Smart Hydrogel Microfluidics for Single‐Cell Multiplexed Secretomic Analysis with High Sensitivity

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2018-12, Vol.14 (49), p.e1802918-n/a
• Main Authors: Hsu, Myat Noe, Wei, Shih‐Chung, Guo, Song, Phan, Dinh‐Tuan, Zhang, Yong, Chen, Chia‐Hung
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Biosensors; Cytokines; droplet microfluidics; Heterogeneity; hydrogel microparticles; Hydrogels; Immunoassay; immunofluorescence assays; Immunosensors; Interleukins; Microfluidics; Microparticles; Nanotechnology; Phase transitions; Proteins; Rangefinding; Secretions; Sensitivity analysis; signal enhancements; single cell protein secretions
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201802918

Secreted proteins determine a range of cellular functionalities correlated with human health and disease progression. Because of cell heterogeneity, it is essential to measure low abundant protein secretions from individual cells to determine single‐cell activities. In this study, an integrated platform consisting of smart hydrogel immunosensors for the sensitive detection of single‐cell secretions is developed. A single cell and smart hydrogel microparticles are encapsulated within a droplet. After incubation, target secreted proteins from the cell are captured in the smart hydrogel particle for immunoassay. The temperature‐induced volume phase transition of the hydrogel biosensor allows the concentration of analytes within the gel matrix to increase, enabling high‐sensitivity measurements. Distinct heterogeneity for live cell secretions is determined from 6000 cells within 1 h. This method is tested for low abundant essential secretions, such as interleukin‐6, interleukin‐8, and monocyte chemoattractant protein‐1 secretions of both suspended cells (HL60) and adherent cells (MCF7 and MDA‐MB‐231). This platform is highly flexible and can be used to simultaneously measure a wide range of clinically relevant cellular secretions; it thus represents a novel tool for precise biological assays. An integrated platform where single cells are encapsulated with smart hydrogel immunosensors within droplets is developed. Temperature‐induced volume phase transition of poly (N‐isopropylacrylamide) hydrogel particles allows analyte concentration within the gel matrix, enabling rapid signal amplification. With this platform, live single‐cell secretions of the multiple cytokines are analyzed, revealing distinct single‐cell secretion heterogeneity.