“Every organ in our body is made up of complex, heterogeneous structures, so the ability to engineer tissues that more closely mimic these natural architectures is a critical challenge for the next wave of tissue engineering,” said Jennifer Phillips, now a postdoctoral research fellow in developmental biology at Emory University.
Ms. Phillips is talking about regenerative medicine. One regenerative challenge has been to keep stem cells positioned so as to create or repair injured organs or tissue in the right place and with the correct orientation. This requires some sort of 'scaffold.' Another challenge is to build the regenerated tissue in a way that causes the transition between heterogeneous organ or tissue parts to exactly mimic that of the 'natural' organ or tissue. The new Georgia Tech developments address this issue.
Ms. Phillips, Andres Garcia, professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology and a research team of graduate students were not only able to create artificial bone that melds into softer tissues, but were also able to implant the technology in vivo for several weeks.
The team created the new bone and tissue by coating a three-dimensional polymer scaffold with a gene delivery vehicle that encodes a transcription factor known as Runx2. They generated a high concentration of Runx2 at one end of the scaffold and decreased that amount until they ended up with no transcription factor on the other end, resulting in a precisely controlled spatial gradient of Runx2. Next, they seeded skin fibroblasts uniformly onto the scaffold.
The result was this: The skin cells on the parts of the scaffold containing a high concentration of Runx2 turned into bone, while the skin cells on the scaffold end with no Runx2 turned into soft tissue. The result is an artificial bone that gradually turns into soft tissue, such as tendons or ligaments.
If the technology is able to pass further testing, one application could be anterior cruciate ligament (ACL) surgery. Oftentimes, ACL surgery fails at the point where the ligament meets the bone. But if an artificial bone/ligament construct with these types of graded transitions were implanted, it might lead to more successful outcomes for patients.
Adapted from the Georgia Tech announcement and other sources.