Imprinting Pentaphyrin on Conductive Electropolymerized Dipyrromethane Films: A New Strategy towards the Synthesis of Photokilling Materials

Abstract

We report herein the synthesis and photoinduced bactericidal activity of two new polymeric materials, obtained by imprinting the photosensitizer 20-(4-carboxyphenyl)-2, 13-dimethyl-3,12-diethyl-[22]pentaphyrin (PCox, 1) into suitable electropolymerized dipyrromethane films. 5-Phenyl-dipyrromethane (5-ph-DP) and 5-(4-pyridyl)dipyrromethane (5-py-DP) have been selected as the monomers for the synthesis of the materials in order to assess the correlation between the substituent in C5 and the capability in Pcox uptake. Both films have been tested in their photokilling ability toward Staphylococcus aureus by using a multi-LED blue lamp at a fluence rate of 40 W/m 2 . Poly-5-py-DP/ PCox, with a PCox load of 10 À 8 mol/cm 2 , achieved a 4-log reduction in microbial viability after 60 min of irradiation. The polymeric films proved to be stable over time and under oxidation conditions; in addition, no loss of photosensitizer was observed during the experiments, thus demonstrating that the bactericidal action was effectively brought by the ROS generated by PCox immobilized in the material. After use, the films were recharged with PCox, with almost complete recovery of their photodynamic efficiency.

Photoactive antimicrobial coating based on a PEDOT-fullerene C60 polymeric dyad

“…In addition, Comuzzi et al reported the photokilling ability of polymeric materials obtained by imprinting a pentaphyrin derivative into electrodeposited dipyrromethane films. 28 Although all these materials showed promising photokilling activity, the photostability of tetrapyrrolic macrocycle can be a disadvantage and a determining factor for practical applications. Taking this condition into account, fullerene C 60 is a more photostable PS than porphyrinoid derivatives under visible light irradiation, since it undergoes relatively less photobleaching than tetrapyrrolic macrocycles.…”

Light-Activated Antibacterial Polymeric Surface Based on Porphycene

“…PDI treatments demonstrated the efficiency of these polymers to photokill Gram-positive and Gram-negative microorganisms after visible light illumination. In addition, Comuzzi and co-workers informed the electrosynthesis of photoactive surfaces using dipyrromethanes as monomers and imprinting a pentaphyrin compound as a PS . These thin organic films were also able to inactivate Staphylococcus aureus suspensions.…”

“…In addition, Comuzzi and co-workers informed the electrosynthesis of photoactive surfaces using dipyrromethanes as monomers and imprinting a pentaphyrin compound as a PS. 18 These thin organic films were also able to inactivate Staphylococcus aureus suspensions. Moreover, Ballatore et al have also proved that a meso-substituted porphyrin monomer containing four carbazole units could generate electrodeposited polymers with interesting antimicrobial activity.…”