双模态磁共振/近红外活体影像纳米探针的制备及其应用研究

The fluorescent magnetic nanoprobes fabricated by combining magnetic nanoparticle with quantum dot (QDs) can obtain dual-modal imaging (including magnetic resonance imaging (MRI) and fluorescent imaging ) showing their intriguing potentials in the field of biomedicine. Up to now, the optical reagents of fluorescent-magnetic nanoprobes has been mainly focused on the Cd-based QDs. The intrinsic heavy metal Cd components of QDs greatly restrict their application in in vivo. Another problem in these nanoprobes is that the fluorescent window of Cd-based QDs as optical regent exists at wavelength between 400 nm and 700nm, which is not suitable for in vivo imaging with high sensitivity. In this program, we plan to synthesize highly photoluminescent and decently biocompatible Ag2Se QDs with near-infrared emission in the second window (NIR-II, 1000-1400 nm), which offer deeper tissue penetration and negligible auto-fluorescence due to the lower photon absorption and tissue scattering, and then used Ag2Se NIR-II QDs with emission centered at 1300 nm as optical reagents to fabricate MRI/NIR-II fluorescent nanoprobe by a facile and general strategy. The obtained MRI/NIR-II dual-modal nanoprobe will provide a new route for in vivo imaging with high resolution and sensitivity. The developed strategy will also provide opportunities for the preparation of other multiple-functional nanomaterials.

构建具有光磁双功能复合的纳米探针，同时实现荧光和磁共振双模态成像，在生物医学领域展现出诱人的研究价值和应用潜力。目前的光磁复合探针主要局限于磁性纳米粒子与可见光荧光发射的Cd基半导体量子点的复合，然而这些光磁复合结构有其局限性和不足：纳米复合结构中的量子点往往含有重金属Cd，生物相容性差；由于发光窗口的限制（400-700nm），在生物活体内光散射和吸收较大，一般无法实现生物活体组织的高灵敏度成像。本课题选择具有较高荧光效率和生物相容性的新型近红外Ag2Se量子点作为光学探针，其1300nm的近红外荧光由于较低的光吸收和散射, 可以实现最大穿透深度的活体荧光成像。然后将其进一步与磁性纳米粒子复合，探索新的合成策略，构建具有磁共振/近红外双模态的活体影像纳米探针，从而为生物活体组织的高分辨率和高灵敏度成像提供新的思路。本项目发展的合成策略，也将为制备其他多功能纳米材料奠定基础。

构建具有光磁双功能复合的功能纳米材料，同时实现荧光和磁共振双模态成像，在生物医学领域展现出诱人的研究价值和应用潜力。在国家自然科学基金的资助下，我们发展了两相界面辅助溶剂热法制备光磁复合多功能纳米材料的新策略，优化反应条件，提高了光磁复合纳米探针的复合效率，构建了具有磁共振/近红外双模态的活体影像纳米探针（Ag2Se/Fe3O4, Ag2Se/Fe3O4/SiO2, Ag2Se/Mn3O4等纳米复合结构），将其应用于小鼠脑部组织的光磁双模态成像。为进一步实现生物活体组织的高分辨率，高效率，高准确度和灵敏度的成像检测奠定了技术基础。此外，我们将本项目发展的制备复合探针的合成策略应用于制备其他纳米功能材料，例如:TiO2@C, TiO 2/WO3, Fe3O4@TiO2, Co3(PO4)2, VSe2，CuInTe2, MnFeOX等一系列纳米特异纳米结构。在本项目的支持下，申请国内发明专利4项，受邀与他人合作撰写了世界上最大的科技出版社之一德国Springer出版的 Handbook of Nanomaterials Properties 中关于体量子点的英文专章。在国际SCI期刊发表论文7篇，包括1篇Chem. Mater., 1篇Chem. Commun., 1篇Electrochim. Acta.等。研究成果引起领域内同行的广泛关注。应邀担任Small(IF=8.32), Applied Catalysis B: Environmental (IF=8.328), Chemical Communications (IF=6.7), RSC Advance等多个国际SCI期刊的审稿人。