Electrospun-aligned fibers in ultrathin
fineness have previously
demonstrated a limited capacity in driving stem cells to differentiate
into tendon-like cells. In view of the tendon’s mechanoactive
nature, endowing such aligned fibrous structure with mechanoactivity
to exert in situ mechanical stimulus by itself, namely,
without any forces externally applied, is likely to potentiate its
efficiency of tenogenic induction. To test this hypothesis, in this
study, a shape-memory-capable poly(l-lactide-co-caprolactone) (PLCL) copolymer was electrospun into aligned fibrous
form followed by a “stretching-recovery” shape-programming
procedure to impart shape memory capability. Thereafter, in the absence
of tenogenic supplements, human adipose-derived stem cells (ADSCs)
were cultured on the programmed fibrous substrates for a duration
of 7 days, and the effects of constrained recovery resultant stress-stiffening
on cell morphology, proliferation, and tenogenic differentiation were
examined. The results indicate that the in situ enacted
mechanical stimulus due to shape memory effect (SME) did not have
adverse influence on cell viability and proliferation, but significantly
promoted cellular elongation along the direction of fiber alignment.
Moreover, it revealed that tendon-specific protein markers such as
tenomodulin (TNMD) and tenascin-C (TNC) and gene expression of scleraxis
(SCX), TNMD, TNC, and collagen I (COL I) were significantly upregulated
on the mechanoactive fibrous substrate with higher recovery stress
compared to the counterparts. Mechanistically, the Rho/ROCK signaling
pathway was identified to be involved in the substrate self-actuation-induced
enhancement in tenodifferentiation. Together, these results suggest
that constrained shape recovery stress may be employed as an innovative
loading modality to regulate the stem cell tenodifferentiation by
presenting the fibrous substrate with an aligned tendon-like topographical
cue and an additional mechanoactivity. This newly demonstrated paradigm
in modulating stem cell tenodifferentiation may improve the efficacy
of tendon tissue engineering strategy for tendon healing and regeneration.