Physico-Chemical Condition Optimization during Biosynthesis lead to development of Improved and Catalytically Efficient Gold Nano Particles

Abstract

Biosynthesis of nanoparticles has gained great attention in making the process cost-effective and eco-friendly, but there are limited reports which describe the interdependency of physical parameters for tailoring the dimension and geometry of nanoparticles during biological synthesis. In the present study, gold nanoparticles (GNPs) of various shapes and sizes were obtained by modulating different physical parameters using Trichoderma viride filtrate. The particles were characterized on the basis of visual observation, dynamic light scattering, UV-visible spectroscopy, transmission electron microscopy, fourier transform infrared spectroscopy, and X ray diffraction. While the size varied from 2–500 nm, the shapes obtained were nanospheres, nanotriangles, nanopentagons, nanohexagons, and nanosheets. Changing the parameters such as pH, temperature, time, substrate, and culture filtrate concentration influenced the size and geometry of nanoparticles. Catalytic activity of the biosynthesized GNP was evaluated by UV-visible spectroscopy and confirmed by gas chromatography-mass spectrometric analysis for the conversion of 4-nitrophenol into 4-aminophenol which was strongly influenced by their structure and dimension. Common practices for biodegradation are traditional, expensive, require large amount of raw material, and time taking. Controlling shapes and sizes of nanoparticles could revolutionize the process of biodegradation that can remove all the hurdles in current scenario.

Biosynthesis of gold nanoparticles by the extreme bacterium <em>Deinococcus radiodurans</em> and an evaluation of their antibacterial properties

“…It was also observed that the characteristic absorption of AuNPs was blue shifted when pH was increased (7-8.5), which was attributed to a decrease in particle size with the change in pH. 50 Figure 5D shows the effects of temperature (25°C, 32°C and 37°C) on the formation of AuNPs by D. radiodurans. Relatively high AuNPs production was demonstrated at 32°C, which approached the optimum growth temperature for D. radiodurans.…”

“…35,44,50,51 As shown in Figure 5, different concentrations of Au(III) aqueous solution, pH, bacterial growth period and reaction temperatures had a marked effect on the formation of AuNPs. The relative intensity of absorption increased with an increase of initial concentration of gold ions or bacterial density ( Figure 5A and B), indicating that the production of AuNPs was higher in the presence of enhanced supplement of metal ion substrate or bacterial cells.…”

Green synthesis of silver nanoparticles using cauliflower waste and their multifaceted applications in photocatalytic degradation of methylene blue dye and Hg2+ biosensing

“…These peaks also exhibited evident broadening thereby, suggesting an increase in nanoparticle size. Higher concentration of CLW extract provides more reducing agents that might abruptly accelerate the process of nucleation and affect the growth of nanoparticles [43]. Based on these results, 3 mL CLW extract was considered optimum for producing desired AgNPs.…”

Effect of Reaction Time and Stability Properties of Gold Nanoparticles Synthesized by <i>p</i>-Aminobenzoic Acid and <i>p</i>-Aminosalicylic Acid

“…Another factor that is very important in the synthesis of gold nanoparticles using p-aminobenzoic acid and p-aminosalicylic acid is reaction time. Kumari et al demonstrated in their study the evolution of the morphology of gold nanoparticles from nanospheres to triangular nanoprisms with an increase in time in T. asperellum [19]. The difference in reaction time using the same method could induce different sizes of gold nanoparticles that could be synthesized.…”