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We fabricated and characterized tailored nanocomposites of rare-earth orthoferrites (RFeO 3) (R = Nd and Y) and magnetite (Fe 3 O 4). The orthoferrites RFeO 3 (R = Nd and Y) were prepared by sol–gel synthesis and added during the co-precipitation synthesis of magnetite in three different nominal concentrations (RFeO 3 /Fe 3 O 4 : 90/10, 50/50, 10/90). X-ray diffraction, Mössbauer spectroscopy, vibrating-sample magnetometry, transmission electron microscopy, ultraviolet–visible spectroscopy, and infrared spectroscopy were employed for structural and magnetic characterizations. The composites exhibited mean particle size distributions in the range of 5–50 nm and a maximum specific absorption rate of 55 W g−1 after 30 min of exposure to an alternating magnetic field of 220 Oe. The results demonstrate that the nanocomposites have ideal characteristics for magneto-hyperthermia applications and thus are promising systems for the treatment of diseases such as cancer. [ABSTRACT FROM AUTHOR]

The limitations of silica-based sorbents boosted the development of new extraction phases. In this study, boron nitride nanotubes functionalized with octadecyl groups were used for the first time as sorbent for extraction of losartan and valsartan, the most used angiotensin receptor blockers in the clinical practice, from human plasma. The nanotubes were synthesized using the chemical vapor deposition technique, purified by acid treatment, functionalized with octadecylamine in a microwave reactor, and characterized by different techniques. The functionalized nanotubes were packed in solid phase extraction cartridges. Extraction conditions were optimized by means of a 23 factorial design with center points. The separation was performed on a biphenyl core-shell (100 × 4.6 mm; 2.6 µm) column, using 0.1 % (v/v) triethylamine solution and methanol (pH 3.2) as mobile phase, at 0.7 mL/min, in gradient elution. The injection volume was 10 µL and fluorescence detection was performed at excitation and emission wavelengths of 250 and 375 nm, respectively. The developed method was validated according to Brazilian Health Regulatory Agency (ANVISA), United States Food and Drug Administration (US FDA) and European Medicines Agency (EMA) guidelines and presented selectivity, precision, accuracy, and linearity in the concentration ranges of 50–1200 ng/mL for losartan and 20–1700 ng/mL for valsartan. Recoveries higher than 80 % were obtained. The method was fit for the quantification of losartan in plasma samples from patients under antihypertensive therapy, being useful in therapeutic drug monitoring, pharmacokinetics and bioequivalence studies. [Display omitted] • Boron nitride nanotubes were used for the first time to extract drugs from biosamples. • The nanotubes obtained by synthesis had adequate chemical and morphological properties. • Factorial planning enabled the rational optimization of the sample preparation step. • The method was successfully applied in the analysis of losartan from plasma samples. [ABSTRACT FROM AUTHOR]

Abstract: In the present study, boron nitride nanotubes (BNNTs) were synthesized from an innovative process and functionalized with a glycol chitosan polymer in CDTN (Centro de Desenvolvimento da Tecnologia Nuclear) laboratories. As a means of studying their in vivo biodistribution behavior, these nanotubes were radiolabeled with 99mTc and injected in mice. Their size, distribution, and homogeneity were determined by photon correlation spectroscopy (PCS), while their zeta potential was determined by laser Doppler anemometry. The morphology and structural organization were evaluated by scanning electron microscopy (SEM). The functionalization in the nanotubes was evaluated by thermogravimetry analysis (TGA) and Fourier transformer infrared spectroscopy. The results showed that BNNTs were obtained and functionalized successfully, reaching a mean size and dispersity deemed adequate for in vivo studies. The BNNTs were also evaluated by ex vivo biodistribution studies and scintigraphic imaging in healthy mice. The results showed that nanostructures, after 24h, having accumulated in the liver, spleen and gut, and eliminated via renal excretion. The findings from this study reveal a potential application of functionalized BNNTs as new potential drugs or radioisotope nanocarriers to be applied in therapeutic procedures. [Copyright &y& Elsevier]

Boron nitride nanotubes (BNNTs) have been growing in notoriety in the development of systems aiming bioapplications. In this work we conducted an investigation about the mechanisms involved in the incorporation of samarium and gadolinium in BNNTs. The process was performed by the reduction of samarium and gadolinium oxides (Sm 2 O 3 and Gd 2 O 3 , respectively) in the presence of NH 3 gas (witch decomposes into N 2 and H 2) at high temperatures. Various characterization techniques were conducted to elucidate how Sm and Gd are introduced into the BNNT structure. Biological in vitro assays were performed with human fibroblasts and a human osteosarcoma cell line (SAOS-2). Our results show that the studied systems have high potential for biomedical application and can be used as non-invasive imaging agents, such as scintigraphy radiotracers or as magnetic resonance imaging (MRI) contrast medium, being able to promote the treatment of many types of tumors simultaneously to their diagnosis. • BNNTs doped in situ with samarium and gadolinium were synthesized by thermal chemical vapor deposition. • The samples were activated by neutron capture, producing 153Sm and 159Gd radioisotopes. • The irradiated samples show high specific activity. • Biocompatibility assays showed high biocompatibility both in fibroblasts and SAOS-2 cells at a concentration of 10 μg mL−1. • The results show that the systems studied have high potential for biomedical application. [ABSTRACT FROM AUTHOR]