目的采用中心组合设计法优化载基因壳聚糖纳米粒的最佳转染制备区域。方法采用复凝聚法制备载质粒基因的壳聚糖纳米粒,选择壳聚糖浓度和质粒基因浓度作为实验考察因素,应用两因素五水平中心组合设计优化最佳转染制备区域,优化指标选择平均粒径和基因转染率。通过透射电镜观察纳米粒的形态;通过动态光散射和电泳光散射技术分别测量纳米粒的粒径和Zeta电位;通过凝胶电泳分析考察质粒在纳米粒制备过程中的稳定性;通过倒置荧光显微镜观察质粒基因在细胞内的表达;通过流式细胞技术测定纳米粒的转染效率。结果成功优化了载基因壳聚糖纳米粒的最佳转染制备区域。优选条件下制备的纳米粒大多呈球形,纳米粒平均粒径为217.6 nm,粒径多分散系数为0.241,表明粒径分布较窄。纳米粒zeta电位为+22.4 m V,表明纳米粒表面带有正电荷,可以增加纳米粒混悬液的稳定性。凝胶电泳分析结果表明质粒基因在纳米粒制备过程中没有遭到破坏。纳米粒的细胞转染效率比较高,能够高效地将绿色荧光蛋白质粒基因递送到细胞内,并且基因表达产生绿色荧光蛋白。结论本研究建立的数学模型具有良好的预测性。在优化的制备区域内制备的载基因壳聚糖纳米粒的转染性能比较理想。
Dichloro（1,2-diaminocyclohexane）platinum（ll） （DACHPt）, a cisplatin （CDDP） analog, has shown lower toxicity than CDDP and no cross-resistance with CDDP in many CDDP-resistant cancers. PEGylated hyaluronan （mPEG-HA） is an mPEG conjugated with hyaluronan biodegradable polymer which is a naturally occurring biopolymer in the interstitium, is primarily cleared by the lymphatic system, mPEG- hyaluronan-DACHPt （PEG-HA-Pt） conjugate could circulate long-term in the bloodstream and increase DACHPt concentration in the tumor site and decrease systemic toxicity, mPEG-HA conjugates with the range of 1%-5% substitution were synthesized, and the structures were confirmed by 1H NMR and IR. The particle size of DACHPt incorporated with mPEG-HA was about 86 nm and the loading content and efficiency were about 19% （w/w） and 86%, respectively. The synthesized mPEG-HA with different PEG substitution degrees presented non toxicity, and the cell viability of DACHPt loaded in mPEG-HA nanoparticles increased with increasing doses of DACHPt. DACHPt release from nanoparticles slightly decreased with increasing PEG substitution degree from 1% to 5% at 37℃, pH 7.4 PBS solution. The DACHPt loaded in mPEG-HA nanoparticles significantly inhibited the growth ofA549 xenografts in nude mice when compared to the DACHPt loaded in HA nanoparticles and the control group after 4 weeks treatment （p 〈 0.01 compared with control）. The body weight change curve shows that the mice weight loss was less than 5% by treating with both DACHPt loaded in mPEG-HA and HA nanoparticles. In conclusion, a novel DACHPt loaded mPEG-HA delivery system was developed with sustained release and increased platinum concentration in the tumor.
The efficacy of chemotherapeutic drug in cancer treatment is often hampered by drug resistance of tumor cells,which is usually caused by abnormal gene expression.RNA interference mediated by si RNA and mi RNA can selectively knock down the carcinogenic genes by targeting specific m RNAs.Therefore,combining chemotherapeutic drugs with gene agents could be a promising strategy for cancer therapy.Due to poor stability and solubility associated with gene agents and drugs,suitable protective carriers are needed and have been widely researched for the co-delivery.In this review,we summarize the most commonly used nanocarriers for co-delivery of chemotherapeutic drugs and gene agents,as well as the advances in co-delivery systems.
Lin KangZhonggao GaoWei HuangMingji JinQiming Wang
