a) The adhesion force between the film and a single hADSC captured by a tipless AFM cantilever measured at the 1, 3, 5, 7, and 9 mm of the gradient film. The top and bottom of the box stand for the 75th and 25th percentile, individually. The middle line in the box stands for the median while the white cubic stands for the mean value. The upper and lower whiskers indicate the maximum and the minimum. The diamonds above boxes are outliers. The significant differences were determined by one-way ANOVA with Bonferroni test, n = 15, *. Inset: Optical microscopy image of a tipless cantilever with a single hADSC attached. b) The average number of jumps Nj at the gradient positions. c) The total number of unbinding events Nj + Nt at the gradient positions. d) The force of jumps Fj at the gradient positions. e) The force of tethers Ft at the gradient position. Fj and Ft are transferred into positive value. Error bars are the standard error of mean. The significance is labeled according to one-way ANOVA analyzed results, Bonferroni test, *. d) and e) are combination of density plot and box plot and the white dot stands for the median value.
