View source for Physics:Synthesis of nanoparticles by fungi

Throughout human history, fungi have been utilized as a source of food and harnessed to ferment and preserve foods and beverages. In the 20th century, humans have learned to harness fungi to protect human health (antibiotics, anti-cholesterol statins, and immunosuppressive agents), while industry has utilized fungi for large scale production of [[Biology:Enzymes|enzymes]], acids, and biosurfactants.<ref name ="Ref1">{{cite book| title = Microbial enzymes and biotransformations| editor = Barredo JL| chapter = Microbial cells and enzymes| year = 2005| pages = 1–10| publisher = Humana Press| isbn = 978-1-58829-253-7}}</ref> With the advent of modern [[Engineering:Nanotechnology|nanotechnology]] in the 1980s, fungi have remained important by providing a greener alternative to chemically synthesized nanoparticle.<ref name=Ref2>{{cite journal|last=Ghorbani|first=HR|author2=Safekordi AA |author3=Attar H |author4=Rezayat Sorkhabadi SM |title=Biological and non-biological methods for silver nanoparticles synthesis|journal=Chemical and Biochemical Engineering Quarterly|year=2011|volume=25|pages=317–326}}</ref>
== Background ==

[[File:Fungal nanoparticles -conglomerate with smaller nanoparticles.tif|300x300px|thumbnail|right|SEM image of fungal hyphae and  fungal derived [[Physics:Silver nanoparticle|silver nanoparticle]]s showing a large conglomeration made up of individual nanoparticles with fungal hyphae (dark areas) in background.]]
A [[Physics:Nanoparticle|nanoparticle]] is defined as having one dimension 100&nbsp;nm or less in size. Environmentally toxic or biologically hazardous reducing agents are typically involved in the chemical synthesis of nanoparticles<ref name="Ref2" /> so there has been a search for greener production alternatives.<ref name=Ref3>{{cite journal|last=Abou El-Nour|first=MM|author2=Eftaiha A |author3=Al-Warthan A |author4=Ammar RAA |title=Synthesis and application of silver nanoparticles|journal=Arabian Journal of Chemistry|year=2010|volume=3|issue=3|pages=135–140 |doi=10.1016/j.arabjc.2010.04.008|doi-access=free}}</ref><ref name=Ref4>{{cite journal|last=Popescu|first=M|author2=Velea A |author3=Lőrinczi A |title=Biogenic production of nanoparticles|journal=Digest J of Nanomaterials and Biostructures|year=2010|volume=5|pages=1035–1040}}</ref> Current research has shown that microorganisms, plant extracts, and fungi can produce nanoparticles through biological pathways.<ref name="Ref2" /><ref name="Ref3" /><ref name=Ref5>{{cite journal|last=Sastry|first=M|author2=Ahmad A |author3=Khan MI |author4=Kumar R |title=Biosynthesis of metal nanoparticles using fungi and actinomycete|journal=Current Science|year=2003|volume=85|pages=162–170}}</ref> The most common nanoparticles synthesized by fungi are [[Chemistry:Silver|silver]] and [[Chemistry:Gold|gold]], however fungi have been utilized in the synthesis other types of nanoparticles including [[Chemistry:Zinc oxide|zinc oxide]], [[Chemistry:Platinum|platinum]], [[Chemistry:Magnetite|magnetite]], zirconia, silica, titanium, and cadmium sulfide and cadmium selenide quantum dots.

== Silver nanoparticle production ==

Synthesis of silver nanoparticles has been investigated utilizing many ubiquitous fungal species including ''[[Biology:Trichoderma|Trichoderma]]'',<ref name=Ref6>{{cite journal|last=Vahabi|first=K|author2=Mansoori GA |author3=Karimi S |title=Biosynthesis of silver nanoparticles by fungus ''Trichoderma reesei'': a route for large-scale production of AgNPs|journal=Insciences Journal|year=2011|volume=1|pages=65–79|doi=10.5640/insc.010165|doi-access=free}}</ref><ref name=Ref7>{{cite journal|last=Basavaraja|first=S|author2=Balaji SD |author3=Lagashetty A |author4=Rajasab AH |author5=Venkataraman A |title=Extracellular biosynthesis of silver nanoparticles using the fungus ''Fusarium semitectum''|journal=Materials Research Bulletin|year=2008|volume=45|issue=5|pages=1164–1170 |doi=10.1016/j.materresbull.2007.06.020}}</ref> ''[[Biology:Fusarium|Fusarium]]'',<ref name=Ref8>{{cite journal|last=Durán|first=N|author2=Marcato PD |author3=Alves OL |author4=IH de Souza G |author5=Esposito E |title=Mechanistic aspects of biosynthesis of silver nanoparticles by several ''Fusarium oxysporum'' strains|journal=Journal of Nanobiotechnology|year=2005|volume=3|pages=8|pmc=1180851|pmid=16014167|doi=10.1186/1477-3155-3-8|doi-access=free}}</ref> ''[[Biology:Penicillium|Penicillium]]'',<ref name=Ref9>{{cite journal|last=Naveen|first=H|author2=Kumar G |author3=Karthik L |author4=Roa B |title=Extracellular biosynthesis of silver nanoparticles using the filamentous fungus ''Penicillium'' sp|journal=Archives of Applied Science Research|year=2010|volume=2|pages=161–167}}</ref> ''[[Biology:Rhizoctonia|Rhizoctonia]]'',{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}} ''[[Biology:Pleurotus|Pleurotus]]'' and ''[[Biology:Aspergillus|Aspergillus]]''.<ref name=Ref12>{{cite journal|last=Bhainsa|first=KC|author2=D’Sousa SF|title=Extracellular biosynthesis of silver nanoparticles using the fungus ''Aspergillus fumigatas''|journal=Colloids and Surfaces B: Biointerfaces|year=2006|volume=47|issue=2|pages=160–164|doi=10.1016/j.colsurfb.2005.11.026|pmid=16420977}}</ref> Extracellular  synthesis has been demonstrated by ''Trichoderma virde'', ''T. reesei'', ''Fusarium oxysporm'', ''F. semitectum'', ''F. solani'', ''Aspergillus niger'', ''A. flavus'',<ref name="Ref24" /> ''A. fumigatus'', ''A. clavatus'', ''[[Biology:Pleurotus ostreatus|Pleurotus ostreatus]]'', ''Cladosporium cladosporioides'',<ref name="Ref6" /> ''[[Biology:Penicillium brevicompactum|Penicillium brevicompactum]]'', ''P. fellutanum'', an endophytic ''Rhizoctonia'' sp., ''[[Biology:Epicoccum nigrum|Epicoccum nigrum]]'', ''Chrysosporium tropicum'', and ''Phoma glomerata'', while intracellular synthesis was shown to occur in a ''[[Biology:Verticillium|Verticillium]]'' <ref name=Ref13>{{cite journal|last=Mukherjee|first=P|author2=Ahmad A, Mandal D, Senapati S, Sainkar S, Khan M, Parishcha R, Ajaykumar P, Alam M, Kumar R, Sastry M|title=Fungus-mediated synthesis of silver nanoparticles and their immobilization in the mycelial matrix; a novel biological approach to nanoparticle synthesis|journal=Nano Letters|year=2001|volume=1|issue=10|pages=515–519|doi=10.1021/nl0155274|bibcode=2001NanoL...1..515M|last3=Mandal|first3=Deendayal|last4=Senapati|first4=Satyajyoti|last5=Sainkar|first5=Sudhakar R.|last6=Khan|first6=Mohammad I.|last7=Parishcha|first7=Renu|last8=Ajaykumar|first8=P. V.|last9=Alam|first9=Mansoor|last10=Kumar|first10=Rajiv|last11=Sastry|first11=Murali}}</ref>  species, and in ''[[Biology:Neurospora crassa|Neurospora crassa]]''.

== Gold nanoparticle production ==

Synthesis of gold nanoparticles has been investigated utilizing ''Fusarium'',<ref name=Ref14>{{cite journal|last=Mukherjee|first=P|author2=Senapati S |author3=Mandal D |author4=Ahmad A |author5=Khan M |author6=Kumar R |author7=Sastry M |title=Extracellular synthesis of gold nanoparticles by the fungus ''Fusarium oxysporum''|journal=ChemBioChem|year=2002|volume=3|issue=5|pages=461–463|doi=10.1002/1439-7633(20020503)3:5<461::AID-CBIC461>3.0.CO;2-X|pmid=12007181|s2cid=34520744}}</ref>  ''Neurospora'',<ref name=Ref15>{{cite journal|last=Castro-Longoria|first=E|author2=Vilchis-Nestor A,and Avales-Borja M|title=Biosynthesis of silver, gold, and bimetallic nanoparticles using the filamentous fungus ''Neurospora crassa''|journal=Colloids and Surface B:Biointerfaces|year=2011|volume=83|pages=42–48|doi=10.1016/j.colsurfb.2010.10.035|pmid=21087843|last3=Avalos-Borja|first3=M.|issue=1}}</ref> ''[[Biology:Verticillium|Verticillium]]'', yeasts,<ref name=Ref16>{{cite journal|last=Agnihotri|first=M|author2=Joshi S |author3=Kumar A |author4=Zinjarde S |author5=Kulkarni S |title=Biosynthesis of gold nanoparticles by the tropical marine yeast ''Yarrowia lipolytica'' NCIM 3589|journal=Materials Letters|year=2009|volume=63|issue=15|pages=1231–1234|doi=10.1016/j.matlet.2009.02.042}}</ref><ref name=Ref17>{{cite journal|last=Chauhan|first=A|author2=Zubair S |author3=Tufail S |author4=Sherwani A |author5=Sajid M |author6=Raman S |author7=Azam A |author8=Owais M |title=Fungus-mediated biological synthesis of gold nanoparticles: potential in detection of liver cancer|journal=International Journal of Nanomedicine|year=2011|volume=6|pages=2305–2319|doi=10.2147/ijn.s23195|pmid=22072868|pmc=3205127|doi-access=free}}</ref> and ''Aspergillus''. Extracellular gold nanoparticle synthesis was demonstrated by ''Fusarium oxysporum'', ''Aspergillus niger'', and cytosolic extracts from ''[[Biology:Candida (fungus)|Candida]] albican''. Intracellular gold nanoparticle synthesis has been demonstrated by a ''Verticillum'' species, ''V. luteoalbum'',<ref name=Ref18>{{cite journal|last=Gericke|first=M|author2=Pinches A|title=Biological synthesis of metal nanoparticles|journal=Hydrometallurgy|year=2006|volume=83|issue=1–4|pages=132–140|doi=10.1016/j.hydromet.2006.03.019|bibcode=2006HydMe..83..132G}}</ref>

== Miscellaneous nanoparticle production ==

In addition to gold and silver, ''Fusarium oxysporum'' has been used to synthesize zirconia, titanium, cadmium sulfide and cadmium selenide nanosize particles. Cadmium sulfide nanoparticles have also been synthesized by ''[[Biology:Trametes versicolor|Trametes versicolor]]'', ''[[Biology:Schizosaccharomyces pombe|Schizosaccharomyces pombe]]'', and ''Candida glabrata''.<ref name=Ref20>{{cite journal|last=Li|first=X|author2=Xu H |author3=Chen Z |author4=Chen G |title=Biosynthesis of nanoparticles by microorganisms and their applications|journal=Journal of Nanomaterials|volume=2011|pages=1–16|year=2011|doi=10.1155/2011/270974|doi-access=free}}</ref> The white-rot fungus ''Phanerochaete chrysosporium'' has also been demonstrated to be able to synthesize elemental selenium nanoparticles.<ref name=Ref25>{{cite journal|last=Espinosa-Ortiz|first=EJ|author2=Gonzalez-Gil G |author3=Saikaly PE |author4=van Hullebusch ED |author5=Lens PNL |title=Effects of selenium oxyanions on the white-rot fungus ''Phanerochaete chrysosporium''|journal=Appl Microbiol Biotechnol|year=2014 | doi=10.1007/s00253-014-6127-3 |volume=99 |issue=5|pages=2405–2418|pmid=25341399 |s2cid=253768254 }}</ref>

== Culture techniques and conditions ==

Culture techniques and media vary depending upon the requirements of the fungal isolate involved, however the general procedure consist of the following: fungal hyphae are typically placed in liquid growth media and placed in shake culture until the fungal culture has increased in biomass. The fungal hyphae are removed from the growth media, washed with distilled water to remove the growth media, placed in distilled water and incubated on shake culture for 24 to 48 hours. The fungal hyphae are separated from the supernatant, and an aliquot of the supernatant is added to 1.0 mM ion solution. The ion solution is then monitored for 2 to 3 days for the formation of nanoparticles. Another common culture technique is to add washed fungal hyphae directly into 1.0 mM ion solution instead of utilizing the fungal filtrate. [[Chemistry:Silver nitrate|Silver nitrate]] is the most widely used source of silver ions, but [[Chemistry:Silver sulfate|silver sulfate]] has also been utilized.{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}} Choloroauric acid is generally used as the source of gold ions at various concentrations (1.0 mM<ref name=Ref14 /> and 250&nbsp;mg to 500&nbsp;mg<ref name=Ref18 /> of Au per liter). [[Chemistry:Cadmium sulfide|Cadmium sulfide]] nanoparticle synthesis for ''F. oxysporum'' was conducted using a 1:1 ratio of Cd<sup>2+</sup> and SO<sub>4</sub><sup>2−</sup> at a 1 mM concentration.<ref name=Ref21>{{cite journal|last=Ahmad|first=A|author2=Mukherjee P |author3=Mandal D |author4=Senapati S |author5=Khan M |author6=Kumar R |author7=Sastry M |title=Enzyme mediated extracellular synthesis of CdS nanoparticles by the fungus, ''Fusarium oxysporum''|journal=Journal of the American Chemical Society|year=2002|volume=124|issue=41|pages=12108–12109 |doi=10.1021/ja027296o|pmid=12371846}}</ref> Gold nanoparticles can vary in shape and size depending on the [[Chemistry:PH|pH]] of the ion solution.<ref name=Ref18 /> Gericke and Pinches (2006) reported that for ''V. luteoalbum'' small (cc.10&nbsp;nm) spherical gold nanoparticles are formed at pH 3, larger (spherical, triangular, hexagon and rods) gold nanoparticles are formed at pH 5, and at pH 7 to pH 9 the large nanoparticles tend to lack a defined shape. Temperature interactions for both silver and gold nanoparticles were similar; a lower temperature resulted in larger nanoparticles while higher temperatures produced smaller nanoparticles.<ref name=Ref18 />

== Analytical techniques ==

=== Visual observations ===

For externally synthesized silver nanoparticles the silver ion solution generally becomes brownish in color,<ref name=Ref7 /><ref name=Ref8 /><ref name=Ref9 /> but this browning reaction may be absent.{{Citation needed|date=December 2019|reason=removed citation to predatory publisher content}}  For fungi that synthesize intracellular silver nanoparticles, the hyphae darken to a brownish color while the solution remains clear. In both cases the browning reaction is attributed to the surface plasmon resonance of the metallic nanoparticles.<ref name=Ref6 /><ref name=Ref23>{{cite journal|last=Shankar|first=S|author2=Ahmad A |author3=Sastry M |title=Geranium leaf assisted biosynthesis of silver nanoparticles|journal=Biotechnol. Prog.|year=2003|volume=19|issue=6|pages=1627–1631|doi=10.1021/bp034070w|pmid=14656132|s2cid=10120705}}</ref> For external gold nanoparticle production, the solution color can vary depending on the size of the gold nanoparticles; smaller particles appear pink while large particles appear purple. Intracellular gold nanoparticle synthesis typically turns the hyphae purple while the solution remains clear. Externally synthesized cadmium sulfide nanoparticles were reported to make the solution color appear bright yellow.<ref name=Ref21 />

=== Analytical tools ===

Scanning electron microscopy ([[Physics:Scanning electron microscope|SEM]]), transmission electron microscopy ([[Engineering:Transmission electron microscopy|TEM]]), energy dispersive analysis of X-ray ([[Physics:Energy-dispersive X-ray spectroscopy|EDX]]), UV-vis spectroscopy, and X-ray diffraction are used to characterize different aspects of nanoparticles. Both SEM and TEM can be used to visualize the location, size, and morphology of the nanoparticles, while UV-vis spectroscopy can be used to confirm the metallic nature, size and aggregation level. Energy dispersive analysis of X-ray is used to determine elemental composition, and X-ray diffraction is used to determine chemical composition and crystallographic structure. UV-Vis absorption peaks for silver, gold, and cadmium sulfide nanoparticles can vary depending on particle size: 25-50&nbsp;nm silver particles peak ca. 415&nbsp;nm, gold nanoparticles 30-40&nbsp;nm peak ca. 450&nbsp;nm, while a cadmium sulfide absorption edge ca. 450 is indicative of quantum size particles.<ref name=Ref21 /> Larger nanoparticle of each type will have UV-Vis absorption peaks or edges that shift to longer wavelengths while smaller nanoparticles will have UV-Vis absorption peaks or edges that shift to shorter wavelengths.

== Formation mechanisms ==

=== Gold and silver ===

[[File:SEM image of fungal derived silvernanoparticles.tif|300x300px|thumbnail|right|SEM image of fungal derived silver nanoparticles stabilized by a capping agent.]]
Nitrate reductase was suggested to initiate nanoparticle formation by many fungi including ''Penicillium'' species, while several enzymes, α-NADPH-dependent reductases, nitrate-dependent reductases and an extracellular shuttle quinone, were implicated in silver nanoparticle synthesis for ''Fusarium oxysporum''. Jain et al. (2011) indicated that silver nanoparticle synthesis for ''A. flavus'' occurs initially by a "33kDa" protein followed by a protein (cystein and free amine groups) electrostatic attraction which stabilizes the nanoparticle by forming a capping agent.<ref name=Ref24>{{cite journal|last=Jain|first=N|author2=Jain, N., Bhargava A, Majumdar S, Tarafdar J, Panwar J|title=Extracellular biosynthesis and characterization of silver nanoparticles using ''Aspergillus flavus'' NJP08: a mechanism perspective|journal=Nanoscale|year=2011|volume=3|issue=2|pages=635–641|doi=10.1039/c0nr00656d|pmid=21088776|bibcode=2011Nanos...3..635J|last3=Majumdar|first3=Sonali|last4=Tarafdar|first4=J. C.|last5=Panwar|first5=Jitendra}}</ref> Intracellular silver and gold nanoparticle synthesis is not fully understood but similar fungal cell wall surface electrostatic attraction, reduction, and accumulation has been proposed.<ref name=Ref21 /> External gold nanoparticle synthesis by ''P. chrysosporium'' was attributed to [[Biology:Laccase|laccase]], while intracellular gold nanoparticle synthesis was attributed to ligninase.<ref name=Ref21 />

=== Cadmium sulfide ===

Cadmium sulfide nanoparticle synthesis by yeast involves sequestration of Cd<sup>2+</sup> by glutathione-related peptides followed by reduction within the cell. Ahmad et al. (2002) reported that cadmium sulfide nanoparticle synthesis by ''Fusarium oxysporum'' was based on a sulfate reductase (enzyme) process.

== References ==

{{Reflist}}

[[Category:Nanoparticles]]

{{Sourceattribution|Synthesis of nanoparticles by fungi}}