rada16-i and arginyl-glycyl-aspartic-acid

Proteinase K and circular dichroism spectroscopy were employed to test the stability and secondary structural properties of peptide D-RADA16-RGD respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the surface of these materials. Confocal laser scanning (CLS), cell counting kit-8 tests (CCK-8), alizarin red S staining, cell immunofluorescence analysis and Western blotting were involved. Proteinase K and circular dichroism spectroscopy demonstrated that D-RADA16-RGD in nHA/PA66 was able to form stable-sheet secondary structure. SEM and TEM showed that the D-RADA16-RGD material was 7-33 nm in width and 130-600 nm in length, and the interwoven pore size ranged from 40 to 200 nm. CLS suggests that cells in nHA/PA66/D-RADA16-RGD group were linked to adjacent cells with more actin filaments. CCK-8 analysis showed that nHA/PA66/D-RADA16-RGD revealed good biocompatibility. The results of Alizarin-red S staining and Western blotting as well as vivo osteogenesis suggest nHA/PA66/D-RADA16-RGD exhibits better bioactivity.. This study demonstrates that our nHA/PA66/D-RADA16-RGD composite exhibits reasonable mechanical properties, biocompatibility and bioactivity with promotion of bone formation.

Topics: Animals; Bone Cements; Bone Regeneration; Cell Line; Cell Proliferation; Durapatite; Endopeptidase K; Female; Femur; Hydrogels; Mice; Nanocomposites; Nylons; Oligopeptides; Osteoblasts; Osteogenesis; Peptides; Protein Stability; Protein Structure, Secondary; Rats; Rats, Sprague-Dawley; Surface Properties

Topics: Amino Acid Motifs; Biocompatible Materials; Cell Adhesion; Cell Proliferation; Cell Survival; Cells, Cultured; Circular Dichroism; Humans; Hydrogels; Hydrophobic and Hydrophilic Interactions; Microscopy, Atomic Force; Nanofibers; Nanostructures; Oligopeptides; Peptides; Protein Structure, Secondary; Spectrum Analysis, Raman

In the current study, we present three designer self-assembling peptides (SAPs) by appending RADA 16-I with epitopes IKVAV, RGD, and YIGSR, which have different net charges and amphiphilic properties at neutral pH. The self-assembly of the designer SAPs is intensively investigated as a function of pH, canion type, and assembly time. The morphologies of the designer SAPs were studied by atomic force microscope. The secondary structure was investigated by circular dichroism. The dynamic viscoelasticity of designer SAP solutions was examined during titration with different alkaline reagents. Our study indicated that both electrostatic and hydrophilic/hydrophobic interactions of the motifs exhibited influences on the self-assembly, consequentially affecting the fiber morphologies and rheological properties. Moreover, NaOH induced a quicker assembly/reassembly of the designer SAPs than Tris because of its strong ionic strength. Therefore, our study gained comprehensive insight into the self-assembling mechanism as references for developing RADA 16-I-based functional SAPs.

Topics: Amino Acid Motifs; Circular Dichroism; Epitopes; Hydrogen-Ion Concentration; Ions; Kinetics; Laminin; Microscopy, Atomic Force; Nanofibers; Oligopeptides; Peptide Fragments; Peptides; Protein Structure, Secondary; Rheology; Static Electricity; Time Factors; Viscoelastic Substances

Three-dimensional (3D) in vitro models of cell culture aim to fill the gap between the standard two-dimensional cell studies and the in vivo environment. Especially for neural tissue regeneration approaches where there is little regenerative capacity, these models are important for mimicking the extracellular matrix in providing support, allowing the natural flow of oxygen, nutrients, and growth factors, and possibly favoring neural cell regrowth. We have previously demonstrated that a new self-assembling nanostructured biomaterial, based on matrigel, was able to support adult neural stem cell (NSC) culture. In this study, we developed a new 3D cell culture system that takes advantage of the nano- and microfiber assembling process, under physiologic conditions, of these biomaterials. The assembled scaffold forms an intricate and biologically active matrix that displays specifically designed functional motifs: RGD (Arg-Gly-Asp), BMHP1 (bone marrow homing peptide 1), and BMHP2, for the culture of adult NSCs. These scaffolds were prepared at different concentrations, and microscopic examination of the cell-embedded scaffolds showed that NSCs are viable and they proliferate and differentiate within the nanostructured environment of the scaffold. Such a model has the potential to be tailored to develop ad hoc designed peptides for specific cell lines.

Topics: Analysis of Variance; Animals; Cell Differentiation; Cell Proliferation; Hydrogels; Male; Mice; Mice, Inbred C57BL; Microscopy, Electron, Scanning; Nanomedicine; Nanostructures; Neural Stem Cells; Oligopeptides; Peptides; Tissue Engineering; Tissue Scaffolds; Viscosity