One of the major challenges in the development of scaffold for nerve regeneration is enhancing mechanical strength of the material to avoid the scaffold to rapidly degrade during regeneration process in nerve system. The aim of this study was to reveal the effect of freeze-thaw to the properties of gelatin-carbonated hydroxy apatite (CHA) membrane in two ratios 7 to 3 and 6 to 4 for gelatin to CHA respectively. Some variations of freeze-thaw cycles were applied for both ratios, which is referred for its biocompatibility in cells.The CHA was synthesized by wet precipitating method of calcium hydroxide and phosphoric acid in gelatin solution at room temperature and open system. The X-Ray Diffraction (XRD) and FTIR analysis was conducted to confirm the formation of type-B CHA in gelatin matrix. The resulted membrane was then subject for membrane characterization.It was known from the study that freeze-thaw treatment during membrane fabrication affects several properties of the membrane. Platelet loading capability decreased when freeze-thaw cycles increased. Meanwhile, the platelet was released more rapidly by freeze-thawed gelatin-CHA membrane compared to non-freeze-thawed one. The degradation percentage of the membrane decreased with the increasing freeze-thaw cycles, showing 4 hours slower degradation in the freeze-thawed membrane compared to the unfreeze-thawed one.Furthermore, it was observed that freeze-thaw improved the tensile strength of the membrane and the modulus elasticity increased simultaneously. Moreover, in general it was observed from this study that freeze-thaw treatment did not affect permeability of the membranes towards glucose transport.
Interaction of 1-butanol (BuOH) with a cationic surfactant, cetyltrimethylammonium bromide (CTAB) aggregate, in water and salt solution has been studied by viscometry, small-angle neutron scattering (SANS), and 2D-NMR techniques. The experimental results are interpreted in terms of a possible micellar growth occurring in the presence of added alcohol and salt. It was observed that the addition of BuOH strongly influences the viscosity of the CTAB/salt micellar system, reaching a peak viscosity at about 0.5% w/v of BuOH over a range of salt concentrations. Scattering measurements support the idea of a structural transformation by the observation of a spectral shift (broadening) as the total concentration of surfactant varies, indicating a decrease in the intermicellar distance and narrow size distribution. The chemical shift from1H NMR measurements gave complementary data on the solubilization of BuOH in CTAB micelles, whereas the expected locus (site) of the additive added to the surfactant including the dynamics of the molecules in micellar aggregates were successfully correlated by significant and positive cross peaks obtained from two-dimensional nuclear Overhauser effect spectroscopy (2D-NOESY).
The analysis of hierarchical structure of mesoporous silica material with template of cetyltrimethylammonium bromide (CTAB) with co-surfactants of tetramethylammonium hydroxide (TMAOH) and Triton X-100 was conducted by using the technique of small angle scattering (SAS) using neutron (SANS) and X-ray (SAXS). The analysis was supported by the data of nitrogen absorption and electron microscopy. The analysis showed that the concentration of CTAB affected the characteristics and pore structures of particles. The increase of co-surfactant concentrations tended to form particles that were more uniform in size and more regular in the shape of the sphere. The results of SAS analysis showed that the morphology, shape, and size of the large particles were arranged by smaller (primary or secondary) particles that had pores. The variation of surfactant templates had influenced the formation of pore structure. For CTAB-TMAOH, it had resembled MCM-41 type which has a hexagonal structure, whereas for CTAB-Triton X-100, it would have resembled MCM-48 type which has a cubic structure. The particles that have a high surface area which resembled pore structure MCM-41 has been able to set up by using 0.25 M of CTAB with 0.040 M of TMAOH. Moreover, the particles which resembled pore structure MCM-48 were able to set up by using 0.03 M of Triton X-100 with 0.4 M of CTAB. The analysis of SANS data that was supported by electron microscopy results is entirely showing a complete information of the particles formed by each template. Whereas SAXS analysis that supported by nitrogen adsorption method is fully confirming the information of pore characteristics.
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