Label-free active single-cell encapsulation enabled by microvalve-based on-demand droplet generation and real-time image processing

• Published in: Talanta (Oxford) Vol. 276; p. 126299
• Main Authors: Wang, Yiming, Wang, Yousu, Wang, Xiaojie, Sun, Wei, Yang, Fengrui, Yao, Xuebiao, Pan, Tingrui, Li, Baoqing, Chu, Jiaru
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.08.2024
• Subjects: Cell Encapsulation - methods; HeLa Cells; Humans; Image Processing, Computer-Assisted; Lab-On-A-Chip Devices; Microfluidic Analytical Techniques - instrumentation; Polystyrenes - chemistry; Single-Cell Analysis - methods
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2024.126299

Droplet microfluidics-based single-cell encapsulation is a critical technology that enables large-scale parallel single-cell analysis by capturing and processing thousands of individual cells. As the efficiency of passive single-cell encapsulation is limited by Poisson distribution, active single-cell encapsulation has been developed to theoretically ensure that each droplet contains one cell. However, existing active single-cell encapsulation technologies still face issues related to fluorescence labeling and low throughput. Here, we present an active single-cell encapsulation technique by using microvalve-based drop-on-demand technology and real-time image processing to encapsulate single cells with high throughput in a label-free manner. Our experiments demonstrated that the single-cell encapsulation system can encapsulate individual polystyrene beads with 96.3 % efficiency and HeLa cells with 94.9 % efficiency. The flow speed of cells in this system can reach 150 mm/s, resulting in a corresponding theoretical encapsulation throughput of 150 Hz. This technology has significant potential in various biomedical applications, including single-cell omics, secretion detection, and drug screening. [Display omitted] •A drop-on-demand technology is developed to achieve single-cell encapsulation.•Multivolume droplets are generated by continuously adjusting the activation time of the microvalve.•Real-time image processing is used for label-free detection.•High flow speed is achieved by setting on-chip microvalves in the oil phase.•The separate design of actuators and microfluidic chips is beneficial for reducing costs.