Species-Based Differences in Mechanical Properties, Cytocompatibility, and Printability of Methacrylated Collagen Hydrogels

Abstract

Collagen methacrylation is a promising approach to generate photo-cross-linkable cell-laden hydrogels with improved mechanical properties. However, the impact of species-based variations in amino acid composition and collagen isolation method on methacrylation degree (MD) and its subsequent effects on the physical properties of methacrylated collagen (CMA) hydrogels and cell response are unknown. Herein, we compared the effects of three collagen species (bovine, human, and rat), two collagen extraction methods (pepsin digestion and acid extraction), and two photoinitiators (lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) and Irgacure-2959 (I-2959)) on the physical properties of CMA hydrogels, printability and mesenchymal stem cell (MSC) response. Human collagen showed the highest MD. LAP was more cytocompatible than I-2959. The compressive modulus and cell viability of rat CMA were significantly higher (p < 0.05) than bovine CMA. Human CMA yielded constructs with superior print fidelity. Together, these results suggest that careful selection of collagen source and cross-linking conditions is essential for biomimetic design of CMA hydrogels for tissue engineering applications.

Adjusting Degree of Modification and Composition of gelAGE-Based Hydrogels Improves Long-Term Survival and Function of Primary Human Fibroblasts and Endothelial Cells in 3D Cultures

“…In contrast to the previous studies, we fabricated two gelAGE-based hydrogels employing the polymer at a low, 3% concentration, 4-arm thiolated PEG cross-linker (PEG-4-SH), as well as LAP, a cytocompatible and water-soluble photoinitiator with a good potential for photo-activated thiol-ene reactions. 23,24 The initially designed gelAGE-based hydrogel (G 1MM ) and the optimized G 2LH formulation were fabricated and extensively characterized over a long-time span (21 days). ratio of allyl and thiol moieties.…”

“…In those studies, the hydrogel precursor solutions were formulated using dithiothreitol and 8-arm thiolated PEG (PEG-8-SH), and the authors applied Irgacure2959 or the ruthenium/sodium persulfate complex (Ru/SPS) as photoinitiators. In contrast to the previous studies, we fabricated two gelAGE-based hydrogels employing the polymer at a low, 3% concentration, 4-arm thiolated PEG cross-linker (PEG-4-SH), as well as LAP, a cytocompatible and water-soluble photoinitiator with a good potential for photo-activated thiol-ene reactions. , The initially designed gelAGE-based hydrogel (G 1MM ) and the optimized G 2LH formulation were fabricated and extensively characterized over a long-time span (21 days).…”

In Vitro and In Vivo Evaluation of 3D Printed Poly(Ethylene Glycol) Dimethacrylate‐Based Photocurable Hydrogel Platform for Bone Tissue Engineering

“…The prolonged structural integrity was achieved by photocross-linking with LAP, which can initiate the cross-linking reaction at higher wavelengths, such as blue light. LAP shows several advantages over the Irgacure 2959, a commonly used photoinitiator in photocross-linking of methacrylate and diacrylate compounds, [1,37,38] including quicker gelation time, higher water solubility, and better absorbance of light over 400 nm. [39] In this study, blue light, in the range of 430-480 nm, was used for 2 min, and required mechanical integrity was obtained.…”

Collagen and Beyond: A Comprehensive Comparison of Human ECM Properties Derived from Various Tissue Sources for Regenerative Medicine Applications

“…The printability of birth ECM inks was inferior compared to other inks, which may be due to the lower apparent viscosity of birth ECM. One approach to improve the printability of birth ECM inks may be to modify the collagen backbone via methacrylation of the free amine groups, which can enable photocrosslinking of the printed construct for better retention of shape fidelity [53,54].…”