TITLE:
The degradation behavior of silk fibroin derived from different ionic liquid solvents
AUTHORS:
Renchuan You, Ying Zhang, Yu Liu, Guiyang Liu, Mingzhong Li
KEYWORDS:
Silk Fibroin; Molecular Weight; Scaffolds; Degradation; Skin Tissue Engineering
JOURNAL NAME:
Natural Science,
Vol.5 No.6A,
June
14,
2013
ABSTRACT: Establishing an appropriate degradation rate
is critical for tissue engineering scaffolds. In this study, the degradation
rate of silk fibroin three-dimensional scaffolds was regulated by changing the molecular weight (MW) of the silk fibroin. The
solubility of silk fibroin depends primarily on the ionic ability of the
slovent to dissolve silk fibroin, therefore, we regulated the MW of the silk fibroin using LiBr, Ca(NO3)2 and CaCl2 to dissolve the silk fibers. SDS-PAGE
analysis showed that the MW of the CaCl2-derived
silk fibroin was lower than the MW produced using LiBr and Ca(NO3)2. In vitro and in vivo degradation results showed that the scaffolds prepared by
low-MW silk fibroin were more rapidly degraded. Furthermore, FTIR and amino acid analysis suggested that the amorphous regions were
preferentially degraded by Collagenase IA, while
the SDS-PAGE and amino acid analysis indicated that the scaffolds were
degraded into polypeptides (mainly at 10-30 kDa) and amino acids. Because the CaCl2-derived scaffolds contained abundant
low MW polypeptides, inter-intramolecular entanglement and traversing of molecular
chains in the crystallites reduced, which resulted in rapid degradation. The in vivo degradation results suggested
that the degradation rate of the CaCl2-derived scaffolds was better
matched to dermis regeneration, indicating
that the degradation rate of silk fibroin can be effectively regulated
by changing the MW to
achieve a suitable dermal tissue regeneration rate.