Abstract
Identification of characteristics of plaque in areas of disruption and cellular inflammation is critical in understanding the pathogenesis of acute coronary syndromes. However, techniques aimed at identifying vulnerable or inflamed plaques are not routinely available for use in vivo. In a novel approach, funded by the British Heart Foundation, we have developed lipid-based microbubbles with echogenicity at 40 MHz similar to that of commercial agents and we have conducted preliminary studies demonstrating that it is feasible to attach specific antibodies to their surfaces. We have also demonstrated that these antibody-loaded microbubbles bind to cell surfaces and that the resultant increase in echogenicity can be detected using high frequency ultrasound. However such results have been undertaken under no-flow conditions where the cells are grown on agar plugs and the microbubbles are attached to them in situ. By extending this work into a flow chamber and obtaining high resolution velocity patterns it will be possible to quantify the strength of the binding mechanisms between the microbubbles and cells. For this purpose, we applied to the British Medical Ultrasound Society for a pump-priming award to purchase a lens for a Laser Doppler Anemometry system, which could be used to obtain high-resolution velocity measurements within a prototype flow chamber. From these measurements the shear rate and, hence, shear stress at the surface of the agar plugs within the flow chamber could be calculated.