Characterization and in-vitro behaviour of bioactive glass / polymeric composites

Chitosan biopolymer characterizes osteoinductive functions and it can be utilized in combination with other bioactive materials that enhances tissue regenerative efficacy and osteoconductivity. Another material of interest is bioactive glass [BG] [45S5] that characterizes its ability to bond to bone and soft tissues very quickly as a result of high level of its surface reactivity. In this study, BG was combined with chitosan to produce novel bio-composites having properties analogous to human cancellous bone. The affinity between BG filler and polymer matrix has been proved by X -ray diffraction [XRD], Fourier transform infrared [FT-IR] and Thermogravimetric analysis [TGA] techniques. The results confirmed that homogeneity and integration between BG filler and polymer matrix especially the composite containing smaller particle size of BG is achieved. Also, the formation of calcium phosphate layer onto the surface of composite was detected post-immersion in simulated body fluid [SBF] for different periods up to 21 days at 37°C and pH 7.4. Conclusions prove that the presence of smaller particle size of BG filler into the polymeric matrix leads to more effective reinforcement of the composite and increased the bioactivity via high formation of carbonated apatite layer onto the composite surface. These biocomposites are promised for bone replacement and scaffold for tissue engineering applications

Morphological study of bone formation induced in by cranial and femoral demineralized bone implants in dog mandible: a comparative study

The aim of this study was to compare between canine cranial [membranous] and femoral [endochondral] demineralized bone matrix [DBM] as an osteoinductive biomaterial. Utilizing histological study and scanning electron microscope [SEM], a comparison between the two types of demineralized implants was conducted to detect bone induction in dog mandible. The expected bone induction process was followed after 4-6 months. FT-IR spectroscopy of cranial and femoral bones before and after demineralization detected the form of protein found and the degree of demineralization obtained. The results proved that as early as four-month implantation, the cranial DBM graft showed early signs of ossification and cancellous bone formation. While in case of femoral DBM, there was a necrotic material in the defect. At 6-month implantation, the cranial DBM showed mesenchymal tissue filling the defect which changed into cancellous bone. In case of femoral DBM, signs of ossification and formation of immature cancellous bone trabeculae were detected in a narrow zone

Some biophysical parameters for detection of heterozygotes B-thalassemia

Heparinized blood was taken from cases of homozygotes Beta and Beta [+] thalassemic children together with their parents as heterozygotes. In addition, samples were taken from iron deficiency anemia, glucose-6- phosphate dehydrogenase deficiency [G-6-pD], sickel cell anemia and normal control samples. Hemoglobin absorption spectra, base and acid buffer capacities, electrophoretical pattern, thermodynamic parameters, conductivity and viscosity of Hb were investigated. The obtained data revealed a four times in base buffer capacity regarding homozygotes compared with control and two time regarding heterozygotes. Hyperchromicity of globin band and half width of the area under Soret band showed a pronounced increase in homozygotes and heterozygotes as well as a drop in A 578/A 542 ratio concomitant with the appearance of a new band at 630 nm. In addition, in homozygotes and heterozygotes a turning point thereshold and decrease in the slope of linear relationship between natural logarithm of spin state constant versus 1/T was detected respectively. The obtained data revealed also that conductivity was 0.7 X 10[-3] [ohm[-1] cm[-1]] and 0.3 X 10[-3] [ohm[-1] .cm[-1]] of control values regarding homozygotes and heterozygotes respectively. Thus, it is easy to detect heterozygotes according ot these biophysical parameters