MRI: Acquisition of a Holographic Laser Tweezer Array for Submicron Control of Soft Materials and Novel Network Dynamics

这笔拨款支持全息激光镊子阵列的收购。该仪器支持非线性动力学、软凝聚态物理、物理化学和生物物理学等广泛的跨学科研究项目。全息激光镊子阵列允许制造复杂的材料和动态过程的研究，使用多达200个独立移动的激光光束聚焦通过显微镜物镜。该仪器允许产生复杂形状的力场，并同时操纵多个被困物体。该系统可以产生光学涡流，可以捕获反射粒子，并对被捕获的物体施加扭矩。基于这些独特的性质，研究者计划以下研究活动：(1)?？形状复杂的物体，如巨大的囊泡和细胞，将被低功率激光光斑环捕获，它们通过强度梯度提供相同的捕获功率，但具有比单个激光光斑更小的峰值强度，因此对样品的破坏更小。它将允许将细胞和囊泡拉伸成任意形状，通过变形激光点环来研究膜弹性，以帮助理解自发细胞变形，例如在神经生长和癌细胞扩散过程中观察到的细胞变形。？(2) ? ?由激光镊子阵列产生的复杂力或扭矩场将用于研究生长的生物聚合物网络所施加的力的分布及其对外力或应变的响应。结合上面描述的环形陷阱，这将允许研究细胞或细菌之间的粘附力或排斥力。一个特殊的应用将是生物膜的研究，生物膜经常感染医疗植入物。(3)吗?激光镊子阵列将允许创建实验版本的小世界网络，由耦合光学振荡器组成，以帮助理解在稀疏连接的网络中同步和相干的条件。这种新型的分布式激光源在医学诊断和微波检测方面具有潜在的应用前景。在物理、化学和生物的交叉点建立一个实验研究设施，将促进教师、博士后和研究生之间的跨学科互动。此外，该仪器将对K-12教育产生影响，通过pi持续参与外展工作，如实验室参观和来自华盛顿地区高中的代表性不足群体的暑期实习。对于大学来说，该仪器将加强研究基础设施，这将增加新的努力，以扩大和连接生物物理学研究成为一个可见的，高质量的研究和教育计划。凭借其独特的能力，该系统也将对区域研究界有用。这些pi与NIH和NIST的研究人员开发了联合项目，这些项目利用了NIH生物科学和NIST材料研究的巨大区域优势。

This grant supports the acquisition of a holographic laser tweezer array. The instrument supports a broad range of cross-disciplinary research projects in nonlinear dynamics, soft condensed matter physics, physical chemistry, and biophysics. The holographic laser tweezer array permits the fabrication of complex materials and the study of dynamical processes using up to 200 independently moveable laser light beams focused through a microscope objective. The instrument permits the generation of complex shaped force fields, and the simultaneous manipulation of multiple trapped objects. The system can generate optical vortices, which can trap reflective particles and apply torque to trapped objects. Based on these unique properties, the investigators plan the following research activities: (1) ??Complex shaped objects such as giant vesicles and cells will be trapped with rings of low power laser spots, which provide the same trapping power through intensity gradient, but have less peak intensity than a single laser spot, and are thus less damaging to the sample. It will permit stretching cells and vesicles into arbitrary shapes by deforming the ring of laser spots for studies of membrane elasticity to aid in understanding spontaneous cell deformations, such as those observed during nerve growth and during the spread of cancerous cells. ?(2) ??Complex force or torque fields generated by the laser tweezer array will be utilized to study the distribution of forces exerted by growing biopolymer networks and their response to external forces or strains. In conjunction with the ring traps described above this will permit studies of sticking or repulsive forces between cells or bacteria. One particular application will be the study of biofilms, which often infect medical implants. (3) ?Arrays of laser tweezers will allow creation of experimental versions of small-world networks, composed of coupled optical oscillators, in order to help understand conditions for synchronization and coherence in sparsely connected networks. Such novel distributed laser sources have potential applications in medical diagnostics and microwave detection. The establishment of an experimental research facility at the interface between physics, chemistry and biology will foster cross-disciplinary interactions among faculty, post- docs and graduate students. Additionally, the instrument will have impact on K-12 education through the PIs ongoing participation in outreach efforts, such as laboratory tours and summer internships for underrepresented groups from DC area high schools. For the University, the instrument will enhance the research infrastructure, which will add to a new effort to expand and connect biophysics research into a visible, top quality research and education program. With its unique capabilities, the system will also be useful for the regional research community. The PIs have developed joint projects with researchers at NIH and NIST, which take advantage of the great regional strengths in the biosciences at NIH, and in materials research at NIST.