Electrospun composite mats of alginate with embedded silver nanoparticles: synthesis and characterization

In this work, a nanocomposite material based on alginate (Alg) and silver nanoparticles (AgNPs) was prepared by the synthesis “in situ” of the metal cores in the polymer solution through a wet, bottom-up approach. The formation of AgNPs within the alginate matrix (Alg–Ag) was confirmed by spectroscopic and morphological investigation. The nanocomposite material was then employed in combination with poly(ethylene oxide) for the production of crosslinked alginate membranes by electrospinning technique, following a simple and effective protocol optimized to obtain nano- to microscaled fibers. Field emission scanning electron microscopy (FESEM) studies on the composite membranes indicated that AgNPs of slightly increased dimensions are well distributed in the electrospun mats, thus proving that the electrospinning process does not significantly alter the morphology of the metal nanofillers and can be successfully adopted for the fabrication of nanofibers. In view of their potential applications in biomedical fields and food industry as antibacterial material, the nanocomposite mats were tested against thermal and UV sterilization, anti-mold treatment (NaClO) and environmental changes (pH) and their stability was monitored by means of thermogravimetric (TGA) and morphological (FESEM) techniques.