Biogenic synthesis of nanoparticles: A review

https://digitalcommons.fiu.edu/cgi/viewcontent.cgi?article=1181&context=cas_bio

Screening of cyanobacteria and microalgae for their ability to synthesize silver nanoparticles with antibacterial activity.

The green synthesis (GS) of different metallic nanoparticles (MNPs) has re-evaluated plants, animals and microorganisms for their natural potential to reduce metallic ions into neutral atoms at no expense of toxic and hazardous chemicals. Contrary to chemically synthesized MNPs, GS offers advantages of enhanced biocompatibility and thus has better scope for biomedical applications. Plant, animals and microorganisms belonging to lower and higher taxonomic groups have been experimented for GS of MNPs, such as gold (Au), silver (Ag), copper oxide (CuO), zinc oxide (ZnO), iron (Fe2O3), palladium (Pd), platinum (Pt), nickel oxide (NiO) and magnesium oxide (MgO). Among the different plant groups used for GS, angiosperms and algae have been explored the most with great success. GS with animal-derived biomaterials, such as chitin, silk (sericin, fibroin and spider silk) or cell extract of invertebrates have also been reported. Gram positive and gram negative bacteria, different fungal species and virus particles have also shown their abilities in the reduction of metal ions. However, not a thumb rule, most of the reducing agents sourced from living world also act as capping agents and render MNPs less toxic or more biocompatible. The most unexplored area so far in GS is the mechanism studies for different natural reducing agents expect for few of them, such as tea and neem plants. This review encompasses the recent advances in the GS of MNPs using plants, animals and microorganisms and analyzes the key points and further discusses the pros and cons of GS in respect of chemical synthesis.

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Biological synthesis of metallic nanoparticles: plants, animals and microbial aspects

Nanoparticle synthesis using microorganisms and plants by green synthesis technology is biologically safe, cost-effective, and environment-friendly. Plants and microorganisms have established the power to devour and accumulate inorganic metal ions from their neighboring niche. The biological entities are known to synthesize nanoparticles both extra and intracellularly. The capability of a living system to utilize its intrinsic organic chemistry processes in remodeling inorganic metal ions into nanoparticles has opened up an undiscovered area of biochemical analysis. Nanotechnology in conjunction with biology gives rise to an advanced area of nanobiotechnology that involves living entities of both prokaryotic and eukaryotic origin, such as algae, cyanobacteria, actinomycetes, bacteria, viruses, yeasts, fungi, and plants. Every biological system varies in its capabilities to supply metallic nanoparticles. However, not all biological organisms can produce nanoparticles due to their enzymatic activities and intrinsic metabolic processes. Therefore, biological entities or their extracts are used for the green synthesis of metallic nanoparticles through bio-reduction of metallic particles leading to the synthesis of nanoparticles. These biosynthesized metallic nanoparticles have a range of unlimited pharmaceutical applications including delivery of drugs or genes, detection of pathogens or proteins, and tissue engineering. The effective delivery of drugs and tissue engineering through the use of nanotechnology exhibited vital contributions in translational research related to the pharmaceutical products and their applications. Collectively, this review covers the green synthesis of nanoparticles by using various biological systems as well as their applications.

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Green Synthesis of Metallic Nanoparticles and Their Potential Applications to Treat Cancer.

Algae-based metallic nanoparticles: Synthesis, characterization and applications.

The cyanobacteria Phormidium valderianum, P. tenue and Microcoleus chthonoplastes and the green algae Rhizoclonium fontinale, Ulva intestinalis, Chara zeylanica and Pithophora oedogoniana were exposed to hydrogen tetrachloroaurate solution and were screened for their suitability for producing nano‐gold. All three cyanobacteria genera and two of the green algae (Rhizoclonium fontinale and Ulva intestinalis) produced gold nanoparticles intracellularly, confirmed by purple colouration of the thallus within 72 h of treatment at 20°C. Extracted nanoparticle solutions were examined by UV‐vis spectroscopy, transmission electron microscopy (TEM) and X‐ray diffractometry (XRD). XRD confirmed the reduction of Au (III) to Au (0). UV‐vis spectroscopy and TEM studies indicated the production of nanoparticles having different shapes and sizes. Phormidium valderianum synthesized mostly spherical nanoparticles, along with hexagonal and triangular nanoparticles, at basic and neutral pHs (pH 9 and pH 7, respectively). Medi...

Screening of different algae for green synthesis of gold nanoparticles

Intracellular bioconversion of auric ion (Au3+) to gold nanorod (Au0) by the cyanobacterium Nostoc ellipsosporum has been observed for the first time in laboratory condition. The nanorods were produced within the cell after exposing the healthy growing filaments to 15 mg L−1 gold (III) solution (pH 4.5) for 48 h at 20°C. The gold nanoparticles were extracted with sodium citrate solution and were subjected to UV–Visible spectroscopy. The characteristic surface-multiple plasmon bands at 560, 610, and 670 nm were observed. The nature and size of the particles were determined by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), and zeta potential studies. The nanorod size ranged from 137 to 209 nm in length and 33 to 69 nm in diameter. DLS study revealed the average hydrodynamic size as 435 nm and XRD study indicated the reduction of Au3+ to Au0. Methods of extraction and preservation of gold nanorod particles have also been studied.

Gold nanorod production by cyanobacteria—a green chemistry approach

In search for a suitable algal bioreagent for monodisperse (homogenous mixture of same size and shape) gold nanoparticle production, a eukaryotic green alga Rhizoclonium fontinale was found to produce spherical (~16 nm size) nanoparticles, when exposed to 15 mg L−1 auric chloride solution at pH 9 for 72 h. In this connection, the effects of different concentrations of gold ions, amount of biomass, and pH of the exposure medium on nanoparticle synthesis were evaluated. Upregulation of stress-related compounds like, carotenoids and stress enzymes—catalase, ascorbate peroxidase, and super oxide dismutase of gold-exposed biomass, were recorded up to 24 h at the onset of gold nanoparticles synthesis, afterwards enzyme activity ceased but the nanoparticle production continued up to 72 h of exposure. Cell wall thickening, rapid akinete formation, pigment loss, giant cell formation, pyknosis, and purple coloration of the filaments during algae–gold interaction were also evident. The nanoparticles were characterized by UV–Vis spectroscopy, dynamic light scattering, high-resolution transmission electron microscopy, and energy dispersive X-ray spectroscopy. Environmental scanning electron microscopy indicated cell wall distortion of the filaments in Au3+ exposure as well as only intracellular production of gold nanoparticles by Rhizoclonium as no nanoparticles were found on the surface.

Biosynthesis of monodisperse gold nanoparticles by green alga Rhizoclonium and associated biochemical changes

Two cyanobacteria Lyngbya majuscula and Spirulina subsalsa were used as bioreagent for the green synthesis of gold nanoparticles. Within 72 h of incubation at 15 mg L-1 Au3+ solution, the cyanobacterial biomass turned purple indicating intracellular reduction of Au3+ to Au0 and subsequent formation of gold nanoparticles. Gold nanoparticles were extracted from the gold-loaded biomass using 7.5 mM sodium citrate solution and characterization was done by UVvisible spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). While Spirulina showed synthesis of spherical nanoparticles of 5 nm -30 nm diameter along with very few nanorods, Lyngbya showed presence of spherical and hexagonal nanoparticles of 2 nm -25 nm diameters. XRD study confirmed the reduction of Au3+ to Au0. FTIR analysis indicated the presence of protein shells around the gold nanoparticles.

http://www.theglobaljournals.com/ijar/file.php?val=January_2014_1389605208_9c452_22.pdf

Green Synthesis of Gold Nanoparticles Using Cyanobacteria and their Characterization

Bioreduction of Au3+ to Au0 and subsequent synthesis of gold nanoparticles using three cyanobacterial strains Leptolyngbya tenuis, Coleofasciculus chthonoplastes, and Nostoc ellipsosporum was investigated. The optimized condition for maximum gold nanoparticle synthesis was determined as 20 mg cyanobacterial biomass per 100 mL of 15 mg L−1 Au3+ solution as inoculum size at pH 5. At the onset of nanoparticle synthesis (up to 3 h) increased activity of catalase, ascorbate peroxidase, super oxide dismutase, and malondialdehyde content along with rapid loss of pigments and protein content (1–72 h) indicated gold toxicity at cellular level. Associated changes in thallus morphology were also significant. Nostoc biomass produced spherical- to irregular-shaped nanoparticles with diverse sizes and small number of nanorods. On the other hand, Coleofasciculus showed nanoparticle synthesis at extracellular medium which was either absent in Nostoc or very low in Leptolyngbya. Biosafety analysis by MTT assay using peripheral blood mononuclear cells (PBMC), two cancer cell lines viz. T cell acute (T-ALL) and human acute lymphoblastic leukemia (MOLT-4) and antibacterial effect against Pseudomonas aeruginosa and Staphylococcus aureus showed no toxic effect of synthesized gold nanoparticles.

Dipannita Parial

Papers

Screening of different algae for green synthesis of gold nanoparticles

Gold nanorod production by cyanobacteria—a green chemistry approach

Biosynthesis of monodisperse gold nanoparticles by green alga Rhizoclonium and associated biochemical changes

Green Synthesis of Gold Nanoparticles Using Cyanobacteria and their Characterization

Gold (III) bioreduction by cyanobacteria with special reference to in vitro biosafety assay of gold nanoparticles