Papers by Keyword: RGD

Abstract: An elastin-like polymer (ELP) was designed by genetic engineering techniques to mimic the extracellular matrix (ECM). The precise control of the polymer sequence offered many advantages that allowed the definition of distinct and specific domains. The cell attachment domain present in the sequence enhances the cell adhesion. Hexamethylene diisocyanate, a lysine-targeted crosslinker, was used to crosslink the purified polymer. The produced matrices presented an adequate mechanical performance and the morphological analysis by scanning electron microscopy show a homogeneous porous structure, ranging from nanometers to few micrometres. The biological tests will be assessed in future work. These results show the big potential of the ELPs in biomedical applications, especially in the development of systems for tissue engineering and drug release.

Abstract: Pluronic F127 has received increasing attention over many years as drug delivery systems, biomaterials, and hydrogels for tissue engineering. In this study, we synthesized temperature-sensitive and cell-adhesive triblock F127 copolymers, in which Arg-Gly-Asp (RGD) peptide ligand was grafted to Pluronic F127-4-methacryloxyethyl trimellitic anhydride (4-META) to obtain F127-META-RGD. The chemical structures of the F127-META-RGD block copolymers were confirmed by FTIR, 1H and 13C NMR, and GPC. The resultant F127-META-RGD showed very similar thermosensitive behaviors to F127 and F127-META. The critical micelle temperature (CMT) of the F127 copolymers decreased in the order of F127 < F127-META < F127-META-RGD, whereas the particle size followed an opposite trend. Interactions between the F127 copolymers and adipose-derived stem cells (ASC) were evaluated in terms of cell adhesion and proliferation on the hydrogel. These thermosensitive RGD-grafted Pluronic hydrogels that display the enhanced cell adhesiveness, are expected to be useful as a functional injectable scaffold for tissue engineering.

Abstract: Biodegradable porous poly(L-lactic acid) (PLLA) scaffolds were prepared using gas foaming method. The PLLA scaffolds with a hydrophobic surface were subjected to Ar plasma treatment and in situ acrylic acid (AA) grafting to obtain hydrophilic PLLA scaffold (PLLA-PAA). Cell-adhesive RGD peptide was then immobilized onto the AA-grafted PLLA (PLLA-PAA-RGD). Once rabbit bone marrow-derived mesenchymal stem cells (BM-MSC) were isolated, MSCs were seeded into PLLA control, PLLA-PAA, and PLLA-PAA-RGD scaffold and cultured for up to 4 weeks in chondrogenic medium with the addition of 10 ng/ml transforming growth factor (TGF)-β1. Surface analysis of AA-grafted PLLA identified significant alterations of surface characteristics, including reduced contact angle and different atomic compositions. From WST-1 assay at 4 weeks, cells were found more proliferative in PLLA-PAA than the others. Upon the histological analysis of Safranin O staining, chondrogenic differentiation of MSCs appeared to be progressed more actively in PLLA-PAA. The effect of RGD immobilization on MSC differentiation was barely notable.

Abstract: For effective bone regeneration, various surface modifications have been tried. In an effort to improve osteogenic repair potential, we evaluated recombinant peptides containing the RGD domain as a bioactive molecule for tissue-engineered bone regeneration. The synthetic peptides slightly suppressed cellular proliferation in the in vitro culture system but induced favorable osteoblastic differentiation, which was determined by MTT and ALP activity staining, respectively. The synthetic peptide coated CMP granules, which were implanted into the mandibular bone defects showed more favorable bone repair compared to the non-coated CMP implantation. In addition, there were not any sign of inflammatory reaction. These findings suggest that synthesized peptides containing the RGD domain enhance cellular attachment and osteogenic activity in vivo condition and that the peptide-coated CMP granules can serve as a biocompatible bone substitute.