RESUMO
Physiologically relevant in vitro models of the human outer retina are required to better elucidate the complex interplay of retinal tissue layers and investigate their role in retinal degenerative disorders. Materials currently used to mimic the function of Bruch's membrane fail to replicate a range of important structural, mechanical, and biochemical properties. Here, we detail the fabrication of a surface-functionalized, fibrous collagen I membrane. We demonstrate its ability to better replicate a range of important material properties akin to the function of human Bruch's membrane when compared with a commonly utilized synthetic polyethylene terephthalate alternative. We further reveal the ability of this membrane to support the culture of the ARPE-19 cell line, as well as human pluripotent stem cell-derived RPE-like cells and human umbilical vein endothelial cells. This material could provide greater physiological relevance to the native Bruch's membrane than current synthetic materials and further improve the outcomes of in vitro outer retinal models.
Assuntos
Lâmina Basilar da Corioide , Colágeno Tipo I , Retina , Humanos , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Lâmina Basilar da Corioide/metabolismo , Lâmina Basilar da Corioide/química , Linhagem Celular , Colágeno Tipo I/química , Colágeno Tipo I/metabolismo , Células Endoteliais da Veia Umbilical Humana , Polietilenotereftalatos/química , Retina/citologia , Retina/metabolismo , Epitélio Pigmentado da Retina/metabolismo , Epitélio Pigmentado da Retina/citologia , Epitélio Pigmentado da Retina/efeitos dos fármacosRESUMO
The development of bio-inks capable of being 3D-printed into cell-containing bio-fabricates with sufficient shape fidelity is highly demanding. Structural integrity and favorable mechanical properties can be achieved by applying high polymer concentrations in hydrogels. Unfortunately, this often comes at the expense of cell performance since cells may become entrapped in the dense matrix. This drawback can be addressed by incorporating fibers as reinforcing fillers that strengthen the overall bio-ink structure and provide a second hierarchical micro-structure to which cells can adhere and align, resulting in enhanced cell activity. In this work, the potential impact of collagen-coated short polycaprolactone-fibers on cells after being printed in a hydrogel is systematically studied. The matrix is composed of eADF4(C16), a recombinant spider silk protein that is cytocompatible but non-adhesive for cells. Consequently, the impact of fibers could be exclusively examined, excluding secondary effects induced by the matrix. Applying this model system, a significant impact of such fillers on rheology and cell behavior is observed. Strikingly, it could be shown that fibers reduce cell viability upon printing but subsequently promote cell performance in the printed construct, emphasizing the need to distinguish between in-print and post-print impact of fillers in bio-inks.