RGD-bearing peptide-amphiphile-hydroxyapatite nanocomposite bone scaffold: anin vitrostudy

Abstract

In this study, a fibrous nanocomposite scaffold was developed by combining hydroxyapatite (HA) fibers produced by electrospinning method and arginine-glycine-aspartic acid (RGD)-bearing peptide-amphiphile (PA) gel (PA-RGD) produced by self-assembly and gelation induced by calcium ions. Scanning electron microscope, transmission electron microscope and atomic force microscopy imaging confirmed the successful production of inorganic and organic components of this nanocomposite material. Within the HA, the presence of a CaCO3 phase, improving biodegradation, was shown by x-ray diffraction analysis. The in vitro effectiveness of the PA-RGD/HA scaffold was determined on MC3T3-E1 preosteoblast cultures in comparison with HA matrix and PA-RGD gel. The highest cellular proliferation was obtained on PA-RGD gel, however, alkaline phosphatase activity results denoted that osteogenic differentiation of the cells is more favorable on HA containing matrices with respect to PA-RGD itself. Microscopic observations revealed that all three matrices support cell attachment and proliferation. Moreover, cells form bridges between the HA and PA-RGD components of the nanocomposite scaffold, indicating the integrity of the biphasic components. According to the real time-polymerase chain reaction (RT-PCR) analyses, MC3T3-E1 cells expressed significantly higher osteocalcin on all matrices. Bone sialoprotein (BSP) expression level is ten-fold higher on PA-RGD/HA nanocomposite scaffolds than that of HA and PA-RGD scaffolds and the elevated expression of BSP on PA-RGD/HA nanocomposite scaffolds suggested higher mineralized matrix on this novel scaffold. Based on the results obtained in this study, the combination of HA nanofibers and PA-RGD gel takes advantage of good structural integrity during the cell culture, besides the osteoinductive and osteoconductive properties of the nanofibrous scaffold.

A Silk Fibroin and Peptide Amphiphile‐Based Co‐Culture Model for Osteochondral Tissue Engineering

“…[ 32 ] In this study, ALP activities of hBMSCs did not signifi cantly change throughout the 28 d culture period in the Silk scaffolds ( Figure 4 ). In contrast, hBMSCs seeded in the Silk scaffolds showed a 3.4-fold increase in ALP activity after cultivation in an osteochondral co-culture system for 2 weeks as compared to cells in single culture ( p < 0.001).…”

“…[30,31,45] Recently, peptide amphiphile hydrogels have been explored for this need due to their design flexibility, ease of synthesis, and similarity to natural ECM of cartilage. [33] PA hydrogels were successfully used in encapsulation processes for different cell types such as MC3T3-E1, [32,46] neural progenitor cells, [47] fibroblasts, [48] hBMSCs. [38] However, they have never been studied in detail for building cartilage layer of an osteochondral scaffold or an osteochondral system composed of multiple cell types in different layers.…”

“…[32] These molecules self-assemble into nanofibrous hydrogels, mediated by cell compatible calcium ions. [32] Further, various bioactive sequences derived from fibronectin, vitronectin, collagen, and laminin, such as arginine-glycine-aspartic acidserine (RGDS), isoleucine-lysine-valine-alanine-valine (IKVAV) can be added into the peptide sequence. [33] Design flexibility and physical, chemical, and mechanical properties of PA hydrogels make them an interesting candidate as a part of multilayered osteochondral scaffolds.…”

PVA Nanofibers Including Biopolymer-grafted Copolymer for Potential Biomedical Applications

“…P olymer nanofibers from various polymers such as engineering plastics, biopolymers, conducting polymers, block and graft copolymers and matrix-partner polymer blend systems have attracted a great deal of attention due to their unique properties, such as high surface area-to-volume ratio, low basis weight, excellent structural mechanical properties, high axial strength combined with extreme flexibility, high functionality and high porosity [1][2][3][4]. Electrospinning is a simple, low cost, and effective technology to prepare nanofibers from these polymers for various applications [5,6].…”

Nanofibrous Scaffolds as Promising Cell Carriers for Tissue Engineering

“…The mineral component can also be added to the nanofibers by biomimetic mineralization in simulated body fluid [69] and other ionic solutions [70]. Nanofibers can also be created exclusively from inorganic or other hard materials, for example hydroxyapatite [71,72] or carbon and bioactive glass [73], and also from SiO 2 [74,75] and diamond [76,77] or their combinations [78,79].…”