Gelatin-based Solid Foams as Scaffolds for Tissue Engineering

Hydrogels based on biopolymers are interesting materials for tissue engineering due to the inherent biodegradability and biocompatibility of many biopolymers [1-3]. Being the hydrolysis product of collagen which is the major component of the natural extracellular matrix of mammals, the polypeptide gelatin is a desirable material for the fabrication of hydrogels for tissue engineering applications. Chemically cross-linked gelatin hydrogels can be obtained by radical cross-linking of methacryloylated gelatin. However, diffusion of large molecules such as nutrients through the hydrogel matrix is often hindered due to the small mesh sizes in chemically cross-linked hydrogels. To overcome these limitations, additional interconnected pores can be introduced into the hydrogels using templating methods [4, 5]. The aim of this project is to develop a hydrogel foam based on gelatin suitable for the photoencapsulation of living cells. To this end, microfluidic foaming techniques are used to generate a monodisperse liquid template. The liquid foam template is subsequently cross-linked with UV-light. As UV-light is cytotoxic, the cross-linking process has to be carefully optimized to ensure cell viability.

By tailoring the liquid fraction of the foam template, the size of the interconnects between pores can be adjusted [6]. Images of a swollen and a freeze-dried gelatin-based hydrogel foam are depicted in Figure 1.  In this project, the influence of different pore and interconnect sizes of the behaviour of encapsulated cells will be studied in cooperation with University of Strasburg. Furthermore, polymerizable surfactants will be synthesized to enable a surface modification of the hydrogel matrix.