超声响应型纳米凝胶诊疗剂开放血脑屏障及诊治脑胶质瘤的机制研究

Brain glioma often recurs after surgery and is not sensitive to radiation therapy. Drug therapy also shows unsatisfactory efficacy due to blood brain barrier (BBB). To open the BBB is the key to improve the diagnostic and therapeutic efficacy to brain glioma. Low intensity focused ultrasound (LIFU) and local NO release is able to open the BBB. In previous work, basing on a continuous cavitation strategy, we obtained a type of “all in one” theranostic radiofrequency ablation enhancement nano-agent. Moreover, we successfully designed a tumor microenvironment-responsive US/MR dual-modal imaging probe and a structurally optimized US/CT/MRI tri-modal molecular probe, respectively. Basing on these experiences, in this project, we will design and construct a hybrid nanohydrogel-based theranostic agents consisting of Fe3O4 nanoparticles as the inner core and nanogel as the outer shell that encapsulates NO donor and therapeutic genes for brain glioma. Upon exposure to LIFU irradiation, NO release from the constructed theranostic agent will open the BBB. Confocal imaging and UV-Vis absorption spectrometer will be employed to investigate the NO release. Marriage of NO and LIFU for opening BBB and related mechanism will be evaluated and explored in detail via various methods, such as biological election microscopy, inductively coupled plasma-atomic emission spectrometry (ICP-AES), in vivo animal fluorescence imaging, confocal imaging, flow cytometroy, etc. Moreover, we will employ some approaches, e.g., signal variation of ultrasound and MR, immunohistochemistry, Western blot, tumor growth profile, etc., to implement investigations of ultrasound/MR dual-modal imaging and synergistic treatment of NO and therapeutic genes for brain glioma, and we expect related investigations in this project can provide a new method for ‘all in one’ theranostic investigation of brain glioma.

脑胶质瘤术后易复发，药物治疗因血脑屏障（BBB）也疗效不佳。开启BBB是提高脑胶质瘤诊疗效果的关键，低强度聚焦超声（LIFU）及局部NO释放可开放BBB。项目组前期基于“连续空化”制备了一种射频增效纳米微囊；设计了肿瘤微环境刺激响应的US/MRI双模态分子探针。基于此，拟通过新型酶催化聚合工艺，设计和构建以Fe3O4纳米颗粒为内核、外壳为纳米凝胶、同时包裹治疗基因和NO供体分子的杂化纳米凝胶诊疗剂。后者在LIFU作用下可释放NO，开启BBB。拟通过共聚焦、紫外-可见光谱等研究该诊疗剂在LIFU作用下NO的释放特性；利用生物电镜、荧光成像、共聚焦等研究NO辅助LIFU开放BBB机制。同时研究NO气体和Fe3O4内核实现US/MRI双模态成像的机制； 并利用免疫组化、蛋白印记、肿瘤生长曲线等探讨NO与治疗基因协同治疗作用的机制。以上研究将为实现脑胶质瘤诊疗一体化提供新的思路。

脑重大疾病诊疗领域是“中国脑计划”三大研究领域之一，而脑胶质瘤作为脑重大疾病之一引起了广泛的关注。然而，由于药物难以突破血脑屏障血脑屏障（Blood brain barrier，BBB），使得脑胶质瘤的诊疗效果不甚理想。本项目针对脑胶质瘤诊疗存在的关键科学问题，按照课题研究计划，围绕研究内容开展了一系列相关研究，开发了一种转运蛋白介导的血脑屏障跨越的新技术，并在脑胶质瘤原位模型上验证了该技术的可行性；构建配位响应的纵向弛豫策略并设计相应的分子探针，定量探测脑胶质瘤特异性靶标分子；建立靶标分子与肿瘤进展之间的关系，为实现脑胶质瘤病理可视化监测以及适时、适当干预提供理论依据；提出原位生成顺磁性CEST造影剂的策略，为活体脑部多巴胺分子的精准影像诊断提供新的手段或工具；开发了一种热疗增强NO气体治疗的新技术，实现NO的靶向可控释放，增强了抗肿瘤效果，为脑胶质瘤多元化治疗模式提供了新的选择。此外，在原计划的基础上，团队进一步拓展项目研究深度，在肿瘤微环境调控增强脑胶质瘤等恶性肿瘤治疗效能方面进行了探索性研究，设计并构建了多种基于肿瘤微环境调控的新型生物材料，并建立相应的治疗体系，增强低强度超声治疗的效能，抑制肿瘤转移、复发并研究其潜在机制，为实现肿瘤的精准、安全、高效以及综合治疗提供新思路。

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