2 research outputs found
Effects of Chitin Whiskers on Physical Properties and Osteoblast Culture of Alginate Based Nanocomposite Hydrogels
Novel nanocomposite hydrogels composed
of polyelectrolytes alginate
and chitin whiskers with biocompatibility were successfully fabricated
based on the pH-induced charge shifting behavior of chitin whiskers.
The chitin whiskers with mean length and width of 300 and 20 nm were
uniformly dispersed in negatively charged sodium alginate aqueous
solution, leading to the formation of the homogeneous nanocomposite
hydrogels. The experimental results indicated that their mechanical
properties were significantly improved compared to alginate hydrogel
and the swelling trends were inhibited as a result of the strong electrostatic
interactions between the chitin whiskers and alginate. The nanocomposite
hydrogels exhibited certain crystallinity and hierarchical structure
with nanoscale chitin whiskers, similar to the structure of the native
extracellular matrix. Moreover, the nanocomposite hydrogels were successfully
applied as bone scaffolds for MC3T3-E1 osteoblast cells, showing their
excellent biocompatibility and low cytotoxicity. The results of fluorescent
micrographs and scanning electronic microscope (SEM) images revealed
that the addition of chitin whiskers into the nanocomposite hydrogels
markedly promoted the cell adhesion and proliferation of the osteoblast
cells. The biocompatible nanocomposite hydrogels have potential application
in bone tissue engineering
Hierarchical Microspheres Constructed from Chitin Nanofibers Penetrated Hydroxyapatite Crystals for Bone Regeneration
Chitin exists abundantly
in crab and shrimp shells as the template
of the minerals, which inspired us to mineralize it for fabricating
bone grafting materials. In the present work, chitin nanofibrous microspheres
were used as the matrix for in situ synthesis of hydroxyapatite (HA)
crystals including microflakes, submicron-needles, and submicron-spheres,
which were penetrated by long chitin nanofibers, leading to the hierarchical
structure. The shape and size of the HA crystals could be controlled
by changing the HA synthesis process. The tight interface adhesion
between chitin and HA through the noncovanlent bonds occurred in the
composite microspheres, and HAs were homogeneously dispersed and bounded
to the chitin nanofibers. In our findings, the inherent biocompatibilities
of the both chitin and HA contributed the bone cell adhesion and osteoconduction.
Moreover, the chitin microsphere with submicron-needle and submicron-sphere
HA crystals remarkably promoted in vitro cell adhesion and in vivo
bone healing. It was demonstrated that rabbits with 1.5 cm radius
defect were almost cured completely within three months in a growth
factor- and cell-free state, as a result of the unique surface microstructure
and biocompatibilities of the composite microspheres. The microsphere
scaffold displayed excellent biofunctions and an appropriate biodegradability.
This work opened up a new avenue to construct natural polymer-based
organic–inorganic hybrid microspheres for bone regeneration