It is envisioned that for the regeneration of highly organized structures, like tendon and ligaments, only aligned fibrous scaffolds can provide adequate topographic guidance to cells. In this study, a novel method to electrospin an aligned scaffold is presented. Electrospun fibres were deposited into a water bath and then the fibres were drawn to a rotating mandrel in a controlled manner. In this way, parallel and cross-aligned fibrous poly (lactide-co-glycolide) (PLGA) scaffolds were fabricated, which were subsequently used to study their effect on the growth behaviour of rat periodontal ligament (PDL) cells. First, the scaffolds were characterized regarding mechanical properties, scaffold stability and degradation in vitro. Then, rat PDL cells were seeded and cultured on these scaffolds for up to 7 days. Randomly oriented PLGA and solvent cast plain PLGA films served as controls. Results showed that the alignment of fibres resulted in a higher tensile stress and Young's modulus. Aligned scaffolds maintained their structural stability better compared to the controls after incubation in phosphate-buffered saline for 6 weeks. Further, cells were observed to elongate along the fibre after 3 days of culture. Proliferation and migration of PDL cells was significantly more prevalent on the aligned fibres compared to the controls. It was concluded that aligned scaffolds seem to be able to promote the organized regeneration of periodontal tissue.
Fibers
that can reversibly and passively change colors along with
body temperatures are highly desired for potential applications including
temperature sensors, smart wearables, and photonic devices. Here,
we develop a facile strategy to fabricate thermochromic photonic fibers,
which could exhibit tunable structural colors as a function of temperatures.
The thermochromic fibers are prepared by aligning superparamagnetic,
carbon-encapsulated Fe3O4 colloidal nanocrystal
clusters (Fe3O4@C CNCs) in a thermoresponsive
hydrogel, poly(N-isopropylacrylamide) (PNIPAM), forming
chain-like structures under an external magnetic field before gelation.
When the fiber is transferred from air to water at room temperature,
it changes color from dark green to red as it swells. The red color
can be reversibly changed back to green as the temperature is raised
to 36 °C, while the fiber shrinks and the reflection peak shifts
from 642 to 494 nm. The swelling of the fiber is anisotropic: by 60%
in the diameter direction but 45% in the length direction. Therefore,
the fiber can act as a thermochromic actuator.
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