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--最近,一篇发表于国际杂志ACS Biomaterials Science & Engineering上的研究论文中,来自美国杜克大学的科学家们设计了一种新方法用以开发潜在的纳米癌症疗法;这种方法可以使得水凝胶薄层沉积在纳米壳表面,而这种纳米颗粒仅有100纳米厚,其可以吸收红外线并且产生热量,当其加热时特殊的水凝胶就会失去水分,释放诸如糖类等分子。

文章中研究者将水凝胶沉积于作用肿瘤的纳米壳上,并且以化疗药物涂层覆盖,Jennifer West教授说道,我们的思路是将破坏肿瘤的热疗法同局部药物运输相结合,这种组合拳或是最有效的癌症治疗手段,研究表明许多化疗药物都可以有效作用于发热的组织上,因此将上述两种方法结合或许存在一定的可能性。

目前光热疗法已经应用于临床试验中进行多种癌症的治疗,纳米壳可以吸收近红外线,近红外线就可以无损伤性地穿过水和组织,然而纳米壳可以快速加热足以杀灭细胞,但其仅会在光照射的地方才会发挥作用。除了精准地靶向作用机体的特殊部位外,这种疗法还会促进纳米壳在肿瘤内部积累发挥作用。

这项研究中,研究人员用特殊的化疗药物覆盖纳米壳,同时在实验室条件下将其运输至肿瘤细胞中,随后疗法就会按照计划开始发挥作用,即纳米壳开始加热,在释放药物的同时破坏大多数的癌细胞;当然完全清除所有的癌变细胞非常重要,因为任何单一癌细胞的逃脱都有可能引发致死性的癌转移。

下一步研究者将利用活体动物来进行新型疗法的试验,当然研究者有信心在不久的将来进行人类临床试验。

Hydrogel-Coated Near Infrared Absorbing Nanoshells as Light-Responsive Drug Delivery Vehicles

Laura E. Strong and Jennifer L. West 

 

Nanoparticle drug delivery carriers that can modulate drug release based on an exogenous signal, such as light, are of great interest, especially for improving cancer therapy. A light-activated delivery vehicle was fabricated by synthesizing a thin, thermally responsive poly(N-isopropylacrylamide-co-acrylamide) hydrogel coating directly onto the surfaces of individual near-infrared (NIR) absorbing gold-silica nanoshells. This hydrogel was designed to be in a swollen state under physiological conditions and expel large amounts of water, along with any entrapped drug, at elevated temperatures. The required temperature change can be achieved via NIR absorption by the nanoshell, allowing the hydrogel phase change to be triggered by light, which was observed by monitoring changes in particle sizes as water was expelled from the hydrogel network. The phase change was reversible and repeatable. As a model drug, the chemotherapeutic doxorubicin was loaded into this delivery vehicle, and rapid release of doxorubicin occurred upon NIR exposure. Further, colon carcinoma cells exposed to the irradiated platform displayed nearly 3 times as much doxorubicin uptake as cells exposed to nonirradiated particles or free drug, which in turn resulted in a higher loss of cell viability. We hypothesize these effects are because the NIR-mediated heating results in a transient increase in cell membrane permeability, thus aiding in cellular uptake of the drug.(来源:生物谷)