Droplet Microfluidics Enables Tracing of Target Cells at the Single-Cell Transcriptome Resolution

Abstract

The rapid promotion of single-cell omics in various fields has begun to help solve many problems encountered in research, including precision medicine, prenatal diagnosis, and embryo development. Meanwhile, single-cell techniques are also constantly updated with increasing demand. For some specific target cells, the workflow from droplet screening to single-cell sequencing is a preferred option and should reduce the impact of operation steps, such as demulsification and cell recovery. We developed an all-in-droplet method integrating cell encapsulation, target sorting, droplet picoinjection, and single-cell transcriptome profiling on chips to achieve labor-saving monitoring of TCR-T cells. As a proof of concept, in this research, TCR-T cells were encapsulated, sorted, and performed single-cell transcriptome sequencing (scRNA-seq) by injecting reagents into droplets. It avoided the tedious operation of droplet breakage and re-encapsulation between droplet sorting and scRNA-seq. Moreover, convenient device operation will accelerate the progress of chip marketization. The strategy achieved an excellent recovery performance of single-cell transcriptome with a median gene number over 4000 and a cross-contamination rate of 8.2 ± 2%. Furthermore, this strategy allows us to develop a device with high integrability to monitor infused TCR-T cells, which will promote the development of adoptive T cell immunotherapy and their clinical application.

Unveiling the Potential of Single‐Cell Encapsulation in Biomedical Applications: Current Advances and Future Perspectives

“…Yang Liu et al [128] Emulsification (water-oil) DMEM or RPMI-1640 T2, Jurkat, NIH/3T3 (CRL-1658), and 293 T…”

Proteomics Methodologies: The Search of Protein Biomarkers Using Microfluidic Systems Coupled to Mass Spectrometry

“…The advantages of this technology are the size and quantity of picoliter droplets with faster and more precise reaction times compared to the level of single molecule in each droplet [ 71 ]. Furthermore, the droplets can provide an environment biocompatible for live cell experiments, ensuring advances in single studies [ 72 , 73 ] and the cultivation of cells [ 74 ]. For example, Utech et al presented that alginate hydrogel droplets could provide a three-dimensional cell culture matrix, providing the nutrients and structural support required for the cells.…”

SeParate: multiway fluorescence-activated droplet sorting based on integration of serial and parallel triaging concepts

“…5,10,11 Because FADS platforms manipulate and sort intact droplets, they allow for the sorting of cells based on their secretion products and products of enzymatic reactions in addition to fluorescent cells. 10 Since every droplet acts as an isolated reaction chamber, FADS enables sorting in highly parallelized experiments where it has been employed either as the sole droplet manipulation technique 10,12 or integrated with other complex droplet manipulation techniques such as picoinjection, 13,14 droplet merging, 15 incubation 16,17 and droplet dispensing. 18,19 Moreover, in FADS platforms, a high-speed camera enables the visualization of each droplet sorting event which is only recently made possible for FACS with the more expensive FACSDiscover™.…”