MRI-Consortium: Development of a Multimode Microscope for Imaging Structure and Dynamics of Soft Materials

Brandeis University, Waltham MA

Investigators

Abstract

0923057 Dogic Brandeis U. "This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." Technical Summary: This project aims to develop a multimode optical microscope which will simultaneously reveal the structure and dynamics of soft and biological materials from various perspectives and across multiple lengthscales. The proposed instrument will be centered around an inverted optical microscope and will have the following four mutually compatible modalities: (1) holographic optical tweezer based on an infrared laser, (2) epi-fluorescecence microscope capable of localizing single molecules with millisecond temporal resolution and nanometer spatial resolution, (3) quantitative polarization microscopy which will reveal either 2D birefringence maps at the highest spatial resolution attainable with visible light or 3D birefringence maps at a reduced spatial resolution and (4) dual view imaging. The new multimode microscope will be used to examine a broad range of soft and biological materials including self-assembled non-amphiphilic membranes whose formation is driven by chiral interactions, spontaneously oscillating eukaryotic flagella, dynamics and structure of semi-flexible polymers absorbed onto a hard wall and synthesis and expression of biopolymer collagen in vivo. The proposed instrument will be developed in a close collaboration between Brandeis University and Woods Hole Institute and the operation of the proposed instrument will be supported by the Brandeis MRSEC center. Special effort will be taken to develop a novel experimental course focused on optics and microscopy, which will enable undergraduate and graduate students to effectively use the multimode microscope. Layman Summary: Optical microscopy uses visible light to directly image the structure and dynamics of various soft materials such as paints, foams, gels and liquid crystals. Over the past few decades various specialized modalities of optical microscopy have been developed, with each modality revealing certain aspects of the material under examination. For example, brightfield microscopy reveals the structure and dynamics of entire micron sized assemblages, fluorescence microscopy yields the dynamics of individual components within such an assemblage, polarization microscopy indicates the orientation of molecules within any given structure and laser tweezers enable studies of how these assemblages respond to external force. So far most soft materials have been examined with either single or dual mode microscopes. This project aims to develop a novel multimode microscope which will enable simultaneous examination of materials with all four different modalities: brightfield microscopy, fluorescence microscopy, quantitative polarization microscopy and holographic laser tweezers. Special care will be taken to ensure that the performance of each module is not compromised by the presence of other modalities. Development of the multimode microscope will enable experiments that will correlate behavior of materials across multiple length scales and will thus provide essential insight into how collective properties of a material such as its equilibrium shape and elasticity arises from interactions of individual components. The proposed instrument will be developed in a close collaboration between Brandeis University and Woods Hole Institute and the operation of the proposed instrument will be supported by the Brandeis MRSEC center. Special effort will be taken to develop a novel experimental course focused on optics and microscopy, which will enable undergraduate and graduate students to effectively use the multimode microscope.