A study on the development of scaffold fabrication using citric acid polyester – nanohydroxyapatite composite

ABSTRACT. Nano hydroxyapatite (n-HAp) and its composites have shown a great development in the field of tissue regeneration and in controlled drug delivery due to its good biocompatibility and bioactivity behavior. Furthermore, HAp-based nanocomposites enhance mechanical properties. These synthetic HAp nanocomposites can also be tailored to fabricate scaffold with controlled porosity which facilitate the growth of the cell in the field of tissue engineering. In this paper, we focus on the synthesis of nano hydroxyapatite (n-HAp) by sol-gel method. The synthesized nano powders were calcined at 500 oC and characterized by FT-IR, XRD and TEM. We have also described the synthesis of citric acid-based polyester by melt polycondensation method without adding catalyst. The monomers used were citric acid, 1,6-hexane diol and sebacic acid. The corresponding synthesized n-HAp/polyester composite have potential application in soft tissue engineering. The structures of polyester and its nanocomposite were studied by FT-IR and 1H NMR spectral studies. The thermal and mechanical properties of polyester, composites and cytotoxicity activity (MTT assay) using vero cells were also studied. Porous scaffold of the nano HAp/Polyester was fabricated by solvent-casting particulate leaching technique which is useful in the development of tissue engineering applications. SEM and TEM studies were carried out for nano HAp, polyester, composites and scaffold.   KEY WORDS: Cytotoxicity, Polycondensation, Sol-gel, Solvent-casting, Tissue engineering Bull. Chem. Soc. Ethiop. 2022, 36(4), 923-934.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i4.17                                                     &nbsp

Investigations on structural, optical, and impedance spectroscopy studies of titanium dioxide nanoparticles

This article explains a novel synthesis for producing titanium dioxide (TiO2) nanoparticles by a sol-gel technique using titanium tetraisopropoxide as a titanium source. The synthesized nanoparticles were analyzed using many measurements like X-ray diffraction (XRD), HRTEM, absorption UV spectroscopy, FTIR, and ac impedance spectroscopy. X-ray peaks were used to calculate the crystallite size and lattice strain by Williamson–Hall method. Crystallite size calculated from x-ray diffraction using the Scherrer equation gives an approximate size and cannot be used for measurements. TiO2 nanoparticles are found to possess a tetragonal structure with a crystalline size around 12 nm. Particle size was confirmed by HRTEM images. The optical studies response for the nanoparticles showed the possible visible absorption peaks for TiO2 nanoparticles are 323 nm. Bandgap energy (Eg) of the TiO2 nanoparticle calculated from UV visible absorption spectra is discussed, and the bandgap is 3.14 eV. FTIR spectra showed vibration bands of the Ti-O network. AC Conductivity properties of TiO2 nanoparticles are studied in the frequency range 1 to 8 MHz at varying temperatures. The conductivity of the TiO2 nanoparticle is found to be constant in the low angular frequency region. Dielectric parameters were analyzed at different temperatures and frequencies.                     KEY WORDS: Conductivity, Dielectric, Nanoparticles, Titanium dioxide, Structural studies   Bull. Chem. Soc. Ethiop. 2021, 35(1), 151-160. DOI: https://dx.doi.org/10.4314/bcse.v35i1.1