(348b) Transforming Growth Factor beta1 Releasing Degradable Nanogels for Chondrogenic Differentiation of Human Mesenchymal Stem Cells

Stem cell therapy has a promise for future medical treatment of a number of diseases due to the ability of the stem cell to differentiate with specialized functions and replace the ailing cells [1]. Growth factors are needed for stem cell differentiation. This can be achieved by the use of nano carriers [2]. Our group has been working on a novel polymeric nanogel system having both thermoresponsive and degradable properties [3]. In the current project, transforming growth factor beta1, TGF beta1, was encapsulated into the nanogels with high efficiency by UV photopolymerization at 45 °C using N-isopropyl acrylamide (NIPAAm) and a cross-linkable macromer, 2-hydroxyethylmethacrylate-lactate-dextran. Dynamic light scattering indicated hydrodynamic radii of the nanogels under 55 nm. Preliminary data indicated a slow release of TGF β1 in PBS (pH 7.4) from the nanogels. Fluorescence microscopy confirmed the up take of DTAF-labeled nanogels by the mesenchymal stem cells. The MTT cell viability data showed non-toxic nature of the nanogels for one week. These studies suggested that the current nanogels have potential for releasing growth factors for stem cell differentiation. Studies on optimization of TGF beta1 release kinetics from the nanogels and in vitro chondrogenic differentiation of the mesenchymal stem cells are underway.