The biocompatibility and antibacterial properties of collagen-stabilized, photochemically prepared silver nanoparticles

Abstract

Spherical 3.5 nm diameter silver nanoparticles (AgNP) stabilized in type I collagen (. AgNP@collagen) were prepared in minutes (5-15 min) at room temperature by a photochemical method initiated by UVA irradiation of a water-soluble non-toxic benzoin. This biocomposite was examined to evaluate its biocompatibility and its anti-bacterial properties and showed remarkable properties. Thus, while keratinocytes and fibroblasts were not affected by . AgNP@collagen, it was bactericidal against . Bacillus megaterium and . E. coli but only bacteriostatic against . S. . epidermidis. In particular, the bactericidal properties displayed by . AgNP@collagen were proven to be due to AgNP in . AgNP@collagen, rather than to released silver ions, since equimolar concentrations of Ag are about four times less active than . AgNP@collagen based on total Ag content. This new biocomposite was stable over a remarkable range of NaCl, phosphate, and 2-(N-morpholino)ethanesulfonic acid concentrations and for over one month at 4 °C. Circular dichroism studies show that the conformation of collagen in . AgNP@collagen remains intact. Finally, we have compared the properties of . AgNP@collagen with a similar biocomposite prepared using α-poly-. l-Lysine and also with citrate stabilized AgNP; neither of these materials showed comparable biocompatibility, stability, or anti-bacterial activity. © 2012 Elsevier Ltd.