Design of a novel scissoring micro-stirrer for blood clot dissolution

In this paper, a novel micro-stirrer which can generate scissor type vibration to efficiently dissolve thrombus is developed. The micro-stirrer consists of a beam with a piezo transducer at one side and two bending slight beams at another side which is connected by a groove structure. The longitudinal force excited by the transducer transmits through the beam and reaches to the groove, converted into transversal bending moment due to the elastic wave reflection on groove's surface. Since the groove structure is inverse symmetrical, it generates opposite bending moments to make the slight beams move in opposite directions as a scissor. Comparing with our previous research, the desired vibration mode is not influenced by the stirrer's length, so the proposed micro-stirrer could be designed any length for narrow blood vessels application. Further the vibrating frequency of the scissor can be designed easily for different thrombus dissolution purpose. In this paper, the design idea was firstly presented, and the mode shape and various output frequencies of the stirrer were verified by FEM models. Next, a prototype of micro-stirrer was fabricated, and its vibration characteristic was tested by a vibration scanning experiment. Finally, the high dissolution performance of the micro-stirrer was verified experimentally.