**Abstract**

Detection of single particle has emerged as a noninvasive technique for diagnostic and prognostic patients with cancer suspected. Microfluidic impedance cytometry has been utilized to detect and measure the electrical impedance of single biological particles at high speed. The detailed information of single cells such as cell size, membrane capacitance, and cytoplasm conductivity also can be obtained by impedance measurement over a wide frequency range. In this work, we developed an integrated microneedle microfluidic device to detect and discriminate 9- and 16-μm microbeads. Two microneedles were utilized as measuring electrodes at the half height of the microfluidic device to perform measurement of electrical impedance under a presence of cells at the sensing area. Furthermore, this device was able to distinguish the cell concentration in the suspension fluid. The reusable microneedles were easy to be inserted and withdrawn from the disposable microfluidic. The ultrasonic cleaning machine has been used to clean the reusable microneedle with a simple cleaning process. Despite of the low-cost device, its capability to detect single particles at the sensing area was preserved. Therefore, this device is suitable for cost-efficient medical and food safety screening and testing process in developing countries.

**Keywords:** impedance, flow cytometry, microfluidics, microneedle, single cell
