Polyester vascular prostheses coated with a cyclodextrin polymer and activated with antibiotics: Cytotoxicity and microbiological evaluation

Polyester (PET) vascular grafts are used to replace or bypass damaged arteries. To minimize the risk of infection during and after surgical interventions, a PET vascular prosthesis (Polythese®) was functionalized with cyclodextrin polymers (PolyCDs) in order to obtain the controlled release of antibiotics (ABs: ciprofloxacin, vancomcyin and rifampicin). An epithelial cell line (L132) was used to determine the viability of the antibiotics, and human pulmonary microvascular endothelial cells (HPMEC) were used for cell proliferation by cell counting and cell vitality with Alamar Blue fluorescent dye. Staphylococcus aureus, Escherichia coli and Enteroccocus sp. were used to determine the antimicrobial activity of AB-loaded virgin and PolyCD-grafted Polythese® by the minimum inhibitory concentration method. The spectrophotometric titration results first showed that a larger amount of ABs was sorbed onto PolyCD-coated Polythese® compared to virgin Polythese® (26.7 vs. 35.3 mg g−1, 51.1 vs. 72.4 mg g−1 and 4.1 vs. 21.0 mg g−1, respectively, for rifampicin, vancomycin and ciprofloxacin). These results were further confirmed by a microbiological test, which showed AB-loaded PolyCD-coated Polythese® displayed better antimicrobial activity. The viability test revealed the toxicity of rifampicin (22 mg l−1) and ciprofloxacin (35 mg l−1), and the absence of toxicity of vancomycin. These tests allow us to further explain the lower vitality and proliferation of HPMEC on the AB-loaded PolyCD-coated Polythese®, which was due not to the functionalization process of prostheses but to the cytotoxicity of certain ABs themselves. Moreover, such a property could be exploited to tackle intracellular bacteria, such as in tuberculosis and other diseases, and will not compromise further in vivo applications of our functionalized vascular prostheses.