surface trapping gold nanoparticles formed.

The mycelium exhibited a pale yellow color before reaction with the auric ion, which changed to a purple color upon completion of the reaction (). Appearance of a burgundy red color in solution containing the biomass was a clear indication of the formation of gold nanoparticles in the reaction mixture and was due to the excitation of surface plasmon vibrations in the nanoparticles [].

(2011) Biosynthesis of Gold Nanoparticles: A Review.

In: Hayat MA (ed) Colloidal gold: principles, methods and application, vol 1.

TABLE 1: BIOLOGICAL AGENTS USED FOR GOLD NANOPARTICLES BIOSYNTHESIS

For particle size analysis of gold nanoparticles, the gold nanoparticle-fungus reaction solution was filtered with Whatman filter paper followed by filtration using 0.2μ filter to remove any spores or mycelia. Filtrate collected was dried, scraped with scalpel, and suspended in ethanol. Particle size was determined using Particle Size Analyzer (MALVERN Instruments) at K. C. Patel R&D center, CHARUSAT, Changa, India.

Biosynthesis of gold nanoparticles using ..

Gold nanoparticles (AuNPs) are a widespread research tool because of their oxidation resistance, biocompatibility and stability. Chemical methods for AuNP synthesis often produce toxic residues that raise environmental concern. On the other hand, the biological synthesis of AuNPs in viable microorganisms and their cell-free extracts is an environmentally friendly and low-cost process. In general, fungi tolerate higher metal concentrations than bacteria and secrete abundant extracellular redox proteins to reduce soluble metal ions to their insoluble form and eventually to nanocrystals. Fungi harbour untapped biological diversity and may provide novel metal reductases for metal detoxification and bioreduction. A thorough understanding of the biosynthetic mechanism of AuNPs in fungi is needed to reduce the time of biosynthesis and to scale up the AuNP production process. In this review, we describe the known mechanisms for AuNP biosynthesis in viable fungi and fungal protein extracts and discuss the most suitable bioreactors for industrial AuNP biosynthesis.

The importantparameter, which controls the size and shape of gold nanoparticles, waspH value.
In this study, the bacteriaRhodopseudomonas capsulata was screened and found to successfullyproduce gold nanoparticles of different sizes and shapes.

Biosynthesis of Gold Nanoparticles: A Review | …

FIG. 4: LIGHT SCATTERING OF CELL LABELED WITH (a–c) GOLD NANOPARTICLES AND (d–f) anti-EGFR COATED GOLD NANOPARTICLES. THE anti-EGFR COATED GOLD NANOPARTICLES BIND SPECIFICALLY TO THE CANCEROUS CELLS, WHILE ALL OTHER GOLD NANOPARTICLES ARE NON-SPECIFICALLY BOUND. (a & d) NONMALIGNANT EPITHELIAL CELL LINE HaCaT (HUMAN KERATINOCYTES), (b & e) MALIGNANT EPITHELIAL CELL LINES HOC 313 CLONE 8 (HUMAN ORAL SQUAMOUS CELL CARCINOMA) (c & f) MALIGNANT EPITHELIAL CELL LINES HSC 3 (HUMAN ORAL SQUAMOUS CELL CARCINOMA)

Biosynthesis of nanoparticles (NPs) using bacteria has emerged ..

Currently, AuNPs biosynthesis process in fungi does not compare favourably with the particle size distribution attainable in advanced physicochemical processes. Transmission electron microscopy-calculated particle size distributions are reported only for a small number of fungal species (Table). The particle size distributions reported in these studies is generally broader (10–40nm) than that observed in physicochemical processes. Furthermore, the particle size distribution depends on the fungal catalyst used, the gold/biomass ratio and other process conditions. As microorganisms produce a variety of proteins that bind to nanoparticles of different sizes (Lundqvist etal., ), genetic and metabolic control of the nanoparticle production in viable fungal biomass is crucial for the reproducibility of the AuNP biosynthesis process.

BIOSYNTHESIS OF GOLD NANOPARTICLES, SCOPE …

Recent studies on extracellular synthesis of AuNPs in fungi suggest that the enzymatic machinery required for their biosynthesis is similar to that used for metal detoxification. Intracellular AuNP biosynthesis is reported to occur when there is a high Au3+ concentration available and when the membrane integrity is compromised to allow for Au3+ ions diffusion within the cell. However, there is no evidence available yet showing that fungi use biosynthetic nanoparticles for their metabolism.