Figure 2. Specialized fluorescence techniques for single-cell analysis.

(A) Determination of traction forces that a cell is exerting on a substrate. Here, a technique based on Förster resonance energy transfer (FRET) is used for the determination of cell traction forces exerted on the surface. Besides localization of the force variation within a single cell, the differences between cells can be identified. Adapted with permission from Blakely, B. L.; Dumelin, C. E.; Trappmann, B.; McGregor, L. M.; Choi, C. K.; Anthony, P. C.; Duesterberg, V. K.; Baker, B. M.; Block, S. M.; Liu, D. R.; Chen, C. S. Nat. Methods 2014, 11, 1229–1232 (ref ⁶³). Copyright 2014 Nature Publishing Group. (B) Analysis of the single cell transciptome. Multiplexed error-robust fluorescence in situ hybridization (MERFISH) of roughly 15 00 cells allows for sequential analysis of 130 RNA targets. A small portion of these measurements is depicted in the images numbered 4–11. Adapted with permission from Moffitt, J. R.; Hao, J.; Wang, G.; Chen, K. H.; Babcock, H. P.; Zhuang, X. Proc. Natl. Acad. Sci. U. S. A. 2016, 113, 11046–11051 (ref ⁶⁴). Copyright 2016 National Academy of Sciences. (C) Multiplexed analysis of biomolecules. The combination of single-cell capture in microchambers, the use of antibody barcode arrays and three-color fluorescence microscopy facilitated the parallel detection of up to 45 parameters on the single-cell level. Adapted with permission from Lu, Y.; Xue, Q.; Eisele, M. R.; Sulistijo, E. S.; Brower, K.; Han, L.; Amir, E. D.; Pe’er, D.; Miller-Jensen, K.; Fan, R. Proc. Natl. Acad. Sci. U.S. A. 2015, 607–615 (ref ⁶⁵). Copyright 2015 National Academy of Sciences. (D) Single-cell Western blotting for analysis of selected proteins of single cells. Adapted with permission from Hughes, A. J.; Spelke, D. P.; Xu, Z.; Kang, C.-C.; Schaffer, D. V; Herr, A. E. Nat. Methods 2014, 11, 749–755 (ref ⁶⁶). Copyright 2014 Nature Publishing Group.