Optimization of singlet oxygen production from photosensitizer‐incorporated, medically relevant hydrogels

Abstract

Photodynamic therapy and photodynamic antimicrobial chemotherapy are widely used, but despite this, the relationships between fluence, wavelength of irradiation and singlet oxygen (1O2) production are poorly understood. To establish the relationships between these factors in medically relevant materials, the effect of fluence on 1O2 production from a tetrakis(4‐N‐methylpyridyl)porphyrin (TMPyP)‐incorporated 2‐hydroxyethyl methacrylate: methyl methacrylate: methacrylic acid (HEMA: MMA:MAA) copolymer, a total energy of 50.48 J/cm2, was applied at varying illumination power, and times. 1O2 production was characterized using anthracene‐9,10‐dipropionic acid, disodium salt (ADPA) using a recently described method. Using two light sources, a white LED array and a white halogen source, the LED array was found to produce less 1O2 than the halogen source when the same power (over 500 − 600 nm) and time conditions were applied. Importantly, it showed that the longest wavelength Q band (590 nm) is primarily responsible for 1O2 generation, and that a linear relationship exists between increasing power and time and the production of singlet oxygen. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 320–326, 2017.

Aptamer-Conjugated Micelles for Targeted Photodynamic Therapy Via Photoinitiated Polymerization-Induced Self-Assembly

“…45,77,78 The reduction in ADPA absorbance indicated the generation and reaction of 1 O 2 with ADPA to form an endoperoxide, which had no absorbance at 378 nm due to the breakdown of the anthryl chromophore. 79 As a negative control, we monitored the reduction of absorbance when ADPA was combined with RBloaded micelles in the dark and found that there was negligible production of 1 O 2 over at least 20 min (Figure S15). We then explored the influence of the concentration of micelles exposed to yellow light on the rate of 1 O 2 release in PBS.…”

Sequential drug delivery by injectable macroporous hydrogels for combined photodynamic-chemotherapy

“…The optical property of DPBF was sensitively affected by 1 O 2 [ 27 ]. With DPBF as the 1 O 2 capture agent, the 1 O 2 generation efficiency of TPP in Gel can be calculated from the slopes of DPBF absorbance variation (410 nm) in the presence of photosensizers.…”

Hydrogels: soft matters in photomedicine

“…In 2014, Craig et al reported an improved method tailored to the analysis of porphyrin-hydrogels using anthracene-9,10-dipropionic acid, which undergoes photobleaching at the 378 nm absorption band via endoperoxide formation. 189,190 For hydrogels, this is compounded by the need to measure singlet oxygen generation (with its short lifetime) in an aqueous environment and to account for the possibility of the sensor migrating into the matrix. Electron paramagnetic resonance, microwave spectroscopy and mass spectrometry can be considered as direct methods that can be used for singlet oxygen determination in hydrogels.…”