Successful long term bone replacement and repair remain a challenge today. Nanotechnology has makes it possible to alter materials' characteristics and therefore possibly improve on the material itself. In this study, biphasic (hydroxyapatite/β-tricalcium phosphate (HA/β-TCP)) nanobioceramic scaffolds were prepared by the electrospinning technique in order to mimic the extracellular matrix (ECM). Scaffolds were characterised by scanning electron microscopy (SEM) and Attentuated Total Reflectance Fourier Transform Infrared (ATR-FTIR). Osteoblasts as well as monocytes that were differentiated into osteoclast-like cells, were cultured separately on the biphasic bioceramic scaffolds for up to 6 days and the proliferation, adhesion and cellular response were determined using lactate dehydrogenase (LDH) cytotoxicity assay, nucleus and cytoskeleton dynamics, analysis of the cell cycle progression, measurement of the mitochondrial membrane potential and the detection of phosphatidylserine expression. SEM analysis of the biphasic bioceramic scaffolds revealed n ano fi be rs spun i n a m e sh -like sc af fold . Re sul ts indi c ate th at th e bi ph asi c bio ce ram ic electrospun scaffolds are biocompatible and have no significant negative effects on either osteoblasts or osteoclast-like cells in vitro.
Auricular reconstruction remains a major challenge facing reconstructive surgeons owing to the complexity of autogenous transplants. In this study, the development of a three-dimensional custom-made polyurethane (PU) auricular implant with hydroxyapatite (HA) coating is described. The PU implant was produced by computerized tomography (CT) scanning and indirect rapid prototyping. To improve the physiological response of the implant, the PU prototype was coated with a microrough, homogenous layer of HA by a novel solvent-compression coating method. Bioactivity of the HA coated PU substrates was confirmed by apatite formation on the HA coating after 9 days in revised simulated body fluid (pH 7.4). Adhesion strength of the HA coating to the PU surface using the tensile pull-off test revealed partial failure of the coating with an average tensile strength of 1.6 MPa. As an initial stage indication of cytocompatibility for a soft tissue application, in vitro cell culturing on the HA-coated PU substrates using Graham 293 fibroblast cells was performed. After 24 and 72 h, the HA coated surfaces displayed significantly higher cell numbers and metabolically active cells compared with the virgin uncoated PU surfaces. This indicates that HA coated PU surfaces are cytocompatible towards fibroblasts and could potentially be applied to auricular cartilage tissue replacement.
Breakthrough curves of naphthalene from n-alkane solution with specific feeds typical of liquid phase processes in packed beds of silica gel which contains pores larger than the critical diameter of the naphthalene molecule are investigated. With measurements under conditions of the linear region of the adsorption isotherm it is found that the observed mass-transport is mainly determined by the mixing process in the flowing bulk phase and by mass transfer through the boundary layer at the interface between the liquid bulk phase and the adsorbent grain. In comparison with these mechanisms, the influence of molecular transport processes in the pore system of the silica gel grain is negligibly small. This information is shown to be available by a direct observation of the elementary steps of molecular transport applying the n.m.r. pulsed field gradient technique.
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