Search Results (2)

Since anionic dyes and surfactants abundantly exist in oily wastewater, both the separation of oil/water mixture and removal of low-molecular-weight pollutants are important to realize the advanced purification of water. By grafting poly(2-dimethylaminoethyl methacrylate) (pDMAEMA) onto polyethylene (PP) membrane via ultraviolet (UV)-initiated polymerization, the obtained PP-g-pDMAEMA membrane presented positively in water and negatively in an alkaline buffer (pH 9.0), respectively. Due to the switchable surface charge, the membrane had high emulsion separation efficiency and flux recovery ratio (approximately 100%). Besides, the dye (reactive black 5, RB-5) adsorption capacity reached 140 mg/m² in water, and approximately 90% RB-5 could be released in pH 9.0. The anionic surfactant (sodium dodecyl benzene sulfonate, SDBS) was also reversely interpreted and released by the membrane via manipulating the ambient pH. The membrane constructed in this study is supposed to realize emulsion separation with smart cleaning capability, as well as the removal of dyes and surfactants, which could be utilized for multifunctional water purification. Full article

The aim of this study was to investigate non-viral pDNA carriers based on diblock-copolymers consisting of poly(2-(dimethyl amino)ethyl methacrylate) (pDMAEMA) and poly(2-hydroxyethyl methacrylate) (pHEMA). Specifically the block-lengths and molecular weights were varied to determine the minimal requirements for transfection. Such vectors should allow better transfection at acceptable toxicity levels and the entire diblock-copolymer should be suitable for renal clearance. For this purpose, a library of linear poly(2-(dimethyl amino)ethyl methacrylate-block-poly(2-hydroxyl methacrylate) (pDMAEMA-block-pHEMA) copolymers was synthesized via RAFT (reversible addition-fragmentation chain transfer) polymerization in a molecular weight (Mw) range of 17–35.7 kDa and analyzed using ¹H and ¹³C NMR (nuclear magnetic resonance), ATR (attenuated total reflectance), GPC (gel permeation chromatography) and DSC (differential scanning calorimetry). Copolymers possessing short pDMAEMA-polycation chains were 1.4–9.7 times less toxic in vitro than polyethylenimine (PEI) 25 kDa, and complexed DNA into polyplexes of 100–170 nm, favorable for cellular uptake. The DNA-binding affinity and polyplex stability against competing polyanions was comparable with PEI 25 kDa. The zeta-potential of polyplexes of pDMAEMA-grafted copolymers remained positive (+15–30 mV). In comparison with earlier reported low molecular weight homo pDMAEMA vectors, these diblock-copolymers showed enhanced transfection efficacy under in vitro conditions due to their lower cytotoxicity, efficient cellular uptake and DNA packaging. The homo pDMAEMA₁₁₅ (18.3 kDa) self-assembled with DNA into small positively charged polyplexes, but was not able to transfect cells. The grafting of 6 and 57 repeating units of pHEMA (0.8 and 7.4 kDa) to pDMAEMA₁₁₅ increased the transfection efficacy significantly, implying a crucial impact of pHEMA on vector-cell interactions. The intracellular trafficking, in vivo transfection efficacy and kinetics of low molecular weight pDMAEMA-block-pHEMA are subject of ongoing studies. Full article