An updated review on particle separation in passive microfluidic devices

Particle separation has been extensively studied in recent years in a wide range of sciences, especially in the field of medicine and biotechnology. On the other hand, the topic has been considered in the context of interdisciplinary research; hence, many experiments have been carried out in this field. Particle separation is used to track particles during the drug-delivery process, the direction of the droplets in a specified path, etc. Both numerical and experimental methods have been used for separating and sorting different particles. Particle separation is performed using both active and passive techniques. In the present work, various passive techniques of particle separation are explained and compared to evaluate the separation efficiency, throughput rate, and clogging in microfluidic devices. The present paper focuses on the investigations conducted in particle separation between 2015 and 2020.