Biomedical Engineering Reference
In-Depth Information
modification (see Section 8.5) is now a crucial factor for blood contacting
applications in the market.
Secondly, as mentioned before, different requirements are usually assigned to
the same biomaterial depending on the clinical applications and the required
mechanical/biomedical functionality of the mechanical device. For example,
ISO 10993 ± Part 4 (ISO, 2002) is a guide for the development of biomaterials
into a specific mechanical device. FDA approval is also only for the medical
device, not for the biomaterial used.
Table 8.1 shows selected commercially available TAHs and VADs as well as
corresponding materials and surface coatings. Table 8.2 shows some of the third
generation blood pumps and corresponding materials and surface coatings. As seen
on the list, titanium, titanium alloys and polycarbonate are the most used materials
for housing blood pumps. Different components of artificial hearts and VADs are
made of polyurethane. These components include mostly housing, chambers and
diaphragms. Bioactive surface coatings are noticeably dominant over others as a
blood-contacting surface for both second and third generation blood pumps.
Table 8.1 Some cardiac devices and corresponding materials and surface coatings
VAD
Continuous flow
Centrifugal pumps
Biomedicus Bio-Pump (Medtronic BioMedicus, Inc.)
Housing Polycarbonate
Optional coating Carmeda BioActive Surface or Trillium Biosurface
Sarns centrifugal pump (3-MHealth Care, Ann Arbor, MI)
Blood contact materials Acrylic, silicone rubber, silicone lubricant, nylon,
aluminium oxide
Housing Durable polycarbonate
Optional coating X Coating
TM
Evaheart (Eveheart Medical USA, Inc.) (long-term support)
Pump
Pure titanium
Entire blood-containing
Coated withMPC (commercially developed
surfaces
coating by NOF Corp. of Japan) or DLC
Inflow and outflow
Expanded polytetrafluoroethylene (ePTFE) or
cannula
polyester vascular graft
Seat ring
Silicon carbide (SiC)
Seal ring
Carbon graphite
Gyro Centrifugal
Prototype pump housing Polycarbonate, titanium
The male pivot bearing Stainless steel, alumina ceramic
The female pivot bearing Ultra-high molecular weight polyethylene
(UHMWPE), gamma ray irradiated high
molecular weight polyethylene (GIHMWPE),
polyethylene
Impeller
Polycarbonate, polyurethane
The shaft of the impeller
Alumina ceramic
Reservoir bag
Polyvinyl
Tubing
Polyvinylchloride
