Therole of nitric oxide (NO) as an "unconventional"therapeutic and the strict dependence of biological effects on itsconcentration require the generation of NO with precise spatiotemporalcontrol. The development of precursors and strategies to activateNO release by excitation in the so-called "therapeutic window"with highly biocompatible and tissue-penetrating red light is desirableand challenging. Herein, we demonstrate that one-photon red-lightexcitation of Verteporfin, a clinically approved photosensitizer (PS)for photodynamic therapy, activates NO release, in a catalytic fashion,from an otherwise blue-light activatable NO photodonor (NOPD) withan improvement of about 300 nm toward longer and more biocompatiblewavelengths. Steady-state and time-resolved spectroscopic and photochemicalstudies combined with theoretical calculations account for an NO photoreleasephotosensitized by the lowest triplet state of the PS. In view ofbiological applications, the water-insoluble PS and NOPD have beenco-entrapped within water-dispersible, biodegradable polymeric nanoparticles(NPs) of mPEG-b-PCL (about 84 nm in diameter), where the red-lightactivation of NO release takes place even more effectively than inan organic solvent solution and almost independently by the presenceof oxygen. Moreover, the ideal spectroscopic prerequisites and therestricted environment of the NPs permit the green-fluorescent co-productformed concomitantly to NO photorelease to communicate with the PSvia Fo''rster resonance energy transfer. This leads to an enhancementof the typical red emission of the PS offering the possibility ofa double color optical reporter useful for the real-time monitoringof the NO release through fluorescence techniques. The suitabilityof this strategy applied to the polymeric NPs as potential nanotherapeuticswas evaluated through biological tests performed by using HepG2 hepatocarcinomaand A375 melanoma cancer cell lines. Fluorescence investigation incells and cell viability experiments demonstrates the occurrence ofthe NO release under one-photon red-light illumination also in thebiological environment. This confirms that the adopted strategy providesa valuable tool for generating NO from an already available NOPD,otherwise activatable with the poorly biocompatible blue light, withoutrequiring any chemical modification and the use of sophisticated irradiationsources.

Red-Light-Photosensitized NO Release and Its Monitoring in Cancer Cells with Biodegradable Polymeric Nanoparticles

Graziano A. C. E.;
2023-01-01

Abstract

Therole of nitric oxide (NO) as an "unconventional"therapeutic and the strict dependence of biological effects on itsconcentration require the generation of NO with precise spatiotemporalcontrol. The development of precursors and strategies to activateNO release by excitation in the so-called "therapeutic window"with highly biocompatible and tissue-penetrating red light is desirableand challenging. Herein, we demonstrate that one-photon red-lightexcitation of Verteporfin, a clinically approved photosensitizer (PS)for photodynamic therapy, activates NO release, in a catalytic fashion,from an otherwise blue-light activatable NO photodonor (NOPD) withan improvement of about 300 nm toward longer and more biocompatiblewavelengths. Steady-state and time-resolved spectroscopic and photochemicalstudies combined with theoretical calculations account for an NO photoreleasephotosensitized by the lowest triplet state of the PS. In view ofbiological applications, the water-insoluble PS and NOPD have beenco-entrapped within water-dispersible, biodegradable polymeric nanoparticles(NPs) of mPEG-b-PCL (about 84 nm in diameter), where the red-lightactivation of NO release takes place even more effectively than inan organic solvent solution and almost independently by the presenceof oxygen. Moreover, the ideal spectroscopic prerequisites and therestricted environment of the NPs permit the green-fluorescent co-productformed concomitantly to NO photorelease to communicate with the PSvia Fo''rster resonance energy transfer. This leads to an enhancementof the typical red emission of the PS offering the possibility ofa double color optical reporter useful for the real-time monitoringof the NO release through fluorescence techniques. The suitabilityof this strategy applied to the polymeric NPs as potential nanotherapeuticswas evaluated through biological tests performed by using HepG2 hepatocarcinomaand A375 melanoma cancer cell lines. Fluorescence investigation incells and cell viability experiments demonstrates the occurrence ofthe NO release under one-photon red-light illumination also in thebiological environment. This confirms that the adopted strategy providesa valuable tool for generating NO from an already available NOPD,otherwise activatable with the poorly biocompatible blue light, withoutrequiring any chemical modification and the use of sophisticated irradiationsources.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11387/163542
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