In this work, we present a method to fabricate a hyaluronic acid hydrogel with spatially controlled cell-adhesion properties based on photo-polymerisation cross-linking and functionalisation. The approach utilises the same reaction pathway for both steps meaning that it is user-friendly and allows for adaptation at any stage during the fabrication process. Moreover, the process does not require any additional cross-linkers. The hydrogel is formed by UV initiated radical addition reaction between acrylamide groups on the hyaluronic acid backbone. Cell adhesion is modulated by functionalising the adhesion peptide sequence RGD (arginine-glycine-aspartate) onto the hydrogel surface via radical mediated thiol-ene reaction using the non-reacted acrylamide groups. We show that 10 x 10 µm² squares could be patterned with sharp features and a good resolution. The smallest area that could be patterned resulting in good cell adhesion was 25 x 25 µm² squares, showing single-cell adhesion. Mouse brain endothelial cells adhered and remained in culture for up to 7 days on 100 x 100 µm² square patterns. We see potential for this material combination for future use in novel organ-on-chip models and tissue engineering where the location of the cells is of importance and to further study endothelial cell biology.

This work reports on an effort to decipher the alignment of brain microvasculature endothelial cells to physical constrains generated via adhesion control on hydrogel surfaces and explore the corresponding responses upon glucose level variations emulating the hypo- and hyperglycaemic effects in diabetes. We prepared hydrogels of hyaluronic acid a natural biomaterial that does not naturally support endothelial cell adhesion, and specifically functionalised RGD peptides into lines using UV-mediated linkage. The width of the lines was varied from 10 to 100 µm. We evaluated cell alignment by measuring the nuclei, cell, and F-actin orientations, and the nuclei and cell eccentricity via immunofluorescent staining and image analysis. We found that the brain microvascular endothelial cells aligned and elongated to these physical constraints for all line widths. In addition, we also observed that varying the cell medium glucose levels affected the cell alignment along the patterns. We believe our results may provide a platform for further studies on the impact of altered glucose levels in cardiovascular disease.