Effective Wound Healing by Antibacterial and Bioactive Calcium-Fluoride-Containing Composite Hydrogel Dressings Prepared Using in Situ Precipitation

Abstract

In this study, we report the development of a hyaluronic acid (HA)-based composite hydrogel containing calcium fluoride (CaF2) with good biocompatibility and antibacterial properties for multifunctional wound dressing applications. CaF2 was newly selected for incorporation within HA because it can release both Ca2+ and F– ions, which are well-known ions for affecting cell proliferation and inhibiting bacterial growth, respectively. In particular, an in situ precipitation process enables easy control over the released amount of F– ions by simply adjusting the precursor solutions (calcium chloride (CaCl2) and ammonium fluoride (NH4F)) used for the CaF2 precipitation. CaF2 particles were uniformly embedded within a HA-based pure hydrogel using an in situ precipitation process. Through variation of the CaCl2 and NH4F concentrations used in the precipitation as well as the precipitation time, composite hydrogels with different ion-release profiles were obtained. By controlling the precipitation time, especially for 10 min and after 30 min, large differences in the ion-release profiles as a function of CaF2 concentration were observed. A shorter precipitation time resulted in faster release of fluoride, whereas for the 30 min and 1 h samples, sustained ion release was achieved. Colony tests and live/dead assays using Escherichia coli and Staphylococcus aureus revealed a lower density of bacteria on the CaF2 composite hydrogels than on the pure hydrogel for both strains. In addition, improved cellular responses such as cell attachment and proliferation were also observed for the CaF2 composite hydrogels compared to those for the pure hydrogel. Furthermore, the composite hydrogels exhibited excellent wound healing efficiency, as evidenced by an in vitro cell migration assay. Finally, monitoring of the wound closure changes using a full-thickness wound in a rat model revealed the accelerated wound healing capability of the CaF2 composite hydrogels compared with that of the pure hydrogel. Based on our findings, these CaF2 composite hydrogels show great potential for application as advanced hydrogel wound dressings with antibacterial properties and accelerated wound-healing capabilities.

Polydeoxyribonucleotide-delivering therapeutic hydrogel for diabetic wound healing

“…The rheological behaviors of the Alg and Alg-PDRN hydrogels were examined using a rheometer (ARES, Rheometric Scientific, USA) 52 , 53 . First, 1 ml of the hydrogels was placed between 20-mm-diameter parallel plates, and then, frequency sweep tests were performed under a constant strain of 0.5% in the frequency range of 1.0–100 rad/s.…”

The Role of Calcium in Wound Healing

“…In another study, the authors prepared chitosan/gelatin/nanocrystalline cellulose/calcium peroxide films for wound treatment application [ 73 ]. Calcium peroxide is an oxygen releasing biomaterial and has been found to possess antibacterial properties.…”

“…However, no in vitro and in vivo wound healing experiments were conducted by the authors. Jeong et al used an in situ precipitation technique to produce calcium fluoride-containing composite hydrogel dressings and found that the presence of calcium fluoride enhanced the migration of fibroblasts and endothelial cells, and inhibited bacterial growth [ 73 ]. In vivo, a calcium fluoride composite hydrogel hastened wound healing by increasing the chemotaxis of immune cells, promoting the migration of surrounding skin cells, and accelerating the re-epithelialization process.…”

Sustainable Coated Nanostructures Based on Alginate and Electrospun Collagen Loaded with Antimicrobial Agents

“…Materials with bioactive properties for tissue engineering and long-term antibacterial properties are strongly desired for wound healing. Although many antibiotic-loaded dressings with excellent antibacterial properties have been developed, toxic effects, anaphylactic reactions and the resulting "super bacteria" that occurred due to drug resistance caused growing concern for finding new treatments [1][2][3]. In addition, various metalbased nanoparticles (NP), such as AgNP, ZnO NP and CeO 2 NP, with broad-spectrum antibacterial properties and without drug resistance are used as antibacterial agents in the study of wound dressings [4,5].…”