Biosyntéza kovových nanočástic a jejich aplikace

Abstract

Since the beginning of the century, biosynthesis and biofabrication of the metallic nanoparticles (NPs) have become important methods for nanomaterial preparation. They represent different approaches in comparison with the chemical or physical methods. Although biosynthetic methods have certain limitations, they can be useful in a wide spectrum of application and supplement chemical and physical methods. This dissertation reviews their utilization from sensing and medicinal applications to catalysis and biosorption. Novel synthesis of gold and silver based bionanocomposites by biologically driven processes employing two diatom strains (Navicula atomus, Diadesmis gallica) is introduced. Transmission electron microscopy (TEM) and electron diffraction analysis (SAED) revealed a presence of metallic nanoparticles in the experimental suspension of the diatom culture mixed with tetrachloroaureate and silver nitrate. Fabricated bionanocomposite was successfully modified to form magnetically responsible material. Scanning electron microscopy (SEM) and TEM showed that the nanoparticles were associated with the diatom frustules and extracellular polymeric substances (EPS) excreted by the diatom cells. Nature of the metallic nanoparticles was confirmed by X-ray diffraction studies. Catalytic activity has been proved by the reduction of 4-nitrophenol in presence of NaBH4. Bionanocomposite also exhibits the ability to inhibit bacterial growth. Disk diffusion test and minimal inhibition concentration assessment were performed for more detailed description of biocomposite antibacterial properties.