Material modifications enhancing the antibacterial properties of two biodegradable poly(3-hydroxybutyrate) implants

Area of Science:

• Biomaterials Science
• Infectious Disease Research
• Nanotechnology

Background:

• Biodegradable poly(3-hydroxybutyrate) (PHB) is a promising material for medical implants.
• Biofilm formation on implants increases the risk of surgical site infections.
• Antimicrobial coatings are crucial for enhancing the safety of implantable biomaterials.

Purpose of the Study:

• To evaluate the antimicrobial efficacy of gentamicin palmitate (GP) and zirconium dioxide (ZrO2) coatings on PHB implants.
• To assess the reduction of Staphylococcus aureus biofilm formation on coated PHB pins.
• To investigate the potential of modified PHB for preventing implant-associated infections.

Main Methods:

• Cylindrical PHB pins, with and without GP and ZrO2 coatings, were incubated with Staphylococcus aureus.
• Biofilm quantification was performed by counting colony-forming units (CFU) after sonication.
• Bacterial metabolic activity was assessed using a cell proliferation assay.
• Scanning electron microscopy (SEM) visualized biofilm structure on pin surfaces.

Main Results:

• GP coating significantly reduced early biofilm formation on PHB pins after 2 days (p < 0.0001).
• GP-coated pins showed significantly lower bacterial metabolic activity compared to uncoated pins (p < 0.0001).
• After 7 days, the PHB with ZrO2 and GP (PHBzr + GP) coating exhibited the lowest metabolic activity (p = 0.001).
• SEM confirmed reduced cell attachment and less structured biofilms on coated pins.

Conclusions:

• Gentamicin palmitate coating effectively inhibits early biofilm development on PHB implants.
• Modified PHB with GP and potentially ZrO2 offers a strategy to reduce implant-associated infection risks.
• These findings support the consideration of GP and ZrO2 modifications for developing safer biodegradable PHB implants.