ABSTRACT
In the present research, an orange extract (OE) was obtained and encapsulated in a zein matrix for its subsequent physicochemical characterization and evaluation of its antioxidant capacity. The OE consists of phenolic compounds and flavonoids extracted from orange peel (Citrus sinensis) by ultrasound-assisted extraction (UAE). The results obtained by dynamic light scattering (DLS) and scanning electron microscopy (SEM) indicated that zein nanoparticles with orange extract (NpZOE) presented a nanometric size and spherical shape, presenting a hydrodynamic diameter of 159.26 ± 5.96 nm. Furthermore, ζ-potential evolution and Fourier transform infrared spectroscopy (FTIR) techniques were used to evaluate the interaction between zein and OE. Regarding antioxidant activity, ABTS and DPPH assays indicated no significant differences at high concentrations of orange peel extract and NpZOE; however, NpZOE was more effective at low concentrations. Although this indicates that ultrasonication as an extraction method effectively obtains the phenolic compounds present in orange peels, the nanoprecipitation method under the conditions used allowed us to obtain particles in the nanometric range with positive ζ-potential. On the other hand, the antioxidant capacity analysis indicated a high antioxidant capacity of both OE and the NpZOE. This study presents the possibility of obtaining orange extracts by ultrasound and coupling them to zein-based nanoparticulate systems to be applied as biomedical materials functionalized with antioxidant substances of pharmaceutical utility.
ABSTRACT
In this research, we conducted a systematic evaluation of the synthesis parameters of a multi-responsive core-shell nanocomposite (Fe3O4 nanoparticles coated by poly(N-isopropylacrylamide) (PNIPAM) in the presence of chitosan (CS) (Fe3O4@PNIPAM-CS). Scanning electron microscopy (SEM) was used to follow the size and morphology of the nanocomposite. The functionalization and the coating of Fe3O4 nanoparticles (Nps) were evaluated by the ζ-potential evolution and Fourier Transform infrared spectroscopy (FTIR). The nanocomposite exhibited a collapsed structure when the temperature was driven above the lower critical solution temperature (LCST), determined by dynamic light scattering (DLS). The LCST was successfully shifted from 33 to 39 °C, which opens the possibility of using it in physiological systems. A magnetometry test was performed to confirm the superparamagnetic behavior at room temperature. The obtained systems allow the possibility to control specific properties, such as particle size and morphology. Finally, we performed vincristine sulfate loading and release tests. Mathematical analysis reveals a two-stage structural-relaxation release model beyond the LCST. In contrast, a temperature of 25 °C promotes the diffusional release model. As a result, a more in-depth comprehension of the release kinetics was achieved. The synthesis and study of a magnetic core-shell nanoplatform offer a smart material as an alternative targeted release therapy due to its thermomagnetic properties.
