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Last Updated: Saturday, 18 October, 2003, 23:00 GMT 00:00 UK
'Bio-scaffolds' spark organ hope
Scaffold with cells
The scaffold became clogged with cell growth
Human cells have been grown on tiny frames - raising hopes that it may be possible to create whole organs for transplant.

The microscopic "scaffolds" - made in the US - release chemicals which help produce various cell types.

Scientists say it will still be many years before whole new organs can be "grown to order" in a laboratory.

However, the 3D tissue samples produced could help doctors study how diseases progress and spread through the body.

The key advance made by the research team, from the Massachusetts Institute of Technology (MIT), is to prompt human "stem cells" to develop into different cell types, such as cartilage, liver, nerve and blood vessel.

"Stem cells" are found in the human embryo, and have the ability to become every different cell type in the body, given the right conditions.

The idea is that the cells grow into the required structure, creating their own "matrix" to support themselves, as well as a blood supply to keep themselves alive.

Disappearing frame

To achieve this, the polymer "frame" on which they are grown is designed to degrade at the right point so it does not get in the way.

The MIT scaffold was actually built from two different types of material, one designed to disappear quickly, and another to provide lasting support.

When the tissue structures they had created were implanted into mice, they continued to thrive, and actually integrated with the blood vessel networks in the animals.

Dr Shulamit Levenberg, one of the authors of the research, published in the Proceedings of the National Academy of Sciences, said: "When you give cells a three-dimensional structure on which to grow, it's really a lot more like what's happening in the embryo."

The cells were exposed to chemical "growth factors", which helped prompt them to grow and to become different types of human cell.

Huge task

Many different research teams around the world are working on ways to encourage their cells to grow in three dimensions rather than just two.

When you give cells a three-dimensional structure on which to grow, it's really a lot more like what's happening in the embryo
Dr Shulamit Levenberg, MIT
Dr Ying Yang, from Keele University, said that the various factors involved were highly complex - and that it would be some time before scientists could recreate the exact conditions which accompany growth of new tissues within the body.

She said: "What we know is that cells grown on our three-dimensional structures are currently not the same as those which grow naturally in the body."

She said that a variety of factors - the number and type of growth factor chemicals used, their concentration, and the timing of their application - could all be subtly adjusted in order to find the right combination.

Her own research involves placing the developing structure under a mechanical force to produce a more life-like structure.

She said: "Our research has already shown that structures built under mechanical force produce better proteins."

She agreed that the growing of replacement organs for transplantation was some distance away.


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