Video Description for the Visually Impaired
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Visual: Dr. Chatterjee on camera.
Text: Dr. Kaushik Chatterjee. PhD
Post Doctorate Fellow
National Institute of Standards and Technology
“In a very broad sense what we’re doing is called tissue engineering or regenerative medicine. So, you want to take a material which will support cell regeneration. You take biological cells, you put them in a material and you want to grow them so that, ultimately, you get a functional tissue or even an organ, perhaps, that you could someday put back in the human body.”
Text: “Fabrication of 3D Combinatorial Polymer Scaffold Libraries for Tissue Engineering”
Text: “Hydrogel Scaffold Libraries”
Narrator:
Billions of dollars have been invested in developing tissue engineered products. But, the return on that investment has yet to be fully realized.
Between 2000 and 2003 tissue engineering, for a number of reasons, was in dire straits. Since then, a remarkable turnaround has taken place.
Still, few profitable tissue engineering products have made their way to the market place. There is, therefore, a need to accelerate research in this field. To this end, the Polymers Division of the National Institute of Standards and Technology has developed several approaches for fabricating combinatorial scaffold libraries for screening cell material interactions in 3D.
One such approach is to assemble a simple, low cost platform to fabricate Hydrogel Scaffold Libraries with gradients in compressive modulus.
Visual: Dr. Chatterjee on camera.
“These hydrogel materials have been shown in this field to be great candidate materials to grow these tissue and organs and, in that sense, you definitely would want to improve them and optimize the properties for the best tissue regeneration and what we can do now with our expertise in this Division is develop methods that you can rapidly optimize properties and that will get you the best results in terms of ability to regenerate these tissues.”
Visual: Dr. Chatterjee illustrates the demonstration he is describing.
“Today, what we’re going to do is use a gradient-maker and generate what’s called a gradient in the properties of these materials. I’ve prepared two solutions. One has five percent bio-mass of this material in water. The other one I have twenty percent by mass of this material. And, then just to visually see the gradients, what I’ve done for this demonstration is added a blue dye that will let us visually see it because otherwise everything looks transparent as we fill our scaffold test system.
This is our mold which is cut from pieces of Teflon and a glass slide. Here is a piece of Teflon 3 millimeters in thickness and then cut this into dimensions of six centimeters by six centimeters and we build a little hole at the bottom for the entry of the needle from which we’re going to pump in the liquid. And, this is just a regular glass slide and to support our mold we’ve got a thicker piece of Teflon and so what you’re going to do is you assemble all these three together and then you use these clips to hold them tightly in place. And, then you insert this needle at the bottom of the mold. You transfer 5.8 milliliters of solution into each of these chambers. Then we’ll gently open these stops.
You see it starts out as clear and then it gets progressively it’ll get darker in color as the contents from the back chamber start mixing into the contents of the front chamber.
Visual: Time lapse photography as contents from back chamber mix into contents of front chamber.
Okay. So the pump’s turned off now. So, what we’re going to do, now that you’ve filled in the mold with the liquid, we’re just gonna use 365 nanometer wavelength light source.”
Visual: Dr. Chatterjee continues illustrating the demonstration he is describing
“What that will do is, basically, turn on a chemistry where these materials respond to alight source and it helps in, basically, gelling the liquid. Right now we have a liquid that will form a gel, like a jell-o, essentially.
We have this thing set up here. That is the light source. So, I can show you, turn it on. You can see the light source coming on. So, now I get it closer and we have optimized the intensity and time for this kind of set-up.
This is still only a liquid so you don’t want to disturb it at this point, And, we’ll make sure it’s close and turn it on again.
For our experiment here what we’ve done is optimized the system because we know how much energy we are putting in. We used a measurement device. We know we’re putting in 2 milliwatts per centimeter square of energy and if we do it for fifteen minutes, we know the solution is fully cured, the whole thing will gell.
So, we unclamp this and we have water in here. I am just going to place it in water. I will gently put in the glass slide.”
Visual: Dr. Chatterjee on camera.
“This field of tissue engineering and regenerative medicine will eventually be able to come up with different kinds of tissues and organs and there is a big demand from patients for all kinds of tissues. In particular, what we’re doing here in terms of the experiments we’ve done recently, we’ve developed methods that you can optimize the material properties and what we feel is there are companies and laboratories working with these kind of materials and they can take these techniques and optimize their material properties and adapt these techniques for their particular materials which would give them the best tissue regeneration. That is where I see these particular studies we’ve done recently going in the near future.”
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