Photobactericidal plastic films based on cellulose esterified by chloroacetate and a cationic porphyrin.
Résumé
The synthesis and characterisation of pyridinium porphyrinic chloroacetyl cellulose ester chlorides, where photosensitizing agents are covalently bounded to the polymeric chain, is presented in this paper. First, cellulose was homogenously converted into chloroacetatecellulose ester in DMAc/LiCl solvent by using chloroacetyl chloride. The complete substitution of cellulose was achieved using 7 equiv of chloroacetyl chloride for a 2 h reaction at room temperature. The absence of base did not prove detrimental to reaction. The grafting of monopyridyltritolylporphyrin onto chloroacetatecellulose ester was then realised by alkylation of the photosensitizer in DMF. These new plasticfilms were found to be thermostable up to 55 °C; higher temperatures led to progressive deacetylation. First results of their photobactericidal activity against Staphylococcus aureus and Escherichia coli strains are very encouraging. Such materials could find applications in medical environments as an alternative to overcome the rampant bacterial multiresistance to classical antibiotics.