For biomedical applications,
a number of ceramic coatings have
been investigated, but the interactions with the components of living
system remain unexplored for oxycarbonitride coatings. While addressing
this aspect, the present study aims to provide an understanding of
the biocompatibility of novel SiC
x
N
y
O
z
coatings that
could validate the hypothesis that such coatings may not only enhance
the cell–material interaction by re-endothelialization but
also can help to reduce bacterial adhesion and activation of blood
cells. This work reports the physicochemical properties, hemocompatibility,
endothelialization, and antibacterial properties of novel amorphous
SiC
x
N
y
O
z
coatings deposited on commercial pure titanium
(Ti) by radiofrequency (RF) magnetron sputtering at varied nitrogen
(N2) flow rates. A comparison is made with diamond-like
carbon (DLC) coatings, which are clinically used. The surface roughness,
surface wettability, nanoscale hardness, and surface energy of SiC
x
N
y
O
z
coatings were found to be dependent on the nitrogen
(N2) flow rate. Importantly, the as-deposited SiC
x
N
y
O
z
coatings exhibited much better nanoscale hardness and scratch
resistance than DLC coatings. Furthermore, Raman spectroscopy analysis
of the SiC
x
N
y
O
z
coating deposited on Ti showed a change
in the graphitic/disordered carbon content. Cytocompatibility and
hemocompatibility properties of the as-deposited SiC
x
N
y
O
z
coating were evaluated using the Mus musculus lymphoid endothelial cell line (SVEC4-10) and rabbit blood in vitro. WST-1 assay analysis showed that these coatings,
when compared to DLC, exhibited a better proliferation of endothelial
cells, which can potentially result in improved surface endothelialization.
Furthermore, qualitative and quantitative analyses of immunofluorescence
images revealed a dense cellular layer of SVEC4-10 on SiC
x
N
y
O
z
coatings, deposited at 15 and 30 sccm nitrogen flow rates.
As far as compatibility with rabbit blood is concerned, the hemolysis
of the SiC
x
N
y
O
z
coatings was less than 4%, with slightly
lower values for coatings deposited without N2 flow. The
SiC
x
N
y
O
z
coatings support less platelet adhesion
and aggregation, with no signature of morphological deformation, as
compared to the uncoated titanium substrate or DLC coatings. Furthermore,
SiC
x
N
y
O
z
coatings were also found to be effectively
extending the blood coagulation time for a period of 60 min. The antimicrobial
study of as-deposited SiC
x
N
y
O
z
coatings on E. coli and S. aureus bacteria revealed the effective inhibition of bacterial proliferation
after 24 h of culture. An attempt has been made to explain the cyto-
and hemocompatibility properties with antimicrobial efficacy of coatings
in terms of the variation in the coating composition and surface energy.
Taken together, we conclude that SiC1.3N0.76O0.87 coating having a roughness of 17 nm and a surface
free energy of 54.0 ± 0.7 mN/m can exhibit the best combination
of hardness, elastic modulus, scratch resistance, cytocompatibility...
