Antimicrobial photodynamic polymeric films bearing biscarbazoltriphenylamine end-capped dendrimeric Zn(II) porphyrin

MARTÍNEZ, SOL R.; MANGIONE, MARIA; OTERO, LUIS; DURANTINI, ANDRÉS M.; DURANTINI, JAVIER; DURANTINI, EDGARDO; HEREDIA, DANIEL; PEREZ, EUGENIA; GERVALDO, MIGUEL

ACS Applied Materials & Interfaces

American Chemical Society

Año: 2019 vol. 11 p. 27574 - 27587

1944-8252

A novel biscarbazol-triphenylamine end-capped dendrimeric zinc(II) porphyrin (DP 5) was synthesized by click chemistry. This compound is a cruciform dendrimer, which bears a nucleus of zinc(II) tetrapyrrolic macrocycle substituted at the meso positions by four identical substituents. These are formed by a tetrafluorophenyl group that possess in the para position a triazole unit. This nitrogenous heterocyclic is connected to a 4,4´-di(N-carbazolyl)triphenylamine group by means of a phenylenevinylene bridge, which allows the conjugation between the nucleus and this external electropolimerizable carbazoyl group. In this structure, dendrimeric arms act as light-harvesting antennas, increasing the absorption of blue light and as electroactive moieties. The electrochemical oxidation of the carbazole groups contained in the terminal arms of the DP 5 was used to obtain novel stable and reproducible fully π-conjugate photoactive polymeric films (FDP 5). First, the spectroscopic characteristics and photodynamic properties of DP 5 were compared with its constitutional components derived of porphyrin P 6 and carbazole D 7 moieties in solution. The fluorescence emission of the dendrimeric units in DP 5 were strongly quenched by the tetrapyrrolic macrocycle, indicating photoinduced energy transfer. In addition, FDP 5 film showed the Soret and Q absorption bands and red fluorescence emission of the corresponding zinc(II) porphyrin. Also, FDP 5 film was highly stable to photobleaching and it was able to produce singlet molecular oxygen in both N,N-dimethylformamide and water. Therefore, the porphyrin units embedded in the polymeric matrix of FDP 5 film mainly retain the photochemical properties. Photodynamic inactivation mediated by FDP 5 film was investigated in Staphylococcus aureus and Escherichia coli. When a cell suspension was deposited on the surface, complete eradication of S. aureus and a 99% reduction in E. coli survival were found after 15 min and 30 min irradiation, respectively. Also, FDP 5 film was highly effective to eliminate individual bacteria attached to the surface. In addition, PDI sensitized by FDP 5 film produced more than 99.99% bacterial killing in biofilms formed on the surface after 60 min irradiation. The results indicate that FDP 5 film represents an interesting and versatile photodynamic active material to eradicate bacteria as planktonic cells, individual attached microbes or biofilms.