Nanoparticle-to-vesicle and nanoparticle-to-toroid transitions of pH-sensitive ABC triblock copolymers by in-to-out switch

Xiao, Xue; He, Suqin; Dan, Meihan; Huo, Fei; Zhang, Wangqing

doi:10.1039/c4cc00813h

Cited by 32 publications

(43 citation statements)

References 43 publications

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“…In addition to temperature, other environmental factors such as pH, electrolytes and chemicals, have been used to trigger order–order transitions of PISA‐prepared block copolymer nanoparticles.…”

Section: Pisa‐made Nanoparticles Responsive To Ph and Other Stimulimentioning

confidence: 99%

Stimulus‐Responsive Nanoparticles and Associated (Reversible) Polymorphism via Polymerization Induced Self‐assembly (PISA)

Pei

Lowe

Roth

2016

Macromol. Rapid Commun.

118

131

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"smart" materials rely on very distinct material responses on a macroscopic and/or microscopic level. This can be achieved by crafting stimulus-responsive polymers into nanostructured materials, including smart nanoparticles, which are receiving increasing attention specifically in the biomedical field. [2,3] Amphiphilic block copolymers are well-known to undergo self-directed assembly in selective solvents providing access to a range of soft matter nanoparticles [4][5][6][7] with applications in coatings, [8] electronics, [9] drug delivery, [10] and cancer therapy, [11,12] among others. Traditionally, the preparation of such nanoparticles has been accomplished by initial synthesis and molecular dissolution of well-defined parent copolymers which are subsequently "processed", often via time-consuming step-wise dialysis, to give the targeted nano-object. Another drawback of this well-established approach is the generally low concentration of the final copolymer nanoparticles (≤1.0 wt% is common) which limits industrial application and study of such nanoparticles in areas where high Polymerization-induced self-assembly (PISA) is an extremely versatile method for the in situ preparation of soft-matter nanoparticles of defined size and morphologies at high concentrations, suitable for large-scale production. Recently, certain PISA-prepared nanoparticles have been shown to exhibit reversible polymorphism ("shape-shifting"), typically between micellar, worm-like, and vesicular phases (order-order transitions), in response to external stimuli including temperature, pH, electrolytes, and chemical modification. This review summarises the literature to date and describes molecular requirements for the design of stimulus-responsive nano-objects. Reversible pH-responsive behavior is rationalised in terms of increased solvation of reversibly ionized groups. Temperature-triggered order-order transitions, conversely, do not rely on inherently thermo-responsive polymers, but are explained based on interfacial LCST or UCST behavior that affects the volume fractions of the core and stabilizer blocks. Irreversible morphology transitions, on the other hand, can result from chemical post-modification of reactive PISA-made particles. Emerging applications and future research directions of this "smart" nanoparticle behavior are reviewed.

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Section: Pisa‐made Nanoparticles Responsive To Ph and Other Stimulimentioning

confidence: 99%

Stimulus‐Responsive Nanoparticles and Associated (Reversible) Polymorphism via Polymerization Induced Self‐assembly (PISA)

Pei

Lowe

Roth

2016

Macromol. Rapid Commun.

118

131

View full text Add to dashboard Cite

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“…By replacing PNIPAM with a statistic copolymer of poly(ethylene oxidestat‐butylene oxide), the micelle‐to‐vesicle transition was achieved within one week . Adopting a similar design method, reversible switch from micelle to high‐ordered structures was reported by other groups . However, most of the previous studies were focused on alteration in the packing parameter ( p ) of the responsive copolymers upon external stimuli.…”

Section: Introductionmentioning

confidence: 95%

“…So far, a number of groups addressed their attempts to reassemble ABC terpolymers in water, which usually contains three components, that is, hydrophilic, hydrophobic, and stimuli‐responsive segments. The hydrophilic unit aims to confer copolymer water solubility; the hydrophobic block contributes to the first level of self‐assembly; and the stimuli‐responsive segment provides the driving force of morphology transition.…”

Section: Introductionmentioning

confidence: 99%

Morphology Transition of Dual‐Responsive ABC Terpolymer in Water: Effect of Hydrophobic Block

Luo

Wei

Luo

et al. 2018

Macro Chemistry & Physics

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To reveal the importance of hydrophobic block in morphology transition of responsive copolymers, four well‐defined ABC terpolymers with the same poly(dimethylamino ethyl methacrylate) (PDMAEMA) and PEG segments are synthesized by sequential RAFT polymerization. Poly (n‐hexyl methacrylate) (PnHMA), poly(n‐butyl methacrylate) (PnBMA), poly(ethyl methacrylate) (PEMA), and poly(methyl methacrylate) (PMMA), with glass transition temperatures of −5, 20, 65, and 100 °C, respectively, are selected as hydrophobic segments. The structures and compositions of four terpolymers, that is, mPEG45‐b‐PnHMA29‐b‐PDMAEMA28(EHD), mPEG45‐b‐PnBMA28‐b‐PDMAEMA32 (EBD), mPEG45‐b‐PEMA31‐b‐PDMAEMA30 (EED), and mPEG45‐b‐PMMA30‐b‐PDMAEMA29 (EMD), are confirmed by gel permeation chromatography and 1H NMR. Their morphology transitions in water are investigated via a combination of UV‐vis spectroscopy, light scattering, zeta potential measurements, and cryogenic transmission electron microscopy. All terpolymers can form spherical micelle by direct dissolution in acidic water. However, the spherical micelles of EBD and EHD progressively switch to cylinders and vesicles upon variations of external pH and temperature. In contrast, the spherical micelles of EMD and EED reversibly form larger aggregates when the temperature is above the cloud point of PDMAEMA in basic water. This study demonstrates the importance of hydrophobic block on the morphology transition of responsive copolymers.

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“…[1][2][3][4][5][6] Particularly, pH-sensitive drug delivery systems comprising polymer nanoparticles (NPs), 7 liposomes/polymersomes, 8,9 inorganic NPs, 10 star polymers, 11 dendrimers, 12 and layer-by-layer (LbL) assembled capsules 13 have attracted a surge of attention, because the pH of most tumor tissues is mildly acidic and lower than that of normal tissues and the blood stream. [1][2][3][4][5][6] Particularly, pH-sensitive drug delivery systems comprising polymer nanoparticles (NPs), 7 liposomes/polymersomes, 8,9 inorganic NPs, 10 star polymers, 11 dendrimers, 12 and layer-by-layer (LbL) assembled capsules 13 have attracted a surge of attention, because the pH of most tumor tissues is mildly acidic and lower than that of normal tissues and the blood stream.…”

mentioning

confidence: 99%

Influence of 2-(diisopropylamino)ethyl methacrylate on acid-triggered hydrolysis of cyclic benzylidene acetals and their importance in efficient drug delivery

et al. 2015

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The ability to tune the degradation rate of a biodegradable polymer, which can achieve precise spatiotemporal control of drug delivery, is of considerable interest for biomedical applications. In this study, a series of amphiphilic copolymers, methoxy poly(ethyleneglycol)-b-poly((2,4,6-trimethoxybenzylidene-1,1,1-tris(hydroxymethyl) ethane methacrylate)-co-2-(diisopropylamino)ethyl methacrylate) (mPEG-b-P (TTMA-co-DPA), PETD) with different numbers of DPA units, were synthesized by Reversible Addition Fragmentation Chain Transfer (RAFT) copolymerization, in which DPA containing tertiary amines were introduced to adjust the hydrolysis behavior of cyclic benzylidene acetals (CBAs). The molecular structure and the chemical composition of PETD were characterized by 1 H NMR and gel permeation chromatography (GPC). PETD could self-assemble into stable nanoparticles with well-defined spherical morphology and displayed high drug loading capacity with doxorubicin (DOX) as the drug model. The hydrolysis behavior of CBAs in the PETD NPs was investigated by UV/vis spectroscopy under different pH values. Compared with PETD-0 bearing no DPA unit, the hydrolysis rate of PETD-3 with more DPA was faster, while PETD-1 with less DPA hydrolyzed much slower, which indicated that the introduction of DPA had an amphoteric effect on the hydrolysis behavior of CBAs under acidic conditions. In addition, the in vitro release of DOX was also investigated under different pH conditions and the result was in accordance with the hydrolysis result. Furthermore, the results of fluorescence microscopy demonstrated improved internalization of DOX-loaded PETD-3 NPs in HepG-2 cells with rapid DOX release intracellularly, which showed considerable cytotoxicity against HepG-2 cells. † Electronic supplementary information (ESI) available. See

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Nanoparticle-to-vesicle and nanoparticle-to-toroid transitions of pH-sensitive ABC triblock copolymers by in-to-out switch

Abstract: An efficient way to achieve nanoparticle-to-vesicle transition of ABC triblock copolymers by in-to-out switch of the pH-sensitive core-forming C block is described.

Cited by 32 publications

References 43 publications

Stimulus‐Responsive Nanoparticles and Associated (Reversible) Polymorphism via Polymerization Induced Self‐assembly (PISA)

Stimulus‐Responsive Nanoparticles and Associated (Reversible) Polymorphism via Polymerization Induced Self‐assembly (PISA)

Morphology Transition of Dual‐Responsive ABC Terpolymer in Water: Effect of Hydrophobic Block

Influence of 2-(diisopropylamino)ethyl methacrylate on acid-triggered hydrolysis of cyclic benzylidene acetals and their importance in efficient drug delivery

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