Biomedical Engineering Reference
In-Depth Information
benefi t most from such coatings is the intravascular device segment, where
the primary requirement for the coating is to mask the metallic surfaces from
coming directly in contact with blood and surrounding tissues, thereby minimiz-
ing the release of metallic ions into the surroundings (Muraleedharan and
Bhuvaneshwar, 2006 ).
DLC and TiN coatings with their excellent friction and wear properties make
them ideal candidates for articulating orthopedic implantations. The reduction in
friction and wear leads to formation of less debris. There can be a substantial
improvement over the current metallic biomaterials as one of the most promi-
nent failure modes of articulating orthopedic implants is aseptic loosening due to
continuous infl ammation caused by wear debris. The debris formed as a conse-
quence of the wear results in tissue infl ammation, osteolysis, and fi nally loosening
of the implants. In prosthetic joints, the coating material should be hard and inert
enough to prevent the wear out and corrosion. (Allen Mathew et al., 2001).
Diamond-like carbon coatings have been investigated for dental implant
applications (Olborska et al., 1994). It was observed that DLC layers showed sig-
nifi cant integration with the surrounding bone tissues. DLC coating might offer a
solution for infections caused by indwelling urinary tract catheters. Researchers
at three institutions are conducting experiments with very thin coatings of carbon
applied to urinary catheters that may help alleviate patients' discomfort and
infection risk.
21.10 FUTURE PERSPECTIVE
The DLC and TiN coatings are new entrants in the cardiovascular biomaterial
segment. Initial indications based on
in vitro
and animal experiments are very
encouraging, but use for specifi c applications will have to be validated, Especially
in the case of intravascular device segment, the main challenge is to ensure good
coating adhesion even under moderate plastic deformation of the substrate. This
will help many balloon mountable devices like vascular stents to be coated with
TiN and DLC. Another challenge will be to impart specifi c functionalities on the
surfaces to help loading of drugs for enhancing healing and incorporation.
ACKNOWLEDGMENTS
The authors wish to thank all staff members of the Division of Artifi cial Organs
for their active contribution in this work. We also wish to acknowledge the invalu-
able contributions the departments/divisions of Thrombosis Research, Histopa-
thology, Tissue culture, Toxicology, Engineering services,
in vivo
models & Testing
and Cardiovascular & Thoracic surgery of the Institute during the conduct of
various studies.
The authors wish to acknowledge the partial fi nancial support by the Indo-
French Center for the Promotion of Advanced Research (IFCPAR) and the
Department of Scientifi c and Industrial Research, Government of India. We wish
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