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.

Autosomal dominant optic atrophy (ADOA) is a rare progressive disease mainly caused by mutations in OPA1, a nuclear gene encoding for a mitochondrial protein that plays an essential role in mitochondrial dynamics, cell survival, oxidative phosphorylation, and mtDNA maintenance. ADOA is characterized by the degeneration of retinal ganglion cells (RGCs). This causes visual loss, which can lead to legal blindness in many cases. Nowadays, there is no effective treatment for ADOA. In this article, we have established an isogenic human RGC model for ADOA using iPSC technology and the genome editing tool CRISPR/Cas9 from a previously generated iPSC line of an ADOA plus patient harboring the pathogenic variant NM_015560.3: c.1861C>T (p.Gln621Ter) in heterozygosis in OPA1. To this end, a protocol based on supplementing the iPSC culture media with several small molecules and defined factors trying to mimic embryonic development has been employed. Subsequently, the created model was validated, confirming the presence of a defect of intergenomic communication, impaired mitochondrial respiration, and an increase in apoptosis and ROS generation. Finally, we propose the analysis of OPA1 expression by qPCR as an easy read-out method to carry out future drug screening studies using the created RGC model. In summary, this model provides a useful platform for further investigation of the underlying pathophysiological mechanisms of ADOA plus and for testing compounds with potential pharmacological action.