Polystyrene Nanofiber Materials Modified with an Externally Bound Porphyrin Photosensitizer

Abstract

Polystyrene ion-exchange nanofiber materials with large surface areas and adsorption capacities were prepared by electrospinning followed by the sulfonation and adsorption of a cationic 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP) photosensitizer on the nanofiber surfaces. The morphology, structure, and photophysical properties of these nanofiber materials were characterized by microscopic methods and steady-state and time-resolved fluorescence and absorption spectroscopies. The externally bound TMPyP can be excited by visible light to form triplet states and singlet oxygen O2((1)Δg) and singlet oxygen-sensitized delayed fluorescence (SODF). The photophysical properties of the nanofibers were strongly dependent on the amount of bound TMPyP molecules and their organization on the nanofiber surfaces. The nanofibers demonstrated photooxidative activity toward inorganic and organic molecules and antibacterial activity against E. coli due to the sensitized formation of O2((1)Δg) that is an effective oxidation/cytotoxic agent. The nanofiber materials also adsorbed heavy metal cations (Pb(2+)) and removed them from the water environment.

Procesos de oxidación avanzada en el ciclo integral del agua

“…Henke y colaboradores describen un sistema del primer tipo, donde una matriz de poliestireno con carga negativa es capaz de retener una porfirina cargada positivamente (Henke, 2013) tal y como se muestra en la figura 6.7. En dicha figura se muestra una imagen del material antes de la carga con el fotosensibilizador (film blanco de poliestireno sulfonado) así como después de interaccionar con la porfirina (film oscuro).…”

“…Izquierda: imagen de film de poliestireno sulfonado antes (a) y después (b) de unión a fotosensitilizador. Derecha: estructura de fotocatalizador soportado por unión iónica (Henke, 2013). Reproducido con permiso: Copyright © 2013, American Chemical Society…”

Ultrafine polystyrene nanofibers and its application in nanofibrous membranes

“…As is well-known, PS nanoparticles can be prepared perfectly nowadays and are used as an important template to prepare porous materials [16]. But for PS nanofibers, there are only one preparation method reported, i.e., the electrospinning [18][19][20][21].…”

Visible light active nanofibrous membrane for antibacterial wound dressing

“…As an alternative method reported by Mosinger et al, hydrophobic PS tetraphenylporphyrin was encapsulated in polyurethane or polystyrene nanofibers. 30,[35][36][37] Therefore, the leakage of the PS could be avoided, but due to the insufficient contact between the hydrophobic fiber surface and the biological targets in an aqueous medium, the photo-oxidation efficiency was significantly decreased. Increasing the surface wettability could improve the photo-oxidation efficiency of the fibers.…”

“…More efficient photo-oxidation was also achieved by attaching a cationic photosensitizer to the surface of sulfonated nanofibers, where the photosensitizer is more sensitive and again may leak into the surrounding tissues. 36,37 Taking the above developments and their limitations into consideration, we present here a new class of visible light-active hydrogel nanofibrous membranes for disinfecting wound dressings (see Scheme 1). This photoactive membrane was fabricated by first synthesizing conjugated microporous polymer nanoparticles in a miniemulsion and subsequently embedding the nanoparticles in polyvinyl alcohol (PVA) hydrogel nanofibers by colloid-electrospinning.…”