A calix[4]arene-based ternary supramolecular nanoassembly with improved fluoroquinolone photostability and enhanced NO photorelease. Issue 9 (11th March 2019)

• Record Type: Journal Article
• Authors: Fraix, Aurore; Afonso, Damien; Consoli, Grazia M. L.; Sortino, Salvatore
• Is Part Of: Photochemical & photobiological sciences. Volume 18:Issue 9(2019)
• Page Start: 2216
• Page End: 2224
• Publication Date: 2019-03-11
• Subjects: Photochemistry -- Periodicals; Photobiology -- Periodicals; 541.35
• DOI: 10.1039/c9pp00011a
• Languages: English
• ISSNs: 1474-905X

Abstract

Abstract : A calix[4]arene-based micellar nanoscaffold allows the co-encapsulation of a photolabile fluoroquinolone drug and a poorly photoreactive NO photodonor, simultaneously overcoming the main limitations of the free individual guests such as photolability and low photoreactivity. Abstract : Micellar-like nanoassemblies of a sulfonate amphiphilic calix[4]arene (1 ) are able to effectively co-entrap the fluoroquinolone antibacterial norfloxacin (2 ) and a hydrophobic nitric oxide (NO) photodonor (3 ), leading to a ternary supramolecular complex having a diameter of ca. 150 nm and a zeta potential of −48 mV. Outstanding photochemical stabilization of the otherwise photolabile fluoroquinolone2 is observed under UVA excitation. Besides, visible light excitation leads to a remarkable enhancement of the NO photorelease efficiency of3 . Both the results can be explained on the basis of a "cage effect" of the micellar host that, in the case of2, hinders the formation of the precursor complex responsible for the photodegradation, whereas in the case of3 it provides a low polarity environment and easily abstractable hydrogens, which facilitate the radical-mediated mechanism involved in NO photorelease. Therefore, this supramolecular ternary nanoassembly simultaneously overcomes the main limitations of the free individual guests such as photolability and low photoreactivity. In view of the well-known antibacterial properties of the NO radical and the biocompatibility of the calixarene host, this nanoassembly represents a suitable bimodal system to be tested in antibacterial research.