In vitro studies of platelet adhesion on laser-treated polyethylene terephthalate surface

In order to improve blood compatibility, the surfaces of polyethylene terephthalate (PET) were treated using CO2 pulsed and KrF excimer lasers. The physico-chemical characterization of the laser-treated PET surfaces was carried out through attenuated total reflectance infrared spectroscopy and contact-angle measurements. The hemocompatibility of the laser-irradiated PET films was examined in vitro to evaluate their capability of inducing platelet adhesion in comparison with unmodified PET. The number of adhered platelets was determined by lactate dehydrogenase (LDH) activity measurement. Platelet adhesion on the untreated PET was relatively high compared to the laser-treated samples. Laser irradiation of PET surface reduced the number of adherent platelets and prevented platelet spreading on the surface. Reduction of platelet adhesion was attributed to the change in morphology, chemical structure, and crystallinity of the PET surface due to laser irradiation with various numbers of pulses. The morphology of adhered platelets on the PET surfaces was investigated by scanning electron microscopy (SEM). The SEM observations were consistent with the results obtained from LDH activity measurement.