Professor Bowles has developed a method to 3D-print cells to produce human tissue. This replacement tissue can greatly improve the recovery of a person with a badly damaged ligament, tendon, or ruptured disc. Currently, replacement tissue is harvested from another part of the patient's body or sometimes from a cadaver, but it may be of poor quality. This 3D-printing technique can solve those problems.

Tech Briefs: What got you interested in this project?

Professor Robby Bowles: We do a lot of phenotype control over cells that in turn produce certain types of tissues. We needed to be able to controllably place these cells into the tissues so we could produce complicated gradients. We recently ran into people at Carterra, Inc. (Salt Lake City) who had developed microfluidic printing cell arrays and thought this might be an interesting way to print and control the cells we make in my lab and to produce new tissues.

Tech Briefs: How do you create differentiated cells?

Bowles: We use CRISPR epigenome editing that essentially allows us to modify the epigenome. We make targeted chemical changes to the genes within the cells, changing how they're expressed and controlling what they become.

Tech Briefs: How do you get from these cells to tendons, ligaments, and discs?

Bowles: All tissues and organs are made up of cells that control the different molecules and composition of the tissues, where they are put, and when they are put in. It's a simple feat of engineering once we have the ability to control what that cell puts out with this epigenome editing. We simply need to control where the cells are placed within a tissue and they will create the tissue we're targeting.

Tech Briefs: What are your next steps in the project?

Bowles: We are now working to take the engineered cells, print them, and show we can produce tissues that have bone interfacing with soft tissues, producing tendons and ligaments. Then, implant them in vivo to test out their ability to replace these tissues in organs.

Tech Briefs: How do you engineer cells that produce soft tissue like ligaments and tendons and then have it morph into bones?

Bowles: That's one of the big challenges for muscular-skeletal tissue engineering: reproducing the interface between bone and soft tissues. From an engineering standpoint, it's a very complicated idea to go from a very soft tissue to a hard tissue. We have genetic modifications that drive the stem cells to produce bone, and then genetic modifications that drive these tissues to produce soft tissues. Then we create the boundary we need to get the bone going into soft tissue.

Tech Briefs: How might this process be used in actual practice?

Bowles: The Holy Grail — the place you want to get to in tissue engineering — is to be able to use “off-the-shelf” cells that are engineered so they don't cause an immune response. These cells would not have to be harvested from the patient. We would print them into tissues that we would grow in a tissue culture hood and implant into the patient.

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