title: Bifunctional ultraviolet/ultrasound responsive composite TiO2/polyelectrolyte microcapsules.
abstract: Designing and fabricating multifunctional microcapsules are of considerable interest in both academic and industrial research aspects. This work reports an innovative approach to fabricate composite capsules with high UV and ultrasound responsive functionalities that can be used as external triggers for controlled release, yet with enhanced mechanical strength that can make them survive in a harsh environment. Needle-like TiO2 nanoparticles (NPs) were produced in situ into layer-by-layer (LbL) polyelectrolyte (PE) shells through the hydrolysis of titanium butoxide (TIBO). These rigid TiO2 NPs yielded the formed capsules with excellent mechanical strength, showing a free standing structure. A possible mechanism is proposed for the special morphology formation of the TiO2 NPs and their reinforcing effects. Synergistically, their response to UV and ultrasound was visualized via SEM, with the results showing an irreversible shell rapture upon exposure to either UV or ultrasound irradiation. As expected, the release studies revealed that the dextran release from the TiO2/PE capsules was both UV-dependent and ultrasound-dependent. Besides, the biocompatibility of the capsules with the incorporation of amorphous TiO2 NPs was confirmed by an MTT assay experiment. All these pieces of evidence suggested a considerable potential medicinal application of TiO2/PE capsules for controlled drug delivery.
authors.affiliation: The School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK. g.sukhorukov@qmul.ac.uk.
authors.forename: Hui
authors.initials: H
authors.lastname: Gao
authors.affiliation: Institute of Particle Science and Engineering, University of Leeds, Leeds, LS2 9JT, UK.
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Wen
authors.affiliation: The School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK. g.sukhorukov@qmul.ac.uk.
authors.forename: Nadezda V
authors.initials: NV
authors.lastname: Tarakina
authors.affiliation: The School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK. g.sukhorukov@qmul.ac.uk.
authors.forename: Jierong
authors.initials: J
authors.lastname: Liang
authors.affiliation: The School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK. g.sukhorukov@qmul.ac.uk.
authors.forename: Andy J
authors.initials: AJ
authors.lastname: Bushby
authors.affiliation: The School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK. g.sukhorukov@qmul.ac.uk.
authors.forename: Gleb B
authors.initials: GB
authors.lastname: Sukhorukov
mesh_terms: D002214:Capsules; D003287:Contrast Media / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D000071228:Polyelectrolytes / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D000069453:Ultrasonic Waves; D014466:Ultraviolet Rays
chemical_list: D002214:Capsules; D003287:Contrast Media; D003692:Delayed-Action Preparations; D000071228:Polyelectrolytes; C009495:titanium dioxide; D014025:Titanium