quotients (HQs) between 0.084 and 0.484. On the basis of the highest level of E. coli removal with the lowest HQ value, the optimum sodium borohydride:silver nitrate ratio for coating the cellulose filter paper as an antibacterial water filter was 2:1 molar ratio (0.002 M:0.001 M). Silver nanoparticle-coated cellulose filter paper was found to be an inexpensive and easy-to-use emergency antibacterial water filter to generate clean drinking water. 相似文献
