Development of photoreactive collagen-based bioinks for stereolithography 3D bioprinting

Abstract

Owing to its significance as a structural protein and essential component of the extracellular matrix (ECM), collagen has found versatile applications in tissue engineering, particularly in the emerging field of 3D bioprinting techniques. Nevertheless, the limited mechanical strength and poor printability of collagen could impede its application as a bioink. In the present study, the combination of collagen methacrylate (ColMA) and poly(ethylene glycol) diacrylate (PEGDA) was investigated as a photocrosslinkable bioink and carrier for human corneal stromal cell (hCSCs) delivery. In this regard, different concentrations of PEGDA and then 1-vinyl-2-pyrrolidinone (NVP) were optimized based on the mechanical properties of the 3D bioprinted samples and their cytocompatibility to hCSCs. It was observed that cell viability decreased as both PEG (ranging from 5 to 10 wt%) and NVP (ranging from 0.25 to 1 wt%) concentrations increased. While the PEG concentration remained constant at 5 wt%, the NVP concentration was optimized. The effect of NVP concentrations of 0.5 and 1 wt% (as the optimal formulations) on the physical, mechanical, and biological properties of the 3D-printed hydrogels was investigated. Additionally, the influence of scaffold geometry on cell alignment was also observed. In all geometries, cells tended to distribute more at sharp ends and proliferated more within 3D bioprinted samples containing 0.5 wt% NVP. On the other hand, the expressions of collagen type I (Col I) and lumican (Lum) were significantly higher in cells encapsulated within 3D bioprinted samples containing 1 wt% NVP compared to samples containing 0.5 wt% NVP. However, both 3D bioprinted samples had great biological properties. Therefore, depending on the desired impact of the 3D bioprinted samples on cells, both combinations demonstrated appropriate cell viability and growth. © 2025 Elsevier B.V., All rights reserved.