Biomedical Engineering Reference
In-Depth Information
8.3 Polyurethane textured surfacewith different length of fibres: (a) 25, (b) 50,
(c) 100m(Fujisawa et al., 2000). (Reprintedwith permission of JohnWiley&
Sons, Inc.)
create a master negative mould of patterned cavities, to fabricate a polyurethane
textured surface (Zapanta et al., 2006). Argon plasma etching is also used to
manufacture micropatterns on titanium oxide films, which is accomplished by
plasma immersion and deposition (Jing et al., 2007).
For excellent biocompatibility, smooth titanium surfaces are textured with
titanium microsphere coatings (smooth surface) and the Dacron portions of the
inlet and outlet cannulas are rough flocked surfaces in HeartMate II. Having
both smooth and rough surfaces in a same device is considered to be beneficial
(Griffith et al., 2001).
However, there are a couple of drawbacks for the textured-surface method.
The textured surface does not work properly in terms of biological requirements
for the small opening areas in VADs such as conduits (Fig. 8.4). For instance,
serious thrombosis has been reported for HeartMate II axial flow pumps (Farrar
et al., 2007).
8.6
Preparation and testing for biocompatibility
and haemocompatibility
There is no generalized test for the evaluation of biological response to artificial
material due to the complexity of the reaction mechanisms of blood and tissue.
