Measurement of resistance of insertion into fertilized minipig ova in microinjection

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 09490039
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 広領域
• Research Institution: Tokyo Denki University (1999); National Cardiovascular Center Research Institute (1997-1998)
• Principal Investigator: MIYAWAKI Fujiio Tokyo Denki University, College of Science and Engineering, Dept of Biotechnology, Professor, 理工学部, 教授 (50174222)
• Co-Investigator(Kenkyū-buntansha): TANIGAWA Manabu CSK Research Park, Director, 部長 ; OMATA Sadao Nihon University, College of Engineering, Proffessor, 工学研究所・工学部, 教授 (90060186) ; TSUJI Takayuki University of Tokyo, Graduate School of Frontier Sciences, Professor, 大学院, 教授 (00075764)
• Project Period (FY): 1997 – 1999
• Keywords: Tactile sensor / Resonance frequency / Insertion resistance / Microinjection / Recombinant gene transfer / Micropipette / Piezo-electric transducer

Research Abstract

The microinjection method for recombinant gene transfer needs and expert. To make it more efficient and even automatic, we investigated whether the resistance of insertion into a fertilized egg with a micropipette in microinjection could be detected by measuring a change in resonance frequency of an ultrasonically-vibrated micropipette that was fixed to a tactile sensor made of a piezoelectric transducer (PZT).
Significant frequency changes were observed in some eggs, but not in others. This poor reproducibility of detection of frequency shift was resulted from a way of fixation between the vibrator and micropipette. Because the two parts were united with glue, this fixation frequently caused both a misalignment of the two parts and a shift of phase angle, thereby impeding the sympathetic vibration.
The vibrated micropipette was, however, found to easily enter the eggs without a sharp depression of the cell body. Depression rates (rates of the depth of depression over the original cell diameter), which were measured using a single micropipette with and without vibration, were 11% and 40%, respectively (P < 0.0001, Student's t-test).
The glue fixation also required disposal of expensive tactile sensors and repeat of complex calibration, thereby limiting the number of experiments. In the final year, we have developed a new tactile sensor that can allow an easy installation of a micropipette by only passing it through the sensor. Because only one micropipette every 20-30 commercially-available ones was found to fit the tactile sensor, the present sensor still remains to be improved.
In this project, so far, we have not published any paper, mainly because a lot of hardware problems have retarded accumulation of data worthe reporting. However, because we have solved some problems, we are now obtaining some fruitful results and will publish some papers in the near future.