Research Progress
New bioinspired gel material could help repair damaged teeth
Post: 2014-09-29 15:48  View:1445

A bit of pressure from a new shrinking, sponge-like gel is all it takes to turn transplanted unspecialized cells into cells that lay down minerals and begin to form teeth.

 

The bioinspired gel material could one day help repair or replace damaged organs, such as teeth and bone, and possibly other organs as well, scientists from the Wyss Institute for Biologically Inspired Engineering at Harvard University, Harvard School of Engineering and Applied Sciences (SEAS), and Boston Childrens Hospital report recently in Advanced Materials.

 

"Tissue engineers have long raised the idea of using synthetic materials to mimic the inductive power of the embryo," said Don Ingber, M.D., Ph.D., Founding Director of the Wyss Institute, Judah Folkman Professor of Vascular Biology at Harvard Medical School, Professor of Bioengineering at SEAS, and senior author of the study. "Were excited about this work because it shows that it really is possible."

 

Embryonic tissues have the power to drive cells and tissues to specialize and form organs. To do that, they employ biomolecules called growth factors to stimulate growth; gene-activating chemicals that cause the cells to specialize, and mechanical forces that modulate cell responses to these other factors.

 

But so far tissue engineers who want to build organs in the laboratory have employed only two of the three strategies - growth factors and gene-activating chemicals. Perhaps as a result, they have not yet succeeded in producing complex three-dimensional tissues.

 

A few years ago, Ingber and Tadanori Mammoto, M.D., Ph.D., Instructor in Surgery at Boston Childrens Hospital and Harvard Medical School, investigated a process called mesenchymal condensation that embryos use to begin forming a variety of organs, including teeth, cartilage, bone, muscle, tendon, and kidney.

 

In mesenchymal condensation, two adjacent tissue layers - loosely packed connective-tissue cells called mesenchyme and sheet-like tissue called an epithelium that covers it - exchange biochemical signals. This exchange causes the mesenchymal cells to squeeze themselves tightly into a small knot directly below where the new organ will form.

 

By examining tissues isolated from the jaws of embryonic mice, Mammoto and Ingber showed that when the compressed mesenchymal cells turn on genes that stimulate them to generate whole teeth composed of mineralized tissues, including dentin and enamel.

 

Inspired by this embryonic induction mechanism, Ingber and Basma Hashmi, a Ph.D. candidate at SEAS who is the lead author of the current paper, set out to develop a way to engineer artificial teeth by creating a tissue-friendly material that accomplishes the same goal. Specifically, they wanted a porous sponge-like gel that could be impregnated with mesenchymal cells, then, when implanted into the body, induced to shrink in 3D to physically compact the cells inside it.

 

To develop such a material, Ingber and Hashmi teamed up with researchers led by Joanna Aizenberg, Ph.D., a Wyss Institute Core Faculty member who leads the Institutes Adaptive Materials Technologies platform. Aizenberg is the Amy Smith Berylson Professor of Materials Science at SEAS and Professor of Chemistry and Chemical Biology at Harvard University.

 

They chemically modified a special gel-forming polymer called PNIPAAm that scientists have used to deliver drugs to the bodys tissues. PNIPAAm gels have an unusual property: they contract abruptly when they warm.

 

 

Story Source:
The above story is based on materials from Upper News Medical
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