Preparation and characterization of collagen/silk fibroin composite scaffold incorporating TGF-β1 nanoparticles

Abstract

Objective To construct a double layered collagen/silk fibroin composite scaffold incorporating transforming growth factor-β1 (TGF-β1) nanoparticles. Methods The chitosan-heparin (Ch-Hep) nanoparticles incorporating TGF-β1 were prepared and the morphology, particle size, Zeta potential and encapsulation efficiency of the nanoparticles were observed and detected. Five kinds of collagen/silk fibroin composites that had different mass ratio of collagen to silk fibroin (2∶8, 3∶7, 7∶3, 8∶2, 10∶0) were prepared, and water absorption, porosity, loss rate in hot water and biocompatibility of the composites were determined. Two kinds of the collagen/silk fibroin composites were selected as the dense and loose layers to construct double layer collagen/silk composite scaffold incorporating TGF-β1 nanoparticles, and the morphology and in vitro TGF-β1 release kinetics of the composite scaffold were observed. Results The average particle size, Zeta potential and encapsulation efficiency of Ch-Hep nanoparticles were (718.2±73.6) nm, (25.5±0.8) mV and (84.82±1.57)%, respectively. As the content of collagen in the composite increased, the water absorption and porosity of composites increased gradually, whereas the loss rate in hot water of the composites decreased gradually. All of the collagen/silk fibroin composites could promote the growth and proliferation of bone mesenchymal stem cells (BMSCs). Based on overall evaluation, collagen/silk fibroin composites with mass ratio of 3∶7 and 7∶3 were selected as the dense layer and loose layer of collagen/silk fibroin composite scaffold. The collagen/silk fibroin composite scaffold constructed was made up of two layers with one dense layer and another loose and porous layer. In vitro TGF-β1 release kinetics study showed that the composite scaffold had the ability of controlling spatiotemporal release of TGF-β1. Conclusions The collagen/silk fibroin composite scaffold incorporating TGF-β1 nanoparticles can control the spatiotemporal release of TGF-β1, and thus has the potential for the application in cartilage tissue engineering as the sustained and controlled release scaffold of growth factor. Key words: Collagen; Silk fibroin; Transforming growth factorβ1; Nanoparticles