A Microfluidic Sensor for Single Cell Detection and Counting Bull Sperms Cell

Abstract

A microfluidic sensor chip for bull sperm detection with ability of detection and counting is presented. The chip was fabricated by UV and soft lithography process in order to create electrodes and microchannel for cell alignment and delivery. Moreover, the chip was integrated with a pair of gold microelectrodes acted as a cell counter based on LCR-impedance circuit. Main objective of this specially designed circuit is reducing the large interface impedance of the microelectrodes, make them easy to use, for higher accuracy and efficiency in counting process. However other cells than those spermatozoa in semen also cause change of impedance when passing the pair of electrodes and interfere with the spermatozoa count. This work demonstrated that the change in electrical impedance is related to the size of cells passing through the electrodes, allowing distinguishable between spermatozoa and other cells, i.e. beads suspended in washing media. Work has been designed to measure average impedance of three samples; media, beads and spermatozoa investigated at signal frequency of 2 MHz, 2.5V. The averaged output impedances were 143.14 kΩ, 151.26 k$\Omega$, and 152.67 k$\Omega$, respectively. Then, these data were normalized as aspect to compare the differences between signal of beads and bull sperms. All analyzed values show consistencies of data with p-value lower than 0.05. This work provided important information as the device can be developed utilizing the impedance as a distinguishable cell-counter when spermatozoa and beads flow pass the area of detecting electrodes.