New optical sensor for monitoring the micropipette motion

A novel noncontact sensor is developed to monitor the displacements of a drawn glass pipette tip. These pipettes are commonly used in various cellular-injection applications, from in vitro fertilization to cloning. The physics of the underlying cellular-piercing process, however, is quite complex and presently not fully understood primarily due to the absence of appropriate motion sensors. A high-sensitivity noncontact sensor is needed to study this delicate microdynamics. We report here on an optical microdevice, which is developed for this objective. In the core of the sensing, properly positioned four photodiodes receive the light, which emanates from the target micropipette. Appropriate electronics and sensitivity-enhancement techniques are also utilized. The experimental results are presented from a preliminary test study on a prototype setup. These results are very encouraging in that we can already report submicrometer-level motion-detection capability.