Design and development of a local microelectrode puller for electrophysiology research in Thailand

Abstract

Fine glass capillaries (also called pipettes) have been extensively used in electrophysiologic method for decades as either a recording or stimulating microelectrode. Fabrication of the electrode requires a special puller. This work presents the initial design and development of a local glass capillary puller to serve electrophysiology research in Thailand. This instrument model was primarily designed for making bipolar-stimulating electrodes from two-barreled borosilicate glass capillaries, which will be used in the study of neuronal control of vascular tone. The main systems include the heating and the pulling components, which were designed to be operated in adjustable manner by users. The heat and pulling force were governed by the controlling current. The design was validated through experimental results. Appling 19A of heater current and 133 W of power for 60-90 second duration onto Kanthal-heating filament was sufficient to melt the glass. The pulling mechanism is generated by a vertical solenoid puller with adjustable force control system. The electrode feature was acceptable for performing in vitro experiment in a large blood vessel (e.g. human tissue). However, similar studies in the rodent of which vascular size is far smaller may require a sharper-tipped electrode. Limitations of the prototype model were also addressed for further improvements, including the limited pulling distance of the solenoid, the firmness of the holders for the heating filament and multi-barreled glass tubing, and the fluctuation of heating current. We anticipate that the invention of sophisticated life-science instrument could enhance multidisciplinary research collaborations in order to reduce overall investment on research instruments for our nation, and may help open a new avenue of production industry of sophisticated instrument in Thailand.