The effective preparation of photoresponsive polymers with precisely controlled location and number of photolabile units in the main chain is essential for their applications. In this study, a series of photocleavable well-defined triblock copolymers with the photocleavable middle block of poly(phenyl vinyl ketone) (PPVK) were readily synthesized by RAFT polymerization. The chain structure and chemical composition of copolymers were characterized by 1HNMR, FTIR and GPC. The well-controlled molecular weights and low polydispersity (<1.30) demonstrated the excellent controllability and living characteristics of the RAFT process for the polymerization of PVK. Then the photocleavage mechanism and kinetics of PPVK-functionalized copolymers were systematically investigated by tracking, fractionating and quantifying the photolysis products using gradient polymer elution chromatography (GPEC). The results not only confirmed the rapid photocleavability of PPVK-based polymers, but also firstly provided direct evidence for the proposed Norrish type reaction mechanism of the chain scission of PPVK. Moreover, the investigation of the effect of the PPVK chain on the photolysis kinetics demonstrated that the photodegradation rate of PPVK-based polymers can be controlled by adjusting the PPVK chain length in block copolymers. As a preliminary application study, the self-assembled micelles of the obtained PPVK-based amphiphilic polymers under light irradiation were found to undergo photo-triggered rapid disassembly and exhibited photo-controllable emulsifiability. In sum, the incorporation of the highly photolabile PPVK into block copolymers by RAFT polymerization provides a promising strategy for the construction of complex polymeric architectures or nanostructures with controllable photocleavability.

Chemo-photothermal therapy has shown enormous potential in treating cancer. To achieve the chemo-photothermal synergistic effect, an efficient nanoparticulate system with the ability for simultaneous codelivery of chemotherapeutic drug and photothermal agent as well as photothermal-triggered drug release is highly desirable. Herein, an in situ polymerization within liposome template was designed to prepare liposome-coated poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAM-co-AAM)) nanogels, which can efficiently coencapsulate a NIR dye indocyanine green (ICG) and high amount of doxorubicin hydrochloride (DOX). The DOX/ICG coloaded hybrid nanogels, denoted as DI-NGs@lipo, integrated the desirable functions of PEGylated liposomes and thermosensitive nanogels. The PEGylated liposome shell provided excellent storage stability, hemodynamic stability, and fluorescence stability. Meanwhile, the thermosensitive P(NIPAM-co-AAM) nanogels core endowed DI-NGs@lipo with volume phase transition temperature (VPTT) at about 40 degrees C, allowing for thermo-controlled transformation and drug release. The significant photothermal effect of DI-NGs@lipo and the simultaneous hyperthermia-triggered DOX release were observed under NIR light irradiation. The DI-NGsplipo was demonstrated to be uptaken by 4T1 murine breast cancer cells via endocytosis, enhancing the distribution of DOX in the cell nucleus. Compared with chemo or photothermal treatment alone, the combination treatment of DI-NGsplipo with NIR light irradiation induced significantly higher cytotoxicity to 4T1 cells, demonstrating the chemo-photothermal synergistic therapeutic effects on tumor cells. In a word, the strategy provided here offers a facile approach to develop a multifunctional nanoplatform for codelivery of DOX and ICG, which can synergistically improve the cancer-cellkilling efficiency, demonstrating great potential in chemo-photothermal therapy.

The nanocarriers modified with nonspecificity targeting groups can not only enrich in tumor sites, but can also accumulate in normal tissues to cause serious side effects. In order to ensure the therapeutic effects and overcome the side effects, herein, a ligand self-detachment targeting system (mPEG-T@A/VB7-PCL micelles) based on hydrogen bond interaction between adenine (A) and thymine (T) for specific tumor targeting is developed. The nuclear magnetic spectrum shows that the successful introduction of biotin VB7 has no effect on formation and pH-responsive property of the micelles. The cellular uptake experiment indicated these micelles can efficiently shield the non-specificity targeting and can hardly be endocytosed by tumor cells in physiological environment. On the contrary, the detachment of poly(ethylene glycol) PEG crown which is triggered by hydrogen bond dissociation at tumor microenvironment pH 6.8 can enhance endocytosis due to the exposure of the VB7. Cytotoxicity assays show that the half maximal inhibitory concentration (IC50) of free doxorubicin DOX, DOX-loaded mPEG-T@A-PCL (mPEG-T@A-PCL (DOX)), and mPEG-T@A/VB7-PCL (DOX) are about 2.03, 7.20, and 1.32 mu g mL(-1), respectively, which indicate that the mPEG-T@A/VB7-PCL (DOX) micelles can significantly improve the therapeutic effects. Accordingly, mPEG-T@A/VB7-PCL (DOX) micelles, as an innovative strategy, suggests feasibility of its broad applications in cancer therapy.

Few layer graphene (FLG) has been used to improve different properties of polymers. FLG-modified waterborne epoxy dispersions were prepared using a hydrophilic epoxy oligomer (HEO-144) as the surfactant, which was prepared using liquid epoxy resin and poly(ethylene glycol) (PEG4000) at a molar ratio of 1.0. To enhance the stability of FLG-modified waterborne epoxy dispersions, fumed silica was added and best stability was reached at a fumed silica content of 1.5%. Thermogravimetric analyses demonstrated enhanced thermal stability of the epoxy films after FLG modification. With FLG content of 1.0%, T-5% of the modified epoxy films has been increased to 332 degrees C from 275 degrees C. Water contact angle and adsorption tests showed improved water resistance with FLG, the water contact angle increased from 49.5 degrees to 76.2 degrees and water adsorption decreased from 9.0% to 2.0%. Furthermore, electrochemical impedance spectroscopy tests and tafel analysis indicated that FLG greatly improved the anticorrosion performance of waterborne epoxy coatings. With a FLG content of 1.0%, modified waterborne epoxy coatings demonstrated significantly low corrosion rate, which was one eighth of that of the unmodified control. These results indicate that FLG modification can be an effective and low cost approach to enhance the anticorrosion performance of waterborne epoxy coatings. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46743.

In recent years, photodynamic therapy (PDT) was considered to be a promising cancer treatment modality, however, the therapeutic efficiency was often attenuated by the intrinsic antioxidant defense systems. Herein, a kind of novel glutathione-induced amino-activatable micelle was designed, which was expected to weaken the antioxidant capacity and in the meantime release the photosensitizer by the exhaustion of intracellular glutathione (GSH). The amphiphilic poly(ethylene glycol)-(2-((2,4-dinitro-N-(ethyl) phenyl)sulfonamido) ethyl methacrylate) copolymers were synthesized and assembled into a core-shell nano structure in aqueous media. The nano structure demonstrated high sensitivity and selectivity to bio-thiols in vitro and in vivo. Subsequently, pheophorbide a (PhA) was encapsulated as the model photosensitizer. Upon internalization by HepG2 cells, the strongly electron-withdrawing 2,4-dinitrobenzenesulfonyl groups on the PADEE segments were readily cleaved by GSH, during which time the secondary amino groups (pKb =3D 11.32) were recovered and completely protonated, leading to disassembly of the micelles and rapid release of PhA. Importantly, the consumption of GSH weakened the intracellular antioxidant capacity, resulting in the synergetic accumulation of reactive oxygen species (ROS) under laser irradiation. As a result, this micellar photosensitization system could overcome the antioxidant capacity of advanced stage tumors through a simultaneous extrinsic and intrinsic strategy, facilitating therapeutic efficiency. These results demonstrate that the as-designed micelles provide a versatile photosensitization platform for on-demand PDT.=20

Toll/IL-1R-domain-containing adaptor-inducing IFN-beta (TRIF) is an important adaptor for TLR3- and TLR4-mediated inflammatory signaling pathways. Recent studies have shown that TRIF plays a key role in vessel inflammation and atherosclerosis; however, the precise mechanisms are unclear. We investigated the mechanisms of the TRIF-regulated inflammatory response in RAW264.7 macrophages under oxidized low-density lipoprotein (ox-LDL) stimulation. Our data show that ox-LDL induces TRIF, miR-155, and BIC expression, activates the ERK1/2 and SOCS1-STAT3-NF-kappaB signaling pathways, and elevates the levels of IL-6 and TNF-alpha in RAW264.7 cells. Knockdown of TRIF using TRIF siRNA suppressed BIC, miR-155, IL-6, and TNF-alpha expression and inhibited the ERK1/2 and SOCS1-STAT3-NF-kappaB signaling pathways. Inhibition of ERK1/2 signaling also suppressed BIC and miR-155 expression. These findings suggest that TRIF plays an important role in regulating the ox-LDL-induced macrophage inflammatory response and that TRIF modulates the expression of BIC/miR-155 and the downstream SOCS1-STAT3-NF-kappaB signaling pathway via ERK1/2. Therefore, TRIF might be a novel therapeutic target for atherosclerosis.=20