Dual‐Function Multilayers for the Photodelivery of Nitric Oxide and Singlet Oxygen

Abstract

In this contribution we report the design, preparation and characterization of bichromophoric Langmuir-Schäfer multilayer films which enable the simultaneous generation of nitric oxide (NO) and singlet oxygen (1)O(2) ((1)Delta(g)). They are achieved by exploiting effective interfacial electrostatic interactions between the floating film of a cationic amphiphilic nitric oxide (NO) photodonor and an anionic porphyrin dissolved in the water subphase. The morphology and the spectroscopic features of the floating films at the water-air interface are inspected by Brewster angle microscopy and UV/Vis reflection spectroscopy, respectively. Multilayer films containing both the chromogenic centres are obtained by horizontal lifting deposition onto hydrophobized quartz substrates and are characterized by steady-state UV/Vis absorption, fluorescence and laser flash photolysis. The anionic porphyrin units are entangled into the films network mainly in their monomeric forms and no significant intra and inter-chromophoric interaction occur in the excited state, preserving the photochemical independency of the two photoactive units in the multilayers. The capability of the bichromophoric films to delivery NO and singlet oxygen, (1)O(2) ((1)Delta(g)), under light excitation is unambiguously demonstrated by the direct and in real time monitoring of these transient species using an ultrasensitive electrode and a time-resolved infrared luminescence apparatus, respectively.

Visible Photolysis and Amperometric Detection of S-Nitrosothiols

“…Photoelectric emission and strategies for circumventing it have been described previously. 32, 33 Nevertheless, irradiation of the RSNO-containing oxygenated PBS solution resulted in a low but measureable amperometric signal (Supporting Information, Figure S-2) similar to that observed previously by others using electrochemical NO sensors in the absence of controlled irradiation to measure RSNOs in oxygenated solutions. 21, 22, 25, 26 As NO is expected to exhibit an extended half-life in aqueous solutions at sub-µM concentrations (due to the negligibly slow autooxidation of NO to nitrite), 34 alternative mechanisms were considered.…”

Photocytotoxic activity of a nitrosyl phthalocyanine ruthenium complex — A system capable of producing nitric oxide and singlet oxygen

“…To the best of our knowledge, few works have demonstrated that NO and 1 O 2 can be synergistically used as anticancer agents [24,52]. In this context, mitochondria, which are the major intracellular sources and targets of reactive species, have been proposed to be associated with both cell necrosis and cell apoptosis [53].…”

Applications of Photoinduced Phenomena in Supramolecularly Arranged Phthalocyanine Derivatives: A Perspective

“…Then, the chosen NO donor, characterized by an adamantyl moiety linked to a nitroaniline commercial derivative, was encapsulated in the CDs exploiting the well-known affinity of the adamantane for CDs [147], avoiding the internalization of the entire chromophore. The tilted configuration of the nitro group with respect to the aromatic ring plane guarantees the NO photorelease and this binding mechanism is able to prevent from the planarization [59]. The final assembly was characterized and, upon 532 nm excitation, both the ZnPc transient triplet state decay at 500 nm and the 1 O 2 phosphorescence decay at 1270 nm were monitored confirming the great potential of this hybrid nanostructured assembly.…”

“…Unlike porphyrins, tetrapyrrolic macrocycles often associated to phthalocyanines for their chemical and physical features [58,59] and for the functionalization approaches usually employed [60], Pcs show both electron donor and electron acceptor characteristics depending on the chemical species they are interfaced. Further, photoinduced phenomena can be tuned changing the phthalocyanine central metal atom [61,62].…”