Biocompatibility study of a hydroxyapatite-aiumina and silicon carbide composite scaffold for bone tissue engineering

To date, several scaffolds have been fabricated for application in bone tissue repair. However, there remains a need for synthesis of scaffolds with better mechanical properties, which can be applied to defects in weight-bearing bones. We constructed a composite ceramic bioscaffold of hydroxyapatite-alumina and silicon carbide [HA-Al2O3- SiC] to take advantage of the mechanical properties of this combination and show that it supports osteoblast-like cell attachment and growth. Ceramic composite microporous scaffolds were synthesized using an organic template [commercial polyurethane sponge with an open, interconnected microporosity]. Osteoblast-like cells [Saos-2] were then cultured on the scaffold and their growth pattern and viability were compared with those cultured in cell culture-treated flasks. Scanning electron microscopy [SEM] was used to assess cell attachment and migration. The fabricated scaffold shows fairly uniform pore morphologies. Cell growth and viability studies show that the scaffold is able to support osteoblast attachment and growth. However, SEM images indicated that the cells do not spread optimally on the scaffold surfaces. Our data suggest that that a ceramic hydroxyapatite-alumina and silicon carbide composite scaffold is a viable option for bone tissue repair. However, its surface properties should be optimized to maximise the attachment of osteoblasts

Cytogenetic damages from iododeoxyuridine-induced radiosensitivity with and without methoxyamine in human glioblastoma spheroids

lododeoxyuridine-induced Radiosensitivityi [IUdR] is a halogenated thymidine analogue recognized to be effective in vitro and in vivo radioserisitizer in human cancers. It is reported that Methoxyamine [MX] potentiates DNA damages in cancer cells with blocking the repair pathway of lUdR damages. But studies, entirely, are restricted on monolayer culture cells from human colon cancer cells. Spheroids are 3D form of cells that aggregate and grow together which resemble in vivo tumor models in several aspects and the results of such studies can be extended to tumor in vivo. The aim of the current study was to evaluate DNA damages from IUdR and gamma rays with and without Methoxyamine in human Glioblastoma spheroids. The DNA induced damages in U87MG cell line were compared using alkaline comet assay method. Experiments were performed with two different sizes of spheroids [100omicrom and 300microm]. Evaluation of the effects of IUdR with and without MX pretreatment on spheroids following ionizing radiation showed that MX increased the cell damages of lUdR with and without irradiation in both diameters spheroids. The damages were further increased in 100microm compared with 300microm diameter. Comparisons of tail moments in spheroids with 100 and 300microm diameter showed that cell damages in larger spheroids, 300microm, are lesser than smaller one, 100microm. This could be due to existence of G[0] cells and cells with longer cycle which lUdR was less incorporated into them. Thus, decrease in lUdR radiosensitization and base wxcision repair [BER], results in reduction of MX activities. Using agents for Inhibiting the activities of proteins which are responsible for carrying the cells to G[0] may be beneficial in solving such problems