INNOVATIVE BIOINSPIRED SIC CERAMICS FROM VEGETABLE RESOURCES - Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine - page 60

2.3 Biocompatibility Studies
The ability of bioinspired SiC ceramics to sustain cell attachment,
spreading, proliferation, and differentiation was assessed by seed-
ing MC3T3-E1 preosteoblastic cells on the materials up to 28 days.
Cellular interaction with sapelli-based SiC ceramics was compared
to cell growth on standard TCP, which represents the experimental
“gold standard” for in vitro studies ofosteoblasts.
The MC3T3-E1 cells are characterized by theircapacity to differ-
entiateintoosteoblastsandosteocytestoform,finally,calcifiedbone
tissue in vitro . The initial interaction with any surface involves pro-
tein adsorption to the surface, contact of rounded cells, attachment
of cell to substrate, and spreading of cells. Cells then start to pro-
liferate across the surface and pores to establish cell-to-cell contact
points,andfinallytheysynthesizetheextracellularmatrix.Afterthe
deposition of extracellular matrix, cell mineralization occurs with
calcium phosphate deposits in the crystalline hydroxyapatite (HA)
form. 21 , 22
Cell proliferation was assessed and quantified with the Cell Pro-
liferation Kit I (MTT) (Roche Applied Science) along the time of cul-
ture (Fig. 2.4a). MC3T3-E1 cells proliferated properly throughout
the culture time on the tested material. The behavior of the cells on
the SiC ceramics followed the same pattern as those grown on the
TCP,withaprogressiveincreaseofthecellulardensityuntilthefour-
teenth day of incubation. An expected decrease of the cell prolifera-
tion on TCP on the twenty-first day was detected on both materials.
At this time, cells had already covered the whole surface and began
toexpresstheosteoblasticgenes.Theincreaseofcelldifferentiation
canhavecausedadecreaseofproliferation.Theseresultsconfirmed
the noncytotoxicity of the sapelli-based SiC ceramics with a healthy
behaviorof the cells along the timeof culture.
Cell adhesion and morphology was analyzed by SEM (Fig. 2.5).
First, it is important to notice the microstructural properties of this
bioinspired material (micrographies, Fig. 2.5a-c), where the long
tubular cells and sap channels (tracheae), used by the angiosperm
species to transport and store nutrients, can be clearly observed. 15
On the first day of incubation (Fig. 2.5a,d), cells appeared closely
attachedtotheSiCceramicswiththeflattenedmorphologytypicalof