3D-Printed Hybrid Collagen/GelMA Hydrogels for Tissue Engineering Applications

Abstract

Bioprinting is an emerging technology involved in the fabrication of three-dimensional tissue constructs for the repair and regeneration of various tissues and organs. Collagen, a natural protein found abundantly in the extracellular matrix of several tissues, can be extracted from collagen-rich tissues of animals such as sheep, cows, rats, pigs, horses, birds, and marine animals. However, due to the poor printability of collagen bioinks, biocompatible collagen scaffolds that mimic the extracellular matrix (ECM) are difficult to fabricate using bioprinting techniques. Gelatin methacrylate (GelMA), a semi-synthetic polymer with tunable physical and chemical properties, has been found to be a promising biomaterial in various bioprinting applications. The printability of collagen can be improved by combining it with semi-synthetic polymers such as GelMA to develop hybrid hydrogels. Such hybrid hydrogels printed have also been identified to have enhanced mechanical properties. Hybrid GelMA meshes have not previously been prepared with collagen from ovine sources. This study provides a novel comparison between the properties of hybrid meshes with ovine skin and bovine hide collagen. GelMA (8% w/v) was integrated with three different concentrations (0.5%, 1%, and 2%) of bovine and ovine collagen forming hybrid hydrogels inks that were printed into meshes with enhanced properties. The maximum percentage of collagen suitable for integration with GelMA, forming hybrid hydrogels with a stable degradation rate was 1%. The water-soluble nature of ovine collagen promoted faster degradation of the hybrid meshes, although the structural crosslinking was identified to be higher than bovine hybrid meshes. The 1% bovine collagen hybrid meshes stood out in terms of their stable degradation rates.

Mitigating reactive oxygen species production and increasing gel porosity improves lymphocyte motility and fibroblast spreading in photocrosslinked gelatin-thiol hydrogels

“…Having established a method to mitigate ROS production, we turned to improving the porosity of the photocrosslinked gel. Given the prevalence of fibrillar structures in the lymph node stroma, and prior reports that addition of fibrillar collagen increased the pore sizes of 3D printed GelMA hydrogel meshes 59 and porosity of PEG hydrogels, 60 we hypothesized that addition of collagen would increase both the porosity of the photocrosslinked GelSH gels and the motility of cells encapsulated within them. Therefore, we mixed varied quantities of collagen precursor into the GelSH precursor, photocrosslinked the gels, and allowed an additional (30 min) incubation for thermal gelation.…”

Development of a 3Din vitrohuman-sized model of cervical dysplasia to evaluate the delivery of ethyl cellulose-ethanol injection for the treatment of cervical dysplasia ablation

“…(28) However, the GelMA hydrogel has enough flexibility in its mechanical properties that allows the incorporation of more ECM components to approximate the human cervix better, a focus of future work. (20,29)…”

Regenerative Therapy for Corneal Scarring Disorders

“…This tunability in degradation rate aligns with the desirable attribute of matching the healing cascade of corneal injuries or diseases. Photo-crosslinked GelMA can be effectively 3D-printed to mimic corneal stroma tissues, enhancing structure and scalability [ 180 ]. Figure 6 illustrates the bioengineering of a biomimetic corneal stroma with an incorporation of native stromal cells (keratocytes) in a GelMA which can be transplanted to the corneal defect and photocured in situ.…”