细胞生物学

Quantifying mechanical forces during vertebrate morphogenesis

Fig. 1 from : Eirini Maniou et al. 2024 “Quantifying mechanical forces during vertebrate morphogenesis”: The i3D bioprinting with accurately determined position, geometry and stiffness. a, Schematic of a chicken embryo illustrating the experimental workflow: 2–3 µl i3D polymer is pipetted directly onto the rhombocervical neuropore (RNP) and photo-crosslinked with a two-photon laser. The iMeSH structures are shown in green throughout. b, Stereoscope image of an embryo with a star shape photo- crosslinked on the flat neural plate. Scale bars, 200 µm. The star dimensions are indicated in the inset. c, Schematic showing iMeSH compression by apposition of the neural folds. d, Time-lapse images showing the sequential displacement of a rigid iMeSH shape, shown as a 3D confocal reconstruction superimposed on the embryo imaged with transmitted light. Cyan shading, open neural tube; *, zippering point; arrow indicates rotation of the printed shape; scale bar, 50 µm. The times are shown. e, Fire lookup table showing the autofluorescence of iMeSH photo-crosslinked with the indicated laser powers on the same embryo. Scale bar, 25 µm. f, Schematic illustration of AFM stiffness testing of an iMeSH shape; 3D reconstructions of the shape are shown superimposed on a dorsal and transverse schematic of the embryo. Scale bar, 100 µm. g, AFM quantification of iMeSH crosslinked on an embryo at the indicated laser powers. The values were calculated from AFM indentations performed at a rate of 0.5 μm s–1 and depths of 1 μm (30% 7-hydroxycoumarin-3-carboxylic acid (HCC) polyethylene glycol (PEG)) or 2 μm (15% PEG). The force–displacement curves were acquired using NANOSENSORS™ PointProbe® Plus PPP-CONTSCR silicon AFM probes with a typical spring constant of 0.2 N/m.

Morphogenesis requires embryonic cells to generate forces and perform mechanical work to shape their tissues. Incorrect functioning of these force fields can lead to congenital… Read More »Quantifying mechanical forces during vertebrate morphogenesis

Distinct Contact Guidance Mechanisms in Single Endothelial Cells and in Monolayers

Supplementary Figure 10 from Claire Leclech et al. (2023) “Distinct Contact Guidance Mechanisms in Single Endothelial Cells and in Monolayers”: Characterization of the secreted basement membrane. (C) Surface topography and stiffness (Young’s modulus) obtained by atomic force microscopy of the secreted ECM or bare PDMS after 72 h of culture on flat surfaces coated with fibronectin (FN) or poly-L-lysine (PLL). Dots represent individual measures on n=2 independent experiments. Error bars represent standard deviations. Please follow the link to the full article to find the full supplementary figure 10 and its description. Atomic Force Microscopy measurements were performed using an AFM probe with circular symmetric rounded AFM tip with typical radius of curvature around 30 nm (0.03–0.09 N m−1) (uniqprobe qp-BIOAC-CI, from NANOSENSORS).

In many tissues, cell shape and orientation are controlled by a combination of internal and external biophysical cues. * Cell shape is closely controlled in… Read More »Distinct Contact Guidance Mechanisms in Single Endothelial Cells and in Monolayers

Mitochondrial-derived vesicles retain membrane potential and contain a functional ATP synthase

by NANOSENSORS
15 March 202415 March 2024
Science & Technology

Figure 2 B from Reut Hazan et al. 2023 “Mitochondrial‐derived vesicles retain membrane potential and contain a functional ATP synthase”: Characterization of MDVs from wild‐type mitochondria B. Atomic force microscopy. Representative AFM image and a 3D AFM image of one representative vesicle (WT), adsorbed on a mica modified with Mg2+ and imaged under PBS. Please refer to the full article cited below to view the full figure. NANOSENSORSTM uniqprobeTM qp-BioAC-CI AFM probes with rounded AFM tips designed for cell imaging were used for the characterization by atomic force microscopy (AFM) in QI mode.

Vesicular transport is a means of communication. * While cells can communicate with each other via secretion of extracellular vesicles, less is known regarding organelle‐to… Read More »Mitochondrial-derived vesicles retain membrane potential and contain a functional ATP synthase

Male-female communication enhances release of extracellular vesicles leading to high fertility in Drosophila

by NANOSENSORS
28 October 202215 March 2023
Science & Technology

Fig. 5 from “Male-female communication enhances release of extracellular vesicles leading to high fertility in Drosophila” by Javier Arturo Sanchez-Lopez et al.: The spermatheca releases EVs with specific characteristics. a–e The spermathecae (SSC > CD63-GFP) were cultured ex vivo to characterize the particles that were released to the spent media: a size distribution of CD63-GFP-positive particles (n = 25 spermathecae from 15 flies) using single-particle tracking of the Nanoimager. b Characterization of CD63-GFP particles by ExoView (100 spermathecae from 50-60 flies) using anti-GFP or anti-CD63. c Representative dSTORM image of EVs found in the spent media of SSC expressing CD63-GFP (n = 25 spermathecae from 15 flies), stained with AlexaFluor555 conjugated anti-CD63 primary antibody. The image shows CD63-GFP-positive EVs and single CD63 AlexaFluor555 molecules the EV’s surface. Scale bars = 1 µm and insets = 20 nm. d–e The morphology of EVs in the spent media was observed by e negative staining in STEM; scale bar = 200 nm; and by d Cryo-TEM; Scale bar = 100 nm (see also Supplementary Fig. 5a-c). f–i The spent media of ex vivo cultured spermathecae were analyzed for the presence of EVs: f Representative AFM scans of SSC-EVs isolated by acoustic sorting (n = 100 spermathecae from 70 flies), showing from left to right: height (nm), adhesion (pN) and Young’s modulus images (MPa). Scale bars = 100 nm (see Supplementary Fig. 5d–g). g–i Single-particle tracking in the nanoimager. g CellMaskTM-positive particle size distribution and concentration profiles of EVs in the spent media of spermathecae incubated in media alone (No ecdy) or with ecdysone (Ecdy) (see also Supplementary Movie 5 for a time lapse of spermathecae end apparatus and endosomal activity post-ecdysone stimulation and methods, ex vivo spermatheca culture section); media with only CellMaskTM stain served as a control for the formation of dye aggregates. h Particle concentration and i mean particle diameter (nm) from g; Box plots are the measurements of particles from four frames of spent media from 25 spermathecae; boxes represent maximum, median and minimum values with outliers; one-way ANOVA, with nonparametric Wilcoxon multiple comparison post-hoc test; *p

The female reproductive tract (female-RT) must decipher the repertoire of molecular cues received from the male during copulation in order to activate and coordinate tract… Read More »Male-female communication enhances release of extracellular vesicles leading to high fertility in Drosophila