Thermosensitive polymers as carriers for DNA delivery
Thermosensitive polymers as carriers for DNA delivery
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DOI：
10.1016/s0168-3659(99)00075-9
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发表时间：
1999-08-05
影响因子：
10.8
通讯作者：
Hennink, WE
中科院分区：
文献类型：
--
作者：
Hinrichs, WLJ;Schuurmans-Nieuwenbroek, NME;Hennink, WE
研究了不同单体比例和不同相对分子质量的甲基丙烯酸二甲氨基乙酯(DMAEMA)和N-异丙基丙烯酰胺(NIPAAm)共聚物作为DNA载体系统的性能。所有的共聚物，即使在DMAEMA含量较低的情况下，也能在25℃下与DNA结合。光散射测量表明，络合伴随着(Co)聚合物在络合物中的沉淀，这是由于(Co)聚合物的较低临界溶解温度下降所致。随着共聚物中NIPAAm含量的增加，(Co)聚合物/质粒形成约200 nm大小的复合体的比例增大，且与(Co)聚合物的相对分子质量无关。然而，在25℃下制备的含有低分子量或高NIPAAm含量的(Co)聚合物的络合物在37℃时迅速聚集，而含有高分子量或较低NIPAAm含量的(Co)聚合物的络合物在37℃时相对稳定。络合物的Zeta电位也与(Co)聚合物的相对分子质量无关，并且随着(Co)聚合物/质粒比的增加而增加，直到达到平台值。达到这一平台的(Co)聚合物/质粒比随着NIPAAm含量的增加而增加。当NIPAAm含量从0增加到85mol%时，平台值从26 mV左右下降到13 mV左右。配合物的细胞毒性随NIPAAm含量的增加而显著降低，且与共聚物的相对分子质量无关。稳定性差的复合体的转染率总体上远低于稳定性好的复合体。转染率随(Co)聚合物/质粒比的变化呈钟形曲线。最大转染率的(Co)聚合物/质粒比随NIPAAm含量的增加而增大，而最大转染率随共聚物中NIPAAm含量的增加而显著降低。本研究的结果表明，稳定的(共)聚合物/质粒复合体的形成约200 nm是有效转导的先决条件。此外，随着Zeta电位的降低，转染率和细胞毒性显著降低。因此，除了大小，Zeta电位也可以作为一个特征来预测这类(Co)聚合物/质粒复合体在转染过程中的行为。带有寻的装置的DMAEMA和NIPAAm的共聚物可能是一种有趣的基因靶向载体系统，因为这些共聚物可以将DNA凝聚成小颗粒，所得到的络合物具有低的细胞毒性和非特异性的转染性。(C)1999 Elsevier Science B.V.保留所有权利。
Copolymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and N-isopropylacryl amide (NIPAAm) of various monomer ratios and molecular weights were evaluated as carrier systems for DNA delivery. All copolymers, even with a low DMAEMA content of 15 mol%, were able to bind to DNA at 25 degrees C. Light-scattering measurements indicate that complexation is accompanied by precipitation of the (co)polymer in the complex caused by a drop of the lower critical solution temperature of the (co)polymer. The (co)polymer/plasmid ratio at which complexes with a size of around 200 nm were formed increased with increasing NIPAAm content of the copolymer and was independent of molecular weight of the (co)polymer. However, complexes containing (co)polymers of low molecular weight or high NIPAAm content prepared at 25 degrees C aggregated rapidly when the temperature was raised to 37 degrees C, whereas complexes containing (co)polymers of high molecular weight or lower NIPAAm content were relatively stable at 37 degrees C. The zeta potential of the complexes was also independent of molecular weight of the (co)polymer and increased with increasing (co)polymer/plasmid ratio until a plateau value was reached. The (co)polymer/plasmid ratio at which this plateau was reached increased with increasing NIPAAm content. The plateau values decreased from around 26 mV to around 13 mV when the NIPAAm content of the copolymer was increased from 0 to 85 mol%. The cytotoxicity of the complexes strongly decreased with increasing NIPAAm content and was independent of molecular weight of the (co)polymer. The transfection efficiency of complexes with poor stability was in general much lower than that of complexes with good stability. The transfection efficiency as a function of the (co)polymer/plasmid ratio showed a bell-shaped curve. The (co)polymer/plasmid ratio at which the transfection efficiency was maximal increased with increasing NIPAAm content, while the maximum transfection efficiency strongly decreased with increasing NIPAAm content of the copolymer. The results of this study show that the formation of stable (co)polymer/plasmid complexes with a size of around 200 nm is a prerequisite for efficient transfection. Furthermore, the transfection efficiency and cytotoxicity strongly decreased with decreasing zeta potential. Therefore, besides the size, the zeta potential can also be used as a characteristic to predict the behavior of this type of (co)polymer/plasmid complexes in transfection. Copolymers of DMAEMA and NIPAAm provided with a homing device may be interesting carrier systems for gene targeting because these copolymers can condense DNA to small particles, and the resulting complexes show a low cytotoxicity and aspecific transfection. (C) 1999 Elsevier Science B.V. All rights reserved.