Hyaluronic acid (HA) has attracted much attention in tumor-targeted drug delivery due to its ability to specifically bind to the CD44 cellular receptor, which is widely expressed on cancer cells. We present HA-capped magnetic nanoparticles (HA-MNPs) obtained via the co-precipitation method, followed by the electrostatic adsorption of HA onto the nanoparticles’ surfaces. A theoretical study carried out with the PM3 method evidenced a dipole moment of 3.34 D and negatively charged atom groups able to participate in interactions with nanoparticle surface cations and surrounding water molecules. The ATR-FTIR spectrum evidenced the hyaluronic acid binding to the surface of the ferrophase, ensuring colloidal stability in the water dispersion. To verify the success of the synthesis and stabilization, HA-MNPs were also characterized using other investigation techniques: TEM, EDS, XRD, DSC, TG, NTA, and VSM. The results showed that the HA-MNPs had a mean physical size of 9.05 nm (TEM investigation), a crystallite dimension of about 8.35 nm (XRD investigation), and a magnetic core diameter of about 8.31 nm (VSM investigation). The HA-MNPs exhibited superparamagnetic behavior, with the magnetization curve showing saturation at a high magnetic field and a very small coercive field, corresponding to the net dominance of single-domain magnetic nanoparticles that were not aggregated with reversible magnetizability. These features satisfy the requirement for magnetic nanoparticles with a small size and good dispersibility for long-term stability. We performed some preliminary tests regarding the nanotoxicity in the environment, and some chromosomal aberrations were found to be induced in corn root meristems, especially in the anaphase and metaphase of mitotic cells. Due to their properties, HA-MNPs also seem to be suitable for use in the biomedical field.

We studied the impact of some magnetic nanoparticles on two wastewater models of Rhodamine B dye, with 5 µM and 10 µM concentrations. The magnetite nanoparticles, synthesized by the co-precipitation technique, having less than 20 nm diameter and typical crystallinity features, were used to treat the Rhodamine B solutions and the results were analyzed using spectral measurements. The biological efficacy of the photo-Fenton-like reactions underlying this wastewater treatment was assessed using the V79-4 fibroblast cell line of Chinese hamster. The MTT test (colorimetric method with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) was applied for the toxicity testing of Rhodamine B 10 µM and 5 µM, initially, and degraded with 8 g/L MNP and 10 mM hydrogen peroxide for 120 min of UV exposure, the cell viability decreasing to 57–59% and 69–74%, respectively, for the dose of 80 µL/mL. Morphological changes were identified by microscopy analysis, such as membrane disruption, cell content extravasation, apoptotic bodies, and also colored spherical inclusions suggesting non-metabolized dye solution aliquots. The simpler molecules consisting of Rhodamine B degradation products, i.e., benzoic acid, benzyloxyamine, and phthalic acid were analyzed for their theoretical reactivity through quantum chemical computational modeling, which revealed a significant chemical potential compared to Rhodamine B.

Cysteamine is a remarkable antioxidant and radioprotector useful in complementary therapies in oncology, as well as for coating metallic nanoparticles for wastewater treatment for the removal of dyes and heavy metals and for photovoltaic cells. We performed a computational study on its chemical reactivity and synthesized magnetite nanoparticles stabilized with cysteamine (MNP@cys) in aqueous suspension. The MNP@cys nanoparticles showed typical crystallization by X-ray diffraction analysis, as anticipated by TEM-SAED analysis, where electron diffraction planes were highlighted. The lattice parameter was 0.8384 nm, the interplanar spacing was 0.2527 nm and the crystallite size was 9.8 nm. The attachment of cysteamine to the surface of the nanoparticles was demonstrated by Raman spectrophotometry and SEM-EDS analysis, which confirmed the good reactivity of cysteamine resulting from quantum chemical simulation. TEM analysis revealed magnetite nanoparticles with a characteristic diameter of approximately 13 nm. Room-temperature VSM measurements indicated very low coercivity and weak hysteresis, consistent with superparamagnetic-like behavior, and yielded an estimated effective magnetic diameter of approximately 10 nm. All these physicochemical characteristics contributed to a good stabilization in an aqueous environment, which is necessary for biomedical applications.