SKM 2023 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 28: Poster Session II
BP 28.50: Poster
Donnerstag, 30. März 2023, 18:00–20:00, P2/EG
Single-molecule tracking in dense images — •Jianfei Jiang1,2, Armina Mortazavi1,2, and Benedikt Sabass1,2 — 1Institute for Infectious Diseases and Zoonoses, Department of Veterinary Sciences, LMU München — 2Department of Physics, LMU München
Traction force microscopy (TFM) quantifies cellular traction forces on a surface. The technique is based on measuring the deformations in the substrate. A standard implementation of TFM involves using first particle image velocimetry (PIV) to measure the two-dimensional deformations. Subsequently, a force reconstruction algorithm calculates the traction field based on PIV measurements. The spatial resolution of TFM can be improved by using smaller-sized fluorescent particles embedded in the substrate. To this end, we develop a new technique that combines TFM with Stochastic Optical Reconstruction Microscopy (STORM). Using STORM, we can record the positions of FluoroCubes (∼ 6nm) that are densely distributed in the substrate. Here, we propose a new single-molecule tracking algorithm to acquire fine-grained displacement fields. We first use PIV with large-sized fluorescent beads (∼ 40nm) to obtain coarse-grained displacement fields, which helps us to estimate the displacement of each FluoroCube. Then, the tracking process is formulated as a linear assignment problem, where we implement the Hungarian algorithm to minimize the overall deviation from PIV estimations. The particle tracking algorithm is parallelized by dividing the image into smaller subimages to reduce computation time. The tracking results enable us to build a high-resolution displacement field for force reconstruction.