基因转染材料PEI-PEG接枝壳聚糖的合成

本文通过聚乙二醇化的聚乙烯亚胺与马来酰化的壳聚糖反应,得到了水溶性良好的聚乙二醇化聚乙烯亚胺接枝的壳聚糖(CS-N-PEI-mPEG),目标物用FT-IR,1H-NMR,UV-Vis进行了表征。实验表明,CS-N-PEI-mPEG对细胞的毒性低,而它的转染效率却较高。     

PEI-PEG接枝壳聚糖对于细胞SMMC7721转染效率的研究

本文通过聚乙二醇化的聚乙烯亚胺与壳聚糖反应,得到了水溶性良好的聚乙二醇化聚乙烯亚胺接枝的壳聚糖( mPEG-O-CS-PEI)。研究表明,纳米mPEG-O-CS-PEI对细胞SMMC7721的转染效率为7．1%。     

Adsorption and Desorption Properties of Polyethylenimine/Polyvinyl Chloride Cross-Linked Fiber for the Treatment of Azo Dye Reactive Yellow 2

In this study, the optimal conditions for the fabrication of polyethylenimine/polyvinyl chloride cross-linked fiber (PEI/PVC-CF) were determined by comparing the adsorption capacity of synthesized PEI/PVC-CFs for Reactive Yellow 2 (RY2). The PEI/PVC-CF prepared through the optimal conditions was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analyses. Several batch adsorption and desorption experiments were carried out to evaluate the sorption performance and reusability of PEI/PVC-CF for RY2. As a result, the adsorption of RY2 by PEI/PVC-CF was most effective at pH 2.0. A pseudo-second-order model fit better with the kinetics adsorption data. The adsorption isotherm process was described well by the Langmuir model, and the maximum dye uptake was predicted to be 820.6 mg/g at pH 2.0 and 25 °C. Thermodynamic analysis showed that the adsorption process was spontaneous and endothermic. In addition, 1.0 M NaHCO₃ was an efficient eluent for the regeneration of RY2-loaded PEI/PVC-CF. Finally, the repeated adsorption–desorption experiments showed that the PEI/PVC-CF remained at high adsorption and desorption efficiencies for RY2, even in 17 cycles.     

Dendritic amphiphile‐decorated polyHIPE as a highly efficient and well recyclable scavenger of micropollutants in water: Topological effect

It is found herein that topology of amphiphiles immobilized on a porous solid of poly(high internal phase emulsion) (HIPE and polyHIPE) is critical to extraction pollutants from water. N‐alkylation of branched polyethylenimine (bPEI) with a glycidyl‐capped polymer of poly(styrene‐co ?2‐ethylhexyl acrylate) [P(S‐EHA)] results in a dendritic amphiphile of bPEI@P(S‐EHA), and a comb‐like counterpart (lPEI@P(S‐EHA) is similarly prepared by replacing bPEI with a linear PEI (lPEI). Each amphiphile can act as a stabilizer to directly prepare polyHIPE whose surface is dictated by the respective amphiphile. It is found that bPEI@P(S‐EHA)‐dictated polyHIPE can be over 50‐fold stronger to eliminate anionic dyes from water than the linear counterpart, indicating a significant topological effect. The optimized adsorbent is over 10,000‐fold stronger to bind a dye than a representative adsorbent, thus may deal with trace pollutants in water. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1294–1302     

Branched Polyethylenimine Improves Hydrogen Photoproduction from a CdSe Quantum Dot/[FeFe]‐Hydrogenase Mimic System in Neutral Aqueous Solutions

Nature uses hydrogenase enzyme to catalyze proton reduction at pH 7 with overpotentials and catalytic efficiencies that rival platinum electrodes. Over the past several years, [FeFe]‐hydrogenase ([FeFe]‐H₂ase) mimics have been demonstrated to be effective catalysts for light‐driven H₂ evolution. However, it remains a significant challenge to realize H₂ production by such an artificial photosynthetic system in neutral aqueous solution. Herein, we report a new system for photocatalytic H₂ evolution working in a broad pH range, especially under neutral conditions. This unique system is consisted of branched polyethylenimine (PEI)‐grafted [FeFe]‐H₂ase mimic (PEI‐g‐Fe₂S₂ ), MPA‐CdSe quantum dots (MPA=mercaptopropionic acid), and ascorbic acid (H₂A) in water. Due to the secondary coordination sphere of PEI, which has high buffering capacity and stabilizing ability, the system is able to produce H₂ under visible‐light irradiation with turnover number of 10 600 based on the Fe₂S₂ active site in PEI‐g‐Fe₂S₂ . The stability and activity are much better than that of the same system under acidic or basic conditions and they are, to the best of our knowledge, the highest known to date for photocatalytic H₂ evolution from a [FeFe]‐H₂ase mimic in neutral aqueous solution.     

Application of a new water-soluble polyethylenimine polymer sorbent for simultaneous separation and preconcentration of trace amounts of copper and manganese and their determination by atomic absorption spectrophotometry

In this work, a water-soluble polymer, polyethylenimine (PEI) was used for the simultaneous separation and preconcentration of trace Cu and Mn prior to their determination by flame atomic absorption spectrometry. For this purpose, the sample and the PEI solution were mixed and the metal-bound polymer was precipitated by adding acetone. The precipitate was separated and dissolved in a minimum amounts of water and aspirated into a flame AAS. By increasing the ratio of the volumes of sample to water used in dissolving the precipitate, the analyte elements were concentrated as needed. The sorption is quantitative in the pH ≥6. Detection limits were 5.2 μg/L for Cu and 5.4 μg/L for Mn. This method is simple, fast and precise.     

Validation of a new method for spectrophotometric determination of polyethylenimine

A new method of determination of polyethylenimine (PEI) is presented. The method is fast, reliable, and easy to perform. It is based on a creation of a complex between Cu²⁺ and PEI and its absorption in UV–VIS spectrum. The complex has a distinct absorption peak in UV part of electromagnetic spectrum and the measurement is optimal at 285 nm. A method is thoroughly analyzed in various concentrations of both PEI and Cu²⁺, temperatures, times of creation of a complex, ionic strengths, background electrolytes types, and pH values. Analytical parameters of the presented method such as linearity, sensitivity, limit of detection (LOD), limit of quantification (LOQ), repeatability, and intermediate precision were also determined.     

CHARMM force field and molecular dynamics simulations of protonated polyethylenimine

As a gene delivery vector, polyethylenimine (PEI) shows one of the highest transfection efficiencies, while effectively protecting DNA from enzyme degradation. The distinctive charge pattern of protonated PEI is widely considered responsible for fundamental process such as DNA condensation into PEI/DNA polyplexes (which are able to enter cells via endocytosis), proton sponge effect (which triggers the release of polyplexes from endosome), and release of DNA from polyplexes (to be further processed inside the nucleus). Our investigations are largely motivated by the crucial need for a realistic molecular mechanics force field (FF) for PEI, and, accordingly, we focus on two major issues: (1) development of a new atomistic (CHARMM) FF for PEI in different protonation states, rigorously derived from high‐quality ab initio calculations performed on model polymers, and (2) molecular dynamics investigations of solvated PEI, providing a detailed picture of the dynamic structuring thereof in dependence on their size and protonation state. The modeled PEI chains are essentially described in terms of gyration radius, end‐to‐end distance, persistence length, radial distribution functions, coordination numbers, and diffusion coefficients. They turn out to be more rigid than in other computational studies and we find diffusion coefficients in fair agreement with experimental data. The developed atomistic FF proves adequate for the realistic modeling of the size and protonation behavior of linear PEI, either as individual chains or composing polyplexes. © 2017 Wiley Periodicals, Inc.     

低分子量聚乙烯亚胺/金纳米棒纳米载体的制备及毒性研究

以表面修饰巯基十一烷酸的金纳米棒 (GNRs/MUA)为骨架, 将低分子量的聚乙烯亚胺(PEI)连接到GNRs/MUA表面, 构建GNRs/MUA/PEI纳米载体.首先采用MUA对GNRs进行表面修饰, 减少由于GNRs表面的十六烷基三甲基溴化铵(CTAB)所造成的生物毒性.然后采用低分子量 PEI 进一步修饰, 同时利用GNRs巨大的比表面积进一步放大 PEI 的携带基因能力, 这样既能够降低阳离子聚合物的毒性, 又能够提高整个体系的转染效率.利用透射电子显微镜(TEM)、紫外可见吸收光谱(UV-Vis)、Zeta电位等对纳米载体进行了表征.结果显示, MUA与PEI已成功修饰到GNRs表面, 并很好地保留了GNRs的光学性质, 其表面电位发生正负交替变化.采用噻唑蓝(MTT)比色法对纳米载体进行细胞毒性研究, 结果显示GNRs/MUA/PEI(1.8 kDa)非病毒纳米载体, 细胞存活率在控制聚合物浓度为300 μg/mL时仍然稳定在75%以上, 明显高于商品化的PEI(25 kDa).     

聚胺界面修饰改善碳量子点可见光光敏化性能

在新兴能源的存储与转化技术中,碳量子点作为新一代光吸收组分得到越来越广泛的关注。然而目前关于对碳量子点复合体系界面的改性,进而有效提高碳量子点光敏化性能的研究还较少。在本研究工作中,我们通过一种简单的静电自组装的方法构建催化体系,碳量子点能够很好地分散在枝状聚乙烯亚胺修饰的二氧化钛表面,其中碳量子点在复合体系中质量分数约为5%(w, mass fraction)时,展现出最优的可见光还原对硝基苯胺的活性。整体活性相比没有经过修饰的二氧化钛/碳量子点复合体系以及作为参比的枝状聚乙烯亚胺修饰的二氧化硅/碳量子点复合体系均有较明显的提高。结构与光谱研究表明,碳量子点与聚乙烯亚胺修饰的二氧化钛形成了较好的界面接触;进一步通过对比二氧化硅复合体系与二氧化钛复合体系表明,枝状聚乙烯亚胺可作为电子传输通道,能够有效地促进光生电子的分离与传递。因此,得益于良好的界面接触与有效地光生载流子的传递,相比未修饰的复合体系,枝状聚乙烯亚胺修饰的二氧化钛/碳量子点展现出更好地光催化反应活性。此研究工作中界面优化的手段,可将二氧化钛/碳量子点复合体系进一步拓展到其他宽带隙半导体光催化体系并设计构建有效的碳量子点基的半导体光吸收体系。