The application of POSS nanostructures in cartilage tissue engineering: the chondrocyte response to nanoscale geometry

Abstract

Despite extensive research into cartilage tissue engineering (CTE), there is still no scaffold ideal for clinical applications. Various synthetic and natural polymers have been investigated in vitro and in vivo, but none have reached widespread clinical use. The authors investigate the potential of POSS-PCU, a synthetic nanocomposite polymer, for use in CTE. POSS-PCU is modified with silsesquioxane nanostructures that improve its biological and physical properties. The ability of POSS-PCU to support the growth of ovine nasoseptal chondrocytes was evaluated against a polymer widely used in CTE, polycaprolactone (PCL). Scaffolds with varied concentrations of the POSS molecule were also synthesized to investigate their effect on chondrocyte growth. Chondrocytes were seeded onto scaffold disks (PCU negative control; POSS-PCU 2%, 4%, 6%, 8%; PCL). Cytocompatibilty was evaluated using cell viability, total DNA, collagen and GAG assays. Chondrocytes cultured on POSS-PCU (2% POSS) scaffolds had significantly higher viability than PCL scaffolds (p < 0.001). Total DNA, collagen and sGAG protein were also greater on POSS-PCU scaffolds compared with PCL (p > 0.05). POSS-PCU (6% and 8% POSS) had improved viability and proliferation over an 18 day culture period compared with 2% and 4% POSS-PCU (p < 0.0001). Increasing the percentage of POSS in the scaffolds increased the size of the pores found in the scaffolds (p < 0.05). POSS-PCU has excellent potential for use in CTE. It supports the growth of chondrocytes in vitro and the POSS modification significantly enhances the growth and proliferation of nasoseptal chondrocytes compared with traditional scaffolds such as PCL.

Star-shaped polyhedral oligomeric silsesquioxane-polycaprolactone-polyurethane as biomaterials for tissue engineering application

“…The reason for the slight hydrophilicity observed in the star-shaped POSS-PCL-PU films could be because of their higher porosity, thereby causing more water to be adsorbed at the surface and resulting in a decrease in the wettability of films, which further affects the cell adhesion. A similar finding was observed earlier in POSS-polycarbonate urethane foam matrices, 16 and the increased hydrophilicity with higher POSS content was attributed to the increased porosity and pore size.…”

“…The rough surface features of the POSS-PCL-PU films have favorable effects on cell response. 16,24 The porosity of the two types of films was characterized using the liquid displacement method. Star-shaped POSS-PCL-PU films possessed a higher porosity of 75.7 ± 7.4% compared with the porosity of the linear PCL-PU films of 43.1 ± 4.4%.…”

“…In addition, these hybrid materials also offer great versatility and can be used in the development of advanced biomaterials. 11 For example, POSS can be incorporated with polycaprolactone (PCL), 13 polyurethane (PU), 14 polycarbonate urethane urea 15 and polycarbonate urethane 16 for improved biological and mechanical properties to achieve better processability, increased strength, toughness and higher stability for tissue engineering applications. 17 Oseni et al 16 reported that the surface topography of POSS enabled nanoscale interactions of cells via a scaffold matrix, which increased the viability of chondrocytes on POSS-polycarbonate urethane scaffolds compared with PCL scaffolds.…”

“…11 For example, POSS can be incorporated with polycaprolactone (PCL), 13 polyurethane (PU), 14 polycarbonate urethane urea 15 and polycarbonate urethane 16 for improved biological and mechanical properties to achieve better processability, increased strength, toughness and higher stability for tissue engineering applications. 17 Oseni et al 16 reported that the surface topography of POSS enabled nanoscale interactions of cells via a scaffold matrix, which increased the viability of chondrocytes on POSS-polycarbonate urethane scaffolds compared with PCL scaffolds. Knight et al 18 reported that there was minimal weight loss for POSS-incorporated polyester PU films in the earlier stage, followed by a large mass loss at the later stage of in vitro degradation, and the hybrid films also exhibited excellent biocompatibility with no inflammatory responses.…”

Biomimetic modified clinical-grade POSS-PCU nanocomposite polymer for bypass graft applications: A preliminary assessment of endothelial cell adhesion and haemocompatibility

“…In fact, the attractive feature of the plasma surface modification process is that the extent of modification can be precisely controlled by the proper selection of involved parameters [18]. Surface modification of POSS-PCU has been achieved using UV light treatment [19], oxygen (O 2 ) plasma treatment [17], physical adsorption of collagen type I on plasma treated POSS-PCU [13], immobilisation of the RGD binding sequence from fibronectin [20], and nitric oxide (NO) delivery [21]. Collagen type I is one of the major common proteins involved in the extracellular matrix (ECM) responsible for cell maintenance and binding to the surface.…”