No abstract

A new cationic polymer, N,N-diethylethylenediamine-polyurethane (DEDA-PU), bearing tertiary amines in the backbone and side chains, was synthesized and used as a nonviral vector for gene delivery. The DEDA-PU readily self-assembled with the plasmid DNA (pCMV-betagal) in water and buffer at physiological pH, as determined by agarose gel retardation, dynamic light scattering, zeta potential, atomic force microscopy (AFM), and restriction endonuclease protection assays. The results revealed that DEDA-PU was able to bind with plasmid DNA, yielding positively charged complexes with a size around 100 nm at a DEDA-PU/DNA ratio of 50/1 (w/w). The DEDA-PU/DNA complexes were able to transfect HEK 293 cells in vitro with an efficiency comparable to a well-known gene carrier [poly(2-dimethylaminoethyl methacrylate), PDMAEMA]. The cytotoxicity of DEDA-PU was substantially lower than PDMAEMA. The degradation studies indicated that DEDA-PU degrades hydrolytically in 20 mM HEPES buffer at pH 7.4 with a half-life of approximately 60 h. This study shows that DEDA-PU holds promise as biodegradable polycations for gene delivery and is interesting candidate for further study.

New phosphorylated epoxy‐imide polymer was obtained using diimide‐diepoxide (DIDE) cured with bis(3‐aminophenyl)methylphosphine oxide (BAMP). In addition, composition of the synthesized diimide‐diepoxide (DIDE) with common curing agents, e.g., 4,4′‐diaminodiphenylether (DDE) and 4,4′‐diaminodiphenylsulfone (DDS), were used for making a comparison of its curing reactivity, heat and flame retardation with that of bis(3‐aminophenyl)methylphosphine oxide. The reactivity of those curing agents toward epoxy‐imide, as measured by differential scanning calorimetry (DSC), was of the order DDE > BAMP > DDS. Through the evaluation of thermal gravimetric analysis (TGA), the new phosphorylated epoxy‐imide polymer demonstrated excellent thermal properties as well as a high char yield. © 1995 John Wiley & Sons, Inc.

A new type of epoxy resin which contained cyclic phosphine oxide group in the main chain was synthesized. The structure of the new type of epoxy resin was confirmed by elemental analyses (EA), infrared spectroscopy (IR), and 1H‐NMR and 13C‐NMR spectroscopies. In addition, compositions of the new synthesized cyclic phosphine oxide epoxy resin (EPCAO) with three curing agents, e.g., bis(3‐aminophenyl)methylphosphine oxide (BAMP), 4,4′‐diamino‐diphenylmethane (DDM), and 4,4′‐diaminodiphenylsulfone (DDS), were used for making a comparison of its curing reactivity, heat, and flame retardancy with that of Epon828 and DEN438. The reactivities were measured by differential scanning calorimetry (DSC). Through the evaluation of thermal gravimetric analysis (TGA), those polymers which were obtained through the curing reactions between the new epoxy resin and three curing agents (BAMP, DDM, DDS) also demonstrated excellent thermal properties as well as a high char yield. © 1996 John Wiley & Sons, Inc.