Lab-on-Chip for Cell Sorting: Main Features and Advantages of Inertial Focusing in Spiral Microchannels

Inertial focusing based Lab-on-Chips represent nowadays a promising technology for cell sorting in various applications, thanks to their coherence with the ASSURED criteria recommended by the World Health Organization, being: Affordable, Sensitive, Specific, User-friendly, Rapid and Ro-bust, Equipment-free and Delivered. Inertial focusing in spiral microchannel can offer a rapid, portable and ease of prototyping solution for cell-sorting. In literature, different geometries of microfluidic channel have been investigated to understand how hydrodynamic forces, due to primary and secondary flow, influence particle focusing. The balancing of these forces in spiral microchannels allows for high throughput and filtration efficiency across different particle and sizes. The understanding of such mechanism represents a key aspect to address the prototyping of spiral devices for the target application. A clear, complete and orderly overview in the current literature is lacking. For this reason, we aim to compare the main features of inertial focusing depending on various cross-section (rectangular, trapezoidal, triangular, hybrid) in spiral devices. Additionally, details about materials and prototyping techniques will be provided. This review study will provide readers a comprehensive overview of current research, guiding future ex-perimentation by expediting the selection of spiral geometries and materials based on the type of particle to be separated.