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Herein, we prepared novel reactive oxygen species (ROS) responsive core crosslinked (CCL/TK) polycarbonate micelles conveniently by click reaction between amphiphilic diblock copolymer poly(ethylene glycol)-poly(5-methyl-5-propargylxycar-bonyl-1,3-dioxane-2-one) (PEG-PMPC) with pendant alkynyl group and thioketal containing azide derivative bis (2-azidoethyl) 3, 3'- (propane-2, 2-diylbis (sulfanediyl)) dipropanoate (TK-N 3 ). The CCL/TK micelles were obtained with small size of 146.4 nm, showing excellent stability against dilution and high doxorubicin (DOX) loading. In vitro toxicity tests demonstrated that the obtained CCL/TK micelles have good biocompatibility and low toxicity with cell viability above 95 %. Furthermore, DOX-loaded CCL/TK micelles showed significantly superior toxicity with IC 50 values for HeLa and MCF-7 cells about 3.74 μg/mL and 3.91 μg/mL, respectively. Confocal laser scanning microscope (CLSM) and flow cytometry showed excellent internalization efficiency and intracellular drug release of DOX-loaded CCL/TK micelles. The obtained ROS-responsive CCL/TK micelles showed great potential for anticancer drug delivery., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Polycarbonate‐based micelles possessed enormous potential for hydrophobic drug delivery. To improve micelle stability and prevent premature leakage during blood circulation, photo‐induced thiol‐yne click reaction was utilized to construct polycarbonate‐based core crosslinked micelles (CCLMs), which avoided the use of toxic copper catalyst. The introduced β‐thiopropionate linkage in the core was demonstrated to endow the CCLMs with pH‐responsiveness. The obtained CCLMs showed good dilution stability against DMF and water. Further MTT assays demonstrated excellent biocompatibility and low toxicity of the CCLMs in HeLa/MCF‐7 cells. Moreover, DOX‐encapsulated CCLMs showed good anticancer effects and excellent internalization efficiency in HeLa cells. The pH‐responsive polycarbonate‐based CCLMs by thiol‐yne click reaction have potential used as smart delivery systems for controlled drug release. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a light and pH dual-sensitive block copolymer PEG- b-poly(MPC-Azo/DEA) was facilely prepared for the first time by azide-alkyne click chemistry between amphiphilic block copolymer bearing pendant alkynyl group poly(ethylene glycol)-poly(5-methyl-5-propargylxycarbonyl-1,3-dioxane-2-one) (PEG- b-poly(MPC)) and two azide-containing compounds azobenzene derivative (Azo-N3) and 2-azido-1-ethyl-diethylamine (DEA-N3). Light response of the polymeric nanoparticles benefits from the azobenzene segments and pH responsiveness is attributed to DEA moieties. The prepared copolymer could self-assemble into spherical micelle particles. The morphological changes of these particles in response to dual stimuli were investigated by UV/vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). Nile Red (NR) was utilized as probe, and fluorescence spectroscopy was served as an evidence for the enhanced release of cargos from polymeric nanoparticles under combined stimulation. Anticancer drug, DOX was loaded into the nanoparticles and the loaded-DOX could be released from these nanoparticles under dual stimuli. MTT assays further demonstrated that PEG- b-poly(MPC) and PEG- b-poly(MPC-Azo/DEA) were of biocompatibility and low toxicity against HepG2 cells as well as SMCC-7721 cells. More importantly, the prepared DOX-loaded nanoparticles exhibited good anticancer ability for the two cells. The synthesized light and pH dual-sensitive biodegradable polymeric nanoparticles were expected to be platforms for precisely controlled release of encapsulated molecules. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 1773-1783 [ABSTRACT FROM AUTHOR]

ABSTRACT A facile method for the construction of pH-responsive core crosslinked micelles (CCLMs) based on polycarbonate was developed. Biodegradable amphiphilic block copolymer monomethoxy poly(ethylene glycol)-b-Poly(AC) (mPEG-b-poly(AC)) with pendant acrylate group was synthesized by means of ring opening polymerization of acryloyl carbonate (AC). Then CCLMs were obtained via thiol-acrylate Michael addition reaction between the pendant acrylate group in the hydrophobic block and the crosslinker 1,6-hexanedithiol. DLS results showed that the CCLMs prepared from mPEG-b-poly(AC)25 were more stable than uncrosslinked micelles (UCLMs) upon dilution by 10-fold DMF. Model drug Coumarin 102 was then encapsulated into the micelles. The pH-responsive release of coumarin 102 from the CCLMs was demonstrated by fluorescence spectroscopy. The core crosslinked polycarbonate micelles have a potential as efficient intracellular smart drug delivery platforms. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44421. [ABSTRACT FROM AUTHOR]

Photo-responsive block copolymer mPEG-b-poly(Tyr)-g-NB was prepared by introduction of o-nitrobenzyl ester group into the side chain of amphiphilic poly(ethylene glycol)-b-poly( α-hydroxy acids) (mPEG-b-poly(Tyr)) containing pendent alkynyl group via copper-catalyzed azide-alkyne cycloaddition reaction. The amphiphilic mPEG-b-poly(Tyr) was synthesized via the ring-opening polymerization of O-carboxyanhydrides, with monomethoxy poly(ethylene glycol) (mPEG) as macroinitiator. The molecular structure, self-assembly, and photo-controlled release of the obtained mPEG-b-poly(Tyr)-g-NB were thoroughly investigated. mPEG-b-poly(Tyr)-g-NB could self-assemble into spherical micelles in water and showed disassembly under UV light irradiation, which was demonstrated by means of UV-vis spectroscopy, scan electron microscopes, and dynamic light scattering measurement. Fluorescence emission measurements demonstrated that Nile red, encapsulated by micelles, can be released upon UV irradiation. This study provides a convenient way to construct smart poly( α-hydroxy acids)-based nanocarriers for controlled release of hydrophobic drugs. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Light-responsive poly(carbonate)s PEG113- b-PMPC n-SP were synthesized via copper catalyzed azide-alkyne cycloaddition reaction between azide-modified spiropyran (SP-N3) and amphiphilic copolymer PEG113- b-PMPC n. PEG113- b-PMPC25-SP can self-assemble to biocompatible micelles with an average diameter of ∼96 nm and a critical aggregation concentration of 0.0148 mg mL−1. Under 365 nm UV light irradiation, the characteristic absorption intensity of merocyanine (MC) progressively increased and most of the micellar aggregations were disrupted within 10 min, suggesting the completion of the transformation of hydrophobic SP to hydrophilic MC. Subsequent exposuring the micelles to 620 nm visible light, spherical micelles aggregated again. The light-controlled release and re-encapsulation behaviors of coumarin 102-loaded micelles were further investigated by fluorescence spectroscopy. This study provides a convenient way to construct smart poly(carbonate)s nanocarriers for controlled release and re-encapsulation of hydrophobic drugs. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 750-760 [ABSTRACT FROM AUTHOR]

Reversibly light-responsive micelles are constructed from an amphiphilic azobenzene-containing diblock copolymer AZO-mPEG-poly(5)25. The copolymer is synthesized via ring-opening polymerization of O-carboxyanhydrides bearing alkyne group, followed by azide-alkyne click chemistry with an azide-containing azobenzene derivative. AZO-mPEG-poly(5)25 can self-assemble to spherical micelles. Light response of the polymeric micelles is demonstrated by UV-vis spectroscopy and scanning electron micro­scopy (SEM). SEM images show that after UV irradiation, the micelles are partly dissociated, which is ascribed to swelling of the hydrophobic chain because of hydrophobicity change during the trans-cis isomerization of the azobenzene group. After subsequent visible-light irradiation, the morphology returns back to micelles. [ABSTRACT FROM AUTHOR]