AI-Sort
The PDMS droplet sorting microfluidic device consist of three key modules, droplet generation, spacer oil junction and a sorting region. Generation of droplets was achieved using flow focusing module. All fluids were actuated using a pressure controller. In the middle portion of the device, a space oil junction was added to space the droplet apart. Pressure flow was adjusted accordingly to prevent droplet generated from flowing into the spacer oil channel. Sorting of droplets were done using an DC electrical field.
The device was observed under an inverted microscope equipped with a high-speed camera. After the images are captured from the camera, they were processed by the computer with droplet classified. The computer then sends a signal to a DAQ which controls the droplet sorting behaviour.
The AI module is trained offline with pre-labelled training samples. A model is then developed and validated using a separate video of unlabelled droplets and repeatedly trained until accuracy of 99% is achieved. During online classification, if single particle droplet is detected, iDrops system triggers an electric pulse for DEP sorting. Otherwise, no actuation occurs and the droplet flows to the waste channel.
Our system can process the droplet at a maximum frequency of 270Hz with an accuracy of 98%.
