The microscopic penetration system driven by the ultrasonic vibration of the piezoelectric ceramics

The nuclear transfer operation is the key step in the biological cloning experiment, and the crucial challenge to the nuclear transfer technology is to make no damage to the inner cell membrane while penetrating into the outer zona pellucida of the oocyte. The current study abroad generally uses the pipette with a blunt tip to vibrate ultrasonically when slightly touching the zona pellucida of the oocyte, which would be penetrated into as soon as its fatigue limit is reached. However, in order to enhance the interaction intensity, a section of mercury is usually introduced into the fine end of the pipette, which would bring great hidden danger to the experimental operation. This paper has designed and put up a microscopic penetration system driven by ultrasonic vibration of the piezoelectric ceramic, which would work successfully without mercury and still keep the high energy of the output of the system. Meanwhile, its vibration frequency and amplitude is adjustable at a large range. The experimental results of the metaphase II (MII) mouse oocytes have shown that this penetration system is able to penetrate into the zona pellucida without the conventional mercury column in the fine tip of the pipette, and the whole penetration process only contributes to subtle deformation of the oocyte, effectively reducing the compression to its inner tissue. Although the 2μm-pipette is a little thin to the unclear transfer experiment, which may somehow bring limitations, the elimination of mercury has largely improved the security and maneuverability of the experiment, laying a foundation for the further study.