Fig. 4. Correlation analysis of the single-cell spreading area and gene expression. (A) Images of single-cell spreading behavior and gene expression of ACTB, PFN1 and CFL1 on different stiffness substrates (4 kPa and 30 kPa). Scale bars, 25 μm. Inset: frequency histograms of RCA amplicons per cell detected. (B) The relationship of single-cell gene expression and cell spreading area for ACTB, PFN1 and CFL1, respectively (n > 100, mean ± s.d.; **P < 0.05, ‘r’ means the correlation coefficient of the single-cell spreading area and copy number per cell).