Biomedical Engineering Reference
In-Depth Information
(b)
(a)
FIGURE 2.2
(a) Four macro-textured total hip replacement implant femoral components prior to hydroxyapatite coating, and
(b) a new macro-textured and hydroxyapatite coated advanced TSI stem design total hip replacement implant
licensed to Omni Life Science by CDD, LLC, Chagrin Falls, Ohio, USA.
on the response to the implant surface, and during the past 40 years three terms have been
defined, which describe a biomaterial with respect to the tissues' responses: bioactive, bio-
inert, and bioresorbable (Hulbert et al. 1970; Heimke and Griss 1980; Oonishi et al. 1988;
Hench 1991; LeGeros 1991).
Bioactive refers to a material which, upon being placed within the human body, interacts
with the surrounding bone and, in some cases, even soft tissue. Bioinert refers to any mate-
rial which, once placed within the human body, has a minimal interaction with its sur-
rounding tissue; examples include stainless steel, titanium, alumina, partially stabilized
zirconia, and ultrahigh molecular weight polyethylene. Bioresorbable refers to a material
which, upon placement within the human body, begins to dissolve or to be resorbed and
slowly replaced by the advancing tissues (e.g., bone).
The main factors in the clinical success of any biomaterial are its biofunctionality and
biocompatibility, both of which are related directly to tissue/implant interface interactions.
This approach is currently being explored in the development of a new generation of nano-
bioceramics with a widened range of medical applications (Dorozhkin 2009).
The improvement of interface bonding by nanoscale coatings, based on biomimetics,
has been of worldwide interest during the past decade, and today several companies are in
early commercialization stages of new-generation, nanoscale-modified implants for ortho-
pedic, tissue regeneration, targeted slow drug delivery, ocular, and maxillofacial surgery.
The aim of this chapter is to provide a brief background on currently used coating meth-
ods and further detailed information relating to our choice of sol-gel derived nanohy-
droxyapatite coatings for medical applications.
FIGURE 2.3
Carbonate hydroxyapatite-nanocoated dental (top) implants and ACL fixation screws.
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