Article Figures & Data
Figures
- Figure 1.
Diagram of diamond knife waterboat with trapping device installed. A, The trapping device, shown within the waterboat, is composed of two semicircular trapping posts and two parallel walls that separate the waterboat into three channels. When the water level is set to a typical cutting level, the channel walls do not protrude significantly from the water; the trapping posts, on the other hand, protrude roughly 1 mm from the nominal water surface, thereby creating curvature-induced capillary interactions (see cross-section view CC). Air needles are attached to the distal end of the waterboat to provide hydrodynamic forces. B, Top view of trapping device, corresponding to the region bounded by the dashed line in A. The air needles supply pressurized air which induce a symmetric water flow pattern with average water velocity, vwater, as shown. The forces trapping the section are modulated by the section size, wsection, the trap width, wtrap, the trap height, htrap (see cross-section view CC), and the average water velocity, vwater. CC, Cross-sectional view of the trapping device at the trapping posts. Outside of the center channel, the water level remains flat, as shown. Near the trapping posts, the water is pins to the height of the trapping posts, htrap, thereby creating local curvature in the water surface.
- Figure 2.
CAD model with finite element analysis. A, Isometric view of the trapping device designed in SolidWorks. This model has a trap width of 3.0 mm and a trap height of 0.5 mm. Scale bar: 3 mm. B, Top view of Young–Laplace equation solution domain. The domain is split symmetrically along the centerline, with the left side showing the finite element mesh and the right side showing the finite element solution for the interfacial height. C, Photograph of experimental setup with inset showing the induced curvature between the trapping posts. The trapping device is shown installed in the waterboat with water filled to appropriate height for sectioning. Air needles are mounted on the distal end of the waterboat using a custom fixture, which provide the hydrodynamic forces. A metal tube is shown protruding from the distal end of the waterboat used for modulating water level. Scale bar: 5 mm.
- Figure 3.
Trap design parameterization experiment and modeling results. A, Single frame showing an individual section trapped within the trapping device. The section is trapped via balance of curvature-induced capillary interactions, Fc (orange), and Stokes drag forces, Fd (green). The calculated centroid (black crosshair) and the defined target (red cross) are shown. The orientation of the x- and y-axes relative to the trapping device is shown in the bottom left. Scale bar: 1 mm. B, Scatter plot of section centroid positions for a single trap design with wtrap = 2.5 mm, htrap = 0.5 mm, wsection = 1.5 mm. Ten sections were individually trapped and their positions recorded over time. For each section, we analyzed its local movement within the trap over 10 s; videos were recorded at 10 fps. All of the centroid positions are shown from all 10 trials (black x). The x-component centroid position distribution is shown above the scatter plot (xst. dev. = 91 μm); the y-component centroid position distribution is shown to the right of the scatter plot (yst. dev. = 62 μm). The centroids are plotted relative to the mean centroid position. Plot axes are given in millimeters. C, Distance between the mean centroid position and target along the y-axis plotted versus the trap height. The mathematical model (black circles) shows a non-linear increase in the distance between the mean centroid position and target along the y-axis as the trap height increases. This trend shows good alignment with our single section (red) and multisection (blue) experiment results (RMSE = 0.27 mm). D, Distance between the mean centroid position and target along the y-axis plotted versus the trap width. The mathematical model (black circles) shows a non-linear decrease in the distance between the mean centroid position and target along the y-axis as the trap width increases, showing good alignment with our single section (red) and multisection (blue) experiment results (RMSE = 0.31 mm).
- Figure 4.
Examples of serial sections placed onto conventional light and EM substrates. A, Photograph of 100 serial sections of mouse brain tissue of nominal thickness 60 nm placed onto a silicon wafer. Scale bar: 10 mm. B, Top-view light micrograph of 100 serial sections placed onto a silicon wafer. Sections are placed in a raster-grid formation, with section 1 being on the bottom left corner, section 2 being above section 1, and section 100 at the top right corner. Scale bar: 3 mm. C, Scanning electron micrograph imaged using a multibeam SEM. Myelinated axons can be observed for potential sparse reconstruction of neuronal networks. Scale bar: 10 μm. D, Mosaic low-magnification light micrograph of 52 rat optic nerve serial sections cut at 250 nm and placed onto a glass slide. Sections are stained with toluidine blue for optical contrast. Scale bar: 3 mm. E, Mosaic high-magnification light micrograph of a rat optic nerve section. Individual axons can be observed within the optic nerve. Scale bar: 100 μm. F, Image of three serial sections (nominal thickness 40 nm) placed onto an aluminum substrate with imaging apertures covered with Luxel support film for TEM. The loop end effector used to pick-up and placed sections is shown. Scale bar: 1 mm. G, Representative high-magnification transmission electron micrograph of an ultrathin human cortical brain tissue section. Scale bar: 1 μm.
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