Gallic acid-grafted chitosan antibacterial hydrogel incorporated with polydopamine-modified hydroxyapatite for enhancing bone healing

Abstract

An open critical-size bone defect is a major medical problem because of the difficulty in self-healing, leading to an increased risk of bacterial infection owing to wound exposure, resulting in treatment failure. Herein, a composite hydrogel was synthesized by chitosan, gallic acid, and hyaluronic acid, termed “CGH.” Hydroxyapatite was modified with polydopamine (PDA@HAP) and introduced to CGH to obtain a mussel-inspired mineralized hydrogel (CGH/PDA@HAP). The CGH/PDA@HAP hydrogel exhibited excellent mechanical performances, including self-healing and injectable properties. Owing to its three-dimensional porous structure and polydopamine modifications, the cellular affinity of the hydrogel was enhanced. When adding PDA@HAP into CGH, Ca2+ and PO43- could release and then promoted differentiation of BMSCs into osteoblasts. Without any osteogenic agent or stem cells, the area of new bone at the site of defect was enhanced and the newly formed bone had a dense trabecular structure after implanting of the CGH/PDA@HAP hydrogel for 4 and 8 weeks. Moreover, the growth of Staphylococcus aureus and Escherichia coli was effectively inhibited through the grafting of gallic acid onto chitosan. Above, this study provides a reasonable alternative strategy to manage open bone defects.

Terpolymer-Hydroxyapatite Hybrid Hydrogel Prepared by Photopolymerization Under Green LED Irradiation for Wound Hemostasis

“…The peak at 1654 cm –1 represents the stretching vibration of amide I bonds (CO). , The peak at 1600 cm –1 represents the bending vibration of amide II bonds (N–H) . And the peak at 1043 cm –1 is generated by the vibration of the P–O bond in PO 4 3– . , …”

Antioxidative, Anti-Inflammatory, Antibacterial, Photo-Cross-Linkable Hydrogel of Gallic Acid–Chitosan Methacrylate: Synthesis, In Vitro, and In Vivo Assessments

“…In addition, dialysis in acidified deionized water is also help to protect GA from oxidation. 49 Good antibacterial activity makes hydrogels more attractive in biomedical applications. 50 Chitosan is well-known for its great antibacterial capacity while chemical modification might compromise its antibacterial activity, especially for the modification processes targeting the amino groups of CS.…”

“…Future studies should consider improving the MA substitution degree by performing the whole synthesis reaction under nitrogen protection. In addition, dialysis in acidified deionized water is also help to protect GA from oxidation …”

Repair of Infected Bone Defects with Hydrogel Materials

“…By grafting GA onto CS, they successfully inhibited the growth of Staphylococcus aureus and Escherichia coli. Additionally, the hydrogels incorporating polydopamine (PDA)-modified HAP exhibited better potential in promoting the differentiation of BMSCs into osteoblasts, thereby displaying exceptional osteogenic activity [107] (Figure 5). acid (GA), CS, and HA.…”