RADARADARADARADA (RADA16-I)
peptide, consisting of 16 alternating hydrophobic and hydrophilic (also alternating negative and positive charges)
amino acids, forms extremely stable beta-pleated sheet structure and then self-assembles into nanofibers to produce high-order interwoven nanofiber scaffold
hydrogel. To investigate its
therapeutic effects, a
burn model of partial thickness-deep dermal injury (the deep second degree
burns) was performed at the dorsal skin of female Sprague-Dawley rats with an electrical scalding machine. The
wounds treated with either
RADA16-I or control materials were carefully examined at morphological, histological and cellular levels. We found that
RADA16-I can advance the time of eschar appearance and the time of eschar disappearance both by 3-5 days, and speed up
wound contraction by 20-30% compared with contrast groups (
chitosan, poly(DL)-
lactic acid (PDLA),
collagen I and the blank) without obvious
edema. Immunohistochemical studies showed that both FGF and
EGF were obviously expressed in nascent tissue such as epidermis and glands when
wounds were treated with the
RADA16-I after injury. When
peptide stock
solution was diluted from 10 to 0.17 mg/mL, atomic force microscopy (AFM) observation showed that the shape of
peptide nanofibers changed from the globular-pieces-clustered filaments with 4.8 +/- 0.38 nm in height, 61.6 +/- 6.10 nm in width and 708 +/- 80.2 nm in length, to general filaments with 1.4 +/- 0.36 nm, 17.5 +/- 1.13 nm and 1108 +/- 184 nm. The nanofiber surface porosity gradually decreased from 49-70% to 12-28%. These characteristics contribute to wound healing by offering an "ideal dressing" moist healing microenvironment and a nanofiber 3D scaffold. These results suggest that the self-assembling
peptide might be a promising
wound dressing with being simple, effective, and affordable.