Design of Injectable Poly(γ-glutamic acid)/Chondroitin Sulfate Hydrogels with Mineralization Ability

Abstract

Biocompatible hydrogels are considered promising agents for application in bone tissue engineering. However, the design of reliable hydrogels with satisfactory injectability, mechanical strength, and a rapid biomineralization rate for bone regeneration remains challenging. Herein, injectable hydrogels are fabricated using hydrazide-modified poly(γglutamic acid) and oxidized chondroitin sulfate by combining acylhydrazone bonds and ionic bonding of carboxylic acid groups or sulfate groups with calcium ions (Ca 2+ ). The resulting hydrogels display a fast gelation rate and good self-healing ability due to the acylhydrazone bonds. The introduction of Ca 2+ at a moderate concentration enhances the mechanical strength of the hydrogels. The self-healing capacity of hydrogels is improved, with a healing efficiency of 87.5%, because the addition of Ca 2+ accelerates the healing process of hydrogels. Moreover, the hydrogels can serve as a robust template for biomineralization. The mineralized hydrogels with increasing Ca 2+ concentration exhibit rapid formation and high crystallization of apatite after immersion in simulated body fluid. The hydrogels containing the aldehyde groups possess good bioadhesion to the bone and cartilage tissues. With these superior properties, the developed hydrogels demonstrate potential applicability in bone tissue engineering.

Post-Implantation Stiffening by a Bioinspired, Double-Network, Self-Healing Hydrogel Facilitates Minimally Invasive Cell Delivery for Cartilage Regeneration

“…The compression testing was carried out on the intact hydrogel at 0.5 mm/s and self-healed hydrogel (wedge is aligned to the junction of healing). The maximum force recorded was noted, and healing efficiency (HE) was calculated using the equation reported by Wei et al HE = F normali F normals × 10 where F i and F s denote the fracture forces of intact and self-healed hydrogels, respectively.…”

Advanced injectable hydrogels for cartilage tissue engineering

“…The ultimate degradation product of PGA is glutamate, a component of collagen. Due to its excellent biocompatibility, biodegradability, and non-toxicity, PGA is used to prepare hydrogels with various functions for tissue engineering matrix, especially cartilage ( Wei et al, 2022 ).…”