Exploring the collagen nanostructure of dermal tissues after injury

•Collagen alignment was different between normal tissue and scar tissues at nanoscale.•Collagen alignment was also different among the different locations of scar tissues at nanoscale.•SAXS and WAXS are excellent tools to demonstrate the nano-structure of the tissues, compared with the TEM and SEM. Scar often occurred during wound repair. It was known that there were differences in collagen structure in dermal tissues at millimeter scale and micron scale, however, it was not known whether there were differences in collagen structure in dermal tissues at nanoscale during wound repair. In order to compare the difference at nanoscale, skin samples from patients were selected, the control groups were the normal skin from the same patients. These samples were tested by the small angle X-ray scattering techniques (SAXS) and wide angle X-ray scattering (WAXS) techniques. The transmission electron microscopy (TEM) was used as a comparison. The results showed that there were not only significantly differences between the normal tissue and scar tissue, but also between the center and the margin of the scar tissue at nanoscale by SAXS and WAXS, which was not demonstrated by other studies. These findings demonstrated that the SAXS and WAXS were excellent tools to detect the collagen structure at nanoscale and the orientation of the collagen alignment, which was beneficial for skin tissue engineering and skin regenerative medicine.