CT和上转换成像多功能纳米发光探针及其活体癌细胞鉴别研究

Current in vitro identification methodologies of benign or malignant tumors suffer from cancer transformation and complication, etc. due to the in vivo tumor sampling approach. To circumvent these drawbakcs, in this project, we shall develp and validate a new identification approach based on a novel dual model imaging nanoprobe of which NaYF4:Er,Yb is taken as core and NaYF4:Yb,Cr as shell, termed as CUNBP. This approach takes the advantage of (1) the remarkable difference in the structure and charge properties between benign and malignant tumor cells, and (2) the strong adsorption of rare earth ions on X-ray, upconversion of near infrared photons into visible high energy photons of different wavelengths which can be used as bioprobes and the energy donors, respectively, together with the fact that the luminescence properties of rare earth ions in nanoparticles are subject to their local environment. In this design, identification of benign or malignant tumors is via dual-mode imaging of enhanced X-ray Computed Tomography (CT) and near infrared upconversion luminescence imaging. For this purpose of the identification, the following issues will be addressed in the project, including (1) the effects of nanoconstruct with core/shell, interface, surface of CUNBP on the properties of upconversion luminescence of trivalent Er ions in core and downconversion luminescence of Cr ions in shell, (2) in vivo behaviour of the dual-mode bioimaging of enhanced CT of trivalent Yb ions and upconversion photons of CUNBP for identification of benign and malignant tumor cells, and (3) effects of CUNBP on bio-safety of mouse model. Two key questions are expected to be answered, i.e. the relationship between the spectral change and the properties of the surface structure a nd charges of benign and malignant tumor cells, and how to improve the upconversion luminescence. This innovation nano-bioprobe platform, i.e. CUNBP, and theoretical foundation shall be provided to develop a novel CUNBP with multi-functions of the dual-mode imaging of enhanced CT of Yb ions and near infrared photons, and in vivo and in situ identification of benign and malignant tumor cells.

为解决体内肿瘤取样体外良恶性识别易导致扩散和并发症等问题，利用良恶性细胞表面电荷性质显著差异的特点，依据稀土离子对X-射线强的衰减能力和将近红外光上转换为不同波长可见发光可分别用于发光生物探针和能量传递供体的特性与过渡族离子发光性质易受微环境干扰的特性，合成具有X-射线计算机断层扫描成像（CT）功能的发光上转换(NaYF4:Er,Yb)核/下转换（NaYF4: Yb,Cr）壳复合纳米发光生物传探针（CUNBP），研究CUNBP结构、界面和表面与核内Er离子上转换发光和壳内Cr离子发光的关系、CUNBP的CT和上转换发光活体成像和受癌细胞表面电荷影响的Cr离子光谱行为、CUNBP生物安全性。重点解决CUNBP发光效率和解析Cr离子光谱线形与微环境生物信息的关系。为建立集CT/发光癌细胞成像定位引导的良恶肿瘤细胞活体光谱识别多功能于一体的新技术和新方法提供新型多功能纳米生物探针和理论依据。

为解决体内肿瘤取样体外良恶性识别,导致肿瘤易扩散和产生并发症等问题，本项目主要开展提高上转换发光效率的有效途径，构建纳米生物探针用于探索解决当前肿瘤良恶性识别困难的科学问题。设计和构建了高活性稀土离子掺杂的NaErF4和NaYbF4等发光体系及过渡离子掺杂的纳米发光探针，并将其作为载体构建用肿瘤诊断和治疗的多功能纳米制剂。经过四年的研究，通过构建功能壳层结构抑制了Er3+浓度猝灭，有效地解决了制约上转换纳米粒子的发光效率的关键科学问题，并解决通过靶向恶性肿瘤细胞的CUNBP发光光谱解析所携带的生物信息的关键科学问题。通过不同Er3+/Yb3+掺杂浓度比的调控研究，首次观察结构从相向相过渡双相共存结构，突破了2 mol%Er3+掺杂浓度极限，将Er3+掺杂浓度先后提高到40 mol%和100 mol%，非常有效地抑制浓度猝灭，提高上转换发光强度具有重要的启发和引导作用。在国际上率先实现了全发光中心（如Er3+）纳米粒子的高效上转换发光。此外，拓展了通过染料敏化来增加上转换发光的新途径；并采用高活性离子（Yb3+）作为激发能量吸收和传递壳层结构，通过设计和制备的core@NaYbF4@ NaYbF4: Tm（Er），双壳层中的Yb3+和Tm3+之间的协同作用，极大的提高了发光效率。并针对性构建肿瘤pH微环境响应性的上转换纳米生物探针作为生物医学诊断治疗多功能纳米平台，实现了恶性肿瘤精准识别和高效抑制的目标，肿瘤抑制率超过85%以上。.本项目通过四年研究，发表论文16，其中SCI论文14篇，影响因子10以上的文章6篇，授权发明专利3项，申请2项。培养硕士研究生3名，博士研究生2名。实现了以下科学研究目标：1）获得1种具有增强CT和高效近红外上转换发光双模成像定位引导功能的上转换纳米粒子上/下发光生物探针；2）揭示该种新型生物探针的结构与表面、界面、溶液环境和良恶性肿瘤细胞相互作用规律。