In this work yttrium oxide (Y2O3) nanocrystallites were synthetized by mean of sol-gel method using two different precursors. The raw materials were: yttrium nitrate, yttrium chloride and methanol as solvent. In order to promote the oxygen vacancies P123 poloxamer was incorporated. All as synthetized system were heat treated at temperatures from 700 ºC to 900 ºC, the systems at 900 ºC were prepared with and without P123 at two different molar ratios of P123:Y (1:1, 2:1). The Infrared Spectroscopy results revealed characteristic absorption band of Y-O vibrations of Y2O3 matrix. The structural phase was analyzed trough X-ray Diffraction, the diffractogram showed the cubic phase in all systems. The major intensity of the diffraction peak was presented for the system prepared from yttrium chloride incorporating P123 in a molar ratio of P123:Y, 2:1 at 900 ºC. The range of the crystallites sizes was determined by Scherer equation obtaining them of 26-32 nm. Antioxidant properties were estimated by DPPH and ABTS assays; the results are presented and discussed.

Existing nanofibrous based tissue engineering scaffolds are poor in cell infiltration and mechanical stability. Microsphere based scaffolds can be suggested as alternative for this problem. Poly (lactide-co-glycolide) (PLGA) with lactide to glycolide ratio 85:15 was used to make virgin and composite microsphere based scaffolds. Nano Hydroxyapatite (nHAP) was synthesized, characterized and incorporated into microspheres to make 15% nHAP composite scaffolds. Microspheres of size range 250-500µm was used for making three scaffold types; virgin, composite and a combination of virgin/composite PLGA, by heat sintering method. Stainless steel molds were designed in cylindrical/rectangular shapes, followed by optimization in sintering time and temperature. Developed scaffolds were characterized through inverted microscope and scanning electron microscope (SEM), for surface-cross section morphology. Pore size distribution and porosity of the scaffolds were evaluated using liquid extrusion porosimetry and swelling studies respectively. Presence of nHAP in composite scaffolds was examined using Fourier Transform Infrared Spectroscopy (FTIR), Transmission electron Microscopy (TEM) and Energy Dispersive Spectrum (EDS). Effect of nHAP in physical properties of scaffolds was investigated through Thermo gravimetrical Analysis (TGA) whereas mechanical stability of the scaffolds from stress-strain curves of compression analysis. Swelling studies were performed to identify the percentage of water absorption, as an indication mark for the initiation of degradation. Bio activity of the scaffold was measured through in-vitro bio mineralization by PBS immersion method. A meaningful comparison between three scaffold types will provide a conclusive declaration for the selection of ideal scaffold for bone tissue engineering.

Electrospinning of polyamides has been used for obtaining porous nanofibres that can be employed in a variety of applications; among them, their use for fabricating tissue scaffolds has attracted a lot of interest. In order to successfully apply these nanofibres in the biomedical field it is important to investigate the diverse parameters involved in this process. Fibre diameter, network morphology and mechanical properties are some of the most important features that can be tailored to mimic specific target tissues. Furthermore, crystallinity of the polymer is related to the mechanical response and biodegradability. This work aims to present a better insight into the structural understanding of fibres obtained from electrospinning process by evaluating the crystallinity percentage in polyamide 6,6 nanofibres obtained at different conditions. The parameters studied in this work are the solution concentration, flow rate, voltage applied and distance from the tip of the needle to the collector surface. Differential scanning calorimetry was used to determine the crystallinity of the samples. The morphology of the nanofibres was observed by scanning electron microscopy. The chemical structure of the nanofibres was analysed by infrared and Raman spectroscopies. The results obtained showed those parameters that were statistically significant on the crystallinity of the poplyamide 6,6 nanofibres.