These points help to make exact calibration of the FRET-based actinin tension sensor method hard. cells treated with calyculin A and Y-27632 tended to become larger and smaller, respectively, than that of control cells. Cell traction force significantly correlates with total cell retardation (for definition of the central and edge areas). The retardation in the central region (0.18??0.10?nm) is significantly larger than that in the edge region (0.11??0.08?nm). Open in a separate window Number 5 Distribution of cell retardation, state. Retardation measurement enables the evaluation of the phenotype of VSMCs based L-Azetidine-2-carboxylic acid on their contractility. Because phenotypic changes of VSMCs are found in vascular diseases, such as atherosclerosis11, hypertension12, and aneurysms13, measurement of retardation could be useful for evaluating the pathophysiological state of VSMCs. To day, the phenotype of VSMCs has been confirmed by -SMA25, SM2226, and calponin26 staining, a process that requires fixation. Fixation not only kills cells but also constitutes a IL18BP antibody time-consuming and expensive process. As an alternative to staining phenotype markers, contractile causes can be assessed in living cells using a FRET-based actinin pressure sensor27 method. In this method, deformation of actinin, which diagonally bundles actin filaments, is evaluated. The results are consequently affected by the bundling angle of actinin. To the best of our L-Azetidine-2-carboxylic acid knowledge, it remains unclear how variable the bundling angle is. The results L-Azetidine-2-carboxylic acid also switch if there is a shear between the bundles of actin filaments. These points make exact L-Azetidine-2-carboxylic acid calibration of the FRET-based actinin pressure sensor method hard. Compared to those methods, our method is definitely capable of very easily and quantitatively evaluating the contractility and phenotype of living VSMCs. Furthermore, retardation allows single cell analysis inside a pool of cells to identify cells having a phenotype of interest. In the future, cell retardation measurement might be used to evaluate pharmacological effects on cells. Retardation is improved from the contraction of SFs, as demonstrated in Fig.?2b. The increase in contraction might be caused by an increase in the amount of myosin intercalated with actin. Software of calyculin A induces contraction of SFs in clean muscle mass28 and raises CTF29. Interestingly, Peterson and represent the number of dishes and cells, respectively. Supplementary info Movie 1(555K, avi) Movie 2(664K, avi) Movie 3(865K, avi) Supplemental Info(430K, pdf) Acknowledgements This work was supported in part by JSPS KAKENHI (Nos JP16K12871 and JP18K19912) and unique operational grants from your Nagoya Institute of Technology. Author Contributions S.S., M.N. and T.M. published the main manuscript. S.S. performed the experiment in Number 1. E.M. performed the experiments in Numbers 2 and 3. M.H. performed the experiments in Numbers 4 and 5. All the authors examined the manuscript. Notes Competing Interests L-Azetidine-2-carboxylic acid The authors declare no competing interests. Footnotes Publishers notice: Springer Nature remains neutral with regard to jurisdictional statements in published maps and institutional affiliations. Supplementary info Supplementary info accompanies this paper at 10.1038/s41598-019-40578-7..