Biomedical Engineering Reference
In-Depth Information
Recent studies have found that matrix stiffness
is an instructive signal for cell differentiation.
For example, mesenchymal stem cells preferen-
tially differentiate into neuronal, myogenic, and
osteogenic cells when cultured on hydrogels
with the lowest (0.1 kPa), intermediate (11 kPa),
or highest (34 kPa) moduli, respectively. In addi-
tion, micro/nanoscaled topography created on
3D scaffold surfaces appears to have a profound
impact on cell shape, organization of the
cytoskeletal structure, and intercellular signal-
ing
[156]
. It is also worth noting that cells release
many soluble biomolecules that dynamically
remodel ECM structures by changing the local
modulus and chemical composition of the tissue
ECM
[157]
. Therefore, identifying the 3D archi-
tecture of the ECM and the interactions between
ECM components in each tissue type is another
key step toward designing more effective
bioscaffolds.
The generation of vascularized tissues also
remains a key challenge in tissue engineering.
Numerous approaches have been conceived in
the last decade to overcome this problem. Today,
only
in vitro
engineered tissues like skin, carti-
lage, and cornea are used in clinics. This limited
success is due to the fact that cells of these tis-
sues can be functional, with nutrients and oxy-
gen via diffusion from blood vessel systems that
are further away. Currently, there are two main
strategies: prevascularization of synthetic scaf-
folds or the use of natural tissue-based 3D scaf-
folds. Furthering the success of tissue engineering
in the clinic and realizing the ultimate goal
of whole-organ generation hinge on the
advancement of these strategies and others by
the continued collaboration of researchers and
technologists across the spectrum of academia
and industry, utilizing each person's expertise.
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