Design on MEMS-based 3D biochip for drug-released dispenser

In this study, the microfluidic emulsion biochip has been fabricated based on micro-electro-mechanical system technique which integrates microfluidic designed micro-pumps, micro-valves and nozzles with different micro-channels. The quantitative droplet nozzle with micro-pump controlled pressure plays a key role to determine the size of the micro-droplets. The designed 3D dispenser using PDMS material provides micro-channels for different samples in different layers. Drug-released process can be performed as follows: micro-pump is first actuated to store the desired fluid sample in the cavity, followed-by micro-valves compression, the sample is spread out through the nozzle and drops into the bottom channel. The features of this multiple sampling microfluidic chips are (1) quantitative droplets by micro-pump pressure control (2) volume of droplets (3) different samples without contamination. The oil-in-water (W/O) emulsion droplet is formed by a connected hydrodynamic focusing T-shaped structure. Similarly, the double emulsion droplets, water-in-oil-in-water (W/O/W) can be formed by using the second T-shaped structure at the intersection of the oil and the external water. The diameter of emulsion droplets strongly depend on the velocity of water or oil. A series of experimental works is conducted in this research.