Question

how do you build a 3d animal cell model?

Answer 1

With LEGO

Answer 2

Well this is quite a big question - it's the goal for a number of researchers. The first obvious difference between a conventional 2D culture and a 3D is the need for a matrix to support the cells. The ones I've used were solutions of proteins like collagen and glycans like hyaluronic acid which had been chemically modified so they can bind together into a gel. This gel can provide a structure for the cells to grow in. If you want to make an organ, then it is possible to model the matrix into the required shape and add cells to adhere and grow on the matrix - I think this has been used recently to make a replacement windpipe for a transplant.

Another thing to consider is the type of cells - these should be as near primary cells as possible so the model is as near a normal tissue as possible. Cancer cells make up the majority of cell lines available but using these gives you a 3D model of a tumour rather than a normal tissue.

Answer 3

"cancer cells make up the majority of cell lines available" - why ?
And shouldn't have those cells the genes for all the regulatory process to differentiate, and mold together to form the tissue or organ?

Answer 4

Thanks for the post - the history of cell culture shows that most cell lines are from tumours - perhaps because these cells have lost the normal cell cycle controls that stop cells dividing. Similarly, cancer cells don't differentiate normally because they have genetic changes - loss of tumour suppressor genes like p53 or loss of control of oncogenes so they are expressed continually.

Answer 5

if you have a sample from a normal kidney tissue, from a normal person, why couldn't you incubate ( whats the best word ? ), inoculate ?, the cells in a petri's case or another recipient, and therefore they would form a new kidney? why do you need a matrix to settle the cells?

Answer 6

in which step of the cell cycle, does the p53 works?
in which step of the cell cycle, does she decided if she remains alive or does apoptosis?

Answer 7

you can say that to form the kidney, cells need the appropriate sensors, like hormones, proteins, involved in the regulatory process, but at an embryo, is there anything similar to a cerebrum? i guess not, and cells start to differentiate anyway.
yesterday, i saw somewhere, that the cells between fingers start to the apoptosis in order to separate the fingers.
Now , its possible that this apoptosis starts only when a thing similar to a brain is already formed.
what does the cells stop to evolve and proliferate ? the p53?

Answer 8

These are some great questions which will take a bit of answering. To start with the kidney, the cells are pretty much terminally differentiated (as far as I know - I'm not a specialist). Therefore it's unlikely that they would divide again. Tissues which can regenerate in the body after injury (like liver for example) are thought to contain stem cells which can produce new liver cells (or hepatocytes as they are also known).

Cells depend on their environment for proper gene expression and hence differentiation, so making a 3D model is demanding - you need all the correct forces acting on a cell as well as chemical signals if they are going to display normal phenotype. So the matrix gives your model structure but it also should signal the cells to act normal.

p53 acts between G1 and S and it's at this stage that cells either stay in cell cycle arrest or go into apoptosis.

Now your last set of questions really get to the heart of stem cell biology - why is it that an egg can form all the tissues of the body whilst adult stem cells can only replace adult cells that have worn out or been lost. The cells that make embryonic kidney must have more potency (in terms of producing different sorts of cells) than adult stem cells. Now how cells know where they are in the embryo and whether to divide or enter apoptosis is the sort of question which, if successfully answered will earn a Nobel prize. (or in other words, I don't know).Best wishes

Answer 9

Nice Work^