particle image velocimetry (piv) analysis  (MathWorks Inc)

Journal: Cells

Article Title: PI 3-Kinase and the Histone Methyl-Transferase KMT2D Collaborate to Induce Arp2/3-Dependent Migration of Mammary Epithelial Cells

doi: 10.3390/cells13100876

Figure Lengend Snippet: PI 3-kinase activity is critical for collective cell migration. Confluent monolayers of parental, PIK3CA H1047R, KMT2D KO and double-mutant MCF10A cells are induced to migrate into the free space obtained by lifting a physical boundary. Displacement vectors within the monolayer are obtained using Particle Image Velocimetry (( A ), PIV). These vectors are analyzed over space and time for their position in terms of their magnitude (( B ), velocity) and directionality (( C ), order parameter, i.e., the cosine of the angle made by the displacement vector with respect to the vector oriented toward the free space). These parameters are represented as heat maps. There are three biological repeats with similar results, and four fields of view in each condition. Plots show the average of all measurements. Each pixel of the heatmaps averages all fields of view in all biological replicates over 42 µm and 40 min. These parameters are compared at a single time point or at a single distance from the edge using two-way ANOVA with Tukey’s test.

Article Snippet: Analysis of time-lapse images was performed using Particle Image Velocimetry (PIV) analysis with a MATLAB PIV script [ ].

Techniques: Activity Assay, Migration, Mutagenesis, Plasmid Preparation

Journal: bioRxiv

Article Title: Motility induced fracture reveals a ductile to brittle crossover in the epithelial tissues of a simple animal

doi: 10.1101/676866

Figure Lengend Snippet: (A) Experimental tagging techniques: (i) Ventral epithelium - A fluorescent lysotracker dye stains the acidic granules present in the lipophil cells, and provides a dense tagging of the entire ventral epithelium at large fields of view (∼3 mm) (Methods). (ii) Dorsal epithelium - We developed an assay to coat the surface of the epithelium with sticky fluorescent microspheres / microbeads. This provides a coarse-grained tagging (1 bead per 8 cells) of the entire dorsal epithelium at large fields of view (∼6 mm) and enables high-speed (10 fps) and long duration (∼1-5 hours) imaging (Methods). Right Insets display control experiments demonstrating that microspheres bind on cell membrane. (B) Computational data analysis techniques: We employ Flowtrace for visualization of particle trajectories, Particle tracking for quantitative non-affine motion analysis, and Particle Image Velocimetry to measure velocity fields and internal strain rate.

Article Snippet: We employed Particle Image Velocimetry (PIV) analysis (PIVlab package in MATLAB) to quantify the flow-fields in the dorsal layer sticky-microbeads time-lapse datasets in large width (13×13mm square) confined PDMS milli-fluidic chips with variable fields-of-view.

Techniques: Imaging, Control, Membrane