Bacterial infection microenvironment-responsive enzymatically degradable multilayer films for multifunctional...

Area of Science:

• Biomaterials Science
• Nanotechnology
• Infectious Disease Research

Background:

• Bacterial adhesion to biomaterials is a critical step in biofilm formation and infection.
• Eliminating adhered bacteria is challenging, often leading to inevitable infection.
• Developing effective antibacterial surfaces for biomedical implants is crucial.

Purpose of the Study:

• To design and construct enzymatically degradable composite multilayer films.
• To evaluate the anti-adhesive and bactericidal properties of these films.
• To assess the material's efficacy in promoting wound healing and its antibacterial effect in vivo.

Main Methods:

• Layer-by-layer self-assembly was used to create hyaluronic acid/chitosan and hyaluronic acid/polylysine composite multilayer films.
• Spectroscopic ellipsometry and scanning electron microscopy characterized film growth.
• In vitro enzymatic degradation assays and bacterial adhesion/viability tests were performed.
• In vivo subcutaneous implantation tests in rabbits assessed wound healing and antibacterial effects.

Main Results:

• Composite multilayer films exhibited exponential growth up to ~2 μm thickness.
• Outer layers rapidly degraded within 24 hours due to enzymes like hyaluronidase and chymotrypsin.
• Films reduced adhesion of Staphylococcus aureus and Escherichia coli by over 99%.
• Remaining inner layers showed bactericidal action against both bacterial types.
• In vivo tests demonstrated accelerated wound healing and a self-defense antibacterial effect.

Conclusions:

• The developed composite multilayer films possess both anti-adhesive and bactericidal properties.
• Enzymatic degradation contributes to the material's antibacterial mechanism.
• These films show potential for modifying biomedical implants to prevent infection and enhance healing.