From Ultrathin Capsules to Biaqueous Vesicles

Khopade, A. J.; Arulsudar, N.; Khopade, Surekha A.; Knocke, Roy; Hartmann, Jürgen; Möhwald, Helmuth

doi:10.1021/bm0504936

Cited by 3 publications

(5 citation statements)

References 27 publications

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“…The vesicle wall thickness is about 23 nm according to the Bragg equation of d = 2π q −1 determined by the small-angle X-ray scattering (SAXS) experiment ( Fig. 2h) 33,34 , which agrees well with the SEM results. The self-assembly of THPG 11 also generated spherical vesicles according to the TEM image ( Supplementary Fig.…”

Section: Preparation and Characterization Of Thpg Polymer Vesiclessupporting

confidence: 82%

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In situ supramolecular polymerization-enhanced self-assembly of polymer vesicles for highly efficient photothermal therapy

et al. 2020

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Vesicular photothermal therapy agents (PTAs) are highly desirable in photothermal therapy (PTT) for their excellent light-harvesting ability and versatile hollow compartments. However, up to now, the reported vesicular PTAs are generally self-assembled from small molecules like liposomes, and polymer vesicles have seldom been used as PTAs due to the unsatisfactory photothermal conversion efficiency resulting from the irregular packing of chromophores in the vesicle membranes. Here we report a nano-sized polymer vesicle from hyperbranched polyporphyrins with favorable photothermal stability and extraordinarily high photothermal efficiency (44.1%), showing great potential in imaging-guided PTT for tumors through in vitro and in vivo experiments. These excellent properties are attributed to the in situ supramolecular polymerization of porphyrin units inside the vesicle membrane into well-organized 1D monofilaments driven by π-π stacking. We believe the supramolecular polymerization-enhanced self-assembly process reported here will shed a new light on the design of supramolecular materials with new structures and functions.

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Section: Preparation and Characterization Of Thpg Polymer Vesiclessupporting

confidence: 82%

“…The photothermal conversion efficiency (η), was calculated using the following Eq. (1) 16,[33][34][35] .…”

Section: Methodsmentioning

confidence: 99%

In situ supramolecular polymerization-enhanced self-assembly of polymer vesicles for highly efficient photothermal therapy

et al. 2020

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“…The two complexes phase separate in water as high-density liquid and viscous liquid droplets that converts to a sticky, plastic, and semisolid/solid complex, respectively, on addition of Zn 2+ ions. The two complexes air-dry as a glassy material with different properties described elsewhere . Analogously, variations in the yield of the capsules were obtained after decomposition of [PE/TbS] n @ZnO cores.…”

Section: Resultsmentioning

confidence: 99%

Ultrathin Antibiotic Walled Microcapsules

et al. 2004

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Ultrathin microcapsules comprised of anionic polyelectrolytes (PE) and a polycationic aminoglycoside (AmG) antibiotic drug were prepared by depositing PE/AmG multilayers on zinc oxide (ZnO) colloid particles using the layer-by-layer self-assembly technique and subsequently dissolving the ZnO templated cores. The polyelectrolytes, dextran sulfate sodium (DxS) and poly(styrenesulfonate) (PSS), were selected owing to their different backbone structure. An aminoglycoside, tobramycin sulfate (TbS), was used for studying DxS/TbS or PSS/TbS multilayer films. The multilayer growth on ZnO cores was characterized by alternating zeta potential values that were different for the DxS/TbS and PSS/TbS multilayers due to the PE chemistry and its interaction with Zn(2+) ions. Transmission and scanning electron microscopy provide evidence of PE/TbS multilayer coating on ZnO core particles. The slow acid-decomposition of the ZnO cores using weak organic acids and the presence of sufficient quantity of Zn(2+) in the dispersion were required to produce antibiotic multilayer capsules. There was no difference in the morphological characteristics of the two types of capsules; although, the yield for [PSS/TbS](5) capsules was significantly higher than for [DxS/TbS](5) capsules which was related to the physicochemical properties of DxS/TbS/Zn(2+) and PSS/TbS/Zn(2+) complexes forming the capsule wall. The TbS quantity in the multilayer films was determined using a quartz crystal microbalance and high performance liquid chromatography techniques which showed less TbS loading in both, capsules and multilayers on planar gold substrate, than the theoretical DxS:TbS or PSS:TbS stoichiometric ratio. The decomposition of the [PE/TbS](6) multilayers was fastest in physiological buffer followed by mannitol and water. The decomposition rate of the [PSS/TbS](6) multilayers was slower than [DxS/TbS](6) monolayers. The incomplete decomposition of DxS/TbS under saline conditions suggests the major role of hydrogen bonding for stability of DxS/TbS multilayers. A combination of hydrogen bonding and hydrophobic interaction between phenyl rings in PSS was responsible for PSS/TbS multilayer stability. In vivo studies in rabbits highlight the safety and sustained drug delivery potential of the PE/AmG microcapsules. The antibiotic walled ultrathin capsules presented here are suitable for sustained ophthalmic antibiotic delivery.

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“…19 In the LbL method, oppositely charged polymers are sequentially layered onto the surface of the template. 20 For medical applications, the use of highly charged polymer materials may not be preferred since polyelectrolytes have known biological activities, such as anti-or procoagulation and protein binding. [21][22][23] Polycations often demonstrate the added problem of toxicity.…”

Section: Introductionmentioning

confidence: 99%

“…Several methods have been employed to fabricate polymer-based micro- and nanocapsules including self-assembly of amphiphlic block copolymers, − layer-by-layer (LbL) coating, − and interfacial or surface polymerization. − Bates et al have demonstrated the utility of block copolymers self-assembled into “polymersomes”, which may be cross-linked within the hydrophobic region of the shell to improve the physical stability of these capsules. , In comparison to liposomes, polymersomes have demonstrated robust stability, acceptable drug loading, and controlled release. , The processes to fabricate hollow capsules by LbL and polymerization methods typically rely on the deposition of polymer films onto the surface of core templates such as colloidal silica, CaCO 3 , etc., followed by the removal of the templates by appropriate chemical etching . In the LbL method, oppositely charged polymers are sequentially layered onto the surface of the template . For medical applications, the use of highly charged polymer materials may not be preferred since polyelectrolytes have known biological activities, such as anti- or procoagulation and protein binding. − Polycations often demonstrate the added problem of toxicity …”

Section: Introductionmentioning

confidence: 99%

Acid-Labile Polyvinylamine Micro- and Nanogel Capsules

Shi

Berkland

2007

Macromolecules

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Hollow nanoparticles represent an emerging area of development for the encapsulation of active ingredients. Expanding the capabilities of these nanomaterials will require continued efforts to infill properties such as size control, biodegradability, and environmental responsiveness. Acid-labile poly(N-vinylformamide) (PNVF) nanocapsules were synthesized by free radical polymerization of N-vinylformamide on the surface of silica nanoparticles. Polymerization in the presence of a novel crosslinker that contains an acid-labile ketal facilitated stable etching of silica nanoparticle templates using sodium hydroxide and recovery of degradable PNVF nanocapsules. The formamido side group of PNVF was then hydrolyzed by extended exposure to sodium hydroxide to produce polyvinylamine (PVAm) micro- and nanocapsules. Both capsule types demonstrated an increasing dissolution rate as pH decreased. In addition, PVAm nanocapsules exhibited swelling in proportion to the relative charge density of the PVAm network (a function of the degree of formamide hydrolysis and pH), presumably due to the repulsion of positively charged amino groups within the elastic shell network. The synthetic approaches reported provide methods to endow nanocapsules with key attributes such as size control, pH sensitive degradation, swelling in response to pH, and amine functionality.

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From Ultrathin Capsules to Biaqueous Vesicles

Cited by 3 publications

References 27 publications

In situ supramolecular polymerization-enhanced self-assembly of polymer vesicles for highly efficient photothermal therapy

In situ supramolecular polymerization-enhanced self-assembly of polymer vesicles for highly efficient photothermal therapy

Ultrathin Antibiotic Walled Microcapsules

Acid-Labile Polyvinylamine Micro- and Nanogel Capsules

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