7 research outputs found
Bioactive glasses functionalized with polyphenols: in vitro interactions with healthy and cancerous osteoblast cells
Bioactive glasses are widely studied as biomaterials for bone contact applications.
In this research work, the opportunity to modify the surface of a bioactive
glass with polyphenols (gallic acid, and natural polyphenols extracted from red
grape skin and green tea leaves) has been investigated in order to induce a
selective anti-tumor activity in vitro. The presence of surface grafted molecules
has been optically proved by fluorescence microscopy exploiting their autofluorescence.
Direct and indirect cytotoxicity assays have been performed with
human bone osteosarcoma cells (U2OS) and human fetal pre-osteoblasts (hFOB),
as well as the quantification of oxygen and nitrogen reactive species (RONS)
engendered from cells in response to the materials. Finally, the DNA damage of
U2OS cells upon contact with the bioactive glass has been evaluated in order to
verify any selective cytotoxic activity of functionalized materials against cancer
cells. Results showed a selective cytotoxic activity of functionalized bioactive
glasses toward osteosarcoma cells that was particularly evident when cells were
cultivated directly onto glasses surface. Moreover, the presence of grafted
polyphenols increased the RONS production and induced a permanent DNA
damage on the U2SOS cells while they promote a certain anti-inflammatory
action toward hFOB. These preliminary results suggest polyphenols grafted
bioactive glasses as promising material for bone substitution in cancer
treatment
Early stage reactivity and in-vitro behavior of silica-based bioactive glasses and glass-ceramics
The surface reactivity of different sets of
glasses and glass-ceramics belonging to the SiO2\u2013P2O5\u2013
CaO\u2013MgO\u2013K2O\u2013Na2O system have been investigated.
The attention was focused on the role of their composition
on the bioactivity kinetics, in terms of pH modifications,
silica-gel formation and its evolution toward hydroxycarbonatoapatite,
after different times of soaking in simulated
body fluid. Glasses and glass ceramics have been characterized
by thermal analysis, SEM-EDS observations and
phase analysis (XRD). XPS measurements have been carried
out on the most representative set of sample in order to
evaluate the evolution of the surface species during the
growth of silica-gel and hydroxycarbonatoapatite. The
response of murine fibroblast 3T3 to the material before
and after a conditioning pre-treatment (immersion in SBF)
has been investigated on the same set of samples in order to
point out the role of the bioactivity mechanism on cell
viability. The main differences among the various glasses
have been related to the modifier oxides ratio and to the
MgO content, which seems to have an influence on the
glass stability, both in terms of thermal properties and
surface reactivity. The surface characterization and in vitro
tests revealed few variations in the reactivity of the
different glasses and glass-ceramics in their pristine form.
On the contrary, the different surface properties before and
after the pre-treatment in SBF seem to play a role on the
biocompatibility of both glass and glass-ceramics, due to
the different ion release and hydrophilicity of the surfaces,
affecting both cell viability and protein adsorption