Svarovsky Sergei, Borovkov Alexandre, Sykes Kathryn
Center for Innovations in Medicine, The Biodesign Institute at Arizona State University, Tempe, AZ 85287, USA.
Biotechniques. 2008 Nov;45(5):535-40. doi: 10.2144/000112991.
Here we report preparation and properties of positively charged gold microparticles, and their use for biolistic DNA delivery. Micron-sized gold microparticles were modified by building self-assembling polyethylenimine monolayers on their surfaces, which enabled their electrostatic interaction with negatively charged molecules such as DNA. One milligram of the surface-modified microparticles was able to bind directly to up to 3.5 microg of DNA, exceeding the 1 microg/mg limit of the conventional protocols. The binding showed no apparent dependency on DNA purity, size, or conformation. The interaction occurred over a broad range of pH values and salt concentrations, and was stable throughout the standard protocol for biolistic cartridge preparation. At the standard 1 microg dose, biological activity of the DNA biolistically delivered on the charge-modified gold was 25% higher than that delivered on conventional microparticles. Loading the charge-modified gold with more DNA stimulated proportionally higher gene expression. The charge-modified gold can be also used for delivery of small biological molecules such as siRNA. Tissue culture cells biolistically transfected with a LUC+ specific siRNA showed 80% reduction of Luc expression relative to those cells transfected with an irrelevant siRNA. Along with its superior properties as a DNA delivery vehicle, charge-modified gold offers a unique opportunity to deliver various DNA formulations in addition to traditional naked DNA.
在此，我们报告带正电荷的金微粒的制备、性质及其在生物弹道式DNA递送中的应用。通过在微米级金微粒表面构建自组装聚乙烯亚胺单分子层对其进行修饰，这使得它们能够与带负电荷的分子（如DNA）发生静电相互作用。一毫克表面修饰的微粒能够直接结合多达3.5微克的DNA，超过了传统方法1微克/毫克的限度。这种结合对DNA的纯度、大小或构象没有明显依赖性。这种相互作用在很宽的pH值和盐浓度范围内都能发生，并且在生物弹道式弹药制备的标准方案中全程稳定。在标准的1微克剂量下，通过电荷修饰的金进行生物弹道式递送的DNA的生物活性比通过传统微粒递送的高25%。用更多DNA负载电荷修饰的金会相应地刺激更高的基因表达。电荷修饰的金还可用于递送小生物分子，如siRNA。用LUC +特异性siRNA进行生物弹道式转染的组织培养细胞相对于用无关siRNA转染的细胞，Luc表达降低了80%。除了作为DNA递送载体具有优异性能外，电荷修饰的金还提供了一个独特的机会，除了传统的裸DNA外，还能递送各种DNA制剂。
