63 Matching Annotations
  1. Last 7 days
    1. (D)

      (D) shows a different reconstruction of a tri-leaflet valve using micro CT. (E) is the middle sectioning of the valve providing yet another vantage point of the constructed valve. (F) Compares the printed valve's surface area in the study to that of the 3D model of an actual valve. It shows where the printed one has shortcomings in terms of over and underprinting in different areas.

    2. (A)

      (A)This image validates precise and accurate hydrogel printing capability of FRESH v2.0.

      (B) This image shows the ability to neutralize acidic solutions with the FRESH support bath. Notice how the pH of the initially printed portions along the needle's path (to left) is adjusted to 7.4 pH (green).

    3. (T and U)

      (T) The end product the FRESH print in a small, specific portion of left ventricle did based of the previously defined G-code provided in (U) initially

      Notice how they are very similar.

      (V) Is also a final product of FRESH printing of the very important wall between each ventricle of the heart. This print job was based on the G-code in (W).

      Yet again, the FRESH print does a great job mimicking the G-code.

    4. (Q)

      (Q) A 3D model of a newborn heart derived from MRI.

      (R) A FRESH print newborn heart to show how it can even small scale replicate accurately.

      (S) Is a cross-section view of the (R) heart, showing its accuracy within the printed model as well.

    5. neonatal

      Newborn child

    6. (O)

      (O) Is the movement of glycerol through the FRESH print to show its interconnectivity success.

      (P) An enhanced view of a portion of O, showing the ability of movement down the vessels.

    7. (K)

      (K) Provides an overview of the entire heart with vessel networks highlighted of the left ventricle.

      (L) Provides a different view of the left ventricle to show more networks of vessels that cannot be seen in K

      (M) A subregion of L that shows the vascular network of the 3D structure.

      (N) Is the same region as M, but is the FRESH printed version instead as comparison of their similarity.

    8. (H)

      Doppler flow is a type of ultrasound that uses sound waves to measure the flow of blood through a blood vessel

      (H) Shows the doppler flow of one cycle when it is closed, semi-open, and open.

      (I) Shows the flow over numerous open/close cycles of the FRESH printed valve.

      (J) Shows the pressure across the alginate and collagen valves in comparison to native valves. Notice how they experience similar pressures.

    9. (G)

      (G) Provides images in roughly one second of the printed valve opening and closing properly.

    10. (A)

      A is a basic 3D model of an adult tri-leaflet valve.

      B&C show two different vantage points of the FRESH printed tri-leaflet valve in comparison.

    11. (H)

      (H) Point stimulation enabled visualization of anisotropic calcium within the FRESH printed ventricle.

      (I) Shows anisotropic calcium wave propagation where the point stimulation took place.

    12. (K)

      (K-L)

      (K) is a top view of the FRESH print ventricle. Yellow outline is the inner wall and red outline is outer wall.

      (L) During contraction, the ventricle expanded both inward and outward. This was found through particle tracking on the deformation field.

      (M) Cross sectional area decreased in the interior chamber during peak contraction.

    13. A

      (A) First the collagen ink is injected into the ventricle, then the cell ink follows after.

      (B-C) The design of the model was meant to mimic that of an ellipsoidal shell with inner/outer collagen walls and stem cells in the center.

      C is the intended design of the ventricles after they are printed and cultured for 28 days according to the B design.

    14. cell-laden hydrogels

      Cell-laden hydrogel is an appealing option that helps engineering potential tissue constructs with biomimetic structure and function.

      Also, cell-laden hydrogel is a promising scaffolding system for tissue engineering applications such as bone, cartilage, cardiac and neural.

    15. (H)

      (H) Compared to the G-code (far left), the FRESH v2.0 has a much better yield stress behavior than that of v1.0. Notice how the printed features on v2.0 is much more similar to the G-code (genetic code) compared to that of v1.0.

      (I) Uniform particle size of the FRESH v2.0 (bottom two) allows the authors to produce much smoother and smaller (high-resolution) filaments, than compared to the large, clumpy FRESH v1.0 filaments.

      (J) The authors can control the 3-D printing resolution (feature size or collagen filament diameter) by adjusting the needle diameter.

    16. (G)

      The storage and loss modulus in viscoelastic materials, like FRESH in this article, measure the stored energy, representing the elastic portion, and the energy dissipated as heat, representing the viscous portion. With that, FRESH v2.0 has a much better yield stress (more storage, less loss modulus) than that of the v1.0 FRESH when both tested.

    17. (C and D)

      In C, the microparticles have a lot of polydispersity in the first version of FRESH. While in D, the new version of FRESH has significantly less polydispersity in microparticle size. For D, the particles are closer together and in similar size, which is important for uniformity of the solution when it is used.

      Polydispersity: A measure of size variation in colloids (liquid mixtures containing microscopically small, dispersed particles, e.g. milk, mayo)

      (E) Feret diameter distibution shows the frequency of the size of gelatin particles used in Fresh v1.0 and v2.0. This graph simply proves how the FRESH 2.0 has much less polydispersity (previously explained), that is a much narrower distribution of particle sizes.

      (F) This graph further demonstrates that microparticles used in FRESH v2.0 has a much narrower size distribution compared to those used in FRESH v1.0. Notice how the narrow black bar on top of the red bar is shorter (compared to that of the blue bar), which tells that the variation in particle size is smaller for FRESH v2.0.

    18. G-code

      in genetics, G-code is genetic code

      G-code is also a language that humans use to tell a machine how to do something. With 3D printing, g-code contains commands to move parts within the printer.

    19. cell infiltration

      Migration of cells into microporous structures.

    20. dextran perfusion

      Dextran is a polysaccharide glucan that is medically used to reduce blood viscosity. Dextran perfusion is based on flowing a dextran solution through the tube/pipe to determine whether is hollow (allows fluid flow), and transports fluids as expected.

    21. pulsatile perfusion

      Perfusion that moves through channels based on pulsative motion similar to that of heart pumping blood to the body.

    22. perfusion

      The passage of blood or fluids through blood vessels or other channels in an organ or tissue. Perfusion is needed to sustain healthy tissues and organs.

    23. slurry

      A semiliquid mixture, typically of fine particles of manure, cement, or coal suspended in water. E,g, cake batter

    24. cardiomyocytes

      Heart muscle cells responsible for contracting of the heart.

    25. collagen scaffolds

      Scaffolds provide support for tissues and organs in the human body. In this article, the scaffolds are made from collagen, a structural protein used in connective tissues

  2. Mar 2020
    1. extracellular matrix

      A network of biological materials surrounding cells throughout the body for protection and support.

    2. cellular infiltration

      The ability of cells to occupy the porous structure in the hydrogel to create a tissue-like structure

    3. J

      Field stimulation could could measure the ventricle baseline spontaneous beat rate of about 0.5 Hz and capture/pace them at 1 Hz and 2 Hz.

    4. (D

      This mapping shows how well the ventricle can contract stem cells from the side (D-E) and from the top (F-G) during contractions.

    5. (M and N)

      (M-P) Using FRESH + VEGF the collagen is much more vascular and can visibly have plenty more red blood cells in the imaging.

    6. H

      (H-L) The usage of the FRESH allowed for much deeper penetration depth for red blood cells. This is clearly demonstrated in figure K.

      (L) From 0 to 300 nuclei penetration depth, both the cast and FRESH printed have around the same quantity of nuclei present. However, after 300 micrometers, the FRESH is vastly more present.

    7. (A)

      (A-F) Dimensions of the FRESH printed tube to put into perspective its size.

      C2C12 is an immortalized mouse muscle building cell lines. That and collagen were placed around the tube and placed in an unchanging environment for 5 days.

      A lot of the living cells come from the top of the cross section, while most below are dead cells.

      C2C12 and the gel mixture are permitted to spread around the tube for 5 days. Notice how compared to B, it is much thicker.

      With the perfusion, the cross section shows all of the cells remained living. This is very different than picture C.

      In a perfused collagen tube, no matter the depth, the viability of the cells was much better than that of a static collagen tube.

    8. yield stress

      Highest amount of force an object can take before deforming.

    9. pH

      A scale from 1 to 14 determining how acidic or basic a solution is. 1 is most acidic, 14 is most basic, and 7 is neutral.

    10. endothelial

      cells that are on inner surface of blood vessels

    11. patent and manifold

      unobstructed (open inside allowing for fluid flow) and has several outlets to be connected to other tubes/pipes.

    12. fidelity

      Reproducibility of features (size and shape) with 3-D printing

    13. decellularized

      cells removed

    14. fidelity

      Reproducibility of features (size and shape) with 3-D printing

    15. resolution

      Smallest feature that can be written by 3-D printers.

    16. micro–computed tomography

      This is a procedure in which x-rays are used to make cross sections of a 3D structure. It is similar to a CT scan, but on a micro-scale.

    17. tri-leaflet valves

      In the aortic valve, the blood moves around based on the opening of the three leaflets within the valve. When they open, blood can move freely. Once they close, blood stops moving.This is the tri-leaflet valve.

    18. pH-driven gelation

      Hydrogels are 3D networks of hydrophilic polymers that can hold a lot of water while still maintaining structure.

      They resemble tissue structure when scaffolded and can provide places for cell growth.

      Hydrogels can be made in environments with changes occurring in them. One of these changes that can occur is that pH in the environment changing.

  3. Feb 2020
    1. (R)

      Imaging showing the presence of a red blood cell in the inside of the blood vessel of the microvasculature in the FRESH printed construct.

      Microvasculature: The part of the circulatory system with the smallest vessels in it (capillaries, arterioles, venules)

    2. (Q)

      FRESH printed collagen disks were successfully able for the vessels to infiltrate it.

    3. (G)

      With the support baths removal, the collagen constructs made by the FRESH appear to have many holes in them.

    4. thermoreversible

      To destroy the properties of a protein or other biological molecule (e.g. by heat, acidity) to disrupt its function.

    5. biofabrication

      Production of complex living and non-living products from bio-compatible materials and cells to address medical challenges.

    6. extracellular matrix

      A network of biological materials surrounding cells throughout the body for protection and support.

    7. microphysiological devices

      Tiny devices that mimic the functions of human physiological systems such as organs and tissues.

    8. synchronous

      Occurring or existing at the same time.

    9. 3D Voronoi lattice

      A lattice structure is a structure made of crisscross patterns of stripping. A 3D Voronoi lattice is used to help make objects lighter, but stronger.

    10. porcine

      relating to pigs

    11. arrhythmogenic disease

      Muscle tissue in the heart dies and is replaced with scar tissue. Leads to weakened blood flow and irregular heartbeats.

    12. electrophysiologic

      Electrical activity of the heart

    13. anisotropic

      Having a physical property that has different values when measured in different directions.

    14. α-actinin

      Needed for attachment of actin to Z-lines in skeletal muscle cells.

    15. hESC-CMs

      Human embryonic stem cell-derived cardiomyocytes

    16. CD31-positive

      CD-31 is a protein that is involved in angiogenesis activation.

    17. angiogenesis

      The development of new blood vessels.

    18. perivascular

      Around a blood vessel.

    19. vessel lumens

      The inside space of the blood vessel.

    20. vasculature

      The arrangement of blood vessels in an organ or tissue.