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采用非酶还原法,以黑曲霉菌原位还原银氨离子制备一种新型银纳米颗粒(AgNPs)/菌体复合抗菌材料,着重考察了反应温度与pH值对还原过程和所得复合材料的抗菌性能及稳定性的影响。结果表明,在温度为30℃、60℃和pH 9.5、11.5条件下,能够合成出粒径为6.9～8.2nm的近球形AgNPs。该AgNPs均匀地分布在菌体表面上,对E.coli显示出高的抗菌性能:最小抑菌浓度(MIC)为217～434mg·L-1(以菌粉总质量表示)或8～20mg Ag·L-1(以银含量表示)。提高反应温度有利于提高菌体银负载量,但AgNPs粒径增大,抗菌性能有所下降;提高反应pH值有利于提高还原速率,而对抗菌性能影响不显著。复合材料中AgNPs与菌体结合牢固,单位质量复合材料释出的Ag+含量为1.7～6.8mg.g-1,提高反应温度和pH值后Ag+的释出均减少。
A new type of silver nanoparticles (AgNPs) / bacterial composite antibacterial materials were prepared by non-enzymatic reduction method using in situ reduction of silver and ammonia ions by Aspergillus niger. The effects of reaction temperature and pH value on the reduction process and antibacterial activity of the resultant composites Performance and stability of the impact. The results showed that near-spherical AgNPs with particle size of 6.9-8.2 nm could be synthesized at 30 ℃, 60 ℃ and pH 9.5, 11.5. The AgNPs uniformly distributed on the surface of the cells and showed high antibacterial activity against E. coli: the minimum inhibitory concentration (MIC) was 217-443 mg · L -1 (expressed as total bacterial powder) or 8-20 mg Ag · L-1 (expressed as silver content). Increasing the reaction temperature is beneficial to increase the silver loading of the bacterial cells. However, the particle size of AgNPs increases and the antimicrobial activity decreases. Increasing the pH of the reaction can improve the reduction rate, but not the antibacterial activity. AgNPs in the composite material bound well with Agrobacterium tumefacien, the content of Ag + per unit mass of the composite material was 1.7-6.8 mg.g-1, and the release of Ag + decreased after the reaction temperature and pH value were increased.