Surface changes of polymer modified by gold nanoparticles

Abstract

A limitation of polymers is that the materials lack active sites or substances that can promote cell adhesion, proliferation and tissue recovery. Biopolymers with functional groups or synthesised polymers modified with different methods show many potential applications. The way to create nanostructured surfaces with new functionalities is grafting of the nanoparticles to polymer surfaces. The different uptake behaviours for surface modified nanoparticles can be explained by different charges on the nanoparticles and on the cell membrane. In this work surface changes of the biopolymers substrate modified by gold nanoparticles were studied. Biopolymer foil of polyhydroxybutyrate with 8% polyhydroxyvalerate was treated by plasma and the activated surface was subsequently modified by gold nanoparticles. Modified substrates were analysed by different methods. The elemental composition and the structure of modified polyhydroxybutyrate with 8% polyhydroxyvalerate were studied by X-ray photoelectron spectroscopy (XPS). Surface morphology was determined using atomic force microscopy (AFM). Changes in the surface wettability were determined from the contact angle by goniometry. Cytocompatibility of the pristine and modified samples was assessed in vitro by determining degree of adhesion and proliferation of mouse fibroblasts. It was found that the plasma treatment and subsequent modification with gold nanoparticles leads to dramatic changes in surface morphology, roughness and wettability. Rate of changes of these features strongly depends on the modification parameters. Plasma treatment and subsequent grafting of nanoparticles significantly affects the adhesion and proliferation of cells on the surface of polymer. Biological experiments indicated favourable effect of the presence of the AuNS grafted from the citrate-stabilised AuNS solution on the cells' adhesion, proliferation and viability.