柔性光子链磁驱动发动机的构筑、传感与可控装卸性能

The magnetically driven micro-/nanoswimmers (MMSs) reported so far do not response to specific substances in the liquid media. This has seriously inhibited their practical applications as intelligent micro-/nanomotors. In this project, the MMSs based on flexible photonic nanochains with the distance between the monodisperse superparamagnetic Fe3O4 colloidal nancrystal cluster particles tunable are proposed for sensing the enviroment changes, as well as loading and releasing cargoes determined by the sensing signals. The photonic nanochain MMS that is sensitive to pH and able to deliver drugs in a controllable way will be constructed by attaching a poly(N-isopropylacrylamide-co-acrylamide) microsphere on the one end of a Fe3O4/Poly(acrylic acid) photonic nanochain, while the photonic nanochain MMS that possesses functionalities of controlled loading and releasing of potassium ions (K+) besides the K+ sensitivity will be constructed based on a Fe3O4/poly(N-isopropylacrylamide-co-4-vinylbenzo-18-crown-6) [P(NIPAM-co-VBC6)] photonic nanochain with one end attached by a P(NIPAM-co-VBC6) microsphere containing numerous Au nanorods. The fabrication methods as well as the microstructure controlling mechanisms of the photonic nanochain MMSs will be studied. The influences of the composition and microstructures on the magnetically driven motion and sensing properties in the liquid media will be investigated in detail. The enhanced sensing capability by the motion of the photonic nanochain swimmers is to be fully explored. Furthmore, the controllable loading, release and transportation of a specific substance will also be demonstrated following the detection signals of the environmental factors such as pH value and K+ concentration. The MMSs developed in this project would be promising for the recognition of tumor cells and targeting drug delivery, as well as the microenvironmental detection and maniputation, and thus promote the development of the next generation "intelligent" MMSs.

目前的磁驱动微纳发动机(MMS)不能感知其所处的液体介质环境，妨碍了它的智能化和实际应用。本项目提出构建场致伸缩光子链MMS来实现对环境的传感，并根据对环境的传感信号选择性执行对特定物质的可控装卸和搬运。设计制备单端连有聚(N-异丙基丙烯酰胺-共-丙烯酰胺)微球的Fe3O4/聚丙烯酸光子链MMS和单端连有内含Au纳米棒的聚(N-异丙基丙烯酰胺-共-4-乙烯基苯并-18-冠-6) [P(NIPAM-co-VBC6)]微球的Fe3O4/P(NIPAM-co-VBC6)光子链MMS。研究它们的制备方法和微结构的控制原理，以及组成和微结构对其在液体介质中的运动行为、传感特性与可控装卸和搬运性能的影响规律；阐明它们的装卸和搬运动作的调控策略，以及运动特性对传感性能的增强作用。项目研制的MMS在肿瘤细胞识别与靶向药物输送、以及微环境的检测和操控方面有重要应用前景，能推动新一代"智能化"MMS的发展。

微纳米发动机是一种可以将环境中的其他形式能量转变为动能的微纳米器件，在液相介质中它具有装载、运输及释放各种微纳“货物”的功能。因此，微纳米发动机在许多重要的领域，如环境修复、细胞分离、生物传感器和药物运输等领域，都具有潜在的应用前景。在本课题中首先我们通过发展一种通用的氢键诱导模板聚合法，制备了一类新的凝胶型光子晶体传感器―响应性一维光子链探针。其结构特点是磁性粒子等间距的包埋在一层十几纳米厚的响应性聚合物壳层中，得到类似豆荚状的响应性一维光子链。与传统的以膜和微球形式存在的传统凝胶型光子晶体相比要小2-3个数量级并能应用于微环境检测和成像。通过更换不同种类的响应性聚合物，能够分别得到晶格常数（衍射光谱）随pH，温度和溶剂变化的响应性光子链。以pH响应的光子链为例展示了它在微环境中的应用。由于其尺寸小，比起传统响应性光子晶体，这种材料无论是在分辨率还是响应速率上都至少高出2-3个数量级。这种新型的材料有望在对响应速度以及分辨率要求较高的多个领域比如显示器或者打印等领域发挥重要的作用。随后基于上述研究结果，针对现有微纳米发动机不具有对环境的实时传感特性，我们提出了一种基于响应性一维光子链的磁驱柔性微米发动机。在振荡磁场下，该发动机能够自主运动而主动与液体介质中的受检离子相结合，并通过自身结构色的改变实时反映出环境条件的改变。通过本项目的执行，发展了具有双组份非对称结构的蝌蚪状磁驱柔性微米链发动机及其制备方法，并探究了该微米发动机在不同条件的液体环境中驱动磁场参数的调节策略，研制出了运动速度及方向高度可控、能实现对环境实时传感和货物运载与可控释放的磁驱柔性光子链发动机。研究成果预期将对柔性微纳米发动机的发展和下一代智能传感器的发展起到推动作用。