Photonic Sensing and Dual-mode Bio-Imaging with Rare Earth Upconversion Nanoparticles

心血管疾病(CVD)包括急性心肌梗死(AMI)和中风，是世界上过早死亡的主要原因。CVD的本质要求比目前无法或耗时的方法更早地高效和同时检测生物标记物。动脉粥样硬化是一种炎症性疾病，炎症标志物高敏C反应蛋白(CRP)已被证明可以识别更多的风险个体。脂蛋白相关磷脂酶A2(LP-PLA2)也是血管炎症的标志。因此，例如，同时使用Lp-PLA2和hs-CRP进行筛查可能比单独使用任何一种测试提供更好的心血管疾病和中风风险评估。在本项目中，我们选择了四个生物标记物NT-proBNP、LpPLA2、GFAP和IL6来实现一个多生物标记物检测和测量系统。目前用于检测和评估动脉粥样硬化斑块的传统诊断工具有其局限性，即使是从CT和MRI等现代技术接收到的对比度较低的图像也是如此。虽然最近在成像技术以及蛋白质组学和代谢图谱方面的进展增强了患者筛查诊断的可行性，但它们不适合于早期诊断可能有利于这些疾病的初级预防和治疗的“看护点”。“金标准”心脏血管造影术是一种有创方法，具有与插管过程相关的风险，目前还没有可靠的非侵入性方法来识别和量化动脉粥样硬化斑块形成的严重程度。目前超声扫描被用于非侵入性地检测斑块负荷，特别是在颈动脉，但目前还没有可用的解释来区分不稳定斑块和稳定斑块。在这个跨学科的项目中，我们将开发基于稀土元素上转换纳米颗粒(UCNPs)和基于生物分子共轭的分析方法，用于快速和同时检测和成像关键的生物标志物-心血管疾病和动脉粥样硬化。UCNP具有特定的激发和发射波长，单个的荧光稀土离子对周围环境的变化非常敏感。该项目旨在创建一种可扩展的稀土(RE)上转换纳米颗粒(UCNP)的制造工艺，适用于基于光致发光的快速生物传感和生物成像，还可以排除由于自发荧光(来自组织的荧光)而产生的信号噪声。UCNPs的结晶度和稀土掺杂浓度有待提高，以便在生物安全的同时获得红外激光激发下的高输出可见光发射。我们建议扩大适合商业开发的UCNP的可制造性。这些在近红外激发下具有强烈可见光发射的纳米粒子将被-Affimers表面功能化，以适合于生物安全和靶向激光以及组织和器官的磁共振成像。仿射体是一种人工合成的结合蛋白，由利兹大学开发，由Avacta生命科学公司销售。作为进一步的发展，这些适当功能化的颗粒将被用于创建芯片上的实验室设备，用于同时快速检测心血管疾病生物标志物。通过将成像和传感模式结合在一起，该项目建议开发识别、监测并最终检测动脉粥样硬化组织的方法。该项目开发的方法学也可能适用于各种形式的癌症生物标记物检测和组织成像。

Cardiovascular diseases (CVD) which include acute myocardial infarction (AMI) and stroke are the main cause of premature deaths in the world. The nature of CVD demands efficient and simultaneous detection of biomarkers earlier than current approaches that are incapable or time consuming. Atherosclerosis is an inflammatory disease, and inflammatory marker high-sensitivity C-reactive protein (CRP), has been shown to identify additional individuals who are at risk. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is also a marker of vascular inflammation. Thus screening with for example both Lp-PLA2 and hs-CRP may provide a better risk assessment for CVD and stroke than using either test alone. In this project we have chosen four biomarkers NT-proBNP, LpPLA2, GFAP and IL6 for implementing a multiple biomarker detection and measurement system. Traditional diagnostic tools currently used for detection and assessing atherosclerotic plaques have their limitations regarding the less contrast images received even from modern techniques such as CT and MRI. Although recent advances in imaging techniques together with proteomics and metabolic profiling have enhanced the feasibility of patient screening for the diagnosis, they are not suitable for the "point-of-care" where the early diagnosis may benefit primary prevention and treatment of these diseases. The "gold standard" cardiac angiography is an invasive method with risks associated with the catheterization procedure and there is no reliable non-invasive method to identify and quantify the severity of atherosclerotic plaque formation. Ultrasound scan is currently used for detecting plaque burden non-invasively, particularly in the carotids, but there is no currently available interpretation of this that allows differentiation of unstable vs stable plaques.In this interdisciplinary project, we will develop lanthanide doped up-conversion nanoparticles (UCNPs) and biomolecular conjugate based assays for the rapid and simultaneous detection and imaging of key biomarkers - for CVD and atherosclerosis. UCNPs have specific excitation and emission wavelengths, and the individual fluorescent lanthanide ions are very sensitive to environmental alterations around them. The project aims to create a scalable manufacturing process for rare earth (RE) upconversion nanoparticles (UCNP) suitable for photoluminescence based rapid bio-sensing and bio-imaging that also preclude signal noise due to autofluorescence (fluorescence from tissues). The crystallinity and RE doping concentration of the UCNPs need improvement for high output visible light emission under infrared laser excitation while being biologically safe. We propose to scale up the manufacturability of the UCNPs suitable for commercial exploitation. These nanoparticles with intense visible light emission under near infrared excitation will be surface functionalised with -Affimers to be suitable for biologically safe and targeted laser based as well as magnetic (MRI) imaging of tissues and organs. Affimers are synthetic binding proteins, developed at the University of Leeds and marketed by Avacta Lifesciences. As a further development, these particles suitably functionalised will be used to create lab-on-a-chip device for simultaneous and rapid sensing of CVD biomarkers. By bringing together imaging and sensing modalities, this project proposes to develop methodologies for identifying, monitoring and finally detecting atherosclerotic tissues. The methodology developed in the project might also be applicable to various forms of cancer biomarker detection and tissue imaging.