Synthesis of Poly(ε-caprolactone) Diacrylate for Micelle-Cross-Linked Sodium AMPS Hydrogel for Use as Controlled Drug Delivery Wound Dressing

This study focuses on the synthesis of poly(epsilon-caprolactone) diacrylate (PCLDA) for the fabrication of micelle-crosslinked sodium AMPS wound dressing hydrogels. The novel synthetic approach of PCLDA is functionalizing a PCL diol with acrylic acid. The influences of varying the PCL diol/AA molar ratio and temperature on the suitable conditions for the synthesis of PCLDA are discussed. The hydrogel was synthesized through micellar copolymerization of sodium 2-acrylamido-2-methylpropane sulfonate (Na-AMPS) as a basic monomer and PCLDA as a hydrophobic association monomer. In this study, an attempt was made to develop new hydrogel wound dressings meant for the release of antibacterial drugs (ciprofloxacin and silver sulfadiazine). The chemical structures, morphology, porosity, and water interaction of the hydrogels were characterized. The hydrogels' swelling ratio and water vapor transmission rate (WVTR) showed a high swelling capacity (4688-10753%) and good WVTR (approximately 2000 g.m(-2.) day(-1)), which can be controlled through variation of the PCLDA concentration. The mechanical property results confirmed that PCLDA improved the mechanical properties of the hydrogel; the stress increased from 37 to 68 kPa, and the strain increased from 198 to 360% with increasing PCLDA (0-30% wt of Na-AMPS). These hydrogels presented no cytotoxicity based on over 70% cell viability responses (L929 fibroblasts) using an in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, the drug release mechanism, kinetic models, and antibacterial activity were determined. The results demonstrated that antibiotics were released from the hydrogel with a Fickian diffusion mechanism and antibacterial activity against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus). Based on the results obtained, and bearing in mind that further progress still needs to be made, the fabricated hydrogels show considerable potential for meeting the stringent property requirements of hydrogel wound dressings.

Automated summary

This study developed a new type of hydrogel wound dressing with high swelling capacity and good water vapor transmission rate, which can be controlled by adjusting the concentration of PCLDA. The hydrogel showed no cytotoxicity at the cellular level, and exhibited antibacterial activity against both Gram-positive and Gram-negative bacteria.