Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
Acta Biomater. 2013 Jan;9(1):4487-95. doi: 10.1016/j.actbio.2012.08.012. Epub 2012 Aug 16.
Currently, the most severe limitation to applying RNA interference technology is delivery, including localizing the molecules to a specific site of interest to target a specific cell population and sustaining the presentation of these molecules for a controlled period of time. In this study, we engineered a functionalized, biodegradable system created by covalent incorporation of cationic linear polyethyleneimine (LPEI) into photocrosslinked dextran (DEX) hydrogels through a biodegradable ester linkage. The key innovation of this system is that control over the sustained release of short interference RNA (siRNA) was achieved, as LPEI could electrostatically interact with siRNA to maintain siRNA within the hydrogels and degradation of the covalent ester linkages between the LPEI and the hydrogels led to tunable release of LPEI/siRNA complexes over time. The covalent conjugation of LPEI did not affect the swelling or degradation properties of the hydrogels, and the addition of siRNA and LPEI had minimal effect on their mechanical properties. These hydrogels exhibited low cytotoxicity against human embryonic kidney 293 cells (HEK293). The release profiles could be tailored by varying DEX (8 and 12% w/w) and LPEI (0, 5, 10 μg/100 μl gel) concentrations with nearly 100% cumulative release achieved at day 9 (8% w/w gel) and day 17 (12% w/w gel). The released siRNA exhibited high bioactivity with cells surrounding and inside the hydrogels over an extended time period. This controllable and sustained siRNA delivery hydrogel system that permits tailored siRNA release profiles may be valuable to guide cell fate for regenerative medicine and other therapeutic applications such as cancer treatment.
目前，应用 RNA 干扰技术的最大限制是递药，包括将分子定位到感兴趣的特定部位以靶向特定的细胞群体，并维持这些分子的呈递时间。在这项研究中，我们设计了一种功能性的、可生物降解的系统，该系统通过可生物降解的酯键将阳离子线性聚乙烯亚胺（LPEI）共价掺入光交联葡聚糖（DEX）水凝胶中。该系统的关键创新在于可以控制短干扰 RNA（siRNA）的持续释放，因为 LPEI 可以与 siRNA 静电相互作用，将 siRNA 保持在水凝胶内，并且 LPEI 与水凝胶之间的共价酯键的降解导致 LPEI/siRNA 复合物随时间的推移可调释放。LPEI 的共价缀合不影响水凝胶的溶胀或降解特性，而 siRNA 和 LPEI 的添加对其机械性能的影响很小。这些水凝胶对人胚肾 293 细胞（HEK293）表现出低细胞毒性。通过改变 DEX（8%和 12%w/w）和 LPEI（0、5、10μg/100μl 凝胶）浓度，可以定制释放曲线，在第 9 天（8%w/w 凝胶）和第 17 天（12%w/w 凝胶）达到近 100%的累积释放。释放的 siRNA 表现出高生物活性，细胞在水凝胶内外长时间存在。这种可控制和持续的 siRNA 递药水凝胶系统，允许定制的 siRNA 释放曲线，可能对指导细胞命运用于再生医学和其他治疗应用，如癌症治疗具有重要价值。
