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The pH-responsive micelles have enormouspotential as nanosizeddrug carriers for cancer therapy due to their physicochemical changesin response to the tumor intracellular acidic microenvironment. Herein,a series of comb-like amphiphilic copolymers bearing acetal-functionalizedbackbone were developed based on poly[(2,4,6-trimethoxybenzylidene-1,1,1-tris(hydroxymethyl)ethane methacrylate-co-poly(ethylene glycol) methylether methacrylate] [P(TTMA-co-mPEGMA)] as effectivenanocarriers for intracellular curcumin (CUR) release. P(TTMA-co-mPEGMA) copolymers with different hydrophobic–hydrophilicratios were prepared by one-step reversible addition fragmentationchain transfer (RAFT) copolymerization of TTMA and mPEGMA. Their molecularstructures and chemical compositions were confirmed by 1H NMR, Fourier transform infrared spectroscopy (FT-IR) and gel permeationchromatography (GPC). P(TTMA-co-mPEGMA) copolymerscould self-assemble into nanosized micelles in aqueous solution anddisplayed low critical micelle concentration (CMC). All P(TTMA-co-mPEGMA) micelles displayed excellent drug loading capacity,due to the strong π–π conjugate action and hydrophobicinteraction between the PTTMA and CUR. Moreover, the hydrophobic PTTMAchain could be selectively hydrolyzed into a hydrophilic backbonein the mildly acidic environment, leading to significant swellingand final disassembly of the micelles. These morphological changesof P(TTMA-co-mPEGMA) micelles with time at pH 5.0were determined by DLS and TEM. The in vitro CUR release from themicelles exhibited a pH-dependent behavior. The release rate of CURwas significantly accelerated at mildly acidic pH of 4.0 and 5.0 comparedto that at pH 7.4. Toxicity test revealed that the P(TTMA-co-mPEGMA) copolymers exhibited low cytotoxicity, whereasthe CUR-loaded micelles maintained high cytotoxicity for HepG-2 andEC-109 cells. The results indicated that the novel P(TTMA-co-mPEGMA) micelles with low CMC, small and tunable sizes,high drug loading, pH-responsive drug release behavior, and good biocompatibilitymay have potential as hydrophobic drug delivery nanocarriers for cancertherapy with intelligent delivery. [ABSTRACT FROM AUTHOR]

Inspired by mussel adhesion chemistry, a kind of hydrophilic poly(vinylidene fluoride) (PVDF) microfiltration membrane with underwater superoleophobicity was prepared using thiolated hyperbranched zwitterionic poly(sulfobetaine methacrylate) (HPS) as a nanoscale surface modifier. The HPS was first synthesized via reversible addition fragmentation chain transfer (RAFT) copolymerization and followed by sulfonation reaction and then coated onto polydopamine (PD) adhesive PVDF membranes via thiol-mediated Michael addition reaction. The successful and uniform coating of HPS onto the membrane surface was demonstrated by X-ray photoelectron spectroscopy and by using an energy dispersive X-ray detector. The surface micro-nano morphology and increased roughness of the PD/HPS-modified (M-PD/HPS) membrane were also investigated by using a field emission scanning electron microscope and an atomic force microscope. The M-PD/HPS membrane could be wetted completely by water, and the underwater oil contact angles were about 160°, indicating the M-PD/HPS membrane has excellent hydrophilicity and underwater superoleophobicity. Compared with the pure PVDF membrane, the M-PD/HPS membrane for hexane-in-water emulsion separation exhibited an enhanced water filtration flux of 10 707 L m -2 h -1 (0.1 MPa), and the oil rejection ratio was above 99.9%. Besides, the excellent antifouling ability and recyclable properties of the M-PD/HPS membranes would make them suitable for long-time use. Thus, the approach of mussel adhesion chemistry employing the RAFT-mediated nanosized hyperbranched zwitterionic polymers as postmodification reagents showed a good application prospect in purification of oily waste water and oil recovery.

Nanoparticle (NP)-assisted drug delivery systems with disassemblable behaviors in response to intracellular microenvironment are urgently demanded in systemic cancer chemotherapy for enhanced intracellular drug release. Curcumin (CUR), an effective and safe anticancer agent, was limited by its water insolubility and poor bioavailability. Herein, pH and reduction dual-induced disassemblable NPs for high loading efficiency and improved intracellular release of CUR were developed based on an acid degradable cyclic benzylidene acetal groups (CBAs)-functionalized poly(2,4,6-trimethoxybenzylidene-1,1,1-tris(hydroxymethyl)ethane methacrylate)-g-SS-poly(ethylene glycol) (PTTMA-g-SS-PEG) graft copolymer, which was readily prepared via RAFT copolymerization and coupling reaction. The NPs self-assembled from PTTMA-g-SS-PEG copolymers were stable at physiological pH, and quickly disassembled in mildly acidic and reductive environments because of the hydrolysis of CBAs in hydrophobic PTTMA core and the cleavage of disulfide-linked detachable PEG shell. PTTMA-g-SS-PEG NPs exhibited excellent CUR loading capacity with drug loading content up to 19.2% and entrapment efficiency of 96.0%. Within 20 h in vitro, less than 15.0% of CUR was released from the CUR-loaded NPs in normal physiological conditions, whereas 94.3% was released in the presence of reductive agent and mildly acidic conditions analogous to the microenvironment in endosome/lysosome and cytoplasm. Confocal fluorescence microscopies revealed that the CUR-loaded PTTMA-g-SS-PEG NPs exhibited more efficiently intracellular CUR release for EC-109 cells than that of CUR-loaded reduction-unresponsive PTTMA-g-PEG NPs and free CUR. In vitro cytotoxicity studies displayed blank PTTMA-g-SS-PEG NPs showed low toxicity at concentrations up to 1.0 mg/mL, whereas CUR-loaded PTTMA-g-SS-PEG NPs demonstrated more efficient growth inhibition toward EC-109 and HepG-2 cells than reduction-unresponsive controls and free CUR. Therefore, the above results indicated that pH and reduction dual-induced disassemblable PTTMA-g-SS-PEG NPs may have emerged as superior nanocarriers for active loading and promoted intracellular drug delivery in systemic cancer chemotherapy.