The effects of different cross-linking conditions on collagen-based nanocomposite scaffolds—an in vitro evaluation using mesenchymal stem cells

Abstract

Nanocomposite scaffolds which aimed to imitate a bone extracellular matrix were prepared for bone surgery applications. The scaffolds consisted of polylactide electrospun nano/sub-micron fibres, a natural collagen matrix supplemented with sodium hyaluronate and natural calcium phosphate nano-particles (bioapatite). The mechanical properties of the scaffolds were improved by means of three different cross-linking agents: N-(3-dimethylamino propyl)-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide in an ethanol solution (EDC/NHS/EtOH), EDC/NHS in a phosphate buffer saline solution (EDC/NHS/PBS) and genipin. The effect of the various cross-linking conditions on the pore size, structure and mechanical properties of the scaffolds were subsequently studied. In addition, the mass loss, the swelling ratio and the pH of the scaffolds were determined following their immersion in a cell culture medium. Furthermore, the metabolic activity of human mesenchymal stem cells (hMSCs) cultivated in scaffold infusions for 2 and 7 days was assessed. Finally, studies were conducted of cell adhesion, proliferation and penetration into the scaffolds. With regard to the structural stability of the tested scaffolds, it was determined that EDC/NHS/PBS and genipin formed the most effectively cross-linked materials. Moreover, it was discovered that the genipin cross-linked scaffold also provided the best conditions for hMSC cultivation. In addition, the infusions from all the scaffolds were found to be non-cytotoxic. Thus, the genipin and EDC/NHS/PBS cross-linked scaffolds can be considered to be promising biomaterials for further in vivo testing and bone surgery applications.

Elastin-PLGA hybrid electrospun nanofiber scaffolds for salivary epithelial cell self-organization and polarization

“…Elastin as a blend electrospinning component of the nanofibers (EP-blend) significantly increased the compliance, or decreased the stiffness, of the scaffold when compared to PLGA nanofibers; Young’s modulus ~ 0.59 ± 0.356 MPa for EP-blend as compared to 4.29 ± 1.789 MPa for P. On the other hand, elastin as a surface modification (EP-covalent) had the opposite effect where it caused a significant increase in the mean scaffold stiffness and heterogeneity of the mechanical properties; Young’s modulus ~ 20.72 ± 5.978 MPa. This can likely be attributed to the fact that the process of covalently conjugating elastin on the surface of PLGA fibers with EDC chemistry is known to crosslink nanofibers, thus increase the bulk stiffness of the material [71–72]. To confirm, the Young’s modulus of PLGA nanofibers treated with EDC chemistry without the addition of elastin was measured; Young’s modulus ~ 20.4 ± 8.6 MPa.…”

Submicrostructural domains in human secondary osteons

“…Torsion moments contribute to the formation of helical structures in the femoral cortical bone. 7) The presented results may become very useful in near future for modern bone tissue replacements based on nanofibrils and nanoparticles 37,38 , applied mainly at older patients.…”

Generating standardized image data for testing and calibrating quantification of volumes, surfaces, lengths, and object counts in fibrous and porous materials using X‐ray microtomography

“…The definitions, abbreviations, and possible biological interpretations in the context of biomaterials are summarized in Table . The simulation of biomaterials was inspired by real tissue scaffolds, namely: (i) electrospun polyesters (polycaprolactone) or polypropylene meshes used for manufacturing artificial vascular prostheses or reinforcement of scars (Horakova et al, ; Plencner et al, ) and consisting of fibers with diameters of 1–6 µm, occupying 25–70% of the volume fraction; and (ii) composite porous scaffolds (Gómez, Vlad, López, & Fernández, ; Prosecká et al, ; Suchý et al, ) manufactured for healing of bone defects and consisting of collagen, polyDL‐lactide sub‐micron fibers, and sodium hyaluronate, containing typically 70%–80% porosities.…”