Tin dioxide (SnO2) nanostructures have been synthesized successfully via solution phase growth technique. Effect of reaction temperature, time and surfactant on morphology, size and bandgap of nanomaterials has been studied. The rods, flowers and spheres like morphologies of SnO2 have been observed using Scanning Electron Microscope (SEM). Structural analysis of synthesized SnO2 has been carried out by X-ray Diffraction (XRD). XRD peaks revealed the tetragonal structure of SnO2 nanocrystals. The increase in grain size was observed with increase in reaction time and reaction temperature of synthesis process. Fourier Transform Infrared spectroscopy (FTIR) has been employed to study the vibrational modes. Optical properties of the SnO2 nanostructures have also been studied by UV-vis spectroscopy. The energy bandgap of the as prepared SnO2 nanocrystals was estimated between 3.76 eV and 4.05 eV. It has been observed that the bandgap of the synthesized SnO2 samples decreased with increase in particle size. This phenomenon can be attributed to the quantum confinement effect at smaller particle size.
Caco-2 cells were used as in vitro models to assess the cell viability characteristics of the carriers Soluplus®, Gelucire 50/13 and PVP K25 and the nanoformulations of Naproxen and Piroxicam. The assessment of cell viability was done using the tetrazolium salt based MTT assay. Gelucire 50/13 and its NFs were observed to have slightly higher cytotoxicity than PVP and Soluplus® and their respective NFs. All the NFs were observed to follow the cytotoxicity trend of the polymers. Our results show that no significant decrease in cell viability was seen until 0.01% concentration of Gelucire 50/13 for 12-h exposure. The NFs as well as the polymers alone had no significant effect on the viability of Caco-2 cells below 0.01% concentrations. The intestine has a protective mucous layer, whereas the cell culture monolayers do not. The intestinal tissues also have more capacity to recover from trauma than the cultured cells. Hence the present NFs can be expected to show lesser cytotoxicity when subjected to in vivo studies