Toxic metal remediation was done by some of the microorganisms through reduction of metal ions and this was considered an interesting research in nanofactories. The current nanotechnological study confirms that aqueous silver nitrate ions may be reduced extracellularly using Aspergillus fumigatus to generate extremely stable silver nanoparticles in water and these particles can be incorporated in materials and cloth, making them sterile. A new generation of dressing incorporating antimicrobial agents like silver was developed to reduce or prevent infections. Extracellular production of A. fumigatus strain and its bactericidal effect in cloth against Staphylococcus aureus were studied in this work. In the silver reduction, approximately 10 g of A. fumigatus biomass was taken in a conical flask containing 100 mL of distilled water, kept for 72 h at 28 ^oC and then the aqueous solution components were separated by filtration. To this, AgNo₃ (10^_3 M) was added and kept for several hours at 28 ^oC, then it was centrifuged and dried to access antibacterial activity when silver nanoparticles were incorporated in cotton cloth. Silver nanoparticles synthesized by A. fumigatus strain incorporated in cotton cloth exhibited antimicrobial activity against Staphylococcus aureus.

An important area of research in nanotechnology deals with the synthesis of nanoparticles of different chemical compositions, size and controlled monodispersity. There is an enormous interest in the synthesis of nanoparticles due to their unusual optical (Krowlikowskaet al., 2003), chemical (Kumar et al., 2003), photoelectrochemical (Chandrasekaran and Kamat, 2000) and electronic (Peto et al., 2002) properties, which is still challenging in material sciences. It is gaining importance in areas such as catalysis, optics, biomedical sciences, mechanics, magnetics and energy sciences.

The use of fungi in the synthesis of nanoparticles is a relatively recent addition to the list of microorganisms. The use of fungi is potentially exciting since they secrete large amounts of enzymes and are simpler to deal within the laboratory. However, genetic manipulation of eukaryotic organisms as a means of over expressing specific enzymes identified in nanomaterial synthesis would be much more difficult than that in prokaryotes (Mandal et al., 2005). The microorganisms such as bacteria and fungi play an important role in remediation of toxic metals through reduction of the metal ions, this was regarded as nanofactories very recently (Fortin and Beverdige, 1995). Using this dissimilatory property of fungi, the biosynthesis of inorganic nanoparticles of gold (Mukherjee et al., 2001a) and silver (Mukherjee et al., 2001b) intracellularly in Verticillium fungal cells (Sastry et al., 2003) was performed and confirmed. Recently, it was found that aqueous chloroaurate ions may be reduced extracellularly using the fungus Fusarium oxysporum to generate extremely stable gold and silver nanoparticles in water (Ahmad et al., 2003; and Duran et al., 2005).

Biotechnology Journal, Antibacterial Activities, Silver Nanoparticles, Aspergillus Fumigatus, Toxic Metal Remediation, Nanotechnological Study, Aspergillus Fumigatus, Staphylococcus Aureus, Nanotechnology, Photoelectrochemical, Biomedical Sciences, Fusarium Oxysporum, Biomedical Applications, Antibiotic Resistance, Carboxylic Acid, Antimicrobial Activities, Thioglycolic Acid.