This study provides deep insight into the adsorption process of doxorubicin onto different types of carbon nanotubes that have been proved to show attractive properties as a drug delivery system. The main aim of the work was to propose probable adsorption mechanisms and interactions between the anticancer drug and surface of modified and pristine carbon nanotubes at blood pH. The carbon nanotubes were oxidized to optimize the absorbance efficiency relative to that of pristine multiwalled carbon nanotubes. The adsorption isotherm of the modified system was well described by the Temkin equation. It confirms that the adsorption in the system studied involves also hydrogen and covalent bonding and is exothermic in nature. The experimental kinetic curves of adsorption were fitted to different mathematical models to check if the kinetics of doxorubicin adsorption onto the modified multiwalled carbon nanotubes follows a pseudo-second-order model and the chemical sorption is bound to be the rate-limiting. On the basis of the molecular dynamics simulation, it was shown that in vacuo the aggregation tendency of doxorubicin molecules is far more favorable than their adsorption on pristine carbon nanotubes (CNTs). It suggests that only functionalization of the nanotube surface can affect the interaction between doxorubicin and functional groups of the carriers and increases the efficiency of the drug loading process.

The article discusses the release process of doxorubicin hydrochloride (DOX) from multi-wall carbon nanotubes (MWCNTs). The studies described a probable mechanism of release and actions between the surface of functionalized MWCNTs and anticancer drugs. The surface of carbon nanotubes (CNTs) has been modified via treatment in nitric acid to optimize the adsorption and release process. The modification efficiency and physicochemical properties of the MWCNTs+DOX system were analyzed by using SEM, TEM, EDS, FTIR, Raman Spectroscopy and UV-Vis methods. Based on computer simulations at pH 7.4 and the experiment at pH 5.4, the kinetics and the mechanism of DOX release from MWNT were discussed. It has been experimentally observed that the acidic pH (5.4) is appropriate for the efficient release of the drug from CNTs. It was noted that under acidic pH conditions, which is typical for the tumour microenvironment almost 90% of the drug was released in a relatively short time. The kinetics models based on different mathematical functions were used to describe the release mechanism of drugs from MWCNTs. Our studies indicated that the best fit of experimental kinetic curves of release has been observed for the Power-law model and the fitted parameters suggest that the drug release mechanism of DOX from MWCNTs is controlled by Fickian diffusion. Molecular dynamics simulations, on the other hand, have shown that in a neutral pH solution, which is close to the blood pH, the release process does not occur keeping the aggregation level constant. The presented studies have shown that MWCNTs are promising carriers of anticancer drugs that, depending on the surface modification, can exhibit different adsorption mechanisms and release.

In this article, a novel method of simultaneous carborane- and gadolinium-containing compounds as efficient agents for neutron capture therapy (NCT) delivery via magnetic nanocarriers is presented. The presence of both Gd and B increases the efficiency of NCT and using nanocarriers enhances selectivity. These factors make NCT not only efficient, but also safe. Superparamagnetic Fe₃O₄ nanoparticles were treated with silane and then the polyelectrolytic layer was formed for further immobilization of NCT agents. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray (EDX), ultraviolet–visible (UV-Vis) and Mössbauer spectroscopies, dynamic light scattering (DLS), scanning electron microscopy (SEM), vibrating-sample magnetometry (VSM) were applied for the characterization of the chemical and element composition, structure, morphology and magnetic properties of nanocarriers. The cytotoxicity effect was evaluated on different cell lines: BxPC-3, PC-3 MCF-7, HepG2 and L929, human skin fibroblasts as normal cells. average size of nanoparticles is 110 nm; magnetization at 1T and coercivity is 43.1 emu/g and 8.1, respectively; the amount of B is 0.077 mg/g and the amount of Gd is 0.632 mg/g. Successful immobilization of NCT agents, their low cytotoxicity against normal cells and selective cytotoxicity against cancer cells as well as the superparamagnetic properties of nanocarriers were confirmed by analyses above.