Immobilization of Gold and Silver on a Biocompatible Porous Silicone Matrix to Obtain Hybrid Nanostructures

Abstract

During the last decade an enormous research effort has been deployed with respect to porous materials. Design, pore size, shape, morphology and density are crucial features for increasing the surface area of silicone materials, aiming for a better biological response so cells can adhere and grow. Many medical applications utilize polydimethylsiloxane (PDMS) in medical implants, despite its hydrophobic surface that does not stimulate cellular adhesion. Porosity and morphology are important factors in the wettability of PDMS, but modifying the hydrophobic surface functionalization is required. To achieve this goal, the use of coatings with gold and silver nanoparticles or nanofilms can be used as a strategy to improve biocompatibility. This is due to the effect on mammalian cell adhesion and proliferation related to gold nanoparticles, as well as the prevention of infections related to silver nanoparticles. In this study, the pores in the silicone matrix were formed using sugar crystals as a template agent, and later passed through a lixiviation process to form a porous silicon matrix. Next, the matrix was placed inside a colloidal suspension; a process that allowed the immobilization of these particles on the surface matrix. A hybrid stable material was synthetized through this process. The water absorption level of the porous silicone matrix with and without the nanoparticles was determined. The water uptake of the matrix was higher when the nanoparticles were immobilized on the surface. Van der Waals and hydrogen bonding interactions account for this, promoting the retention of a higher concentration of water molecules. Higher water uptake has been identified as being a key factor for improving biological response, cellular adhesion and growth, which accelerates implant integration in the body.