Rational design of soft nanoparticles for non-invasive drug delivery

基因治疗是将编码治疗基因的DNA靶向插入病变细胞或组织的细胞核中，然后进行表达，是治疗许多疾病和病症最有前途的新疗法之一。首个基因治疗产品Gendicine（基于腺病毒载体）于2003年在中国获批用于头颈癌。2012年7月24日，欧洲药品管理局批准了腺相关病毒（AAV）基因疗法Glybera by unique，用于治疗脂蛋白脂肪酶缺乏症（一种孤儿病）。unique公司也在开发一种GDNF（胶质细胞源性神经营养因子）基因在其AAV-2传递载体中的应用，用于治疗帕金森病。目前bbb1300基因治疗临床试验正在进行中（www.clinicaltrials.gov）。*尽管取得了巨大的进步，但在实现这种治疗模式的全部益处方面仍存在一些挑战。特别是，为了充分发挥基因治疗的效益，需要开发具有靶向能力、转染效率高、安全性高的基因传递载体。目前，病毒是最有效的DNA传递载体，但它们的使用有许多缺点：高免疫原性和毒性，可封装的DNA序列大小的限制，以及潜在的诱变。新的非病毒传递系统没有这些缺点，为基因治疗提供了巨大的希望。然而，非病毒系统在临床应用中还不够有效和特异性。这些系统的结构和功能都需要改进。此外，在靶部位是外部可及的器官/组织（如眼睛、皮肤、鼻/阴道/口腔粘膜）的应用中，一种非侵入性的基因治疗方法，如局部和口服给药，是非常可取的，但由于缺乏有效的递送系统，目前尚不可行。*该研究项目将重点关注核酸传递系统设计的基础和应用方面，特别关注质粒DNA和siRNA。在开发新的、更先进的非病毒技术在体内传递和靶向基因和siRNA的过程中，必须充分了解相互作用的细胞和亚细胞途径。诱导正确和特定的治疗反应取决于递送系统的“智能”，以到达预定的靶点并在那里被激活。*在这些系统的设计过程中，交互过程的可视化和交付效率的量化是必需的。以核酸为基础的治疗剂是特别难以成功递送的分子。这就是为什么目前只有一种给药方式：注射。在局部给药后，可以通过皮肤、角膜、鼻腔和阴道粘膜运输药物的非侵入性给药系统的发展可以提供一种局部无痛靶向基因治疗的方法。此外，局部方法可以克服药物在口服和肠外给药和吸收过程中的稳定性、注射时的局部毒性和刺激性以及由于药物半衰期短而多次给药等问题。纳米技术方法在设计和开发局部非侵入性核酸递送和靶向系统方面提供了巨大的潜力。我们建议开发基于复合纳米粒子的无创药物递送系统，该系统使用自组装和可靶向的生物材料，包括磷脂、gemini表面活性剂、酰化氨基酸和碳纳米管。

Gene therapy, the targeted insertion of DNA coding for a therapeutic gene into the nuclei of diseased cells or tissues followed by its expression, is one of the most promising new therapies for a host of diseases and conditions. The first gene therapy product, Gendicine (adenoviral vector-based) was approved in China in 2003 for head and neck cancer. On July 24, 2012 the European Medicines Agency approved the adeno-associated viral (AAV) gene therapy, Glybera by uniQure, for lipoprotein lipase deficiency, an orphan disease. uniQure is also developing the use of a GDNF (glial cell derived neurotrophic factor) gene in their AAV-2 delivery vector for the treatment of Parkinson's disease. Currently >1300 gene therapy clinical trials are in progress (www.clinicaltrials.gov). *In spite of the tremendous progress, a number of challenges remain in realizing the full benefit of this treatment mode. In particular, to achieve the full benefit of gene therapy, it is necessary to develop gene delivery vectors with targeting ability, high transfection efficiency and improved safety. Currently, viruses are the most efficient vectors for DNA delivery, but their use has many disadvantages: high immunogenicity and toxicity, limitations in the size of DNA sequences that can be encapsulated, and potential for mutagenesis. Novel non-viral delivery systems do not present these disadvantages and offer tremendous promise for gene therapy. However, non-viral systems are not yet effective and specific enough for clinical applications. Improvements in both the structure and function of these systems are required. Moreover, in applications where the target site is an externally accessible organ/tissue, such as the eye, skin, nasal/vaginal/oral mucosa, a non-invasive approach to gene therapy, such as topical and oral administration, is highly desirable but not presently feasible due to the lack of effective delivery systems. *The research program will focus on both the fundamental and applied aspects of delivery system design for nucleic acids, with specific focus on plasmid DNA and siRNA. In the process of developing new, more advanced non-viral technologies to deliver and target genes and siRNA in the body, the cellular and subcellular pathways of interaction must be fully understood. Induction of the correct and specific therapeutic responses is dependent upon the `intelligence' of the delivery system to arrive to the intended target sites and be activated there. *During the design of these systems, visualization of the interaction process and the quantification of the delivery efficiency are required. Nucleic acid-based therapeutic agents are especially difficult molecules to deliver successfully. This is one of the reasons why there is currently only one way administer these compounds: by injection. Development of non-invasive delivery systems that can transport drugs through the skin, cornea, nasal and vaginal mucosa after topical administration could provide an approach to target gene therapies locally and painlessly. In addition, the localized approach could overcome problems related to drug stability during oral and parenteral dosing and absorption, local toxicity and irritation from injection, and multiple dosing because of short drug half-lives. Nanotechnological approaches provide significant potential in the design and development of topical non-invasive delivery and targeting systems for nucleic acids. We propose developing non-invasive drug delivery systems based on composite nanoparticles using self-assembling and targetable biomaterials, including phospholipids, gemini surfactants, acylated amino acids and carbon nanotubes.