Chapter 19 - Functionalized biogenic nanoparticles and their applications

Abstract

The activity of nanomaterials is largely dependent on their size, shape, and surface properties. Although physical and chemical methods are well documented for tailoring the morphological features of the nanoparticles, recent advances have made great progress toward the biological synthesis of nanoscale materials with defined dimensions. Furthermore, various surface functionalization strategies have been employed for enhancing the properties of biogenic nanoparticles. This unique chapter describes surface-functionalized biogenic nanoparticles from bacteria, fungus, algae, and medicinal plants. Nanoparticles like gold (AuNPs), silver (AgNPs), and palladium-magnetite nanohybrids have been synthesized using various bacteria like Bacillus subtilis, Geobacter sulfurreducens, Kocuria rosea, Komagataeibacter xylinus, Streptomyces sp., Thermomonospora curvata, Thermomonospora fusca, and Thermomonospora chromogena for antibacterial, antibiofilm, and dye bioremediation applications. Similarly, fungi like Fusarium oxysporum, Penicillium polonicum, and Penicillium rugulosum have also been reported to synthesize AuNPs and AgNPs with exotic shapes like spheres, hexagons, or triangles. Mycogenic nanoparticles have been effectively functionalized with biomolecules like chitosan, genomic DNA, or bacterial cellulose for therapeutic property enhancement. Medicinal plants have a rich source of phytochemicals, which play a critical role in the synthesis of nanoparticles as well as stabilization. Various plants like Adiantum philippense, Citrus limon, Ferula persica, Jatropha curcas, Justicia adhatoda, Solanum tuberosum, and Syzygium cumini have been reported to synthesize nanostructured manganese oxide, cerium oxide, and magnetic nanoparticles apart from AuNPs and AgNPs. Numerous bioactive molecules like amoxicillin, salicylalchitosan, β-cyclodextrin, and curcin have been used for the surface modification of phytogenic nanoparticles. Similarly, plant-synthesized nanoparticles have also been doped with Ag or Au or alternatively embedded in a cellulose matrix to promote antimicrobial and wound healing activities. Purified biomolecules like lysozymes and tyrosines have been employed for the synthesis of Au nanostructures, which have been further functionalized with ampicillin and polyoxometalates—lysine, respectively, to enhance antibacterial and antibiofilm properties. In view of this background, it can be concluded that rationally designed surface-functionalized biogenic nanoparticles have a tremendous scope as improved candidates in nanomedicine and for environmental applications.