Biomedical breakthrough: Blood vessels for lab-grown tissues (w/ Video)

Jan 12, 2011

Researchers from Rice University and Baylor College of Medicine (BCM) have broken one of the major roadblocks on the path to growing transplantable tissue in the lab: They've found a way to grow the blood vessels and capillaries needed to keep tissues alive.

The new research is available online and due to appear in the January issue of the journal .

"The inability to grow blood-vessel networks -- or vasculature -- in lab-grown tissues is the leading problem in regenerative medicine today," said lead co-author Jennifer West, department chair and the Isabel C. Cameron Professor of Bioengineering at Rice. "If you don't have blood supply, you cannot make a tissue structure that is thicker than a couple hundred microns."

As its base material, a team of researchers led by West and BCM molecular physiologist Mary Dickinson chose (PEG), a nontoxic plastic that's widely used in medical devices and food. Building on 10 years of research in West's lab, the scientists modified the PEG to mimic the body's -- the network of proteins and that make up a substantial portion of most tissues.

This video is not supported by your browser at this time.
This time-lapse image shows how two types of cells -- which were tagged with fluorescent dye -- organize themselves into a functioning capillary networks within 72 hours.

West, Dickinson, Rice graduate student Jennifer Saik, Rice undergraduate Emily Watkins and Rice-BCM graduate student Daniel Gould combined the modified PEG with two kinds of cells -- both of which are needed for blood-vessel formation. Using light that locks the PEG polymer strands into a solid gel, they created soft hydrogels that contained living cells and growth factors. After that, they filmed the hydrogels for 72 hours. By tagging each type of cell with a different colored fluorescent marker, the team was able to watch as the cells gradually formed capillaries throughout the soft, plastic gel.

To test these new vascular networks, the team implanted the hydrogels into the corneas of mice, where no natural vasculature exists. After injecting a dye into the mice's bloodstream, the researchers confirmed normal blood flow in the newly grown .

Another key advance, published by West and graduate student Joseph Hoffmann in November, involved the creation of a new technique called "two-photon lithography," an ultrasensitive way of using light to create intricate three-dimensional patterns within the soft PEG hydrogels. West said the patterning technique allows the engineers to exert a fine level of control over where cells move and grow. In follow-up experiments, also in collaboration with the Dickinson lab at BCM, West and her team plan to use the technique to grow in predetermined patterns.

Explore further: Automating the selection process for a genome assembler

More information: Paper online: dx.doi.org/10.1016/j.actbio.2010.08.018

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gmurphy
5 / 5 (2) Jan 12, 2011
Incredible, I would think that once this tech is cost effective, it would be useful for In vitro meat too.
danlgarmstrong
not rated yet Jan 12, 2011
Wow - I think this is a MAJOR development. As said in the article this was the main roadblock for tissue engineers trying to regenerate organs. I bet we see some swift progress now. When the government reworks health care I sure hope they add provisions to get all the new biotech developments into the system as quickly as possible. Regenerative medicine and the many other technologies that have come on to the scene are the disruptive elements we need to totally change the conservative, insurance dominated, bureaucratic mess that our health care system is today. Making old people healthy and strong is the only way to prevent bankrupting Medicare, and having older people working (happily) is the only way to keep Social Security solvent as well. We need to invest in companies that will develop and distribute this technology to everyone. There are whole new industries to be built on developments like this, and thousands, tens of thousands, of new jobs as well.