About this Research Topic
This Research Topic will focus on applied aspects of microbial generation of nanoparticles.
Nanoparticles of varied shapes and sizes can be synthesized by using physical, chemical, or biological pathways. However, exploiting physical and chemical routes lead to high energy consumption, low yield, high cost, and environmental damage by employing harsh reducing agents. The biological formation of nanoparticles is a well-known process. However, only recently, perspectives and applications have been considered and reported.
This article collection will welcome contributions focused on the discovery and understanding of the microbial processes leading to the generation of nanoparticles.
The biological pathways for the synthesis of nanoparticles involve the use of microorganisms (bacteria, fungi, yeast, algae, etc.) or plants. The natural ability of microorganisms to protect themselves from the toxic effects of cations by reduction of them to a zero-valence metals form (non-toxic Meº) can be targeted to produce metal nanoparticles (MeºNPs). This process has been extensively reported by different research groups. Additionally, the size distribution of biogenic nanoparticles can be used as an indicator of the metabolic activity of microbial communities and presence of alive forms of microorganisms in different ecosystems.
The biologically generated nanoparticles can be represented by different types: monometallic, metal oxides and sulfides, complex bi - and polymetallic, coated. The biosynthesis of metal sulfide nanoparticles via a chemical reaction between metal and sulfur ions is performed by microbial cells as the function of suppliers of biological molecules, mainly proteins, for the formation of a covering layer on the surface of the particles. The presence of a "protein corona" on the surface prevents agglomeration and sedimentation of nanoparticles. The composition of the coating layer of molecules adsorbed on the surface of nanoparticles is diverse and unique for each strain of microorganisms used to produce nanoparticles. There is a selectivity of adsorption of certain proteins on the surface of nanoparticles, but the principles of this selectivity have not been studied.
Bacteria are potent bio-factories for the synthesis of metallic nanoparticles such as silver and gold, because they are known to produce various inorganic materials either intra- or extracellularly. The most widely accepted mechanism of silver biosynthesis involve the presence of the nitrate reductase enzyme, which converts nitrate into nitrite. The study of microbial processes of the formation of nanoparticles will provide new information on the biochemical mechanisms and resistance limits of individual microorganisms and microbial communities as a whole to heavy metal cations.
Of particular interest for this Research Topic are the unique features of biogenic metal nanoparticles for practical applications. The synthesis of nanoparticles by the above mentioned living organisms with the aid of various biotechnological techniques is defined as green nanotechnology. The nanoparticles so generated are free of toxic chemicals, environment-friendly and cost-effective. Using green synthesis, allows the synthesis of different varieties of nanoparticles with different applications. For example, bacteria can accumulate silver on their cell wall to as much as 25% of their dry weight biomass, suggesting their potential use in the industrial recovery of silver from ore materials.
It should be emphasized that many characteristics of the nanomaterial depend on the composition of the protein coating of nanoparticles (polydispersity, zeta potential, fluorescence intensity, biocidal and photocatalytic properties, biocompatibility). Studies on the composition of the coating layer and its relationship with the characteristics of nanoparticles and their application are of great interest.
One of the interesting directions is the production of complex nanoparticles, including various types of metals, chalcogenides and others using biological substances. Such complex composite nanomaterials have unexpected properties and can be used in various applications.
We welcome manuscripts dealing with various aspects of biogenic nanoparticles formation such as nature, mechanism, methods of detection, applications.
We welcome manuscripts dealing with but not limited to various aspects of biogenic nanoparticles formation such as nature, mechanism, methods of detection, applications.
Keywords: Nanoparticles, microorganisms, DBNG, extrabiology, spectrometry, Biogenic synthesis
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.