A schematic for the mechanism of accelerating the assembly of intercalated discs (IDs) in cardiac myocytes regulated by gold nanoparticles (AuNPs) is presented. AuNPs with local nanoscale stiffness in the substrate activate β1-integrin signaling, which mediates the activation of integrin-linked kinase (ILK) and its downstream signal kinase by stimulating expression of the transcription factors GATA4 and MEF-2c.
Tissue engineering promises to restore tissue and organ function following injury or failure by creating functional and transplantable artificial tissues. The development of artificial tissues with dimensions that exceed the diffusion limit (1-2 mm) will require nutrients and oxygen to be delivered via perfusion (or convection) rather than diffusion alone. One strategy of perfusion is to prevascularize tissues; that is, a network of blood vessels is created within the tissue construct prior to implantation, which has the potential to significantly shorten the time of functional vascular perfusion from the host. The prevascularized network of vessels requires an extracellular matrix or scaffold for 3D support, which can be either natural or synthetic. This review surveys the commonly used biomaterials for prevascularizing 3D tissue engineering constructs.
Cardiac tissue engineering (CTE) has developed rapidly, but a great challenge remains in finding practical scaffold materials for the construction of engineered cardiac tissues. Carbon nanohorns (CNHs) may be a potential candidate due to their special structure and properties. The purpose of this study was to assess the effect of CNHs on the biological behavior of neonatal rat ventricular myocytes (NRVMs) for CTE applications. CNHs were incorporated into collagen to form growth substrates for NRVMs. Transmission electron microscopy (TEM) observations demonstrated that CNHs exhibited a good affinity to collagen. Moreover, it was found that CNH-embedded substrates enhanced adhesion and proliferation of NRVMs. Immunohistochemical staining, western blot analysis, and intracellular calcium transient measurements indicated that the addition of CNHs significantly increased the expression and maturation of electrical and mechanical proteins (connexin-43 and N-cadherin). Bromodeoxyuridine staining and a Cell Counting Kit-8 assay showed that CNHs have the ability to inhibit the proliferation of cardiac fibroblasts. These findings suggest that CNHs can have a valuable effect on the construction of engineered cardiac tissues and may be a promising scaffold for CTE.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-016-1464-z) contains supplementary material, which is available to authorized users.
Biomechanical models of implanting prostheses into femora by means of press fit, i.e. the
mechanics of non-homogeneous layer-like composites, have been used to quantify the press-fit strength
and circumferential stress of the interface, when femora are partially replaced by different thicknesses of
bioactive ceramic coatings on a prosthesis surface during the initial implant stage. The maximum press-fit
strength appears on the interface between femora and Ti alloy prostheses with non-coating; the press-fit
strength decreases with the increased thickness of the coating. The circumferential stress displayed as the
large tensile stress at the femoral side of the interface; the compressive stress, appeared at the side of the
coating and Ti alloy prosthesis. The shearing strength, jointing between the prostheses and femora would
be bigger with the thinner bioactive ceramic coatings. Considering the biodegradability of bioactive
ceramic coatings, e.g. hydroxyapatite, HA, it is concluded that the optimum thickness of the bioactive
ceramic coatings will be about 50-60 microns.
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