title: Hydrogen peroxide mechanosynthesis in siloxane-hydrogel contact lenses.
abstract: Drug-loaded contact lenses are emerging as the preferred treatment method for several ocular diseases, and efforts are being directed to promote extended and controlled delivery. One strategy is based on delivery induced by environmental triggers. One of these triggers can be hydrogen peroxide, since many platforms based on drug-loaded nanoparticles were demonstrated to be hydrogen-peroxide responsive. This is particularly interesting when hydrogen peroxide is the result of a specific pathophysiological condition. Otherwise, an alternative route to induce drug delivery is here proposed, namely the mechano-synthesis. The present work represents the proof-of-concept of the mechanosynthesis of hydrogen peroxide in siloxane-hydrogel contact lenses as a consequence of the cleavage of siloxane bonds at the interface between the polymer and water in aqueous phase. Their spongy morphology makes contact lenses promising systems for mechanical-to-chemical energy conversion, since the amount of hydrogen peroxide is expected to scale with the interfacial area between the polymer and water. The eyelid pressure during wear is sufficient to induce the hydrogen peroxide synthesis with concentrations which are biocompatible and suitable to trigger the drug release through hydrogen-peroxide-responsive platforms. For possible delivery on demand, the integration of piezoelectric polymers in the siloxane-hydrogel contact lenses could be designed, whose mechanical deformation could be induced by an applied wireless-controlled voltage.
authors.affiliation: Materials Science Department, University of Milano Bicocca , Via Cozzi 55, I-20125 Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Tavazzi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Ferraro
authors.forename: Federica
authors.initials: F
authors.lastname: Cozza
authors.forename: Valentina
authors.initials: V
authors.lastname: Pastori
authors.forename: Marzia
authors.initials: M
authors.lastname: Lecchi
authors.forename: Stefano
authors.initials: S
authors.lastname: Farris
authors.forename: Alessandro
authors.initials: A
authors.lastname: Borghesi
mesh_terms: D003261:Contact Lenses; D016503:Drug Delivery Systems; D005128:Eye Diseases / Q000188:drug therapy*; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry
chemical_list: D012833:Siloxanes; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D006861:Hydrogen Peroxide
keywords: Fenton reaction; contact lenses; hydrogen peroxide; mechanochemistry; water/polymer interface