title: Biological synthesis of nanoparticles in biofilms.
abstract: The biological synthesis of nanoparticles (NPs) by bacteria and biofilms via extracellular redox reactions has received attention because of the minimization of harmful chemicals, low cost, and ease of culturing and downstream processing. Bioreduction mechanisms vary across bacteria and growth conditions, which leads to various sizes and shapes of biosynthesized NPs. NP synthesis in biofilms offers additional advantages, such as higher biomass concentrations and larger surface areas, which can lead to more efficient and scalable biosynthesis. Although biofilms have been used to produce NPs, the mechanistic details of NP formation are not well understood. In this review, we identify three critical areas of research and development needed to advance our understanding of NP production by biofilms: 1) synthesis, 2) mechanism and 3) stabilization. Advancement in these areas could result in the biosynthesis of NPs that are suitable for practical applications, especially in drug delivery and biocatalysis. Specifically, the current status of methods and mechanisms of nanoparticle synthesis and surface stabilization using planktonic bacteria and biofilms is discussed. We conclude that the use of biofilms to synthesize and stabilize NPs is underappreciated and could provide a new direction in biofilm-based NP production.
authors.affiliation: The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
authors.forename: Abid H
authors.initials: AH
authors.lastname: Tanzil
authors.affiliation: The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
authors.forename: Sujala T
authors.initials: ST
authors.lastname: Sultana
authors.affiliation: The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Saunders
authors.affiliation: Department of Biological Sciences and Technology, School of Environmental Studies, China University of Geoscience in Wuhan, 388 Lumo Road, Wuhan, Hubei 430074, PR China.
authors.forename: Liang
authors.initials: L
authors.lastname: Shi
authors.affiliation: Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore 637551, Singapore.
authors.forename: Enrico
authors.initials: E
authors.lastname: Marsili
authors.affiliation: The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA. Electronic address: beyenal@wsu.edu.
authors.forename: Haluk
authors.initials: H
authors.lastname: Beyenal
mesh_terms: D001419:Bacteria / Q000378:metabolism; D018441:Biofilms; D004579:Electron Transport; D055772:Green Chemistry Technology; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D033362:Powder Diffraction; D013057:Spectrum Analysis
keywords: Biofilms; Biological synthesis; Mechanism; Nanoparticles; Stabilization