Amino Acid-Based Zwitterionic Polymer Surfaces Highly Resist Long-Term Bacterial Adhesion

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Surface Science

Background:

• Long-term suppression of bacterial adhesion is crucial for biomedical applications.
• Existing antifouling materials often face limitations in durability and efficacy.
• Development of novel biocompatible materials is essential for preventing implant-associated infections.

Purpose of the Study:

• To investigate the long-term bacterial anti-adhesion properties of amino acid-based zwitterionic polymers (pAAZ).
• To evaluate the stability and performance of pAAZ coatings in biological environments.
• To compare the efficacy of pAAZ against established antifouling materials.

Main Methods:

• Synthesis of pAAZ brushes from natural amino acids (serine, ornithine, lysine, aspartic acid, glutamic acid).
• Grafting of pAAZ onto gold surfaces using surface-initiated photoiniferter-mediated polymerization (SI-PIMP).
• Assessment of bacterial adhesion using Gram-positive (Staphylococcus epidermidis) and Gram-negative (Pseudomonas aeruginosa) bacteria over 14 days.
• Evaluation of protein adsorption from human serum and plasma.
• Testing of structural stability in phosphate-buffered saline (PBS).

Main Results:

• pAAZ coatings effectively suppressed adsorption from undiluted human serum and plasma.
• Surfaces exhibited at least 95% reduction in bacterial adhesion for both bacterial species at all tested time points (1, 5, 9, 14 days).
• Bacterial accumulation on pAAZ surfaces after 9 or 14 days was lower than on poly[poly(ethyl glycol) methyl ether methacrylate] (pPEGMA) surfaces.
• pAAZ brushes demonstrated excellent structural stability in PBS after 4 weeks of incubation.

Conclusions:

• Amino acid-based zwitterionic polymers (pAAZ) provide highly effective and durable resistance to bacterial adhesion.
• pAAZ coatings show superior antifouling performance compared to established materials like pPEGMA.
• These findings highlight the significant potential of pAAZ for biomedical applications requiring long-term prevention of bacterial attachment.