The fractal dimension (FD) is another measure to quantify the organization of structures appearing in a microscopic image. FDs values close to 2 indicate smoother surfaces, and values close to 3 indicate a high degree of roughness. Fractal analysis can be performed either on grayscale images or binary (black and white) images. In the case of the analysis carried out on samples within the experiment, we considered the case of grayscale images. We performed fractal analysis by ImageJ's FracLac plugin, which computes the fractal dimension using the "box counting" method. With this method, the image is covered by successively smaller squares. At each step, the number of squares containing the image elements is counted. Such image elements are different in pixel intensity in the area occupied by the squares. The fractal dimension, which is a measure of the complexity of the image, is calculated as the slope of the regression line of the log-log plot of the difference in pixel intensity in the area covered by the squares and the size of the squares.