Biomedical Engineering Reference
In-Depth Information
and medicine. Silver nanoparticles show good antimicrobial activity and
therefore can be used for purii cation in water i ltration apparatus [186].
Both gold and silver nanoparticles have been commonly found to have
broad spectrum antimicrobial activity against human and animal patho-
gens [195]. Silver nanoparticles are widely used as antimicrobial agents
in commercial, medical and consumer products [196]. h e interaction of
metallic nanoparticles with biomolecules, microorganisms and viruses is
another expanding i eld of research. It was noticed that silver nanoparticles
undergo a size-dependent interaction with HIV-1. Nanoparticles ranging
in size from 1 to 10 nm readily interact with the HIV-1 virus via pref-
erential binding to gp120 glycoprotein knobs. h is specii c interaction of
silver nanoparticles inhibits the virus from binding to host cells, demon-
strated by
in vitro
study. Hence, silver nanoparticles could i nd application
in preventing as well as controlling HIV infection [197]. Silver nanopar-
ticles are larvicidal against i lariasis and malaria vectors [198], and have
been found to be active against plasmodial pathogens [186] and human
cervical cancer cells [199]. Antifungal ef ects of silver nanoparticles have
also been demonstrated [200]. Silver nanoparticles also i nd application in
topical ointments and creams used to prevent the infection of burns and
open wounds [201]. Another interesting utilization for biosynthesized sil-
ver NPs is immobilization on cotton cloth or cotton i bers. h is approach
demonstrates the possible use of such a cloth for disinfection or steriliza-
tion. Hydrophobic Ag-Au composite nanoparticles show strong adsorp-
tion and good electrical conducting properties and therefore can be used
in enzyme electrode design. Current response of Ag and Au nanoparticles
has been reported to be much higher than that without nanoparticles.
h ese nanoparticles can assist electron transfer between the enzyme and
the bulk electrodes [202]. Gold and silver nanoparticles have also found
application in surface-enhanced Raman spectroscopy (SERS). Palladium
and copper nanoparticles also show antimicrobial activity against
E. coli
[186]. Applications of metal nanoparticles are emerging in crop protection
and agriculture [203].
8.4 Conclusions
In this chapter, the biological synthesis of metal nanoparticles has been
discussed. In general, either a cell-based system (living organisms or inac-
tivated biomass) or a cell-free system (mixtures of biomolecules from the
organisms or metabolic products secreted by the cells) may be used for
the synthesis. Whilst many biosynthesized nanoparticles are identical or
