MECHANO-ACTIVE SCAFFOLDS - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 551

Articular hyaline cartilage is subjected to particularly complex
loads that affect its development and maintenance in the body. 44
Hence, mechanical stimulation associated with normal bodily func-
tions is crucial in properly re-forming articular cartilage with tissue
engineering. During hyaline cartilage engineering, scaffolds do not
just provide a temporary substrate to which transplanted cells can
adhere; they also play an important role in maintaining mechan-
ical integrity during the healing process and delivering appropri-
ate mechanical signals to adherent cells in dynamic physiological
systems. 47 - 50 Much previous work has been devoted to evaluating
scaffolds composed of various biodegradable polyesters, including
PGA, PLA, poly( ε -caprolactone) (PCL), and their copolymers. 21 , 51 - 53
In particular, the mechanical properties of the PLCL copolymer can
be altered by changing the monomer content, and the physically
cross-linkedstructureofPLCLexhibitsarubberlikeelasticity. 54 Suc-
cessfullygeneratingfunctionalengineeredcartilagerequiresusinga
mechano-active scaffold that can transmit mechanical signals to its
adherent cells in physiologically dynamicbodily environments.
To deliver the required mechanical signals associated with the
surrounding biological environment of cartilage, we fabricated a
sponge-type microporous scaffold from the elastic PLCL copolymer
by a gel-pressing method. Xie et al . evaluated microporous PLCL
scaffolds in an ex vivo system for mechano-active, scaffold-based
cartilage tissue engineering. A new cell-seeding technique was
devised to improve chondrocyte distribution into and viability
in microporous PLCL scaffolds under compression force-induced
suction. They successfully delivered cells to microporous PLCL
scaffolds with high cell-seeding e ciency, cell viability, and homo-
geneous cell distribution under multiple cycles of suction. Xie et
al . focused on how chondrocytes respond biomechanically to var-
ious modes of compressive loading, specifically loading frequency,
loading duration per cycle, loading period, and continuous or inter-
mittent compression, in mechano-active PLCL scaffolds. The mRNA
expression of ECM molecules associated with cartilage is observed
in chondrocyte-containing PLCL scaffolds cultured at three differ-
ent loading frequencies: 0.05, 0.1, and 0.5 Hz. Type II collagen
expression is the highest in scaffolds cultured at 0.1Hz, whereas
little difference is observed in aggrecan mRNA levels at these