3D Printing of Chitosan Scaffolds and Films with Varying Roughness for Cultivation of Human Retinal Progenitor Cells

Chitosan was used for three-dimensional (3D) printing of films and well-resolved scaffolds. Three different molecular weights with a comparable degree of de-N-acetylation were studied for 3D printing; inks were characterized using rheology, and the resulting two-dimensional (2D) and 3D architectures were characterized by scanning electron microscopy (SEM). Printing and fixation were optimized for retention of shape fidelity. The films and scaffolds were functionalized with a short peptide containing the integrin-binding arginylglycylaspartic acid (Arg-Gly-Asp, RGD) sequence using a postprinting grafting approach. The 2D films and 3D scaffolds prepared were studied as support materials for human retinal progenitor cells (hRPCs), and the properties of native and RGD-modified chitosan were compared as support materials for hRPCs. The adhesion and proliferation of hRPCs were studied over a period of 6 or 18 days, and Matrigel was used as a positive control. Grafting with the RGD-containing peptide generally improved the biocompatibility of the materials. When comparing films with varying surface roughness resulting from the method used for drying, the cellular response differed significantly. The best performing material was air-dried chitosan films, which resulted in the formation of axons and larger cell clusters with observable live cells after 18 days of culture time. This work demonstrates effective methods for the preparation of 3D printed architectures and the promise of these materials for cell therapies and bioengineering applications.