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Cell-membrane hybrid nanoparticles (NPs) are designed to improve drug delivery, thermal therapy, and immunotherapy for several diseases. Here, we report the development of distinct biomimetic magnetic nanocarriers containing magnetic nanoparticles encapsulated in vesicles and IR780 near-infrared dyes incorporated in the membranes. Distinct cell membranes are investigated, red blood cell (RBC), melanoma (B16F10), and glioblastoma (GL261). Hybrid nanocarriers containing synthetic lipids and a cell membrane are designed. The biomedical applications of several systems are compared. The inorganic nanoparticle consisted of Mn-ferrite nanoparticles with a core diameter of 15 ± 4 nm. TEM images show many multicore nanostructures (∼40 nm), which correlate with the hydrodynamic size. Ultrahigh transverse relaxivity values are reported for the magnetic NPs, 746 mM-1s-1, decreasing respectively to 445 mM-1s-1 and 278 mM-1s-1 for the B16F10 and GL261 hybrid vesicles. The ratio of relaxivities r2/r1 decreased with the higher encapsulation of NPs and increased for the biomimetic liposomes. Therapeutic temperatures are achieved by both, magnetic nanoparticle hyperthermia and photothermal therapy. Photothermal conversion efficiency ∼25-30% are reported. Cell culture revealed lower wrapping times for the biomimetic vesicles. In vivo experiments with distinct routes of nanoparticle administration were investigated. Intratumoral injection proved the nanoparticle-mediated PTT efficiency. MRI and near-infrared images showed that the nanoparticles accumulate in the tumor after intravenous or intraperitoneal administration. Both routes benefit from MRI-guided PTT and demonstrate the multimodal theranostic applications for cancer therapy.

RESUMO

Superparamagnetic iron oxide nanoparticles (SPIONs) have their use approved for the diagnosis/treatment of malignant tumors and can be metabolized by the organism. To prevent embolism caused by these nanoparticles, they need to be coated with biocompatible and non-cytotoxic materials. Here, we synthesized an unsaturated and biocompatible copolyester, poly (globalide-co-ε-caprolactone) (PGlCL), and modified it with the amino acid cysteine (Cys) via a thiol-ene reaction (PGlCLCys). The Cys-modified copolymer presented reduced crystallinity and increased hydrophilicity in comparison to PGlCL, thus being used for the coating of SPIONS (SPION@PGlCLCys). Additionally, cysteine pendant groups at the particle's surface allowed the direct conjugation of (bio)molecules that establish specific interactions with tumor cells (MDA-MB 231). The conjugation of either folic acid (FA) or the anti-cancer drug methotrexate (MTX) was carried out directly on the amine groups of cysteine molecules present in the SPION@PGlCLCys surface (SPION@PGlCLCys_FA and SPION@PGlCLCys_MTX) by carbodiimide-mediated coupling, leading to the formation of amide bonds, with conjugation efficiencies of 62% for FA and 60% for MTX. Then, the release of MTX from the nanoparticle surface was evaluated using a protease at 37 °C in phosphate buffer pH~5.3. It was found that 45% of MTX conjugated to the SPIONs were released after 72 h. Cell viability was measured by MTT assay, and after 72 h, 25% reduction in cell viability of tumor cells was observed. Thus, after a successful conjugation and subsequent triggered release of MTX, we understand that SPION@PGlCLCys has a strong potential to be treated as a model nanoplatform for the development of treatments and diagnosis techniques (or theranostic applications) that can be less aggressive to patients.

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The increase in large-scale production of magnetic nanoparticles (NP) associated with the incomplete comprehensive knowledge regarding the potential risks of their use on environmental and human health makes it necessary to study the biological effects of these particles on organisms at the cellular level. The aim of this study to examine the cellular effects on fibroblast lineage LA-9 after exposure to mixed iron oxide NP (Fe3O4 NP). The following analyses were performed: field emission gun-scanning electron microscopy (SEM-FEG), dynamic light scattering (DLS), zeta potential, ultraviolet/visible region spectroscopy (UV/VIS), and attenuated total reactance-Fourier transform infrared (ATR-FTIR) spectroscopy analyses for characterization of the NP. The assays included cell viability, morphology, clonogenic potential, oxidative stress as measurement of reactive oxygen species (ROS) and nitric oxide (NO) levels, cytokines quantification interleukin 6 (IL-6) and tumor necrosis factor (TNF), NP uptake, and cell death. The size of Fe3O4 NP was 26.3 nm when evaluated in water through DLS. Fe3O4 NP did not reduce fibroblast cell viability until the highest concentration tested (250 µg/ml), which showed a decrease in clonogenic potential as well as small morphological changes after exposure for 48 and 72 hr. The NP concentration of 250 µg/ml induced enhanced ROS and NO production after 24 hr treatment. The uptake assay exhibited time-dependent Fe3O4 NP internalization at all concentrations tested with no significant cell death. Hence, exposure of fibroblasts to Fe3O4 NP-induced oxidative stress but not reduced cell viability or death. However, the decrease in the clonogenic potential at the highest concentration demonstrates cytotoxic effects attributed to Fe3O4 NP which occurred on the 7th day after exposure.

Assuntos

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Mesenchymal stem cell (MSC) therapy has emerged as a potential therapeutic option for several diseases due to their unique properties of releasing important bioactive factors. Despite the advances in stem cell therapy, it is still difficult to accurately determine the mechanisms of cell activities after in vivo transplantation. The application of noninvasive cell tracking approaches is important to determine tissue distribution and the lifetime of stem cells following their injection, which consequently provides knowledge about the mechanisms of stem cell tissue repair. Superparamagnetic iron oxide nanoparticles (SPION) can provide a very useful tool for labeling and tracking stem cells by magnetic resonance imaging without causing toxic cellular effects and do not elicit any other side effects. Here we describe how to use SPIONs to label mesenchymal stem cells and evaluate efficacy and potential cytotoxicity in vitro.

Assuntos

RESUMO

Magnetic hyperthermia (MHT) has been shown as a promising alternative therapy for glioblastoma (GBM) treatment. This study consists of three parts: The first part evaluates the heating potential of aminosilane-coated superparamagnetic iron oxide nanoparticles (SPIONa). The second and third parts comprise the evaluation of MHT multiple applications in GBM model, either in vitro or in vivo. The obtained heating curves of SPIONa (100 nm, +20 mV) and their specific absorption rates (SAR) stablished the best therapeutic conditions for frequencies (309 kHz and 557 kHz) and magnetic field (300 Gauss), which were stablished based on three in vitro MHT application in C6 GBM cell line. The bioluminescence (BLI) signal decayed in all applications and parameters tested and 309 kHz with 300 Gauss have shown to provide the best therapeutic effect. These parameters were also established for three MHT applications in vivo, in which the decay of BLI signal correlates with reduced tumor and also with decreased tumor glucose uptake assessed by positron emission tomography (PET) images. The behavior assessment showed a slight improvement after each MHT therapy, but after three applications the motor function displayed a relevant and progressive improvement until the latest evaluation. Thus, MHT multiple applications allowed an almost total regression of the GBM tumor in vivo. However, futher evaluations after the therapy acute phase are necessary to follow the evolution or tumor total regression. BLI, positron emission tomography (PET), and spontaneous locomotion evaluation techniques were effective in longitudinally monitoring the therapeutic effects of the MHT technique.

Assuntos

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This in vitro study aimed to find the best method of granulocyte isolation for subsequentlabeling with multimodal nanoparticles (magnetic and fluorescent properties) to enable detectionby optical and magnetic resonance imaging (MRI) techniques. The granulocytes were obtained fromvenous blood samples from 12 healthy volunteers. To achieve high purity and yield, four differentmethods of granulocyte isolation were evaluated. The isolated granulocytes were labeled withmultimodal superparamagnetic iron oxide nanoparticles (M-SPIONs) coated with dextran, and theiron load was evaluated qualitatively and quantitatively by MRI, near-infrared fluorescence (NIRF)and inductively coupled plasma mass spectrometry (ICP-MS). The best method of granulocyteisolation was Percoll with Ficoll, which showed 95.92% purity and 94% viability. After labeling withM-SPIONs, the granulocytes showed 98.0% purity with a yield of 3.5 × 106 cells/mL and more than98.6% viability. The iron-loading value in the labeled granulocytes, as obtained by MRI, was 6.40 ±0.18 pg/cell. Similar values were found with the ICP-MS and NIRF imaging techniques. Therefore,our study shows that it is possible to isolate granulocytes with high purity and yield and labelingwith M-SPIONs provides a high internalized iron load and low toxicity to cells. Therefore, these MSPION-labeled granulocytes could be a promising candidate for future use ininflammation/infection detection by optical and MRI techniques.

Assuntos

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Higher quality magnetic nanoparticles are needed for use as magnetic nanoprobe in medical imaging techniques and cancer therapy. Moreover, the phytochemistry benefits of some Amazonian essential oils have sparked great interest for medical treatments. In this work, a magnetic nanoprobe was developed, allying the biocompatibility and superparamagnetism of iron oxide nanoparticles (SPIONs) with benefits associated with Amazonian oils from Copaiba and Andiroba trees. SPIONs were obtained by two thermal decomposition procedures and different amounts of precursors (iron acetylacetonates). Their characterization was accomplished by Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy (TEM), X-ray diffraction (XRD), Mössbauer spectroscopy and magnetization. The obtained nanoparticles composition and magnetic properties were not affected by the relative proportion of iron(II) and iron(III) in the precursor system. However, when changing the reducing and stabilizing agents the coating layer shows different compositions/relative weight - the more promising SPIONs have a coating mainly composed by oleylamine and an iron oxide:coating wt% ratio of 55:45. Nanoparticles size distributions were very narrow and centred in the average size of 6-7nm. Cellular assays confirmed the biocompatibility of SPIONs and their effective internalization in human colon cancer cells. Mössbauer/XRD results indicated maghemite as their main iron oxide phase, but traces of magnetite proved to be present. Magnetization saturations of 57emu/g at 5K and 42emu/g at 300K were achieved. With incorporation of SPIONs into Copaiba and Andiroba essential oils, these values show a 4-fold decrease, but the supermagnetic behaviour is preserved providing the effective formation of a nanofluid.

Assuntos