Nanosilver and its Medical Implications
The advancement in the field of nanoscience has truly brought revolutionary changes in industrial, medicine, textile, food packaging and agriculture fields [14-18]. We all are very much aware of silver as an antimicrobial agent since time immemorial in the form of metallic silver, silver nitrate, silver sulfadiazine for the treatment of burns, wounds and several bacterial infections [19-24]. After the flooding of a number of antibiotics, usage of silver for the treatment of bacterial infection reduced. Moyer introduced the use of 0.5% silver nitrate for the treatment of burns. He proposed that it possess antibacterial property against Staphylococcus aureus, Pseudomonasareuginosa, and Escherichia coli [25-27]. Silver nanoparticles also act as effective fungicide against common fungi including Aspergillus, Candida and Saccharomyces . The antifungal activity of silver nanoparticle has received less attention, yet some of the studies revealed that silver nanoparticles can be as effective for fungal strains as like that of bacterial strains. Ales Panacek et al.  has examined effect of silver NPs on pathogenic strain of Candida spp. by determining the minimum inhibitory concentration, minimum fungicidal concentration and time dependency of yeast growth inhibition and concluded that silver nanoparticles exhibit high antifungal activity against Candida spp. at the concentration of 1mg/L of Ag. Silver nanoparticles inhibit growth of yeast at very low concentration as compared to those of common antifungal . Virucidal effect of silver nanoparticles is still in closed envelops, however recently the antiviral effect of silver nanoparticles on the hepatitis B virus have been reported using a HepAD38 human hepatoma cell line [ 30]. Although antiviral effect of silver nanoparticle has not been come in attention yet there are some of the evidences given by Humberto H Lara et al. . Sun and colleagues showed that agNPs were superior to gold nanoparticles for cytoprotective activities towards HIV-1-infected helper cells. Nanosilver may interfere with the fusion of the viral membrane, inhibiting viral penetration into the host cell. Silver nanoparticles specifically refer to silver containing material with modified physicochemical properties due to their nanosized scale. Antimicrobial properties of silver nanoparticles are being exploited by many pharmaceutical companies for making antibiotics, used in biomedical applications [31-33]. The use of Silver nanoparticles in the field of medicine could revolutionize the way we detect and treat damage to the human body and disease in the future, and many techniques only imagined a few years ago are making remarkable progress towards becoming realities . Hippocrates, the “father of medicine”, advocated the sprinkling of silver powder on ulcers to expedite healing, and silver has been used since World War I (and continues to be used) in wound dressings. This rapidly developing field of nanoscience has raised the possibility of using therapeutic nanoparticles in the diagnosis and treatment of human cancers .