Curcumin loading capacity of polyethylene glycol (PEG) functionalized graphene and graphene oxides are investigated using molecular dynamics and Monte Carlo (MC) adsorption locator simulations. These simulation methods were performed as a function of oxidation extent to study the effect of functional groups on curcumin loading and release properties. Adsorption locator energy calculations suggest that the curcumin drug molecule prefers to adsorb at the less oxidized sites of graphene oxide. One of the phenolic rings of curcumin drug prefers to have a planar interaction with graphene and graphene oxide framework due to the pi-pi interaction. Molecular dynamic studies are conducted in aqueous medium under neutral pH. Mean square displacement and radial distribution functions are obtained to determine the nature of the curcumin attachment and release in aqueous medium. The molecular simulations show that separation distance of the curcumin molecule from GO sheet is 4.4 Å. The molecular simulations presented in this work will help to design new synthetic methods of nanocarriers for curcumin delivery applications.

Density functional theory with the basis set of 6-31+G(d) was used to investigate on the carbon nano layers, C(sp2), potential as a drug delivery system for transferring of anti-cancer drug temozolomide to the target tissue. In order to elucidate the possibility of drug transmission by utilizing a carrier, the mechanisms of direct drug degradation, and loaded drug on the carrier are analyzed and examined completely. Two possible and different pathways for direct drug hydrolysis have been considered. According to obtained results activation barriers of these two pathways are 62.17 and 72.10 kcal mol^-1, and 64.30 and 70.10 kcal mol^-1 for two gas mode and also two aqueous solvent conditions respectively. By comparison of outcomes, it can be found out that these activation barriers for both degradation pathways are significantly greater than the activation barriers for drug separation from the surface of carbon carrier (18.59 and 51.92 kcal mol^-1 for gas mode and 11.79 and 44.67 kcal mol-1 for aqueous solvent). Therefore, by studying the achieved outcomes, it can be deduced that separation and releasing of the drug from the carrier occurs faster kinetically than direct degradation of temozolomide, so the drug can reach to the target before direct decomposition.

In this work, we report on the synthesis of SiO2 hollow spheres using carbon nanospheres as the sacrificial template by hydrothermal method. The synthesized substrates are in a spherical morphology and uniform size distribution. The effects of hydrothermal process, concentration and the reaction temperature were optimized during synthesis of carbon nanospheres. Infrared spectroscopy (IR), and scanning electronic microscopy (SEM) methods were used for identification of the synthesized products. The synthesized SiO2 nanospheres were used as drug carrier to investigate in vitro release behavior of monoterpenic phenol isomers, carvacrol and thymol, in simulated body fluid (SBF). Ultraviolet-visible spectroscopy (UV-vis) method was carried out to determine the amount of the drugs entrapped in the carrier. The results indicated that SiO2 nanospheres have high ability to adsorb the drugs and there is no need for adjusting the pH during the adsorption process. The drug release profile shows a three stages pattern and indicates a delayed release action.