Combining polyesters of citric and azelaic acids to obtain potential topical-application biomaterials with antimicrobial activity

Aleksandra BandzerewiczAnna HermanEwa DutkowskaKlara NiebudaPaweł RuśkowskiAgnieszka Gadomska-Gajadhur^*

• Warsaw University of Technology, Warsaw, Poland

Biomaterials with antimicrobial properties are a key research area due to the increasing threat of infections and the growing resistance of microorganisms to existing antibiotics. . The aim of the study was to produce thermally cross-linked polymer films based on poly(1,5pentanediol azelate) and poly(1,4-butanediol citrate) with antimicrobial activity for medical applications.Polyesters were synthesised, mixed and cross-linked at different times and temperatures. Selected properties were investigated: gel content, surface hydrophilicity (water contact angle) and stability in aqueous environments (degradation tests). A modified time-kill procedure (ASTM E2315-23) was performed to test the antimicrobial properties of the films against Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans.Well-formed, cross-linked, flexible materials differing in appearance depending on the conditions of the cross-linking process were obtained. In general, a lower cross-linking temperature was found to promote less brittle and more flexible films with greater structure uniformity. The polymer films had hydrophilic surfaces (water contact angle 40-60°). All polymer films maintained integrity after immersion in PBS buffer. Most likely, the lower hydrophilicity of the polyazelate phase limited their degradation. A modified time-kill procedure (ASTM E2315-23) was performed to test the antimicrobial properties of the films against Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans. The antimicrobial activity of polycitrate-based films against Pseudomonas. aeruginosa has been reported with >90% reduction of the pathogen after 6 h of contact and 100% biocidal effect after 24 h. The antimicrobial activity of the film is pH-based.The biocidal effect of polycitrate film against P. aeruginosa is the most important anda promising result for its future application, especially given the resistance of the pathogen to commonly used antibiotics. The material should be further evaluated for safety in topical applications. However, a local acidic environment could positively influence the wound-healing processPolyesters were synthesised, mixed and cross-linked at different times and temperatures. Selected properties were investigated: gel content, surface hydrophilicity (water contact angle) and stability in aqueous environments (degradation tests). A modified time-kill procedure (ASTM E2315-23) was performed to test the antimicrobial properties of the films against Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans.