Navegando por Autor "Campos, Andrea"

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    Chemical and cellular characterization of SPIONs stabilized with sodium citrate
    (Springer Nature Link) Cândido, Marcela Aparecida; Jesus, Viviane Paula dos Santos; Vieira, Paula Fonseca Antunes; Campos, Andrea; Raniero, Leandro José
    Introduction Iron oxide nanoparticles (IONPs) represent a class of magnetic and biocompatible nanomaterials that have been widely used in research and medical applications, such as hyperthermia studies, as contrast agents for magnetic reso- nance imaging, biosensors, among others. Some studies have already evaluated several formulations containing IONPs in preclinical and clinical trials under the approval of the US Federal Agency. Methods IONPs were obtained by chemical coprecipitation, in which aqueous solutions of precursors containing iron (Fe3+) and ferrous (Fe2+) ions are alkalized under control of temperature and pH. The stabilization process of iron oxide nano- particles was done by sodium citrate and characterize the hydrodynamic diameter and the zeta potential by dynamic light scattering (DLS), the morphology and the diameter by transmission electron microscopy (TEM), crystal structure by X-ray diffraction (XRD), chemical composition by Fourier transform infrared spectroscopy (FT-IR), and magnetic properties by vibrating sample magnetometer (VSM). Results The DLS, MET, and FT-IR analyses confirmed that the superparamagnetic IONPs (SPIONs) syntheses had diameters smaller than 100 nm and were stabilized since the vibrational bands were present both in the sodium citrate and SPIONs spectra. IONPs exhibit superparamagnetic behavior due to the magnetic properties of the crystalline phase. Finally, pho- tothermal therapy study was carried out to determine the cell viability of MDA-MB-468 cell line after the application of SPIONs at concentrations of 0.5, 10, and 75 μg mL−1 by flow cytometry. Conclusion IONPs were synthesized in the nanometric range, and photothermal therapy shows promising results for triple- negative breast cancer treatment.
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    Gold-Coated Superparamagnetic Iron Oxide Nanoparticles Functionalized to EGF and Ce6 Complexes for Breast Cancer Diagnoses and Therapy
    (MDPI) Cândido, Marcela Aparecida; Vieira, Paula Fonseca Antunes; Campos, Andrea; Soares, Cristina Pacheco; Raniero, Leandro José
    Superparamagnetic iron oxide nanoparticles (SPIONs) have some limitations in the physio- logical environment, however, a modification on their surface, such as a core–shell structure with gold (SPIONs@Au), can enhance their applicability. In this study, SPIONs were synthesized by the chemical coprecipitation method, stabilized by sodium citrate, and followed by the gold-coating process. SPIONs@Au were functionalized with EGF-α-lipoic acid and chlorin e6 (Ce6)-cysteamine complexes, composing a Theranostic Nanoprobe (TP). The outcomes showed that the SPIONs@Au had changed in color to red and had an absorption band centered at 530 nm. The coating was verified in the TEM micrographs in bright and dark fields by EDS mapping, which indicated the presence of Au and Fe. The Ce6-cysteamine complex had a resonant band at 670 nm that enabled the diagnosis of biological samples using fluorescence analysis. In the measure of TNBC cell uptake, the maximum value of TP fluorescence intensity was obtained within 4 h of internalization. At 2 h, the incorporation of the TP in the cytoplasm as well as in the nuclei was observed, suggesting that it could be employed as a diagnostic marker. The PTT results showed significant percentages of apoptosis in the TNBC cell line, which confirms the efficacy of the TP.