Improved, Injectable Hydrogel to Treat Injuries and Promote Healing

Rice University scientists have created a new version of a hydrogel that can be injected into an internal wound and help it heal - while slowly degrading as it is replaced by natural tissue. The hydrogel is made of a self-assembling synthetic peptide that forms nanofiber scaffolds. Like earlier versions, the material can be injected in liquid form and turns into a nanofiber-infused gel at the site of the injury. Without blood to deliver oxygen and nutrients and carry out waste, new tissue growth is limited. So synthetic peptides that form the hydrogel incorporate a mimic of vascular endothelial growth factor, a signal protein that promotes angiogenesis, the growth of a network of blood vessels. In simulations and lab tests, the researchers say the new material works very well.

Transcript

00:00:12 we're really excited about this recent publication of ours which is really the culmination of at least eight years of work that starts from really fundamental basic science and that's work that we've been doing as i said for at least eight years but in this publication we take that basic science and we start to move it

00:00:36 in a much more translational direction we start moving into experiments and ideas that could have real clinical application and so the the video that we're going to see here shows the the basic science part of this where what we can do is control how many peptides come together

00:00:56 and organize themselves into a nanostructure and that nanostructure that they form controls both materials properties as well as the in the end of the biological function the movie starts off by showing a single peptide and the different portions of that molecule one portion of which is hydrophilic or

00:01:15 water loving the other portion is hydrophobic or water hating this green portion is the important part of the molecule for this paper which is the angiogenic portion that's going to grow blood vessels and these peptides come together or self-assemble through what we call a hydrophobic sandwich

00:01:33 and many of these peptides come together and begin forming a fiber and we have looked a lot into exactly how these peptides come together and here the video shows that it's an anti-parallel beta sheet hydrogen bonding network that's formed from these peptides so at first these peptides are in equilibrium with one another

00:01:54 where they basically maintain a rather small size but when we add the right kinds of salts to these things they expand into much larger fibers and more and more of these fibers are created until eventually the fibers cross-link into a hydrogel and it's that hydrogel that forms that then has the materials properties

00:02:16 necessary for a useful clinical application and it's those hydrogels that we inject into animals and then look at the body's response to those hydrogels in vivo as jeff mentioned the process of angiogenesis is essentially wherein blood vessels grow from existing vasculature

00:02:35 towards any disease site in the research that we've done we've been very interested to develop new blood vessels or neoangiogenesis to allow tissue recovery to increase blood profusion to ischemic or low blood flow tissues to promote tissue regeneration what we have here are these injectable scaffolds

00:02:54 which is entirely in this region which shows a very high level of angiogenesis as seen in these blood vessels both in circular cross section as well as in oblique cross sections which suggest that we're having blood vessels grow from the external tissue into these scaffolds what's very interesting is where we can take these materials next

00:03:13 can we use these materials for highland ischemia or for myocardial infarctions essentially to regenerate tissue after there's an acute loss of blood flow to a specific region you