3D-Printed Hydrodynamic Focusing Lab-on-a-Chip Device for Impedance Flow Particle Analysis

Abstract

Particles analysis, such as cell counting and differentiation, are widely used for the diagnosis and monitoring of several medical conditions, such as during inflammation. Three-dimensional-printed lab-on-a-chip (LOC) devices, which can utilize one of the cell counting methods, can bring this technology to remote locations through its cost-efficient advantages and easy handling. We present a three-dimensional-printed LOC device with integrated electrodes. To overcome the limited resolution of a 3D printer, we utilized a flow-focusing design. We modeled and simulated the mass transfer and flow dynamics in the LOC by incorporating a flow-focusing design and reached an optimal channel diameter of 0.5 mm, resulting in a flow-focusing distance of <60 µm. We also used electrochemical impedance spectroscopy to enable the dependence of the electrode–solution interface on the flow-focusing properties. Finally, we highlighted the proof-of-concept detection of microspheres (6 µm diameter), which model biological cells that flow in the channel, by recording the electrochemical impedance at 10 kHz, thus showing the potential of a future point-of-care (POC) device.