Biomedical Engineering Reference
In-Depth Information
2
Blood interface biomaterials
X. ZHAO, J. M. COURTNEY and H. QIAN,
University of Strathclyde, UK
Abstract
: In this chapter, the blood response to the biomaterial is
reviewed, focusing on the use of plasticised poly(vinyl chloride) (PVC)
as an example for blood interaction. Hypotheses on designing an ideal
blood-compatible biomaterial are reviewed. Based on these hypotheses,
different approaches for modifi cation of biomaterial surfaces to achieve
improved blood compatibility are reviewed. Future trends in developing
a blood compatible biomaterial are discussed.
Key words
: blood-biomaterial interaction, surface modifi cation, blood
compatibility, plasticised poly(vinyl chloride) (PVC).
2.1
Introduction
A defi nition of a blood-biomaterial interaction is 'an interaction between
a biomaterial (device) and blood or any component of blood, resulting in
effects on the biomaterial (device), or on the blood, or on any organ or
tissue'. Such effects may or may not have clinically signifi cant or undesir-
able consequences.' (ISO/TC 194, 1991; Missirlis, 1992).
The highly complex 'blood-biomaterials' interaction has a multivariable
character (Courtney
et al.
, 1994). When a blood-biomaterial interface is
established, a rapid sequence of processes occurs. It is now generally
accepted that the processes can be divided arbitrarily into the following
groups of events (which partly occur simultaneously) (Dawids, 1993;
Courtney
et al.
, 1994):
1. Adsorption of plasma proteins onto the polymer surface.
2. Activation of the of the complement and kinin/kallikrein systems
(Murabayashi & Nosé, 1986), blood cells and intrinsic coagulation initi-
ated by the adsorbed proteins from the system.
3. Adhesion of cell components (thrombocytes, granulocytes and mono-
cytes) to the protein coating.
4.
Formation of fi brin onto the surface and also possible activation of the
fi brinolytic system (Sundaram
et al.
, 1994).
The blood-biomaterial interaction is infl uenced by many factors, including
the bulk and surface properties of the materials, the chemical and physical
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