3D Force Microscopy for Microrheology & Active Transport

描述（由申请人提供）： 生物介质（包括细胞质、细胞外基质和生物凝胶如粘液）的流变学性质的重要性在理解细胞内运输、病原体清除、药物递送等方面受到重视。相应地，生物学背景下的力，如由分子马达和细丝聚合驱动的，被理解为对于理解细胞分裂和运动、囊泡的细胞内运输以及负责细菌运动和粘液流体动力学的纤毛的跳动至关重要。我们建议将磁珠操作发展成一种新的显微技术，用于研究生物系统中的力和流变学。有三个趋势使现在成为取得迅速进展的适当时机。首先，磁分离技术的发展不断增长，这导致了尺寸和功能上的各种磁性颗粒的可用性，以及将微制造磁极系统结合到硅晶片上。第二，虽然珠流变学是一个几十年的老技术，有最近的发展应用亚微米尺寸的珠测量生物凝胶的复杂的粘弹性模量，包括布朗运动和两个粒子的相关函数的分析。第三个发展是在用户界面领域。先进的三维可视化在真实的时间，结合触觉（触摸敏感）控制和显示力探针的应用程序已被证明在原子力显微镜。我们建议将这三个发展纳入一个系统，a）使用微制造的磁极几何形状，将允许B）同时使用h数值孔径光学纳米级粒子跟踪和三维共聚焦显微镜，和c）先进的用户界面，用于立即理解复杂的数据集和控制的仪器。该系统的最后一个特点，即用户界面和仪器控制，将几乎完全由现有的NCRR赠款支持。

DESCRIPTION (provided by applicant): The importance of the rheological properties of biological media, including the cytoplasm, the extracellular matrix and biological gels such as mucus is being appreciated in understanding intracellular transport, pathogen clearance, drug delivery, to name a few. Correspondingly, forces in biological contexts, as driven by molecular motors and filament polymerization, is understood as essential for the understanding of cell division and motility, intracellular trafficking of vesicles, and the beating of cilia that are responsible for bacterial locomotion and mucus hydrodynamics. We propose to develop magnetic bead manipulation into a new microscopic technology for studying forces and rheology in biological systems. There are three trends that make now the opportune time to make rapid progress. First, there has been a growing development of magnetic separation technology that has led to the availability of a wide range of magnetic particles, in size and functionality, and the incorporation of micro-fabricated magnetic pole systems onto silicon wafers. Second, while bead rheology is a decades old technology, there have been recent developments in the application of submicron-sized beads for measuring the complex viscoelastic moduli of biological gels, including the analysis of Brownian motion and two-particle correlation functions. The third development has been in the area of user interfaces. The application of advanced 3D visualization in real time, combined with haptic (touch-sensitive) control and display of force probes has been demonstrated in atomic force microscopy. We propose to bring these three developments into a system that a) applies forces to magnetic beads suspended inside biological media using micro-fabricated pole geometries that will allow b) the simultaneous use of h numerical aperture optics for nanometer scale particle tracking and 3D confocal microscopy, and c) advanced user interfaces for the immediate understanding of complex data sets and control of the instrument. The last feature of the system, the user interface and instrument control, will be supported almost entirely from an existing NCRR grant.