Automation and control of biological samples and solutions at micro-scale is a major advantage for biochemistry analysis and biological diagnostics. Despite the known potential of miniaturization in biochemistry and biomedical applications, comparatively little is known about fluid automation and control at micro and nano-scale. Here, we study the electric field effect inside a fluidic channel and proper electrode structures with different patterns propose to form forward, reversal and rotational flows inside the channel. The simulation results confirmed that the ac electro-thermal flow is efficient for control and automation of high conductive solutions. In this research, the fluid pumping and mixing effects were numerically studied by solving physic-coupled electric, temperature, hydrodynamic and concentration fields inside a micro-channel. From experimental point of view, the electrode structures deposited on a silicon substrate and bonding to a PDMS micro-channel to form a micro-fluidic chip. A printed circuit board (PCB) is designed for providing the electrical signals to the electrodes and the bio-chip is mounted on the chip holder part. The motions of fluorescent particles in pumping and mixing mode were captured by using a CCD camera (The experimental test setup and some of the experimental and numerical results are indicated in Figure 1). By measuring the frequency response of the fluid and exciting the electrodes with proper voltage, the fluid motions (including pumping and mixing effects) are observed inside the channel through the CCD camera. Based on the results, there is good agreement with the experimental and simulation studies.
Audience Takeaway Notes:
- Investigation of frequency effect on electrokinetic excitation method.
- How to manipulate fluid sample inside a microfluidic chip for biologivcal applications?
- How to control fluid speed and flow direction inside a microfluidic chip?
- How to use a FEM simulation tools to check the possibility of your idea?
- How to fabricate and develop a microfluidic bio-chip?