Graphene-based poly(vinyl alcohol)/chitosan hydrogels with electrochemically synthesized silver nanoparticles for medical applications – A review

Abstract

Silver nanoparticles (AgNPs) have become an interesting alternative to antibiotics for potential applications in biomedicine, since nanocrystalline silver is proved to be highly efficient antimicrobial agent with a wide inhibiting spectrum against many types of microorganisms. AgNPs embedded in hydrogel matrices are attractive for biomedical applications due to the possibility for their controlled release resulting in enhanced antimicrobial activity. Thus, combination of AgNPs with biocompatible hydrogels, poly(vinyl alcohol) (PVA) and chitosan (CHI), provides potential for design of improved medical treatments and devices (antimicrobial wound dressings, soft tissue implants). Graphene (Gr) has exceptional mechanical properties and has therefore been applied as adequate reinforcing component for polymer-based composite materials. The synthesis of AgNPs is always subject to innovation and improvements, as it is desirable to minimize the use of chemical agents with the aim of improving the biocompatibility of the obtained material. With this in mind, a green alternative to traditional chemical synthesis methods would be the electrochemical reduction of silver ions, especially as this method provides the option of direct in situ synthesis of AgNPs inside the polymer matrix. In this paper, we provide an overview of the state of the art regarding graphene-reinforced polymer matrices with electrochemically synthesized silver nanoparticles for medical application. We show that the electrochemical method of AgNPs synthesis in PVA/CHI hydrogel matrices has emerged as an excellent method to obtain nanoparticles, and that the incorporation of graphene improved the hydrogels` mechanical properties and elasticity.