Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
1.
Cancer Immunol Immunother ; 73(10): 192, 2024 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-39105820

RESUMO

PURPOSE: Immune checkpoint inhibitors have revolutionized the treatment of renal cell carcinoma (RCC), but many patients do not respond to therapy and the majority develop resistant disease over time. Thus, there is increasing need for alternative immunomodulating agents. The co-inhibitory molecule T-cell immunoglobulin and ITIM domain (TIGIT) may play a role in resistance to approved immune checkpoint inhibitors and is being investigated as a potential therapeutic target. The purpose of this study was to quantify TIGIT positivity in tumor-infiltrating T cells in RCC. METHODS: We employed tissue microarrays containing specimens from primary RCC tumors, adjacent normal renal tissue, and RCC metastases to quantify TIGIT within tumor-infiltrating CD3+ T cells using quantitative immunofluorescent analysis. We also compared these results to TIGIT+ CD3+ levels in four other tumor types (melanoma, non-small cell lung, cervical, and head and neck cancers). RESULTS: We did not observe significant differences in TIGIT positivity between primary RCC tumors and patient-matched metastatic samples. We found that the degree of TIGIT positivity in RCC is comparable to that in lung cancer but lower than that in melanoma, cervical, and head and neck cancers. Correlation analysis comparing TIGIT positivity to previously published, patient-matched spatial proteomic data by our group revealed a negative association between TIGIT and the checkpoint proteins PD-1 and LAG3. CONCLUSION: Our findings support careful evaluation of TIGIT expression on T cells in primary or metastatic RCC specimens for patients who may be treated with TIGIT-targeting antibodies, as increased TIGIT positivity might be associated with a greater likelihood of response to therapy.


Assuntos
Antígenos CD , Carcinoma de Células Renais , Neoplasias Renais , Proteína do Gene 3 de Ativação de Linfócitos , Linfócitos do Interstício Tumoral , Receptor de Morte Celular Programada 1 , Receptores Imunológicos , Humanos , Carcinoma de Células Renais/imunologia , Carcinoma de Células Renais/patologia , Carcinoma de Células Renais/metabolismo , Receptores Imunológicos/metabolismo , Neoplasias Renais/imunologia , Neoplasias Renais/patologia , Neoplasias Renais/metabolismo , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Receptor de Morte Celular Programada 1/metabolismo , Antígenos CD/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Feminino , Masculino , Biomarcadores Tumorais/metabolismo
2.
Sensors (Basel) ; 24(6)2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38544003

RESUMO

The modern healthcare landscape is overwhelmed by data derived from heterogeneous IoT data sources and Electronic Health Record (EHR) systems. Based on the advancements in data science and Machine Learning (ML), an improved ability to integrate and process the so-called primary and secondary data fosters the provision of real-time and personalized decisions. In that direction, an innovative mechanism for processing and integrating health-related data is introduced in this article. It describes the details of the mechanism and its internal subcomponents and workflows, together with the results from its utilization, validation, and evaluation in a real-world scenario. It also highlights the potential derived from the integration of primary and secondary data into Holistic Health Records (HHRs) and from the utilization of advanced ML-based and Semantic Web techniques to improve the quality, reliability, and interoperability of the examined data. The viability of this approach is evaluated through heterogeneous healthcare datasets pertaining to personalized risk identification and monitoring related to pancreatic cancer. The key outcomes and innovations of this mechanism are the introduction of the HHRs, which facilitate the capturing of all health determinants in a harmonized way, and a holistic data ingestion mechanism for advanced data processing and analysis.


Assuntos
Registros Eletrônicos de Saúde , Neoplasias Pancreáticas , Humanos , Saúde Holística , Reprodutibilidade dos Testes , Semântica , Aprendizado de Máquina
3.
Ann Hematol ; 98(9): 2089-2096, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31203423

RESUMO

Myelodysplastic syndromes are clonal hematopoietic stem cell disorders characterized by cytopenia and intramedullary apoptosis. BCL-2 Ovarian Killer (BOK) is a pro-apoptotic member of the BCL-2 family of proteins which, when stabilized from endoplasmic reticulum-associated degradation (ERAD), induces apoptosis in response to ER stress. Although ER stress appropriately activates the unfolded protein response (UPR) in BOK-disrupted cells, the downstream effector signaling that includes ATF4 is defective. We used Nup98-HoxD13 (NHD13) transgenic mice to evaluate the consequences of BOK loss on hematopoiesis and leukemogenesis. Acute myeloid leukemia developed in 36.7% of NHD13 mice with a Bok gene knockout between the age of 8 and 13 months and presented a similar overall survival to the NHD13 mice. The loss of BOK exacerbated anemia in NHD13 mice, and NHD13/BOK-deficient mice exhibited significantly lower hemoglobin, lower mean cell hemoglobin concentration, and higher mean cell volume than NHD13 mice. Hematopoietic progenitor cell assays revealed a decreased amount of erythroid progenitor stem cells (BFU-E) in the bone marrow of NHD13-transgenic/BOK-deficient mice. RT-qPCR analysis demonstrated decreased mean value of ATF4 in the erythroid progenitors of NHD13 and NHD13/BOK-deficient mice. Our results suggest that in addition to induction of apoptosis in response to ER stress, BOK may regulate erythropoiesis when certain erythroid progenitors experience cell stress.


Assuntos
Estresse do Retículo Endoplasmático , Degradação Associada com o Retículo Endoplasmático , Células Precursoras Eritroides/metabolismo , Eritropoese , Síndromes Mielodisplásicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Animais , Apoptose/genética , Modelos Animais de Doenças , Células Precursoras Eritroides/patologia , Hemoglobinas/metabolismo , Camundongos , Camundongos Knockout , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologia , Proteínas Proto-Oncogênicas c-bcl-2/genética
4.
Front Immunol ; 13: 1054962, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36466830

RESUMO

Inflammation is a central pathogenic feature of the acute respiratory distress syndrome (ARDS) in COVID-19. Previous pathologies such as diabetes, autoimmune or cardiovascular diseases become risk factors for the severe hyperinflammatory syndrome. A common feature among these risk factors is the subclinical presence of cellular stress, a finding that has gained attention after the discovery that BiP (GRP78), a master regulator of stress, participates in the SARS-CoV-2 recognition. Here, we show that BiP serum levels are higher in COVID-19 patients who present certain risk factors. Moreover, early during the infection, BiP levels predict severe pneumonia, supporting the use of BiP as a prognosis biomarker. Using a mouse model of pulmonary inflammation, we observed increased levels of cell surface BiP (cs-BiP) in leukocytes during inflammation. This corresponds with a higher number of neutrophiles, which show naturally high levels of cs-BiP, whereas alveolar macrophages show a higher than usual exposure of BiP in their cell surface. The modulation of cellular stress with the use of a clinically approved drug, 4-PBA, resulted in the amelioration of the lung hyperinflammatory response, supporting the anti-stress therapy as a valid therapeutic strategy for patients developing ARDS. Finally, we identified stress-modulated proteins that shed light into the mechanism underlying the cellular stress-inflammation network in lungs.


Assuntos
COVID-19 , Síndrome do Desconforto Respiratório , Humanos , SARS-CoV-2 , Inflamação , Chaperona BiP do Retículo Endoplasmático , Pulmão
5.
Nat Commun ; 13(1): 4597, 2022 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-35933486

RESUMO

SARS-CoV-2 infection can cause an inflammatory syndrome (COVID-19) leading, in many cases, to bilateral pneumonia, severe dyspnea, and in ~5% of these, death. DNA methylation is known to play an important role in the regulation of the immune processes behind COVID-19 progression, however it has not been studied in depth. In this study, we aim to evaluate the implication of DNA methylation in COVID-19 progression by means of a genome-wide DNA methylation analysis combined with DNA genotyping. The results reveal the existence of epigenomic regulation of functional pathways associated with COVID-19 progression and mediated by genetic loci. We find an environmental trait-related signature that discriminates mild from severe cases and regulates, among other cytokines, IL-6 expression via the transcription factor CEBP. The analyses suggest that an interaction between environmental contribution, genetics, and epigenetics might be playing a role in triggering the cytokine storm described in the most severe cases.


Assuntos
COVID-19 , COVID-19/genética , Síndrome da Liberação de Citocina , Citocinas , Metilação de DNA/genética , Humanos , SARS-CoV-2/genética
6.
Brain Sci ; 12(5)2022 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-35624975

RESUMO

Preclinical evidence suggests a main role of lysophosphatidic acid (LPA) signaling in drug addiction. Recently, we reported alterations in the plasma concentrations of LPA species in patients with alcohol use disorder (AUD). As there are sex differences in drug addiction, the main aim of the present study was to investigate whether relevant LPA species (16:0-LPA, 18:0-LPA, 18:1-LPA, 18:2-LPA and 20:4-LPA) were associated with sex and/or substance use disorder (SUD). This exploratory study was conducted in 214 abstinent patients with lifetime SUD, and 91 healthy control subjects. The SUD group was divided according to the diagnosis of AUD and/or cocaine use disorder (CUD). Participants were clinically assessed, and plasma samples were collected to determine LPA species and total LPA. We found that LPA concentrations were significantly affected by sex, and women showed higher concentrations than men. In addition, there were significantly lower 16:0-LPA, 18:2-LPA and total LPA concentrations in patients with SUD than in controls. Namely, patients with CUD and AUD + CUD showed lower LPA concentrations than controls or patients with AUD. In conclusion, our data suggest that LPA species could be potential biomarkers for SUD in women and men, which could contribute to a better stratification of these patients in treatment programs.

7.
Biomedicines ; 10(5)2022 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-35625874

RESUMO

(1) Background: Co-occurrence of mental and substance use disorders (SUD) is prevalent, but complicates their clinical courses, and specific biomarkers are required. Amino acids are altered in primary mental disorders; however, little is known about SUD and psychiatric comorbidity. Because most psychiatric disorders and biomarkers show sex differences, we investigated amino acids in men and women with alcohol and/or cocaine use disorders (AUD and/or CUD) and psychiatric comorbidity. (2) Methods: A cross-sectional study was conducted in 295 participants, who were divided into four groups (AUD, n = 60; CUD, n = 41; AUD + CUD, n = 64; and control, n = 130). Participants were clinically assessed, and plasma amino acid concentrations were analyzed in relation to sex, diagnosis of SUD and psychiatric comorbidity (3) Results: In the total sample, there were sex differences, and women showed lower Iso, Leu, Gln and Glu than men. While patients with CUD and AUD + CUD had higher Glu, Gly, Orn and Ser than controls, patients with AUD showed no differences. In SUD, patients with psychiatric comorbidity had lower Orn and higher Ala than non-comorbid patients in the AUD group. (4) Conclusions: There was a dysregulation of plasma amino acids in abstinent patients with SUD. However, our results suggest the importance of considering the clinical characteristics and sex in the validity of amino acids as potential biomarkers for SUD.

8.
Nutrients ; 14(19)2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-36235746

RESUMO

The present study characterizes the oral pharmacokinetics of D-Pinitol, a natural insulin mimetic inositol, in human healthy volunteers (14 males and 11 females). D-Pinitol absorption was studied in (a) subjects receiving a single oral dose of 15 mg/kg (n = 10), or (b) 5 mg/kg pure D-Pinitol (n = 6), and (c) subjects receiving D-Pinitol as part of carbohydrate-containing carob pods-derived syrup with a 3.2% D-Pinitol (Dose of 1600 mg/subject, n = 9). The volunteers received a randomly assigned single dose of either D-Pinitol or carob pod-derived syrup. Blood samples were collected at 0, 15, 30, 45, 60, 90, 120, 180, 240, 360 and 1440 min after intake. Plasma concentration of D-Pinitol was measured and pharmacokinetic parameters obtained. The data indicate that when given alone, the oral absorption of D-Pinitol is dose-dependent and of extended duration, with a Tmax reached after almost 4 h, and a half-life greater than 5 h. When the source of D-Pinitol was a carob pods-derived syrup, Cmax was reduced to 40% of the expected based on the data of D-Pinitol alone, suggesting a reduced absorption probably because of competition with monosaccharide transport. In this group, Tmax was reached before that of D-Pinitol alone, but the estimated half-life remained the same. In the D-Pinitol groups, plasma concentrations of glucose, insulin, glucagon, ghrelin, free fatty acids, and pituitary hormones were additionally measured. A dose of 15 mg/kg of D-Pinitol did not affect glucose levels in healthy volunteers, but reduced insulin and increased glucagon and ghrelin concentrations. D-Pinitol did not increase other hormones known to enhance plasma glucose, such as cortisol or GH, which were surprisingly reduced after the ingestion of this inositol. Other pituitary hormones (gonadotropins, prolactin, and thyroid-stimulating hormone) were not affected after D-Pinitol ingestion. In a conclusion, D-Pinitol is absorbed through the oral route, having an extended half-life and displaying the pharmacological profile of an endocrine pancreas protector, a pharmacological activity of potential interest for the treatment or prevention of insulin resistance-associated conditions.


Assuntos
Fabaceae , Jejum , Glicemia , Ácidos Graxos não Esterificados , Feminino , Grelina , Glucagon , Glucose , Voluntários Saudáveis , Humanos , Hidrocortisona , Inositol/análogos & derivados , Insulina , Masculino , Prolactina , Tireotropina
9.
Sci Rep ; 11(1): 13629, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34211033

RESUMO

Granulocyte colony-stimulating factor (G-CSF) has raised much interest because of its role in cocaine addiction in preclinical models. We explored the plasma concentrations of G-CSF in patients diagnosed with substance use disorder (SUD) and highly comorbid psychiatric disorders. In particular, we investigated the association between G-CSF concentrations and comorbid major depressive disorder (MDD) in patients with cocaine and alcohol use disorders (CUD and AUD, respectively). Additionally, patients with MDD but not SUD were included in the study. Three hundred and eleven participants were enrolled in this exploratory study: 136 control subjects, 125 patients with SUD (SUD group) from outpatient treatment programs for cocaine (N = 60, cocaine subgroup) and alcohol (N = 65, alcohol subgroup), and 50 patients with MDD but not SUD (MDD group) from primary-care settings. Participants were assessed based on DSM-IV-TR criteria, and a blood sample was collected to examine the plasma concentrations of G-CSF. G-CSF concentrations were negatively correlated with age in the entire sample (r = - 0.233, p < 0.001) but not in the patients with MDD. G-CSF concentrations were lower in patients with SUD than in controls (p < 0.05), specifically in the cocaine subgroup (p < 0.05). Patients with SUD and comorbid MDD had lower G-CSF concentrations than patients with SUD but not comorbid MDD or controls (p < 0.05). In contrast, patients with MDD but not SUD showed no differences compared with their controls. The negative association between G-CSF concentrations and age in the sample was not observed in patients with MDD. G-CSF concentrations were decreased in patients with SUD and comorbid MDD but not in patients with MDD. Therefore, G-CSF may be useful to improve the stratification of patients with dual diagnosis seeking treatment. Further investigation is needed to explore the impact of sex and type of drug on the expression of G-CSF.


Assuntos
Transtorno Depressivo Maior/sangue , Fator Estimulador de Colônias de Granulócitos/sangue , Transtornos Relacionados ao Uso de Substâncias/sangue , Adulto , Alcoolismo/sangue , Alcoolismo/epidemiologia , Transtornos Relacionados ao Uso de Cocaína/sangue , Transtornos Relacionados ao Uso de Cocaína/epidemiologia , Comorbidade , Transtorno Depressivo Maior/epidemiologia , Diagnóstico Duplo (Psiquiatria) , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos Relacionados ao Uso de Substâncias/epidemiologia
10.
Biomedicines ; 9(9)2021 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-34572393

RESUMO

Lysophosphatidic acid (LPA) is an endogenous lysophospholipid and a bioactive lipid that is synthesized by the enzyme autotaxin (ATX). The ATX-LPA axis has been associated with cognitive dysfunction and inflammatory diseases, mainly in a range of nonalcoholic liver diseases. Recently, preclinical and clinical evidence has suggested a role of LPA signaling in alcohol use disorder (AUD) and AUD-related cognitive function. However, the ATX-LPA axis has not been sufficiently investigated in alcoholic liver diseases. An exploratory study was conducted in 136 participants, 66 abstinent patients with AUD seeking treatment for alcohol (alcohol group), and 70 healthy control subjects (control group). The alcohol group was divided according to the presence of comorbid liver diseases (i.e., fatty liver/steatosis, alcoholic steatohepatitis, or cirrhosis). All participants were clinically evaluated, and plasma concentrations of total LPA and ATX were measured using enzyme-linked immunosorbent assays. Data were primarily analyzed using analysis of covariance (ANCOVA) while controlling for age, body mass index, and sex. Logistic regression models were created to assess the association of the ATX-LPA axis and AUD or liver disease. LPA and ATX were log10-transformed to fit the assumptions of parametric testing.The main results were as follows: total LPA and ATX concentrations were dysregulated in the alcohol group, and patients with AUD had significantly lower LPA (F(1,131) = 10.677, p = 0.001) and higher ATX (F(1,131) = 8.327, p = 0.005) concentrations than control subjects; patients with AUD and liver disease had significantly higher ATX concentrations (post hoc test, p < 0.05) than patients with AUD but not liver disease; significant correlations between AUD-related variables and concentrations of LPA and ATX were only found in the non-liver disease subgroup (the duration of alcohol abstinence with LPA and ATX (r = +0.33, p < 0.05); and the severity of AUD with ATX (rho = -0.33, p < 0.05)); and a logistic regression model with LPA, ATX, and AUD-related variables showed an excellent discriminative power (area under the curve (AUC) = 0.915, p < 0.001) for distinguishing patients with AUD and comorbid liver disease. In conclusion, our data show that the ATX-LPA axis is dysregulated in AUD and suggest this lipid signaling, in combination with relevant AUD-related variables, as a reliable biomarker of alcoholic liver diseases.

11.
Neuropharmacology ; 162: 107840, 2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31704270

RESUMO

Cocaine induces neuroinflammatory response and interleukin-1 beta (IL1ß) is suggested a final effector for many cocaine-induced inflammatory signals. Recently, the chemokine fractalkine (CX3CL1) has been reported to regulate hippocampus-dependent neuroinflammation and synaptic plasticity via CX3C-receptor 1 (CX3CR1), but little is known about the impact of cocaine. This study is mainly focused on the characterization of CX3CL1, IL1ß and relevant inflammatory signal transduction pathways in the hippocampus in acute and repeated cocaine-treated male mice. Complementarily, the rewarding properties of cocaine were also assessed in Cx3cr1-knockout (KO) mice using a conditioned place preference (CPP). We observed significant increases in CX3CL1 and IL1ß concentrations after cocaine, although repeated cocaine produced an enhancement of CX3CL1 concentrations. CX3CL1 and IL1ß concentrations were positively correlated in acute (r = +0.61) and repeated (r = +0.82) cocaine-treated mice. Inflammatory signal transduction pathways were assessed. Whereas acute cocaine-treated mice showed transient increases in p-ERK1/2/ERK1/2 and p-p65/p65 NFκB ratios after cocaine injection, repeated cocaine-treated mice showed transient increases in p-ERK1/2/ERK1/2, p-p38/p38 MAPK, p-NFκB p65/NF-κB p65 and p-CREB/CREB ratios. Baseline p-p38/p38 MAPK and p-CREB/CREB ratios were downregulated in repeated cocaine-treated mice. Regarding the cocaine-induced CPP, Cx3cr1-KO mice showed a notably impaired extinction but no differences during acquisition and reinstatement. These results indicate that cocaine induces alterations in CX3CL1 concentrations, which are associated with IL1ß concentrations, and activates convergent inflammatory pathways in the hippocampus. Furthermore, the CX3CL1/CX3CR1 signaling could mediate the processes involved in the extinction of cocaine-induced CPP.


Assuntos
Quimiocina CX3CL1/efeitos dos fármacos , Cocaína/farmacologia , Inibidores da Captação de Dopamina/farmacologia , Hipocampo/efeitos dos fármacos , Inflamação/metabolismo , Interleucina-1beta/efeitos dos fármacos , Animais , Quimiocina CX3CL1/genética , Quimiocina CX3CL1/metabolismo , Condicionamento Clássico/efeitos dos fármacos , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/efeitos dos fármacos , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Extinção Psicológica/efeitos dos fármacos , Hipocampo/metabolismo , Interleucina-1beta/metabolismo , Masculino , Camundongos , Camundongos Knockout , Proteína Quinase 1 Ativada por Mitógeno/efeitos dos fármacos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/efeitos dos fármacos , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação/efeitos dos fármacos , Transdução de Sinais , Fator de Transcrição RelA/efeitos dos fármacos , Fator de Transcrição RelA/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
12.
Sci Total Environ ; 550: 45-52, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26803683

RESUMO

Nanoparticles (NPs) have been synthetized and studied to be incorporated in many industrial and medical applications in recent decades. Due to their different physical and chemical properties compared with bulk materials, researchers are focused to understand their interactions with the surroundings. Living organisms such as plants are exposed to these materials and they are able to tolerate different concentrations and types of NPs. Cobalt ferrite (CoFe2O4) NPs are being studied for their application in medical sciences because of their high coercivity, anisotropy, and large magnetostriction. These properties are desirable in magnetic resonance imaging, drug delivery, and cell labeling. This study is aimed to explore the tolerance of Solanum lycopersicum L. (tomato) plants to CoFe2O4 NPs. Tomato plants were grown in hydroponic media amended with CoFe2O4 nanoparticles in a range from 0 to 1000mgL(-1). Exposure to CoFe2O4 NPs did not affect germination and growth of plants. Uptake of Fe and Co inside plant tissues increased as CoFe2O4 nanoparticle concentration was increased in the media. Mg uptake in plant leaves reached its maximum level of 4.9mgg(-1) DW (dry weight) at 125mgL(-1) of CoFe2O4 NPs exposure and decreased at high CoFe2O4 NPs concentrations. Similar pattern was observed for Ca uptake in leaves where the maximum concentration found was 10mgg(-1) DW at 125mgL(-1) of CoFe2O4 NPs exposure. Mn uptake in plant leaves was higher at 62.5mgL(-1) of CoFe2O4 NPs compared with 125 and 250mgL(-1) treatments. Catalase activity in tomato roots and leaves decreased in plants exposed to CoFe2O4 NPs. Tomato plants were able to tolerate CoFe2O4 NPs concentrations up to 1000mgL(-1) without visible toxicity symptoms. Macronutrient uptake in plants was affected when plants were exposed to 250, 500 and 1000mgL(-1) of CoFe2O4 NPs.


Assuntos
Cobalto/toxicidade , Poluentes Ambientais/toxicidade , Compostos Férricos/toxicidade , Nanopartículas Metálicas/toxicidade , Solanum lycopersicum/crescimento & desenvolvimento , Hidroponia , Solanum lycopersicum/efeitos dos fármacos
13.
Nanoscale Res Lett ; 7(1): 210, 2012 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-22490731

RESUMO

Hollow magnetite microspheres have been synthesized by a simple process through a template-free hydrothermal approach. Hollow microspheres were surface modified by coating with a silica nanolayer. Pristine and modified hollow microparticles were characterized by field-emission electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, FT-IR and Raman spectroscopy, and VSM magnetometry. The potential application of the modified hollow magnetite microspheres as a drug carrier was evaluated by using Rhodamine B and methotrexate as model drugs. The loading and release kinetics of both molecules showed a clear pH and temperature dependent profile. GRAPHICAL Hollow magnetite microspheres have been synthesized. Load-release experiments with Rhodamine-B as a model drug and with Methotrexate (chemotherapy drug used in treating certain types of cancer) demonstrated the potential applications of these nanostructures in biomedical applications.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA