Development and Optimisation of Hydrogel Scaffolds for Microvascular Network Formation

HIGHLIGHTS: This research presents the development of a hydrogel scaffold for an in vitro microvascultature. Here, the optimal hydrogel composition in terms of polymer type, ratio, and solvent is investigated. Scaffold optimisation for endothelial cells is based on a multipronged evaluation encompassing seeding number, cell adhesion, migration rate, cell viability, hydrogel consistency, and endothelial tube formation. The developed hydrogel constructs enabled the formation of interconnected capillary-like networks, which are also characterised to gain further insights into their microarchitecture. ABSTRACT: Traumatic injuries are a major cause of morbidity and mortality worldwide; however, there is limited research on microvascular traumatic injuries. To address this gap, this research aims to develop and optimise an in vitro construct for traumatic injury research at the microvascular level. Tissue engineering constructs were created using a range of polymers (collagen, fibrin, and gelatine), solvents (PBS, serum-free endothelial media, and MES/NaCl buffer), and concentrations (1–5% w/v). Constructs created from these hydrogels and HUVECs were evaluated to identify the optimal composition in terms of cell proliferation, adhesion, migration rate, viability, hydrogel consistency and shape retention, and tube formation. Gelatine hydrogels were associated with a lower cell adhesion, whereas fibrin and collagen ones displayed similar or better results than the control, and collagen hydrogels exhibited poor shape retention; fibrin scaffolds, particularly at high concentrations, displayed good hydrogel consistency. Based on the multipronged evaluation, fibrin hydrogels in serum-free media at 3 and 5% w/v were selected for further experimental work and enabled the formation of interconnected capillary-like networks. The networks formed in both hydrogels displayed a similar architecture in terms of the number of segments (10.3 ± 3.21 vs. 9.6 ± 3.51) and diameter (8.6446 ± 3.0792 [Formula: see text] m vs. 7.8599 ± 2.3794 [Formula: see text] m).