Biodegradable HEMA‐based hydrogels with enhanced mechanical properties

Abstract

Hydrogels are widely used in the biomedical field. Their main purposes are either to deliver biological active agents or to temporarily fill a defect until they degrade and are followed by new host tissue formation. However, for this latter application, biodegradable hydrogels are usually not capable to sustain any significant load. The development of biodegradable hydrogels presenting load-bearing capabilities would open new possibilities to utilize this class of material in the biomedical field. In this work, an original formulation of biodegradable photo-crosslinked hydrogels based on hydroxyethyl methacrylate (HEMA) is presented. The hydrogels consist of short-length poly(2-hydroxyethyl methacrylate) (PHEMA) chains in a star shape structure, obtained by introducing a tetra-functional chain transfer agent in the backbone of the hydrogels. They are cross-linked with a biodegradable N,O-dimethacryloyl hydroxylamine (DMHA) molecule sensitive to hydrolytic cleavage. We characterized the degradation properties of these hydrogels submitted to mechanical loadings. We showed that the developed hydrogels undergo long-term degradation and specially meet the two essential requirements of a biodegradable hydrogel suitable for load bearing applications: enhanced mechanical properties and low molecular weight degradation products.

Tensile Fatigue of Poly(Vinyl Alcohol) Hydrogels with Bio‐Friendly Toughening Agents

“…Ultimately, the weak resistance to chain breakage limits hydrogels to an extremely narrow range of load‐bearing applications, especially with respect to use in the human body. [ 15 ] This restriction of attainable mechanical properties has increased the need for improvement of a hydrogel's network structure. Approaches have turned to multifunctional crosslinkers, [ 16–18 ] hydrogen bonding interactions, [ 19,20 ] grafting to a support structure, [ 21,22 ] and polymerization via irradiation as common solutions to improve the weak mechanical properties of hydrogels.…”

Volume-by-volume bioprinting of chondrocytes-alginate bioinks in high temperature thermoplastic scaffolds for cartilage regeneration

“…Many thermoplastic polymers with optimal mechanical properties for the application of cartilage regeneration, that are already approved for clinical use, have a high melting temperature that decreases the cell viability in a normal FDM bioprinting process. Low temperature biomaterials [19][20][21] and printing procedures 22 have been reported in the literature, but these constructs present a lower mechanical and biodegradability behavior. The optimal mechanical stiffness and biodegradation time of the construct depend on the rehabilitation procedure, and higher joint loading after surgery will demand higher stiffness of the constructs and a higher biodegradation time.…”

Swelling characteristics and biocompatibility of ionic liquid based hydrogels for biomedical applications

“…This compound class has shown no or little cytotoxic degradation products in literature. [44][45][46] However, since different functionalities such as sulfonic acid or amino groups may have a huge impact on the biocompatibility, especially of degradation products, this behavior has to be investigated before application testing in vivo and regarding potential approval processes for biomedical uses. Another aspect for potential approval processes is the immunotoxicity of the body to different kind of materials.…”