- Multistimuli-responsive hydrogel particles prepared via the self-assembly of PEG-based hyperbranched polymers
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Generally, it is very difficult to obtain multistimuli-responsive hydrogel particles. Here, we introduce a novel method for the preparation of multistimuli-responsive hydrogel particles by adding water into the poly(ethylene glycol) (PEG)-based hyperbranched polymers. The produced PEG-base polymers via reversible addition-fragmentation chain transfer (RAFT) polymerization become temperature-sensitive and less soluble when heated above the lower critical solution temperature (LCST) after directly adding water. Subsequently, the hydrogel particles can be formed via hyperbranch-hyperbranch coupling through disulfide exchange. The resulting hydrogel particles are temperature-, photo-, and redox-responsive.
- Chen, Qian-Bao,You, Ye-Zi
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- DOX-UCNPs@mSiO2-TiO2 nanocomposites for near-infrared photocontrolled chemo/photodynamic therapy
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Currently, incorporating multiple therapeutic functions into one nanostructure has attracted more and more attention for the development of efficient anticancer agents. In this study, a uniform core-shell UCNPs@mSiO2 nanocomposite was prepared as the carrier to develop the NIR light-controlled chemotherapy associated with photodynamic therapy (PDT). In view of the novel UV emission, the semiconductor photosensitizer TiO2 was exploited due to its high efficiency and chemical stability. The host modification method was used to integrate TiO2 doping and mesoporous structure, which can store anticancer drug molecules (doxorubicin, DOX). To improve the utilization of emission, a photolabile o-nitrobenzyl derivative was incorporated to form a sensitive linker (NB linker) as a "gate" to make sure the few leak. Upon NIR irradiation, the UV emission can not only excite TiO2 to produce reactive oxygen species (ROS), but also induce the breaking of NB linker as well as drug release. The NIR-triggered performances were further demonstrated by the cell experiment using HeLa cells as the model cancer cell. The synergistic effect of chemotherapy and PDT induces enhanced cytotoxicity, which is more powerful than their simple effects added together. Therefore, the novel NIR light-controlled double-therapeutic nanocomposite should be a potential candidate for anticancer agents.
- Chen, Yuhua,Tong, Ruihan,An, Na,Lin, Huiming,Qu, Fengyu
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- Photodegradable bridged silane and preparation method thereof
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The invention relates to photodegradable bridged silane and a preparation method thereof. The photodegradable bridged silane has a structure as shown in a formula I which is described in the specification. The method comprises the following steps: taking 1, 3-dimethyl-2-nitrobenzene as a raw material, carrying out oxidation reaction to obtain 2-nitro 1, 3-phthalic acid, carrying out reduction reaction on a carboxylic acid group to obtain 2-nitro-1, 3-benzenedimethanol, carrying out acylation reaction on the 2-nitro-1, 3-benzenedimethanol and chloroacetyl chloride to obtain 2-nitro-1, 3-benzenedichloroacetate, and finally carrying out substitution reaction on the 2-nitro-1, 3-benzenedichloroacetate and amino-containing silane to obtain the photodegradable bridged silane containing 2-nitrobenzyl. The photodegradable bridged silane obtained in the invention has good photoresponse performance, can be used for designing and preparing photoresponsive functional materials, and has important application value. The synthesis process is simple, raw materials are easy to obtain, reaction conditions are mild, and operability is high.
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- PROGRAMMED DEGRADATION OF POLYMERS DERIVED FROM BIOMASS
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Novel photodegradable polymers derived from biomass are provided, together with methods of making and methods of using said polymers.
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- Programmed photodegradation of polymeric/oligomeric materials derived from renewable bioresources
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Renewable polymeric materials derived from biomass with built-in phototriggers were synthesized and evaluated for degradation under irradiation of UV light. Complete decomposition of the polymeric materials was observed with recovery of the monomer that was used to resynthesize the polymers.
- Rajendran, Saravanakumar,Raghunathan, Ramya,Hevus, Ivan,Krishnan, Retheesh,Ugrinov, Angel,Sibi, Mukund P.,Webster, Dean C.,Sivaguru, Jayaraman
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p. 1159 - 1163
(2015/01/30)
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- Photodegradable macromers and hydrogels for live cell encapsulation and release
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Hydrogel scaffolds are commonly used as 3D carriers for cells because their properties can be tailored to match natural extracellular matrix. Hydrogels may be used in tissue engineering and regenerative medicine to deliver therapeutic cells to injured or diseased tissue through controlled degradation. Hydrolysis and enzymolysis are the two most common mechanisms employed for hydrogel degradation, but neither allows sequential or staged release of cells. In contrast, photodegradation allows external real-time spatial and temporal control over hydrogel degradation, and allows for staged and sequential release of cells. We synthesized and characterized a series of macromers incorporating photodegradbale ortho-nitrobenzyl (o-NB) groups in the macromer backbone. We formed hydrogels from these macromers via redox polymerization and quantified the apparent rate constants of degradation (kapp) of each via photorheology at 370 nm, 10 mW/cm2. Decreasing the number of aryl ethers on the o-NB group increases kapp, and changing the functionality from primary to seconday at the benzylic site dramatically increases kapp. Human mesenchymal stem cells (hMSCs) survive encapsulation in the hydrogels (90% viability postencapsulation). By exploiting the differences in reactivity of two different o-NB linkers, we quantitatively demonstrate the biased release of one stem cell population (green-fluoroescent protein expressing hMSCs) over another (red-fluorescent protein expressing hMSCs).
- Griffin, Donald R.,Kasko, Andrea M.
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p. 13103 - 13107
(2012/10/07)
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- Benzo-Fused Bicyclic Imides
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The benzo-fused bicyclic imides, 2 and 3, were synthesized via acetic anhydride promoted ring closure of lactam acids 10 and 15.Attempts to carry out the analogous reaction with lactam acid 21 failed to afford the desired 5,5-benzo-fused bicyclic imide 4.Possible reasons for the failure of this reaction are discussed.
- Pavia, Michael R.,Moos, Walter H.,Hershenson, Fred M.
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p. 560 - 564
(2007/10/02)
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- Benzobicyclic lactam acids and derivatives as cognition activators
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Benzobicyclic lactam acids having a fused aromatic carbocyclic and a saturated lactam ring of five- or six-members, their salts, esters, and amides, are useful for reversing amnesia. Pharmaceutical compositions including these compounds, a method of preparing the compounds, and a method of treating senility and reversing amnesia are also disclosed.
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- Benzotricyclic nitrogen-containing diones and their use in reversing electroconvulsive shock-induced amnesia
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A class of novel fused-ring, benzotricyclic, nitrogen-containing diones useful as agents in reversing electroconvulsive shock-induced amnesia. A method of preparing the compounds, pharmaceutical compositions including the compounds, and a method of reversing electroconvulsive shock-induced amnesia are disclosed.
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