Silver nanoparticles (AgNPs) are among the various types of the metallic nanoparticles considered to possess antimicrobial potential. The use of biogenic sources as a potential reducing agent for synthesis nanoparticle is promptly increasing in comparison to physical and chemical methods. Amongst the biogenic sources, fungi are more preferred microorganisms to use for AgNPs synthesis as they are easy to culture and can control the size and morphology of the synthesized nanoparticles and help in low-cost large-scale production. The use of fungi for AgNPs synthesis is a rapid, environmentally safe, and cost-effective approach for vector control strategies in the future. Fungi can act as an effective agent in comparison to other microorganisms as it has the ability of producing higher amount of enzymes and proteins with the potential for synthesizing nanoparticles. Fungi-mediated synthesized nanoparticles possess coatings of biomolecules, which increases their activity. Organisms like Aspergillus flavus, Rhizopus sp., and Fusarium oxysporum were reported to possess extracellular material or biomass, which helps in the reduction of silver ions to AgNPs. This chapter focusses solely on fungi-mediated AgNPs synthesis, with their preferred physico-chemical parameters, their mode of action, and their applications in various modern aspects.
Nanomedicine has gained prime attention over the past decades due to the application of nanomaterials for noninvasive diagnosis and treatment. Nanoscale carriers are immensely significant for the targeted delivery of drugs, genes, and immunomodulatory agents to specific tissues. The dimensions of the nanocarriers and assembly of the building blocks can be finely tuned by biogenic nanotemplates. Recently, viruses with a nucleic acid core and protein capsid are being explored for their potential to synthesize size- and shape-controlled nanostructures for biomedical applications. Herein, this chapter presents the current advances in the field of virus-mediated synthesis of nanoparticles and their applications. As an example of this exciting field, the tobacco mosaic virus (TMV) was used for facilitating the crystal growth of CdS and PbS nanostructures. Furthermore, TMV also induced specific nucleation with the growth of crystalline iron oxide, ferrihydrite, on the external surface of the protein microstructure. Likewise, self-assembled silica/TMV nanotubular superstructures were also reported where the silica shell was as thin as 3 nm. Similarly, the M13 bacteriophage served as ideal nanotemplate for synthesizing viral–semiconductor hybrid nanowires composed of ZnS or CdS quantum dots. Rationally engineered viral proteins were also found to effectively assemble freestanding chemically ordered CoPt and FePt nanowires. The M13 bacteriophage was also employed to obtain exotic hetero-nanostructural arrays consisting of CdSeQDs bound to pIII proteins and AuNPs arrays bound to pVIII proteins. The squash leaf curl China virus (SLCCNV), engineered P22 virus, and cowpea chlorotic mottle virus (CCMV) were all reported as a model system for the fabrication of virus-metallic hybrid nanomaterials. However, fewer studies have been conducted to date on virus-mediated nanoparticle synthesis which emphasizes the scope of extending the exploration of nanobiotechnological prospects for other viruses like the brome mosaic virus (BMV), red clover necrotic mosaic virus (RCNMV), cowpea mosaic virus (CPMV), cucumber mosaic virus (CMV), hibiscus chlorotic ringspot virus (HCRSV), TMV, and potato virus X (PVX). A more detailed investigation will help reveal the promises of virogenic nanomaterials for drug delivery, targeting, triggered release, and stability. Similarly, toxicity and the environmental impact of virus-synthesized nanoparticles needs to be addressed before considering them for theranostic applications.
Nanobiotechnology is an interdisciplinary field that encompasses the applications of nanomaterials in biotechnology. This field has significant applications in medicine, health, imaging, immunoproteomics, drug delivery, tissue engineering, cosmetics, agriculture, and pharmacy. Nanobiotechnology has been instrumental in developing intelligent drug delivery and gene therapy tools, nanobiosensors, nanodiagnostics, nanobioconstructs, nanofluidic devices, and bio-compatible nanodevices. Nanoparticles, nanomaterials, and nanocolloids can be synthesized by using biological, chemical, and physical methods. Currently, there is an impending need for the development of cost-effective and environment-friendly methods for the synthesis of biocompatible nanoparticles. In the present chapter, we have attempted to present an overview of the different methods for the synthesis of nanoparticles, the underlying mechanisms of biological synthesis, and the recent trends in their applications in nanobiotechnology.
