A Pittsburgh-based research team has created and used an
innovative ink-jet system to print "bio-ink" patterns that direct
muscle-derived stem cells from adult mice to differentiate into both muscle
cells and bone cells. Technology could revolutionize the design of replacement
body tissues and one day benefit millions of people whose tissues are damaged
from a variety of conditions, including fatal genetic diseases like Duchenne
Muscular Dystrophy (DMD), wear and tear associated with aging joints,
accidental trauma, and joint deterioration due to autoimmune disorders.
"Previously, researchers have been limited to directing
stem cells to differentiate toward multiple lineages in separate culture
vessels. This is not how the body works: the body is one vessel in which
multiple tissues are patterned and formed. The ink-jet printing technology
allows us to precisely engineer multiple unique microenvironments by patterning
bio-inks that could promote differentiation towards multiple lineages
simultaneously," explained Phil Campbell, research professor at Carnegie
Mellon's Institute for Complex Engineered Systems.
"Controlling what types of cells differentiate from
stem cells and gaining spatial control of stem cell differentiation are
important capabilities if researchers are to engineer replacement tissues that
might be used in treating disease, trauma or genetic abnormalities," said
Lee Weiss, research professor at Carnegie Mellon's Robotics Institute.
The custom-built ink-jet printer, developed at Carnegie
Mellon's Robotics Institute, can deposit and immobilize growth factors in
virtually any design, pattern or concentration, laying down patterns on native
extracellular matrix-coated slides (such as fibrin). These slides are then
placed in culture dishes and topped with muscle-derived stem cells (MDSCs).
Based on pattern, dose or factor printed by the ink-jet, the MDSCs can be
directed to differentiate down various cell-fate differentiation pathways (e.g.
bone- or muscle-like).
The long-term promise of this new technology could be the
tailoring of tissue-engineered regenerative therapies. In preparation for
preclinical studies, the Pittsburgh researchers are combining the versatile
ink-jet system with advanced real-time live cell image analysis developed at
the Robotics Institute and Molecular Biosensor and Imaging Center to further
understand how stem cells differentiate into bone, muscle and other cell types.