An on-chip imaging droplet-sorting system: a real-time shape recognition method to screen target cells in droplets with single cell resolution

Abstract

A microfluidic on-chip imaging cell sorter has several advantages over conventional cell sorting methods, especially to identify cells with complex morphologies such as clusters. One of the remaining problems is how to efficiently discriminate targets at the species level without labelling. Hence, we developed a label-free microfluidic droplet-sorting system based on image recognition of cells in droplets. To test the applicability of this method, a mixture of two plankton species with different morphologies (Dunaliella tertiolecta and Phaeodactylum tricornutum) were successfully identified and discriminated at a rate of 10 Hz. We also examined the ability to detect the number of objects encapsulated in a droplet. Single cell droplets sorted into collection channels showed 91 ± 4.5% and 90 ± 3.8% accuracy for D. tertiolecta and P. tricornutum, respectively. Because we used image recognition to confirm single cell droplets, we achieved highly accurate single cell sorting. The results indicate that the integrated method of droplet imaging cell sorting can provide a complementary sorting approach capable of isolating single target cells from a mixture of cells with high accuracy without any staining.

Rational design of a high-throughput droplet sorter

“…If the electrodes and the channel are chosen to be symmetric, droplets in the channel center only need to be moved by half the distance for reliable sorting (switching the field on the opposite electrode would then lead to a similar displacement in the other direction) This actuation can be achieved by always activating one of the two electrodes. Such a symmetric design strategy effectively doubles the sorting frequency and is used for example in the multiplexed sorter discussed by Girault et al 18 In summary, the combination of one active electrode and appropriately designed shielding electrodes allows for Fig. 3.…”

“…Second, the geometry of the microchannel ensures that the droplets deflected to different streamlines are actuated into the right outlet. Based on these simple considerations, many different electrode shapes have been designed for droplet sorters, 3,4,12,13,[15][16][17][18] reaching sorting throughputs of up to 30 kHz. 15 A part of the rich genealogy of sorter designs is presented in Fig.…”

From Mouth Pipetting to Microfluidics: The Evolution of Technologies for Picking Healthy Single Cells

“…However, such a method is a good way to solve the “chip‐to‐world” problem. On the other hand, imaging‐based computer vision was recently demonstrated for microfluidic devices, with and without a slow sorting strategy . In this manner, the picking process can be operated on demand.…”

Type 1 Diabetes Mellitus reversal via implantation of magnetically purified microencapsulated pseudoislets

“…Active sorting can be categorized, according to the actuation mechanism, as electric, acoustic, magnetic, pneumatic and thermal sorting (Adeyemi, 2017;Ahne Myklatun, Michele Cappetta et al, 2017;Girault, Kim et al, 2017;Wyatt Shields IV et al, 2015). Among all, magnetic actuation is the most commonly used method in many applications (Wyatt Shields IV et al, 2015;Xi et al, 2017).…”