RGD‐functionalized polyurethane scaffolds promote umbilical cord blood mesenchymal stem cell expansion and osteogenic differentiation

Abstract

Biomimetic materials are essential for the production of clinically relevant bone grafts for bone tissue engineering applications. Their ability to modulate stem cell proliferation and differentiation can be used to harness the regenerative potential of those cells and optimize the efficiency of engineered bone grafts. The arginyl-glycylaspartic acid (RGD) peptide has been recognized as the adhesion motif of various extracellular matrix proteins and can affect stem cell behaviour in biomaterials.Attempts to functionalize biomaterials with RGD have been limited to a maximum of 1-to 3-mm thickness scaffolds, overlooking the issue of core infiltration that represents a major hurdle in developing real thickness scaffolds. Herein, we present the cross-linking of RGD on the surface of "real thickness" (5 × 5 × 5 mm) porous polyurethane scaffolds (PU-RGD), to be used for the expansion and osteogenic differentiation of umbilical cord blood mesenchymal stem cells (UCB MSCs). RGD-functionalized scaffolds increased initial cell adhesion (1.5-fold to twofold) and achieved a 3.4-fold increase in cell numbers at the end of culture compared with a 1.5-fold increase in non-functionalized controls. Homogenous cell infiltration to the scaffold core was observed in the PU-RGD scaffolds. Importantly, PU-RGD scaffolds were able to enhance the osteogenic differentiation of UCB MSCs. Osteogenic gene and protein expression increased in scaffolds functionalized with 100 μg/ml RGD. Higher RGD concentrations (200 μg/ml) were less efficient in stimulating osteogenic differentiation. We conclude that robust RGD tethering to 3D PU "real thickness" scaffolds is possible and that it promotes core infiltration, expansion, and osteogenic differentiation of UCB MSCs for the purposes of bone regeneration.

Chemoradiotherapy screening in a novel biomimetic polymer based pancreatic cancer model

“…More specically, scaffolds were collected at appropriate time points, snap frozen in liquid nitrogen for 15 min and then preserved at À80 C. The method of scaffold preservation has been widely used in the eld of tissue engineering and is known to aid in preservation without harming the cells. [83][84][85] For live/dead cell analysis a Live/Dead Viability/ Cytotoxicity kit was used 7 (Molecular Probes, Thermo Scien-tic, UK). Prior to analysis scaffolds were sectioned and washed twice with PBS, stained with 2 mM of Calcein-AM (4 mM stock) and 4 mM of Ethidium Homodimer (2 mM stock) and were incubated at 37 C for 1 h. The solution was then removed, and the samples were washed twice in PBS followed by imaging using a Nikon Ti-Eclipse inverted confocal microscope (Nikon Instruments, Europe).…”

Poly(vinyl alcohol)‐methacrylate with CRGD peptide: A photocurable biocompatible hydrogel

“…However, there was no significant difference between the Young's modulus of the two types of hydrogels (Figure 3, 110 vs. 100 kPa), suggesting that only a small quantity of the cysteine reacts with the methacrylate double bond. The small quantity of bound CRGD precludes reliable quantitation of the conjugation, however, the successful cell attachment to the hydrogel, despite low polymer binding of the CRGD, aligns with the very low concentrations of bound RDG reported necessary to enhance cell attachment (Tahlawi et al, 2019).…”

A Systematic Comparative Assessment of the Response of Ovarian Cancer Cells to the Chemotherapeutic Cisplatin in 3D Models of Various Structural and Biochemical Configurations—Does One Model Type Fit All?

“…More specifically, PU scaffolds were collected at appropriate time points, snap-frozen in liquid nitrogen for 15 min and then preserved at −80 °C for further analysis, as previously described [ 75 , 76 , 77 ]. This method has been widely used in the field of tissue engineering for sample preservation without harming the cells [ 81 , 82 , 83 ]. Prior to analysis, scaffolds were sectioned and washed twice with PBS.…”