Laser Doppler anemometry measurements of the shear stresses on ultrasonic contrast agent microbubbles attached to agar.
Ultrasonic contrast agents are currently being developed to target and bind to specific areas of interest such as atheromous plaque. A microbubble has been developed in-house which can be targeted to attach to specific cell-lines. To assess the feasibility of using the microbubble in vivo, the shear stresses which the bound microbubbles can withstand need to be known. A flow chamber was developed for use with intravascular ultrasound (IVUS) and laser Doppler anemometry (LDA). Biotin was incorporated into the microbubble shells and streptavidin was used to attach them to agar. IVUS at 40 MHz was then used to image the attached microbubbles under steady flow at a range of flow rates from 75 to 480 mL min(-1) through a flow area of 9 mm(2). LDA was employed to find high resolution velocity profiles of the flow in the chamber at a selection of these flow rates and the shear stresses on the bubbles were calculated. The bubbles were found to remain attached to the agar for shear stresses of up to 3.4 Pa. This compares with mean physiological arterial shear stresses of less than 1.5 Pa for pulsatile flow.
Butler
Mairead B
MB
Department of Medical Physics, University of Edinburgh, Edinburgh EH16 4SB, UK. M.Butler@ed.ac.uk
Moran
Carmel M
CM
Anderson
Tom
T
Cunningham
Carrie
C
Ross
James A
JA
Easson
William J
WJ
Fox
Keith A A
KA
McDicken
W Norman
WN
D000362:Agar; D001161:Arteriosclerosis / Q000000981:diagnostic imaging; D001710:Biotin; D003287:Contrast Media; D006801:Humans; D017078:Laser-Doppler Flowmetry; D045423:Microbubbles; D011673:Pulsatile Flow; D012212:Rheology; D019809:Streptavidin; D013314:Stress, Mechanical; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods*
D003287:Contrast Media; D001710:Biotin; D000362:Agar; D019809:Streptavidin