Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA.
Biomaterials. 2012 Feb;33(4):1154-61. doi: 10.1016/j.biomaterials.2011.10.033. Epub 2011 Nov 5.
Controlled gene silencing technologies have significant, unrealized potential for use in tissue regeneration applications. The design described herein provides a means to package and protect siRNA within pH-responsive, endosomolytic micellar nanoparticles (si-NPs) that can be incorporated into nontoxic, biodegradable, and injectable polyurethane (PUR) tissue scaffolds. The si-NPs were homogeneously incorporated throughout the porous PUR scaffolds, and they were shown to be released via a diffusion-based mechanism for over three weeks. The siRNA-loaded micelles were larger but retained nanoparticulate morphology of approximately 100 nm diameter following incorporation into and release from the scaffolds. PUR scaffold releasate collected in vitro in PBS at 37 °C for 1-4 days was able to achieve dose-dependent siRNA-mediated silencing with approximately 50% silencing achieved of the model gene GAPDH in NIH3T3 mouse fibroblasts. This promising platform technology provides both a research tool capable of probing the effects of local gene silencing and a potentially high-impact therapeutic approach for sustained, local silencing of deleterious genes within tissue defects.
基因沉默技术在组织再生应用中具有显著的、尚未实现的潜力。本文所述的设计提供了一种将 siRNA 包装并保护在 pH 响应性、内体溶酶体胶束纳米颗粒（si-NPs）内的方法，该纳米颗粒可整合到无毒、可生物降解和可注射的聚氨酯（PUR）组织支架中。si-NPs 均匀地整合到多孔 PUR 支架中，并通过扩散机制释放，持续超过三周。负载 siRNA 的胶束在整合到支架中和从支架中释放后，尺寸更大，但仍保持约 100nm 直径的纳米颗粒形态。在 37°C 的 PBS 中收集体外 1-4 天的 PUR 支架释放液，能够实现剂量依赖性的 siRNA 介导的基因沉默，约 50%的模型基因 GAPDH 在 NIH3T3 小鼠成纤维细胞中被沉默。这项有前途的平台技术提供了一种研究工具，能够探测局部基因沉默的效果，同时也为组织缺陷内有害基因的持续、局部沉默提供了一种潜在的高影响力的治疗方法。
