High intensity near infrared femtosecond laser is a promising tool for three-dimensional processing of biological materials. During the processing of cells and tissues, long lasting gas bubbles randomly appeared around the laser focal point, however physicochemical and mechanical effects of the gas bubbles has not been emphasized. This paper presents characteristic behaviors of the gas gabbles and their contact effects on cell viability. High-speed imaging of the gas bubble formation with various additives in physiological medium confirms that the gas bubble consists of dissolved air, and amphipathic proteins stabilize the bubble surface. This surface protective layer reduces interactions of gas bubbles and cell membranes. Consequently, the gas bubble contact does not cause critical effects on cell viability. On the other hands, burst of gas bubbles stimulated by an impact of femtosecond laser induced cavitation can lead to liquid jet flow that might cause serious mechanical damages on cells. These results provide insights for the parameter of biological tissue processing with intense fs laser pulses.

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与细胞培养基中飞秒激光击穿产生的气泡接触相关的细胞活力评估

高强度近红外飞秒激光是一种很有前途的生物材料三维加工工具。在细胞和组织的加工过程中，激光焦点周围随机出现持久的气泡，但并未强调气泡的物理化学和机械效应。本文介绍了气隙的特征行为及其对细胞活力的接触影响。在生理介质中使用各种添加剂对气泡形成的高速成像证实了气泡由溶解的空气组成，两亲性蛋白质稳定了气泡表面。该表面保护层减少了气泡和细胞膜的相互作用。因此，气泡接触不会对细胞活力造成严重影响。另一方面，由飞秒激光诱导的空化作用刺激的气泡破裂可导致液体射流，这可能对细胞造成严重的机械损伤。这些结果为使用强飞秒激光脉冲的生物组织加工参数提供了见解。