Release of Silver Nanoparticles Synthetized by Green Chemistry and Encapsulated in Alginate Beads

A. Guerrero-Guzmán, I. Cruz-Soto, T. Rodríguez, J.M. Hugo, G. Velázquez-Juárez, D.R. Sánchez-Chiprés, A. Zamudio-Ojeda
Universidad de Guadalajara,
Mexico

Keywords: alginate, Ag Nps, beads

Summary:

In the last years, the silver nanoparticles (Ag NPs) have been studied and used with different purposes but, the most important application is in the medical area because their anticancer properties with a significant decrement in the cellular proliferation by the NPs, but the most relevant characteristic of them is their inhibitory and antibacterial activity against many microorganism [1]. In this research, we proposed the use of Ag NPs because, the resistance against created of the bacteria against the antibiotics commonly use for the past of the years and, they didn´t developed any mechanism against those NPs, for other side, the encapsulation in alginate beads can release the Ag NPs at specific sites because, the bacteria are not always harmful to the human body [2]. The choice of this biopolymer it´s because it has low degree of toxicity and side effects, as well as its adaptability at different pH making it compatible with any environment used, besides their chains blocks can be intercrossing using different concentration of divalent ions like Barium or Calcium for control the stability and the speed injection for the alginate solution for size of the beads [3]. The main characteristics acquired of the beads are soft, firm, hyaline and biodegradable. In order to destabilize the spheres and control the time of the release it has to be necessary to use a chelator agent such as ethylenediaminetetraacetic acid (EDTA). The Ag NPs were synthesized by green chemistry, because the natural extracts are not toxic for the tissues, for the other hand, the use of natural herbs have great benefit for their antioxidant effect in the alive cells at the body in this case, were selected two native plants: Cymbopogon citratus (Cc) and Hypericum perforatum (Hp). Each sample of the extracts were evaluated for their antioxidant effect by DPPH test, the presence of the Ag NPs in the solutions and their release by spectroscopy UV-vis showing peaks of maximum absorbance in 418 (Hp) and 433 (Cc) nm (fig.1a and b), the characterization of the beads was with Scanning and transmission electron microscopy (SEM and TEM) (fig.2) and with optical microscopy for the size of alginate beads. For their antimicrobial functions were exanimated in two strains of bacteria one gram- positive (Streptococcus aureus) and another gram- negative (Pseudomona spp) [4].