Development of local cell stimulation method using ultrasound exposure in presence of microbubbles

为了研究活细胞的机械转导，提出了一种新的细胞局部机械刺激技术。这种技术是利用施加在气泡上的声辐射力比施加在细胞上的声辐射力大的效应来刺激带有微米大小气泡的细胞。光学镊子被用来控制气泡的位置。用分离的乳鼠心肌细胞进行机械刺激，建立了细胞培养箱，用于超声辐照下的显微镜观察。超声辐照附着有微泡的心肌细胞，证实机械刺激产生室性早搏。用这种技术进行了评估心肌细胞不应期的实验，发现不应期随搏动频率的变化而变化，这表明所提出的技术在研究细胞对机械刺激的反应时是有用的。

A novel technique for local mechanical stimulation of cells was proposed to studymechanotransduction of living cells. A cell with an attached micron-sized bubble is stimulated by this techniqueby using the effect of larger acoustic radiation force being applied to the bubble than to the cell. Optical tweezerswere used to control the position of a bubble. Cardiac myocytes isolated from neonatal rats were used formechanical stimulation, and a cell culture chamber for microscopic observation under exposure of ultrasoundexposure was developed. Cardiac myocytes with attached microbubbles were irradiated with ultrasound, and thegeneration of premature ventricular contraction by the mechanical stimulation was confirmed. Experiments toevaluate the refractory period of the myocytes were carried out using this technique, and changes in the perioddepending on the beating frequency were found, suggesting the usefulness of the proposed technique for studying cell reactions to mechanical stimulation.