Jun Song,Yanlong Wei,Jiwen Hu,Guojun Liu,Zhengzhu Huang,Shudong Lin,Feng Liu,Yangmiao Mo,Yuanyuan Tu,Ming Ou
Graphical Gated delivery : pH-Responsive porous nanocapsules have been prepared from ternary graft copolymers and used as potential vehicles for controlled release of drugs, food, and bioactive compounds (see figure). In this work pH-responsive porous nanocapsules have been successfully prepared from a ternary graft copolymer, poly(glycidyl methacrylate)- g -[poly(2-cinnamoyloxyethyl methacrylate)- r -poly(ethylene glycol) methyl ether- r -poly(2-diethylaminoethyl methacrylate)] or PGMA- g -(PCEMA- r -MPEG- r -PDEAEMA). The graft copolymers were fabricated by grafting three types of polymer chains onto the backbone polymer by using click chemistry. These ternary copolymers underwent self-assembly to form vesicles in a DMF/water solvent mixture. While the MPEG chains served as the corona and stabilized the vesicles, the vesicle wall was composed of a dominant PCEMA continuous phase that was interspersed by PDEAEMA domains. After photo-cross-linking, the PDEAEMA domains were embedded in the structurally locked PCEMA wall. By decreasing the pH of the external solution, we were able to trigger the release of encapsulated pyrene due to the capsule wall becoming porous as a result of the PDEAEMA chains bearing positively charged amine groups stretching into the water. While these pH-responsive porous nanocapsules exhibited potential applications in drug delivery, detection and catalysis, the strategy reported in this contribution also represented a new paradigm for the design and preparation of other novel stimuli-responsive porous nanocapsules.
A new polymer monolith with three modes of reverse-phase, hydrophilic and cation-exchange interaction was synthesized in 100 μm i.d. fused-silica capillary by in situ polymerization procedure. The pre-polymerization mixture consisted of glycidyl methacrylate (GMA) and 4-vinylphenylboronic acid (VPBA) as bifunctional monomers, ethylene dimethacrylate (EDMA) as crosslinker, 1,4-butanediol (BDO) and diethylene glycol (DEG) as binary porogenic solvents, and azobisisobutyronitrile (AIBN) as initiator. The resulting poly(GMA-co-VPBA-co-EDMA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of monolithic column. The column performance was assessed by the separation of a series of neutral solutes, charge solutes, phenols and anilines. Compared with poly(GMA-co-EDMA) monolith, the proposed monolith exhibited more flexible adjustment of selectivity in terms of hydrophobic, hydrophilic, as well as cation-exchange interaction in the same chromatographic conditions. High column efficiencies for benzene derivatives with 70,000–102,000 theoretical plates/m could be obtained at a linear velocity of 0.265 mm/s. The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention times were less than 8.23%. Additionally, the purposed monolith was also applied to efficient separation of alkaloids and proteins for demonstrating its potential in biomolecule separation.
A polymer monolith microextraction method coupled with high-performance liquid chromatography was developed for the determination of adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate. The monolithic column was synthesized inside fused-silica capillaries using thermal initiation free-radical polymerization with glycidyl methacrylate as the monomer, ethylene dimethacrylate as the cross-linker, cyclohexanol, and 1-dodecanol as the porogen. N -Methylolacrylamide, an important hydrophilic monomer, was incorporated into the polymerization mixture to enhance the hydrophilicity of the poly(glycidyl methacrylate- co -ethylene dimethacrylate) column. The obtained poly(glycidyl methacrylate- co - N -methylolacrylamide- co -ethylene dimethacrylate) monolith was characterized by scanning electron microscopy, Fourier-transform infrared spectra, and X-ray photoelectron spectroscopy. Optimum conditions for the preconcentration and separation of the target adenosines were also investigated. Under the optimum conditions, we obtained acceptable linearities, low limits of detection, and good relative standard deviations. The developed polymer monolith microextraction with high-performance liquid chromatography method exhibited a good performance with recovery values in the range of 76.9−104.7% when applied to the determination of the adenosines in five royal jelly samples.
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