Nanocomposites and nanomaterials
 
Hydrogel-Silver Nanoparticle Composites and Their Antibacterial Efﬁcacy
Nadtoka O., Virych P., Kutsevol N., Naumenko A., Bezugla T.
Taras Shevchenko National University of Kyiv. Volodymyrska Street, 64/13, Kyiv-01601, Ukraine. 
E-mail: oksananadtoka@ukr.net

Nanometer-size metallic particles show unique and considerably changed physical, chemical and biological properties compared to their macro scaled counterparts, due to their high surface-to-volume ratio. One of the most interesting prospects deals with developing of hydrogel-silver nanoparticle composites which are widely used in various fields related to medicine and biotechnology. The urgent tasks for today is the creation of dressings for the treatment of wounds and burns, special requirements for which are the ability to absorb and hold the liquid, the possibility of drug transport, atraumaticity and antibacterial properties.
We present a simple way of preparing silver nanoparticles under photo irradiation where silver nitrate is the source of silver particles. We have employed a number of chemically cross-linked hydrogels based on copolymers of acrylamide and dextran/dextran sulfate which acts as a reducing agent in the presence of UV-irradiation and also serves as a stabilizing agent of the silver nanoparticles. We varied the molecular weight of dextran component during hydrogel synthesis, the hydrolysis degree of polymer hydrogel, concentrations of AgNO3 as well as irradiation time for reduction of Ag+ into AgNPs.
The kinetics of swelling, UV–vis absorption, surface morphology and FTIR characteristics of hydrogel-silver nanoparticle composites depending on the cross-linking agent concentration and dextran component were studied. All the nanocomposite aqueous solutions have shown absorption peaks at 420 nm in UV–visible absorption spectrum corresponding to the Plasmon absorbance of AgNPs.
In this work we have investigated the antibacterial properties of composites against the gram-negative bacterium Escherichia coli and gram-positive bacterium Staphylococcus aureus. Diffusion method on the Mueller-Hinton agar was used for investigation. Obtained hydrogels loaded with silver nanoparticles show the inhibition of the bacteria growth of both species.
Consequently, the results indicate the possibility of hydrogel-silver nanoparticle composites as an effective agent for prevention the bacterial contamination and treatment of wound and ulcers and can be used for antibacterial and wound dressing applications.