Li Yuanpei, Bharadwaj Gaurav, Lee Joyce S
Department of Biochemistry & Molecular Medicine, University of California, Davis; UC Davis Comprehensive Cancer Center, University of California, Davis;
Department of Biochemistry & Molecular Medicine, University of California, Davis.
J Vis Exp. 2016 Dec 23(118):54722. doi: 10.3791/54722.
Nanomedicine is an emerging form of therapy that harnesses the unique properties of particles that are nanometers in scale for biomedical application. Improving drug delivery to maximize therapeutic outcomes and to reduce drug-associated side effects are some of the cornerstones of present-day nanomedicine. Nanoparticles in particular have found a wide application in cancer treatment. Nanoparticles that offer a high degree of flexibility in design, application, and production based on the tumor microenvironment are projected to be more effective with rapid translation into clinical practice. The polymeric micellar nano-carrier is a popular choice for drug delivery applications. In this article, we describe a simple and effective protocol for synthesizing drug-loaded, disulfide cross-linked micelles based on the self-assembly of a well-defined amphiphilic linear-dendritic copolymer (telodendrimer, TD). TD is composed of polyethylene glycol (PEG) as the hydrophilic segment and a thiolated cholic acid cluster as the core-forming hydrophobic moiety attached stepwise to an amine-terminated PEG using solution-based peptide chemistry. Chemotherapy drugs, such as paclitaxel (PTX), can be loaded using a standard solvent evaporation method. The O2-mediated oxidation was previously utilized to form intra-micellar disulfide cross-links from free thiol groups on the TDs. However, the reaction was slow and not feasible for large-scale production. Recently, an H2O2-mediated oxidation method was explored as a more feasible and efficient approach, and it was 96 times faster than the previously reported method. Using this approach, 50 g of PTX-loaded, disulfide cross-linked nanoparticles have been successfully produced with narrow particle size distribution and high drug loading efficiency. The stability of the resulting micelle solution is analyzed using disrupting conditions such as co-incubation with a detergent, sodium dodecyl sulfate, with or without a reducing agent. The drug-loaded, disulfide cross-linked micelles demonstrated less hemolytic activity when compared to their non-cross-linked counterparts.
纳米医学是一种新兴的治疗形式，它利用纳米级粒子的独特性质用于生物医学应用。改善药物递送以最大化治疗效果并减少药物相关副作用是当今纳米医学的一些基石。特别是纳米粒子在癌症治疗中已得到广泛应用。基于肿瘤微环境在设计、应用和生产方面具有高度灵活性的纳米粒子预计在快速转化为临床实践中会更有效。聚合物胶束纳米载体是药物递送应用中的热门选择。在本文中，我们描述了一种基于明确的两亲性线性 - 树枝状共聚物（端树枝状聚合物，TD）自组装合成载药、二硫键交联胶束的简单有效方案。TD由聚乙二醇（PEG）作为亲水链段和硫醇化胆酸簇作为形成核心的疏水部分组成，通过基于溶液的肽化学逐步连接到胺端基PEG上。化疗药物，如紫杉醇（PTX），可使用标准溶剂蒸发法加载。先前利用O2介导的氧化从TD上的游离硫醇基团形成胶束内二硫键交联。然而，该反应缓慢且不适用于大规模生产。最近，探索了一种H2O2介导的氧化方法作为一种更可行和有效的方法，它比先前报道的方法快96倍。使用这种方法，已成功生产出50克载有PTX的二硫键交联纳米粒子，其粒径分布窄且药物负载效率高。使用诸如与去污剂十二烷基硫酸钠共同孵育等破坏条件，在有或没有还原剂的情况下，分析所得胶束溶液的稳定性。与未交联的对应物相比，载药的二硫键交联胶束表现出较低的溶血活性。
