Liu Yarui, Zhu Xuemei, Zhao Qian, Yan Xuejun, Du Qing, Li Nan, Liao Chengmei, Wang Xin
MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, China.
School of Environmental Science and Engineering, Tianjin University, No. 92 Weijin Road, Nankai District, Tianjin 300072, China.
iScience. 2021 Jul 31;24(8):102933. doi: 10.1016/j.isci.2021.102933. eCollection 2021 Aug 20.
The biosynthesis of metal nanoparticles from precious metals has been of wide concern. Their antibacterial activity is a main bottleneck restricting the bacterial activity and reduction performance. Here, bio-electrochemical systems were used to harvest electroactive biofilms (EABs), where bacteria were naturally protected by extracellular polymeric substances to keep activity. The biofilm was further encapsulated with polydopamine (PDA) as additional shield. Silver nanoparticles (AgNPs) were biosynthesized on EABs, whose electroactivity could be fully recovered after Ag reduction. The PDA increased bacterial viability by 90%-105%, confirmed as an effective protection against antibacterial activity of Ag/AgNPs. The biosynthetic process changed the component and function of the microbial community, shifting from bacterial Fe reduction to archaeal methanogenesis. These results demonstrated that the electrochemical acclimation of EABs and encapsulation with PDA were effective protective measures during the biosynthesis of AgNPs. These approaches have a bright future in the green synthesis of nanomaterials, biotoxic wastewater treatment, and sustainable bio-catalysis.
从贵金属生物合成金属纳米颗粒已受到广泛关注。它们的抗菌活性是限制细菌活性和还原性能的主要瓶颈。在此，利用生物电化学系统收获电活性生物膜（EABs），其中细菌受到细胞外聚合物的自然保护以保持活性。生物膜进一步用聚多巴胺（PDA）封装作为额外的屏障。在EABs上生物合成了银纳米颗粒（AgNPs），在银还原后其电活性可完全恢复。PDA使细菌活力提高了90%-105%，证实其对Ag/AgNPs的抗菌活性具有有效保护作用。生物合成过程改变了微生物群落的组成和功能，从细菌铁还原转变为古菌产甲烷。这些结果表明，EABs的电化学驯化和用PDA封装是AgNPs生物合成过程中的有效保护措施。这些方法在纳米材料的绿色合成、生物毒性废水处理和可持续生物催化方面具有光明的前景。
