BODIPY Photocage-Enabled Visualization and Optical Control of saRNA Delivery and Immunogenicity

基于RNA的疫苗由于其增强的免疫应答和无细胞制造，在持续的SARS-CoV-2大流行期间已成为常规疫苗接种方法的有效且经济的替代方案。然而，RNA固有的单链性质常常导致化学不稳定性，从而降低效率。规避这个问题的一种方法是使用先进的递送策略，其可以稳定RNA结构以及允许有效的体内递送和释放。本提案的目的是通过将NIR光激活的BODIPY光笼（Bpc）整合到RNA负载的阳离子聚合物中来开发光响应和荧光自我报告的RNA递送系统。在目前的设计中，Bpc既作为发射自报告子又作为光敏单元。Bpc发射将允许实时监测纳米载体分布，并且光笼化过程将使得能够使用光按需释放负载的RNA。为了进一步探索这种递送平台，我还将研究硝基官能化的Bpc（BpcNO 2）的递送和控释特性，其光依赖性荧光变化可以作为量化释放RNA量的内部指示剂。所提出的工作的成功将提供1）一种新颖的、直接的和生物相容性的策略来构建NIR光响应和荧光可追踪的RNA递送系统，其能够保持结构完整性并确保RNA的翻译效率;和2）一种化学生物学工具来探测免疫原性RNA的体内分布并调节剂量。

RNA-based vaccines because of their enhanced immune response and cell-free manufacturing have become a potent and economical alternative to conventional vaccination approaches during the ongoing SARS-CoV-2 pandemic. The intrinsic single-stranded nature of RNA, however, oftentimes results in chemical instability and thus attenuated efficiency. One way to circumvent this issue is to use advanced delivery strategies which can stabilize RNA structures as well as allow efficient in vivo delivery and release. The objective of this proposal is to develop a light-responsive and fluorescent self-reporting RNA delivery system through integrating NIR light activated BODIPY photocages (Bpc) into RNA-loaded cationic polymers. In the current design, Bpc function both as the emissive self-reporters and photosensitive units. The Bpc emission will allow for real-time monitoring of the nanocarrier distribution and the photocaging process will enable on-demand release of the loaded RNA using light. To further explore this delivery platform, I will also investigate the delivery and controlled release properties of the nitro-functionalized Bpc (BpcNO2), the light-dependent fluorescence change of which can serve as an internal indicator to quantify the amount of released RNA. The success of the proposed work will offer 1) a novel, straightforward and biocompatible strategy to construct NIR light responsive and fluorescence traceable RNA delivery systems which are capable of maintaining the structural integrity and ensuring the translational efficiency of RNAs and 2) a chemical biology tool to probe the in vivo distribution and modulate the dose of immunogenic RNAs.