Immobilized photosensitizers for antimicrobial applications

Abstract

Photodynamic antimicrobial chemotherapy (PACT) is a very promising alternative to conventional antibiotics for the efficient inactivation of pathogenic microorganisms; this is due to the fact that it is virtually impossible for resistant strains to develop due to the mode of action employed. PACT employs a photosensitizer, which preferentially associates with the microorganism, and is then activated with non-thermal visible light of appropriate wavelength(s) to generate high localized concentrations of reactive oxygen species (ROS), inactivating the microorganism. The concept of using photosensitizers immobilized on a surface for this purpose is intended to address a range of economic, ecological and public health issues. Photosensitising molecules that have been immobilized on solid support for PACT applications are described herein. Different supports have been analyzed as well as the target microorganism and the effectiveness of particular combinations of support and photosensitizer.

Superior performance of macroporous over gel type polystyrene as a support for the development of photo-bactericidal materials

“…aPDI can be applied using soluble 12 or supported photosensitizers. [13][14][15][16][17][18][19][20] A broad number of chemical families have been proposed as effective generators of ROS, especially singlet oxygen ( 1 O 2 ). 21 Among those molecules, xanthenic dyes, phenothiazinium compounds, porphyrins and phthalocyanins have been studied.…”

“…[24][25][26][27][28][29][30][31][32][33][34][35] Regarding the supports for the photoactive agents, a variety of materials have been described in the literature, like polyurethane, cellulose, nylon, chitosan, silica and polystyrene. [13][14][15][16][17][18][19][20] This last polymer is one of the most popular supports employed so far, dating back to the pioneering works of Schaap and Neckers. 36 Polystyrene is a versatile system, used in applications as diverse as fluorescence sensing 37 or catalysis.…”

A photobleaching resistant polymer supported hexanuclear molybdenum iodide cluster for photocatalytic oxygenations and photodynamic inactivation of Staphylococcus aureus

“…Also a new polymeric photosensitizer derived from 1 is described, which shows not only outstanding stability for repeated use in photocatalytic cycles, but also photodynamic antimicrobial activity against S. aureus, which is, to the best of our knowledge, the first demonstrated bactericidal photodynamic application of this class of complexes, thus adding a new agent to the current toolbox for the treatment of bacterial infections. 7,8 The synthesis and characterization of 1 has been reported. 10 In order to explore the potential application of this complex in photocatalysis and photoinactivation of microorganisms, cluster 1 was immobilized onto a solid polystyrene matrix to yield 1@PS.…”

“…These are only preliminary results but they are worth mentioning since they offer the first evidence of photodynamic antibacterial activity of a molybdenum cluster. Although the absorption properties of the described supported photosensitizer could seem as not optimal for all PDT applications, since the absorption in the visible range is low, it must be recalled that a number of materials for use in photodisinfection have been described (for instance sterilisable catheters) not requiring long wavelength absorptions 8 19 Hence, it seems clear that the role of the cationic matrix is not merely to serve as a simple support for the photosensitizer, and consequently this consideration will be taken into account in future studies with a comprehensive series of polymer matrices.…”

Procesos de oxidación avanzada en el ciclo integral del agua

“…Los sistemas soportados en matriz polimérica resultan de gran atractivo desde el punto de vista medioambiental dado que combinan la capacidad de absorber luz solar visible, generar una especie oxidante como 1 O 2 y, a su vez, poder ser eliminados (y reciclados en su caso). En la bibliografía existen algunas publicaciones de revisión sobre materiales orgánicos generadores de oxígeno singlete, pero normalmente orientados a aspectos específicos como la inactivación bacteriana o la síntesis orgánica (Lacombe, 2016;Spagnul, 2015;Wahlen, 2004;Wang, 2004). En este trabajo se hará una recopilación de diversos avances publicados sobre polímeros fotoactivos generadores de Índice Sistemas no convencionales para procesos fotoquímicos de oxidación 123 6 primer lugar, se comentarán ejemplos de materiales orgánicos fotoactivos en los cuales la unión es covalente.…”