Talk:CH391L/S13/Cell Scaffolding and Printing

• Dwight Tyler Fields 16:22, 15 April 2013 (EDT): Several times you mention the "lack of avalable materials" for these processes? This seems like a both a big challenge and a big opportunity for innovation. Can you elaborate on the biomaterials used for creating these various scaffolds and organs, and why they aren't available, and maybe any advances in solving this problem that synthetic bio is solving or might solve?
  • Evan Weaver 12:43, 16 April 2013 (EDT): My guess is that the reason why lots of biomaterials aren't compatible with these scaffolding processes is because these materials don't have the right properties. For example, some biomaterials wouldn't be able to be dissolved and used in electrospinning. I'll update the page with the actual biomaterial names and molecular formulas.
  • Evan Weaver 21:25, 17 April 2013 (EDT): Additionally, it seems that many materials are not bioinert. Lots of them seem to cause inflammatory and/or immune responces and can form toxic byproducts upon degradation. There has bees some research into building artificial extracellular matrix scaffolds using electrospinning. They're spun by combining them with synthetic materials since they can't be spun on their own.
    • Gabriel Wu 23:02, 17 April 2013 (EDT): As anybody thought about materials beyond just being bio-inert. I know that lots of biomaterials are chosen because of their lack (or reduction) of inflammation, etc. and I know that some people have tried chemical coatings designed to actively suppress immune responses, but can we do better. In theory, don't our cellular scaffolds promote cell growth and differentiation and not just hide from our own immune systems. It seems like there's some notion that if we build a scaffold, cells will grow. Is there any evidence to suggest we can just coat a scaffold with cells and make an organ?
      • Evan Weaver 22:31, 17 April 2013 (EDT): Just putting cells on scaffolding doesn't make it turn into an organ. The cells have to be induced to differentiate in the correct way. This can be done using a combination of adding molecules to the scaffold during the manufacturing process and washing stuff over the scaffold. Correct me if I'm mistaken.

• Benjamin Gilman 15:13, 18 April 2013 (EDT): Aside from material choice, you might mention something about controlling the pore sizes in scaffold materials so that cells can populate them at the right density. I know that PEG scaffolds have become very popular, but it's not trivial to generate even, cell-sized holes.
  • Evan Weaver 17:52, 21 April 2013 (EDT): It seems that there is an optimal pore size for each type of cell, or at least for bone tissue growth. (From this paper) I'll add this to the list of scaffold properties.
  • Evan Weaver 18:19, 21 April 2013 (EDT): It appears that PEG by itself is a hydrogel, but can be modified and dried to form mesh-like scaffolding. Also, hydrogels do seem to obtain meshlike structures when immersed in water, cool.
• Dwight Tyler Fields 16:31, 15 April 2013 (EDT): I get the impression from your page that current printing technology available to consumers, like that made by MakerBot, is not that different from the scaffolding printers you discuss. What would it take to upgrade a consumer 3D printer (or regular ink jet, etc) to do this kind of thing? Just a different material?
  • Evan Weaver 12:50, 16 April 2013 (EDT): Here's a cell printer that you can buy online, its probbly super expensive. http://www.digilabglobal.com/celljet Here's a step-by-step guide to creating a ink-jet cell printer. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3353707/ I can't believe this thing works.

• Kevin Baldridge 16:35, 15 April 2013 (EDT):A better introduction would be helpful for the cell printing section, maybe talk about applications and problems with cell printing vs scaffolding. the same information could be included as a general page intro before you delve into scaffolding topics. Also, I hate that the talk page just rejects what you type if someone else saved it because all the time I have to retype my comments.
  • Gabriel Wu 22:56, 17 April 2013 (EDT): I find that my browser (safari or chrome on mac) usually will save my comments in my history. I can backup a few pages and find my "unsaved" comments. I then just cut and paste and submit again.
• Yunle Huang 14:29, 18 April 2013 (EDT):Maybe mention some techniques for actually depositing the cells into the scaffolds?
  • Evan Weaver 13:46, 18 April 2013 (EDT): In the video I showed, it showed some people seeding the scaffold by literally pipetting the cells over the the scaffolding. That's probably how it's done. I'll look into cell seeding though.
    • Siddharth Das 14:30, 22 April 2013 (EDT): That's interesting! I would think you'd purposefully pipette cells over the scaffold so that you can affect the growth of the tissues. Do you think pipetting excess cells on a particular region of the scaffold would cause any problems to the tissue?
• Yunle Huang 14:32, 18 April 2013 (EDT):Why isn't the ECM affected by detergents in the decellularization method?
  • Evan Weaver 14:02, 18 April 2013 (EDT): It probably only washes away the lipids and phospholipids and leaves the sugars and proteins (which make up the ECM) behind.