Study on Antimicrobial Gel Combined with Electrospun Polyvinyl Alcohol Fibers for Enzymatically Controlled Reactive Oxygen Species Release

Academic Background

The skin is the body’s first line of defense against infections, and the presence of wounds can compromise this barrier, increasing the risk of infection. With the rise of antibiotic resistance, the development of novel antimicrobial therapies has become increasingly important. Traditional antibiotic treatments not only risk fostering resistance but can also cause side effects such as cellular and organ toxicity, allergic reactions, and negative impacts on the gut microbiome. Therefore, localized antimicrobial treatments have emerged as a superior alternative, particularly by integrating antimicrobial agents into wound dressings to enhance efficacy and reduce toxicity.

In recent years, reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), have gained attention for their antimicrobial properties. ROS not only kill pathogens but also play crucial roles in various stages of wound healing. However, achieving sustained release of ROS while maintaining effective concentrations at the wound site remains a challenge. To address this, researchers developed an antimicrobial gel called RO-101®, which enzymatically releases H2O2 at the wound site. However, the direct application of gels in clinical settings presents challenges, such as difficulty in maintaining direct contact with the wound and short-term antimicrobial effects.

To overcome these issues, researchers attempted to integrate RO-101® gel into electrospun polyvinyl alcohol (PVA) fibers to create an antimicrobial wound dressing capable of sustained H2O2 release. Electrospinning technology can produce nanofibers with high surface area and porosity, making them ideal drug delivery carriers. Additionally, PVA exhibits excellent biocompatibility and water solubility, making it suitable for tissue engineering and wound dressings.

Source of the Paper

This paper was co-authored by Joel Yupanqui Mieles, Cian Vyas, Evangelos Daskalakis, and others from the Department of Mechanical, Aerospace, and Civil Engineering at the University of Manchester, UK, and the School of Mechanical and Aerospace Engineering at Nanyang Technological University, Singapore, among other institutions. The paper was published online on November 7, 2024, in the journal Bio-design and Manufacturing, with the DOI 10.1007/s42242-024-00312-3.

Research Process and Results

1. Fabrication of Electrospun PVA/RO-101 Fibers

Researchers first prepared a PVA solution and mixed it with RO-101® gel to form a homogeneous polymer solution. To improve fiber uniformity, the surfactant Triton-X 100 was added. Subsequently, a vertical electrospinning system was used to fabricate PVA/RO-101 fibers. By adjusting the concentration of RO-101®, fibers with different ratios were prepared, namely PVA RO20, PVA RO30, PVA RO40, and PVA RO50.

2. Morphological and Chemical Characterization of Fibers

Scanning electron microscopy (SEM) revealed that all fibers exhibited smooth and uniform morphology, with diameters ranging from 200 to 500 nanometers. As the concentration of RO-101® increased, the fiber diameter gradually increased. Nuclear magnetic resonance (NMR) spectroscopy further confirmed the successful integration of RO-101® gel into the PVA fibers, with no significant changes in its chemical structure during electrospinning.

3. H2O2 Release Performance Evaluation

Researchers used the Amplex® Red assay kit to measure the H2O2 release performance of PVA/RO-101 fibers. Results showed that PVA/RO-40 fibers released H2O2 at concentrations exceeding 1 mmol/(g·ml) within 24 hours, with H2O2 release significantly increasing as the RO-101® concentration increased. Additionally, the effects of different sterilization methods (ultraviolet and gamma irradiation) on H2O2 release were evaluated. Gamma irradiation had minimal impact on H2O2 release, while ultraviolet sterilization significantly reduced it.

4. Antimicrobial Performance Testing

Researchers assessed the antimicrobial performance of PVA/RO-101 fibers through agar diffusion assays and 24-hour time-kill experiments. Results demonstrated that PVA/RO-40 fibers exhibited significant antimicrobial activity against both Gram-positive bacteria (e.g., Staphylococcus aureus) and Gram-negative bacteria (e.g., Pseudomonas aeruginosa), reducing colony-forming units (CFU) by 1 log unit. Furthermore, PVA/RO-101 fibers effectively inhibited biofilm formation, particularly against drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA).

5. Cytocompatibility Testing

To evaluate the biocompatibility of PVA/RO-101 fibers, researchers conducted fibroblast viability and proliferation assays. Results indicated that low concentrations of RO-101® (e.g., PVA RO20) had no significant impact on cell viability and proliferation, demonstrating good cytocompatibility. However, as the RO-101® concentration increased, cell viability and proliferation rates gradually decreased, suggesting potential cytotoxicity at higher concentrations.

Conclusions and Significance

This study successfully integrated RO-101® antimicrobial gel into PVA electrospun fibers, creating an antimicrobial wound dressing capable of sustained H2O2 release. The dressing not only exhibited excellent antimicrobial properties but also effectively inhibited biofilm formation, particularly against drug-resistant strains. Additionally, PVA/RO-101 fibers demonstrated good cytocompatibility, making them suitable for wound healing and tissue engineering applications.

The scientific value of this research lies in providing a novel method for preparing antimicrobial wound dressings. By utilizing electrospinning technology, sustained ROS release was achieved, addressing the limitations of traditional gel dressings in clinical applications. Furthermore, the study revealed the impact of different sterilization methods on H2O2 release performance, offering important insights for future antimicrobial dressing development.

Research Highlights

1. Innovative Antimicrobial Dressing: Integration of RO-101® gel into PVA fibers via electrospinning enabled sustained H2O2 release, overcoming the limitations of traditional gel dressings.
2. Excellent Antimicrobial Performance: PVA/RO-101 fibers exhibited significant antimicrobial activity against various bacteria, including drug-resistant strains, and effectively inhibited biofilm formation.
3. Good Cytocompatibility: Low concentrations of RO-101® had no significant impact on cell viability and proliferation, making the fibers suitable for wound healing and tissue engineering.
4. Impact of Sterilization Methods: The study highlighted the effects of different sterilization methods on H2O2 release performance, providing valuable guidance for future antimicrobial dressing development.

This research offers new insights into the development of antimicrobial wound dressings, with significant potential for clinical applications.