Electronic Thesis and Dissertation Repository


Master of Science


Medical Biophysics


James Lacefield


Micro-manipulators provide tools for researchers to improve workflow in common preclinical and clinical applications. Following drug delivery injections where drugs did not reach their target will squander research time, experimental animals and other resources. An ultrasound-guided robot developed at Robarts Research Institute was revised to implement closed-loop force feedback to compensate for tissue deformation during micro-interventions. Force sensors can detect puncture events as the needle penetrates tissue membranes, thereby reducing damage to surrounding tissues by preventing the needle from overshooting its target. Changing the angle of injection determined that the range of detectable forces during injections into tissue-mimicking phantoms suggests that sensors accurately measure projection of the needle force onto the vertical direction and are sensitive to puncture events through relatively thick (0.15 mm) membranes. Injections into mouse tissue yielded low success rates, suggesting different experimental designs are necessary to provide safer and less traumatic procedures, thus accelerating preclinical research.