Poly(hexamethylene biguanide) (PHMB) as high-efficiency antibacterial coating for titanium substrates.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Infectious Disease Research

Background:

• Bacterial infections pose a significant challenge for metallic implants in clinical settings.
• Developing effective strategies to prevent implant-associated infections is crucial for patient outcomes.

Purpose of the Study:

• To create a novel polymer coating for titanium alloy (TC4) to combat bacterial infections.
• To establish a structure-activity relationship between polymer composition and antibacterial efficacy.

Main Methods:

• Synthesis of phosphonate/active ester block copolymers (pDEMMP-b-pNHSMA) with varying active ester segment lengths.
• Construction of polymeric coatings on TC4 substrates via a two-step process.
• In vitro antibacterial evaluations and cytocompatibility assessments.

Main Results:

• A robust relationship was found between polymer structure and antibacterial properties.
• The optimal block polymer (64 repeat units in active ester segment) enabled dense poly(hexamethylene biguanide) (PHMB) coating.
• This coating achieved 100% bacterial kill for S. aureus and E. coli without compromising cytocompatibility.
• PHMB coating significantly inhibited bacterial growth and reduced inflammation in a rat infection model.

Conclusions:

• The developed phosphonate/active ester block copolymer coating is a promising strategy for preventing implant-associated bacterial infections.
• Optimizing the polymer structure is key to achieving high antibacterial efficacy and maintaining biocompatibility.
• The PHMB-coated TC4 substrates show potential for reducing implant-associated inflammatory responses.