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In this study silver nanoparticles were synthesized by microwave irradiation method using soluble starch as a green capping and reducing agent. The as-prepared soluble starch coated silver nanoparticles (S-Ag NPs) were incorporated in polyvinyl alcohol (PVA) matrix to fabricate nanofibers through electrospinning process. Two different types of crosslinking treatments were used to make the nanofiber mats insoluble in physiological environments. Experimental studies revealed that the choice of the crosslinking treatment led to affect the silver ion release. The nanofiber mats crosslinked with glutaraldehyde have superior silver ion release and stability in simulated body fluid (SBF). The released amounts of silver ions were lower than the toxic level of silver ions for HaCat keratinocytes and human epidermal keratinocytes. After proving antibacterial properties of the glutaraldehyde crosslinked S-Ag NPs loaded PVA nanofiber mats against E. coli and S. aureus it was thought that the nanofibrous mats fabricated in this study can be good candidates as antibacterial scaffolds for wound dressing applications.

Use of cationic pigment-intercalated bentonite (montmorillonite, Mt) as the latent print development powder was investigated. The cationic dyes, crystal violet (CV) and pararosaniline (PS), were substituted with sodium ions present in the interlayers of Mt by ion exchange mechanism. Organophilic montmorillonites (OMts) were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), elemental analysis and Fourier transform infrared spectroscopy (FTIR). TGA results determined the average amount of dye molecules in OMts as 52 mmol/100 g for both PS and CV. Modified bentonite powders were applied to develop fresh and aged (1, 7 and 15 days) fingermarks deposited on non-porous surfaces such as glass, metal and porcelain using a fiberglass brush. Sharp and clear prints with complete ridge details were developed on glass and metal surfaces even for the 15-day-old fingermarks. Surprisingly, CV- and PS-intercalated fingerprint powders successfully worked for the development of the seven-month-old fingerprints on the glass surface. In contrast, physically mixed bentonite and dye mixtures were not very successful in the development of even fresh fingerprints on the glass surface. CV-tagged bentonite also exhibited strong fluorescence at around 500 nm when excited at 450 nm. (C) 2013 Elsevier B.V. All rights reserved.