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Abstract
It is believed that the blood compatibility of artificial
material are greatly influenced by the material's surface
properties. Henceforth, plasma-induced graft polymerization
technique is employed to modify polyethylene surface properties
with an aim to improve its blood compatibility.
Methacryloxyethyl phosphate(MOEP) is used as the monomer in this
study in order to incorporate phosphate functionalities onto PE
surface. Oxygen plasma
is used to active the substrate with the formation of surface
peroxide groups. Oxygen pressure, duration of plasma and RF
input power are varied throughout the study. It was found that
the amount of surface peroxide group, determined by DPPH method,
increases with oxygen pressure and RF input power , and
decreases with duration of plasma. Then, the virgin PE and
plasma-activated PE(500mtorr、25watts、10mins and 100mtorr、25
watts、5mins) were chosen for further MOEP polymerization
reaction by 15min、2hr、4hr、8hr of UV irradiation.(0.01 wt%
riboflavin was added into monomer solution , and nitrogen were
bubbling for 30mins.) After polymerization, static contact
angle, ATR-FTIR＆ ESCA analysis indicate the amount of grafted-
MOEP increases with UV irradiation and the amount of surface
peroxide groups. In vitro
platelet adhesion studies have shown plasma-activated PE
exhibited high level of platelet adhesion and activation. After
MOEP was grafted onto PE surface, the number of adherent
platelet increased slightly with the duration of UV irradiation.
There were no significant change in the number of adherent
platelet between 4 and 8 hours of UV irradiation. Furthermore,
it was also found that the degree of platelet activation in
MOEP-grafted PE was less than the plasma-activated PE. It seems
that negative charge characteristic of phosphate functional
group or its chemical structure plays some important roles for
platelet adhesion and activation.
【key words】plasma-induced graft polymerization、MOEP、blood
compatibility
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