5475
Sara Ibrahim Attia Mohamed
Comparative study of 3D composite
scaffolds containing some inorganic
ingredients for hepatic cell regeneration
selenium, hydroxyapatite, scaffolds, liver, mesenchymal stem cells,
nanoparticles, bone marrow, umbilical cord
Hydroxyapatite (HA) is a biocompatible material with high binding activity to DNA and protein. Also, its lattice is eligible for substition in both Ca and P sites. Thus, Ca can be substituted by Sr, Na, and Fe while P is easily substituted by CO3, Si and Se. Incorporation of selenium which is known to play a specific role in human health, may endow the materials with novel characteristics. Therefore, it was selected for the present study. A series of substituted nano-hydroxyapatite with 1-5% Se, (SeHA) powders were synthesised by an aqueous precipitation method using sodium selenite. The produced precipitates were dried at 60°C. The dried ground powders were characterised by XRF, XRD, FTIR and TEM. The XRD patterns obtained confirm the substitution of Se ions in the crystal lattice of HA and was accompanied by the presence of Na ion as was detected by XRF; (SeHA1, SeHA1.5, SeHA2, SeHA2.5, SeHA3 and SeHA5). No change in the morphology of the rod shaped particles took place. Instead a reduction in their size was observed with increase in the selenium content. The cytotoxicity of the produced powders was evaluated in vitro on human bone marrow mesynchymal stem cells (BM-MSCs) and umbilical cord derived mesenchymal stem cells (UC-MSCs). The 0.59 mM of Se corresponding to 2% substitution in the lattice of HA (SeHA2) does not show cytotoxicity and stimulated the proliferation of UC-MSCs in contrast to pure HA powders which inhibited proliferation of the same cells. Toxicity started to appear in samples when the substitution exceeded 2%. The highest concentration (5%) was severely cytotoxic. The results suggest that selenium substitution might be an attractive modification ofhydroxyapatite nanoparticles for cell delivery purposes for future work in tissue engineering. Four types of scaffolds were successfully prepared by freeze-dryingtechnique: collagen-chondroitin sulfate (Co-CS), collagen-sodium hyalurnate (Co- SH), collagen-chondroitin sulfate-selenium substituted hydroxyapatite (Co-CSSeHA2) and collagen/sodium hyalurnate-selenium substituted hydroxyapatite (Co- SH-SeHA2) and using gluteraldehyde as cross-linker to increase the scaffolds strength. The formed scaffolds were characterized by SEM and the results showed porous structured with desirable pore sizes ranging from 73.7 to 103 nm, for hepatocytes culture. The cell compatibility was tested using MTT test on BM-MSCs. The best results were displayed by the scaffold (Co-CS-SeHA2). Results of fluorescent microscopy of the scaffolds showed that the highest number of cells was on Co-CS-SeHA2 scaffold. The cells were distributed in groups which suggested they proliferated on this material. The Co-CS-SeHA2 prepared scaffold can be used for further liver/hepatocytes studies.
2017
Ph.d
Cairo
Science