黑磷量子点掺杂层状双氢氧化物复合体的构建及其光诱导促心肌分化作用与机理研究

The rapid progress of theranostic nanomedicine has evidenced the generation of diverse inorganic nanosystems with intrinsic functionalities for diverse biomedical applications. However, these inorganic biomaterials suffer from various critical issues such as low biodegradation rates and subsequently long-term accumulation-induced biosafety risk. In this project, we are anticipated to develop the multi-functional robust platform based on black phosphorus quantum dots (BPQDs)-impregnated ultra-thin layered double hydroxides (LDHs) nanosheets where BPQDs will be doped in these plates via exfoliation for light-induced cardiac differentiation that include both cardiomyocyte growth and accelerating the electrical conductivity. Intravenously administered composites will be internalized through enhanced permeation and retention (EPR) effect as the damaged myocardium possess leaky vasculature, where these nanoparticles could be targeted and accumulate in the damaged tissue region. Cardiac growth can be achieved by releasing the ascorbic acid (antioxidant) loaded in the gallery spaces of LDHs in the cardiomyocytes to protect the cells from oxidative stress-induced injury based on glutathione (GSH)-depleted cell protection mechanism through inhibition of reactive oxygen species (ROS) formation. Moreover, the LDHs also can induce the differentiation of intracardiac administered stem cells to cardiomyocytes through decreasing the expression of stemness genes i.e., octamer-binding transcription factor 4 (OCT4) and sex determining region Y-box 2 (SOX2) and junctional crosstalk between cardiomyocyte and stem cells. The light-induced activation of BPQDs enhances the impulse conductivity in differentiated cardiomyocytes. In addition, the components of LDHs i.e., manganese (Mn) and iron (Fe) synergistically enhance the electrical conductivity of BPQDs. To accomplish this project, various tasks including synthesis of BPQDs-LDHs, application both in vitro at cellular level and in vivo at animal level along with the mechanistic elucidations will be explicitly investigated. Moreover, in-depth analyses of interactions between BPQDs and LDHs, as well as the BPQDs-LDH hybrid and cardiomyocytes are investigated. This strategy promises the clinical translation and biomedical applications of inorganic nanosystems based on their intriguing nature of easy biodegradation and single phosphorus composition, as necessarily required in vivo. Moreover, we strongly have faith in this project that this will certainly remain as one of the efficient findings and this supramolecular design will potentially find its way in various biomedical applications.

电导率不足和细胞再生能力差是目前心脏疾病治疗的最大困难之一，虽然无机纳米材料能提供较好的导电性，但其在体内积累导致的安全性问题仍须解决。本项目拟构建黑磷量子点（BPQDs）掺杂层状双氢氧化物（LDHs）并装载抗坏血酸的复合结构，光调控BPQDs活化电子沿LDHs金属离子传播，结合药物提高电导率、促心肌分化与细胞再生，治疗心肌梗死。由反应条件调控复合体形貌，在细胞和动物层面，评价生物安全性，检测胞内活性氧水平，考察其在近红外光激活下活化电子、整体提高心脏导电性的能力以及细胞保护和再生效果；在分子水平探究干细胞基因（OCT-4、SOX2）、心肌细胞与干细胞连接串扰因子及心肌标记基因等表达，揭示其诱导心肌细胞分化和增强导电性机制，解决电导率不足和心肌分化和再生能力的问题。本项目在保障BPQDs稳定的同时增强电子传递效率，提高再生组织电传导性，增强与原位心肌电机械偶联，开辟心血管疾病治疗的新思路。

基于电导率不足和细胞再生能力差是目前心脏疾病治疗的最大困难之一，无机纳米材料虽然能提供较好的导电性，但其在体内积累导致的安全性问题仍须解决。进一步研究黒磷（BP）体系无机纳米颗粒合成制备以及在细胞的安全性问题，为黒磷量子点（BPQDs）在心血管疾病治疗方面提供有意义的建议。.首先，通过调控制备过程，采用液相剥离法中冰浴超声和探针超声相结合方法制备BPQDs，再进一步通过共沉淀和剥离再自组装方法与层状双氢氧化合物（LDHs）合成BPQDs-LDHs纳米复合体，以及再加载药物，形成BPQDs-LDHs-AA纳米复合体。结果表明BPQDs可以有效地通过液相剥离法获取，与LDHs可以进行良好的自组装。LDHs可以在水溶液中有效地保护BPQDs不被氧化，使其保持正常的光热转化效率以及其他基本性质。由于纳米复合体呈现正电位，同时LDHs层间仍存在大量活性位点，可以有效搭载负电位的药物。在另外的工作中，黒磷纳米片（BPNS）通过聚乙二醇（PEG）修饰形成BPNS-PEG，以及通过超临界流体技术实现一步包覆BPQDs形成BGP，均可实现对BP体系物质的有效保护，同时对BPQDs的光热性能影响较小。在生物安全性方面分别对这几种BP体系的物质进行细胞毒性以及增殖迁移测试，结果表明纯BPQDs在高浓度下对细胞具有较大的毒性，而使用LDHs、PEG以及超临界技术直接修饰包裹后的BP体系，具有良好的细胞相容性和促进细胞生长能力，同时其热效应能进一步促进复合体中所搭载药物的有效释放。另一方面，探索了无机物促进细胞钙化的研究，生物活性玻璃BG能有效的促进细胞内环境产生钙盐沉积以修复受损骨组织。.以上结果表明，通过超声合成的BPQDs，在LDHs以及其他聚合物修饰的情况下，可以具有良好的生物相容性，同时有效地促进细胞生长，并可能在心血管治疗中具有应用前景。.在本项目的资助下，发表SCI论文12篇，第一标注6篇，第二标注1篇，第三标注5篇。