title: Niosomes as Drug Nanovectors: Multiscale pH-Dependent Structural Response.
abstract: The use of nanocarriers, which respond to different stimuli controlling their physicochemical properties and biological responsivness, shows a growing interest in pharmaceutical science. The stimuli are activated by targeting tissues and biological compartments, e.g., pH modification, temperature, redox condition, enzymatic activity, or can be physically applied, e.g., a magnetic field and ultrasound. pH modification represents the easiest method of passive targeting, which is actually used to accumulate nanocarriers in cells and tissues. The aim of this paper was to physicochemically characterize pH-sensitive niosomes using different experimental conditions and demonstrate the effect of surfactant composition on the supramolecular structure of niosomes. In this attempt, niosomes, made from commercial (Tween21) and synthetic surfactants (Tween20 derivatives), were physicochemically characterized by using different techniques, e.g., transmission electron microscopy, Raman spectroscopy, and small-angle X-ray scattering. The changes of niosome structure at different pHs depend on surfactants, which can affect the supramolecular structure of colloidal nanocarriers and their potential use both in vitro and in vivo. At pH 7.4, the shape and structure of niosomes have been maintained; however, niosomes show some differences in terms of bilayer thicknesses, water penetration, membrane coupling, and cholesterol dispersion. The acid pH (5.5) can increase the bilayer fluidity, and affect the cholesterol depletion. In fact, Tween21 niosomes form large vesicles with lower curvature radius at acid pH; while Tween20-derivative niosomes increase the intrachain mobility within a more interchain correlated membrane. These results demonstrate that the use of multiple physicochemical procedures provides more information about supramolecular structures of niosomes and improves the opportunity to deeply investigate the effect of stimuli responsiveness on the niosome structure.
authors.affiliation: Department of Drug Chemistry and Technology, University of Rome "Sapienza" , 00185 Rome, Italy.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Marianecci
authors.affiliation: Department of Pharmacy, University of Chieti - Pescara "G d'Annunzio" , 66100 Chieti - Pescara, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Di Marzio
authors.affiliation: Department of Medical Biotechnologies and Traslational Medicine, University of Milan , LITA, 20122 Milan, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Del Favero
authors.affiliation: Department of Medical Biotechnologies and Traslational Medicine, University of Milan , LITA, 20122 Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Cantù
authors.affiliation: Department of Medical Biotechnologies and Traslational Medicine, University of Milan , LITA, 20122 Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Brocca
authors.affiliation: Department of Medical Biotechnologies and Traslational Medicine, University of Milan , LITA, 20122 Milan, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Rondelli
authors.affiliation: Center for Life Nano Science@Sapienza, Fondazione Istituto Italiano di Tecnologia , 00197 Rome, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Rinaldi
authors.affiliation: Department of Biological and Environmental Sciences and Technologies, University of Salento , 73100 Lecce, Italy.
authors.forename: Luciana
authors.initials: L
authors.lastname: Dini
authors.affiliation: Department of Physics Applied to Materials Science Laboratory (PAMS-Lab), University of Salento , 73100 Lecce, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Serra
authors.affiliation: Department of Translational Imaging, Houston Methodist Research Institute , Houston, Texas 77030, United States.|Department of Drug Discovery and Development, Fondazione Istituto Italiano di Tecnologia , 16163 Genoa, Italy.|Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Græcia" , 88100 Catanzaro, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Decuzzi
authors.affiliation: Department of Pharmacy, University of Chieti - Pescara "G d'Annunzio" , 66100 Chieti - Pescara, Italy.|Department of Nanomedicine, Houston Methodist Research Institute , Houston, Texas 77030, United States.
authors.forename: Christian
authors.initials: C
authors.lastname: Celia
authors.affiliation: Department of Experimental and Clinical Medicine, University of Catanzaro "Magna Græcia" , 88100 Catanzaro, Italy.|IRC FSH-Interregional Research Center for Food Safety & Health, University of Catanzaro "Magna Græcia" , 88100 Catanzaro, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Paolino
authors.affiliation: IRC FSH-Interregional Research Center for Food Safety & Health, University of Catanzaro "Magna Græcia" , 88100 Catanzaro, Italy.|Department of Health Sciences, University of Catanzaro "Magna Græcia" , 88100 Catanzaro, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Fresta
authors.affiliation: Department of Drug Chemistry and Technology, University of Rome "Sapienza" , 00185 Rome, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Carafa
mesh_terms: D002627:Chemistry, Physical; D002784:Cholesterol / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D011136:Polysorbates / Q000737:chemistry*; D053838:Scattering, Small Angle; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D011136:Polysorbates; D002784:Cholesterol