Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 7.687
Filtrar
1.
Top Curr Chem (Cham) ; 378(1): 13, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31925680

RESUMO

The use of magnetic nanoparticles (MNPs), such as iron oxide nanoparticles (IONPs), in biomedicine is considered to be a valuable alternative to the more traditional materials due to their chemical stability, cost-effectiveness, surface functionalization, and the possibility to selectively attach and transport targeted species to the desired location under a magnetic field. One of the many main applications of MNPs is DNA separation, which enables genetic material manipulation; consequently, MNPs are used in numerous biotechnological methods, such as gene transfection and molecular recognition systems. In addition, the interaction between the surfaces of MNPs and DNA molecules and the magnetic nature of the resulting composite have facilitated the development of safe and effective gene delivery vectors to treat significant diseases, such as cancer and neurological disorders. Furthermore, the special recognition properties of nucleic acids based on the binding capacity of DNA and the magnetic behavior of the nanoparticles allowing magnetic separation and concentration of analytes have led to the development of biosensors and diagnostic assays; however, both of these applications face important challenges in terms of the improvement of selective nanocarriers and biosensing capacity. In this review, we discuss some aspects of the properties and surface functionalization of MNPs, the interactions between DNA and IONPs, the preparation of DNA nanoplatforms and their biotechnological applications, such as the magnetic separation of DNA, magnetofection, preparation of DNA vaccines, and molecular recognition tools.


Assuntos
DNA/química , Compostos Férricos/química , Nanopartículas de Magnetita/química , Nanomedicina , DNA/isolamento & purificação , Portadores de Fármacos/química , Humanos , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Vacinas de DNA/química , Vacinas de DNA/imunologia
2.
Environ Technol ; 41(5): 658-668, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30074861

RESUMO

Monolayers of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane have been established on magnetite nanoparticles to develop a novel magnetic adsorbent for fast decontamination of hexavalent chromium (Cr(VI)) from water. Results indicated that monolayer adsorption of the silane from water took place at low concentrations (<300 mg/L) and around 100% surface coverage was obtained at temperatures ≥90°C. The hydrolysed silane was anchored to the magnetite surface through condensation reactions between its silanol groups and the surface hydroxyl groups of magnetite. The functional amine groups were protonated by acid treatment for adsorbing Cr(VI). The monolayer of the silane on magnetite (MSM) with approximately 100% surface coverage showed extremely rapid adsorption kinetics for Cr(VI), such that the process was complete within 1 min. This enables the treatment of large amounts of sewage per unit time. The adsorption capacity for Cr(VI) was 8.0 mg/g, as estimated from the Langmuir isotherm model. The saturation magnetization of the MSM reached 64.16 emu/g, allowing easy magnetic recovery from water. In the presence of up to 50-fold molar excesses of chloride and nitrate anions, little effect on Cr(VI) removal was seen, but moderate and large impacts were observed with sulphate and hydroxyl anions, respectively. Desorption of adsorbed Cr(VI) and regeneration of the MSM were successfully achieved by NaOH and HCl treatments to deprotonate and protonate the amine groups, respectively. By selecting a silane with suitable functional groups, the surface properties may be tailored for a particular pollutant.


Assuntos
Nanopartículas de Magnetita , Compostos de Organossilício , Minorias Sexuais e de Gênero , Poluentes Químicos da Água , Purificação da Água , Adsorção , Cromo , Homossexualidade Masculina , Humanos , Concentração de Íons de Hidrogênio , Cinética , Masculino , Água
3.
J Photochem Photobiol B ; 202: 111716, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31821944

RESUMO

Though anesthetic drug delivery system and drug vehicles is generally applied for pain relief, there are have many difficulties and issues due to its short duration carrier and low biocompatibility, effectiveness at the conditions of inflammation at acidic pH. To resolve this issue, we have designed and developed the dual (pH and temperature) responsive bio-nanomaterial to improve the efficiency anesthetic drug delivery system. Chitosan is a unique class of biomaterials that is widely used in medical devices. The surface engineering of ZnFe2O4 nanoparticles was performed by coating with chitosan using simple precipitation method. Then, multi-active anesthetic drug (Lidocaine) was loaded into nano-ferrite to form a drug delivery vehicle. The prepared drug-vesicle was characterized by using XRD, FTIR, SEM, XPS and TGA analysis. XRD analysis proved the face center cubic structure of zinc nanoferrite. The sustained delivery of Lidocaine (LDC) from CS coated nanoferrite (CS/ZnFe2O4) was stimulated by pH and temperature responsive characteristics of vesicles. The in vitro cytotoxicity of the CS/ZnFe2O4 particles towards fibroblast cells was analyzed by using MTT assay. The drug loaded CS/ZnFe2O4 particles exhibit high biocompatibility and sustained drug release in the physiological pH environment (4.8, 5.5 and 7.4) and temperature responsive (25 and 37 °C) of normal tissues and also drug loading efficiency was measured.


Assuntos
Anestésicos/química , Quitosana/química , Portadores de Fármacos/química , Nanoestruturas/química , Anestésicos/metabolismo , Anestésicos/uso terapêutico , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Liberação Controlada de Fármacos , Humanos , Concentração de Íons de Hidrogênio , Lidocaína/química , Lidocaína/metabolismo , Magnetismo , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/toxicidade , Nanoestruturas/toxicidade , Dor/tratamento farmacológico , Ratos , Temperatura Ambiente
4.
Chemosphere ; 239: 124723, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31514012

RESUMO

Humic acid (HA) compounds in drinking water and wastewater disinfection processes are viewed as precursors of highly toxic, carcinogenic, and mutagenic disinfection by-product chemicals. In recent times, these compounds have gained considerable attention of scientists for their successful removal from aqueous solutions to permissible limits. To achieve this aim, the present study investigated, for the first time, the photocatalytical performance of the synthesis FeNi3@SiO2@TiO2 nanoparticles for the HA degradation under different environmental conditions. The photocatalytic reactions were performed using ultraviolet (UV) radiation, whose intensity was fixed at 2500 µW/cm2 throughout the experimental study. The characterization study performed, using specific diagnostic techniques, revealed the presence of several good morphological, magnetic, and catalytic specifications of the synthesized nanoparticles. The use of the simplified form of the Langmuir-Hinshelwood equation sufficiently describes the experimental data of the HA kinetic degradation, as it shows a high coefficient of regression values. Furthermore, the complete HA degradation was reached under conditions of pH = 3; initial HA concentration = 10 mg/L; FeNi3@SiO2@TiO2 nanoparticles dosage = 0.01 g/L; and reaction time >30 min. Thus, the results obtained from this research suggested that the catalyst of FeNi3@SiO2@TiO2 nanoparticles was an attractive, novel, and effective agent, which could be used for the degradation of HA in the photocatalytic processes.


Assuntos
Substâncias Húmicas , Nanopartículas de Magnetita/química , Purificação da Água/métodos , Catálise , Água Potável , Concentração de Íons de Hidrogênio , Cinética , Processos Fotoquímicos , Dióxido de Silício/química , Titânio/química , Raios Ultravioleta , Águas Residuárias , Poluentes Químicos da Água/química
5.
Food Chem ; 302: 125275, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442701

RESUMO

2,6-Dimethoxy-ρ-benzoquinone (DMBQ) is a potential anti-tumor substance found in the fermented wheat germ. In this study, ultrasound and Fe3O4 nanoparticles were used to improve the DMBQ yield. An artificial neural network (ANN) embedded separately with the back-propagation algorithm (BP), genetic algorithm (GA), particle swarm optimized algorithm (PSO), ant colony optimized algorithm (ACO), GA-ACO, GA-PSO and PSO-ACO, were used to establish the relationship between 11 factors and DMBQ yield. The robustness and generalization of PSO-ACO-ANN, which gave the minimum mean squared error and mean absolute percentage error for the training and test dataset, was superior to the others. Next, a modified Garson's algorithm and mixed partial derivatives algorithm indicated that the most influential paired-parameters were ultrasonic power and concentration of nanoparticles. Finally, the factors were optimized by six optimization algorithms, and confirmatory experimental results indicated that the optimum DMBQ yield was 0.213 ±â€¯0.007 mg/g, which was 161.2% higher than the control.


Assuntos
Algoritmos , Benzoquinonas/metabolismo , Fermentação/efeitos dos fármacos , Nanopartículas de Magnetita , Triticum/efeitos dos fármacos , Triticum/metabolismo , Ondas Ultrassônicas
6.
Food Chem ; 303: 125396, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31446365

RESUMO

This study describes the determination of lead at trace levels by slotted quartz tube flame atomic absorption spectrophotometry (SQT-FAAS) after preconcentration by the help of stearic acid coated magnetic nanoparticle (SAC-MNPs) based sonication assisted dispersive solid phase extraction (SA-DSPE). SAC-MNPs were used due to their easy separation advantages by the application of external magnetic field. All extraction parameters were optimized by response surface methodology based experimental design. The experimented data was evaluated by the analysis of variance. Under the optimum conditions, about 31 folds enhancement in detection power was obtained over the conventional FAAS. The recovery results obtained for samples spiked at 60 and 120 ng mL-1 were 106.6 and 102.6%, respectively, validating the method as accurate and applicable to the red pepper matrix. The percent relative standard deviations of the results were under 5.0% even at low concentrations that established high precision for replicate extractions and instrumental readings.


Assuntos
Capsicum/química , Chumbo/análise , Chumbo/isolamento & purificação , Microextração em Fase Líquida/métodos , Magnetismo/métodos , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodos , Contaminação de Alimentos/análise , Frutas/química , Magnetismo/instrumentação , Nanopartículas de Magnetita/química , Quartzo/química , Sensibilidade e Especificidade , Sonicação , Ácidos Esteáricos/química
7.
Bioresour Technol ; 296: 122265, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31678705

RESUMO

Performance of methane-producing microbial electrochemical systems (MESs) is highly reliant on electron transfer efficiency from electrode to microorganisms and vice versa. In this study, magnetite nanoparticles were used as electron carriers to enhance extracellular electron transfer in single chamber MESs. The MES with magnetite exhibited the highest methane yield and current generation of 0.37 ±â€¯0.009 LCH4/gCOD and 9.6 mA, respectively among the tested reactors. The experimental data was observed to be highly consistent with modified Gompertz model results (R2 > 0.99), which also showed 74.2% and 22.1% enhanced methane production rate in MES with magnetite as compared to control AD and MES without magnetite, respectively. Cyclic voltammetry and electrochemical impedance spectroscopy analysis confirmed that magnetite enhanced catalytic activity of biofilm and lowered both solution and charge transfer resistance. Therefore, supplementing magnetite in MESs could be a strategy to develop an efficient syntrophic biomethanation in field scale applications.


Assuntos
Nanopartículas de Magnetita , Anaerobiose , Transporte de Elétrons , Óxido Ferroso-Férrico , Metano
8.
Talanta ; 206: 120204, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514833

RESUMO

As a rapid and facile means for foodborne bacteria detection in situ, lateral flow immunoassay (LFA) still has intrinsic limitations in the construction of the existing sandwich LFA format, e.g. screening difficulties of paired antibodies (Abs), poor stability of Ab probe, etc. Here, combined the strong affinity of antibiotic with the superior specificity of antibody molecules, a novel and robust LFA based on a dual recognition strategy and magnetic separation was designed to achieve specific and sensitive determination of Salmonella enteritidis (S. enteritidis). In this work, ampicillin (Amp), a broad-spectrum antibiotic against bacteria, was employed as an ideal Ab replacer to anchor cells of target bacteria. By coating Amp on magnetite nanoparticles (MNPs), the Amp-MNPs showed remarkable binding, separation and enrichment capacities toward bacteria even under complex sample matrices. To ensure the selectivity of this protocol, anti-S. enteritidis monoclonal antibody was then adopted as the second anchoring agent to form a sandwich complex with Amp-MNPs. Based on these facts, S. enteritidis, as low as 102-103 CFU/mL, could be detected by naked eyes in food samples. Therefore, this creative antibiotic-bacteria-antibody LFA sandwich pattern shows great application potential in the monitoring of food contamination and infectious diseases caused by pathogenic bacteria. Compared to the common paired Abs based sandwich method, the proposed approach was cost-effective, non-labor intensive, stable, sensitive and efficient.


Assuntos
Contaminação de Alimentos/análise , Imunoensaio/métodos , Separação Imunomagnética/métodos , Salmonella enteritidis/isolamento & purificação , Ampicilina/química , Animais , Anticorpos Monoclonais/imunologia , Citrullus/microbiologia , Sucos de Frutas e Vegetais/análise , Sucos de Frutas e Vegetais/microbiologia , Limite de Detecção , Nanopartículas de Magnetita/química , Leite/microbiologia , /microbiologia , Salmonella enteritidis/imunologia , Suínos/microbiologia
9.
Talanta ; 206: 120212, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514841

RESUMO

Graphene oxide-Fe3O4 (GO-Fe3O4) nanocomposite was synthesized by a facile chemical co-precipitation method. The GO-Fe3O4 was used as magnetic sorbent to extract the eight psychoactive drugs from urine samples. The analytes are morphine (MOR), 6-monoacetylmorphine (6-MAM), amphetamine (AMP), methamphetamine (MAMP), codeine, cocaine, dolantin and benzoylecgonine (BZE), which were determined by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). This method has high selectivity for the target analytes. The limit of detection (LOD) and limit of quantification (LOQ) were 0.02-0.2 µg L-1 and 0.05-0.5 µg L-1, respectively. The Mandel's fitting test revealed good linearity within all linear ranges. The linear ranges were calculated as 0.05-1000 µg L-1 for AMP, MAMP, cocaine and dolantin; 0.1-1000 µg L-1 for 6-MAM and codein; and 0.5-1000 µg L-1 for MOR and BZE. The recoveries ranged in 80.4-105.5%. The intra-day and inter-day RSDs are in the range of 2.7-13.1% and 3.9-13.7%, respectively. Magnetic solid phase extraction (MSPE) with GO-Fe3O4 provides a convenient, rapid and green sample pretreatment method for extracting the target psychoactive drugs from urine. This methodology can be used for simultaneous or individual detection of eight major psychoactive drugs with high sensitivity. This method has high potential in clinical and forensic areas for psychoactive drugs analysis.


Assuntos
Grafite/química , Nanopartículas de Magnetita/química , Nanocompostos/química , Psicotrópicos/urina , Cromatografia Líquida de Alta Pressão/métodos , Óxido Ferroso-Férrico/síntese química , Grafite/síntese química , Limite de Detecção , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
10.
Talanta ; 206: 120218, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514867

RESUMO

Proteinase K (ProK) is used for the degradation of proteins in cell lysates to isolate nucleic acids, and for the speciation of proteins for mass spectrometry analysis. In this work, a novel and sensitive immobilization process was developed for examination of protein mixtures by combining MALDI-ToF-MS and nLC-TIMS-ToF-MS/MS systems. To achieve these goals, magnetic nanoparticles (MPs) were prepared via thermal coprecipitation reaction under alkaline condition. The MPs were grafted with a silica layer (i.e., 3-(2,3-epoxypropoxy) propyltrimethoxysilane; EPTES) containing reactive epoxy groups. Then, the silica-grafted magnetic particles were coated with a long chain hydrophilic poly(ethylene glycol) diamine polymer (PEGDAP). The prepared materials were characterized by the Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), scanning electron microscopy (SEM) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. The VSM data show that the MPs@EPTES@PEGDAP has paramagnetic performance with a saturation magnetization of approximately 32.3 emu g-1. Proteinase K (EC 3.4.21.64) was covalently immobilized on the MPs@EPTES by reaction of its epoxy groups with amine groups of the enzyme. On the other hand, the ProK was immobilized on the MPs@EPTES@PEGDAP after activation with glutaraldehyde and the immobilization reaction was realized by the coupling reaction between aldehyde groups of the support and amine groups of the enzyme. The amounts of immobilized ProK on the MPs@EPTES and MPs@EPTES@PEGDAP were found to be 27.4 and 19.6 mg g-1and the retained activities were determined to be 29 and 87%, respectively. For the first time, some important features such as thermal and storage stabilities, reusability and potential use in protein speciation for mass spectrometry-based techniques were also evaluated. For examples, after six weeks of storage at 4 °C, the immobilized ProK on the MPs@EPTES@PEGDAP-ProK still maintained 59% of its initial activity. However, at the end of the six-week storage period, its free counterpart had lost all of its initial activity. The immobilized ProK was also utilized for degradation and identification of model proteins (i.e., α-2-HS glycoprotein, ß-casein, bovine serum albumin and immunoglobulin). After enzymatic treatment, the digested peptides were analyzed and mapped by using nLC-TIMS-ToF-MS/MS systems.


Assuntos
Endopeptidase K/química , Enzimas Imobilizadas/química , Nanopartículas de Magnetita/química , Fragmentos de Peptídeos/análise , Proteínas/química , Cinética , Estrutura Molecular , Polietilenoglicóis/química , Proteólise , Dióxido de Silício/química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Espectrometria de Massas em Tandem/métodos
11.
Talanta ; 206: 120205, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514877

RESUMO

We report an attomolar sensitive electrochemical genosensor for the detection of cauliflower mosaic virus 35S (CaMV35S) gene. The sandwich-type genosensor uses gold-silver core-shell (Au@Ag)-loaded iron oxide (Fe3O4) nanocomposite (Fe3O4-Au@Ag) as label of signal DNA probe (sDNA). Electrochemical sensing is accomplished at interface of electrodeposited AuNPs and carboxylated multiwalled carbon nanotubes-modified glassy carbon electrode through the specific interaction between the capture probe and target CaMV35S (tDNA), and tDNA and the labeled sDNA. The detection sensitivity was improved by the amplified reduction signal of hydrogen peroxide (H2O2), which takes advantage of the enhanced electrocatalytic activity of Fe3O4-Au@Ag. Under the optimal experimental conditions, an ultralow limit of detection was calculated to be 1.26 × 10-17 M (S/N = 3), and the blank value subtracted reduction signal of H2O2 of the sensor increased linearly with the logarithm of CaMV35S concentration over a wide range (1 × 10-16 M to 1 × 10-10 M). This genosensor displayed excellent stability, selectivity and reproducibility, and was successful in detecting the target CaMV35S in genetically modified tomato samples.


Assuntos
Técnicas Biossensoriais/métodos , Caulimovirus/genética , DNA Viral/análise , Nanopartículas de Magnetita/química , Nanocompostos/química , Plantas Geneticamente Modificadas/genética , Sondas de DNA/química , Sondas de DNA/genética , DNA Viral/genética , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Peróxido de Hidrogênio/química , Lycopersicon esculentum/genética , Nanotubos de Carbono/química , Hibridização de Ácido Nucleico , Oxirredução , Prata/química
12.
Talanta ; 206: 120213, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514887

RESUMO

Phthalate esters (PAEs) are an important kind of environmental endocrine disrupting chemicals, and have attracted great attention in environmental field. Present study described a new method for rapid and sensitive determination of PAEs including dibenzyl phthalate (DPhP), dibutyl phthalate (DnPP), and dicyclohexyl phthalate (DCHP) from aqueous matrices based on magnetic solid-phase extraction. Polyamidoamine (PAMAM) dendrimers-grafted magnetic-nanoparticles were synthesized and characterized, and the expected integration of more multifunctional sites of PAMAM dendrimers and rapid separation property was utilized for method development. To achieve the best extraction efficiency, several important parameters were optimized including the dosage of the adsorbent, sample pH, kind and volume of eluent, extraction time, desorption time, ionic strength. Under the optimal conditions, three phthalate esters were well enriched and simultaneously determined by high performance liquid chromatography with variable wavelength detector (VWD). Excellent linearities were observed in the range of 0.1-600 µg L-1 for DPhP and DnPP and 0.5-600 µg L-1 for DCHP, and all correlation coefficients (R2) were larger than 0.997. The limits of detection (LODs, S/N = 3) were ranged from 0.025 to 0.16 µg L-1. The spiked recoveries of PAEs in real water samples were in the range of 93.5-101.8% with satisfied relative standard deviations (RSDs) ranging from 0.9 to 4.1%. The prepared magnetic materials have shown good adsorption capability for PAEs and the developed method earned merits such as high sensitivity, simplicity, rapidness and environmental friendliness, which can be used as a robust alternative tool for monitoring PAEs in water samples.


Assuntos
Dendrímeros/química , Ésteres/análise , Nanopartículas de Magnetita/química , Ácidos Ftálicos/análise , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão/métodos , Dibutilftalato/análise , Lagos/análise , Limite de Detecção , Oceanos e Mares , Extração em Fase Sólida/métodos
13.
Talanta ; 206: 120220, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514891

RESUMO

This work addresses a technological advance applied to the construction of a magnetogenoassay with electrochemical transduction for the maize taxon-specific (HMGA gene) detection using gold-coated magnetic nanoparticles as nanosized platform. Superparamagnetic core-shell Fe3O4@Au nanoparticles (10.4 ±â€¯1.7 nm) were used to assemble the genoassay through the covalent immobilization of HMGA DNA probes onto carboxylated self-assembled monolayers at the nanoparticles surface. A hybridization reaction using sandwich format was selected to prevent inefficient hybridization connected with stable secondary DNA structures using also fluorescein isothiocyanate as DNA signaling tag. The labelling of the hybridization reaction with enzymes allowed the chronoamperometric measurement of the peroxidase activity linked to the nanoplatform located on gold surface. Using this electrochemical magnetogenoassay a linear concentration range from 0.5 to 5 nM and a LOD of 90 pM with a RSD <1.2% was calculated. Certified maize was evaluated without further purification after PCR amplification. This work highlights the efficacy of the electrochemical magnetogenoassay for the HMGA detection, showing its potential as alternative procedure for the verification of the compliance of the legislation.


Assuntos
Técnicas Biossensoriais/métodos , Genes de Plantas , Ouro/química , Proteínas HMGA/genética , Nanopartículas de Magnetita/química , Zea mays/genética , Sequência de Bases , Sondas de DNA/química , Sondas de DNA/genética , DNA de Plantas/química , DNA de Plantas/genética , DNA de Cadeia Simples/química , DNA de Cadeia Simples/genética , Técnicas Eletroquímicas/métodos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Limite de Detecção , Hibridização de Ácido Nucleico , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética
14.
Talanta ; 206: 120217, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514897

RESUMO

MicroRNAs (miRNA) involve in regulating different physiological processes whose dysregulation is associated with a wide range of diseases including cancers, diabetes and cardiovascular problems. Herein, we report a direct, sensitive and highly selective detection assay for circulating microRNA (miRNA). This detection strategy employs magnetic nanoparticles as the reaction platform which can not only allow online pre-concentration and selective separation but also integrates ligation reaction with amplification to enhance the sensitivity of the detection assay. With the presence of the target miRNA, the locked nucleic acid (LNA)-modified molecular beacon (MB) opens up, exposing the binding sites at two ends. The 3'- and 5'-end of the MB responsible for the attachment onto the magnetic nanoparticles, and reporting probe for the attachment of the pair of amplification probes respectively. The ligase ligate RNA to DNA enhance the amplification efficiency. Upon labelled with intercalating fluorophores (YOYO-1) on the hybrids, the quantification of the target miRNA was determined by measuring the fluorescence intensity. A detection limit of 314 fM was achieved with trace amount of sample consumption (~20 µL). As a proof of concept, miRNA-149 was chosen as the target miRNA. This assay is capable of discriminating single-base and reliably quantifying circulating miRNA-149 in both healthy and cancer patient's serums. The result obtained was comparable with that of quantitative reverse transcription polymerase chain reaction (qRT-PCR), suggesting that this direct and sensitive assay can be served as a promising, non-invasive tool for early diagnosis of breast cancer and colorectal cancer.


Assuntos
MicroRNA Circulante/sangue , MicroRNAs/sangue , Microscopia de Fluorescência/métodos , RNA Ligase (ATP)/química , Proteínas Virais/química , Benzoxazóis/química , MicroRNA Circulante/genética , DNA/química , DNA/genética , Corantes Fluorescentes/química , Humanos , Substâncias Intercalantes/química , Limite de Detecção , Nanopartículas de Magnetita/química , MicroRNAs/genética , Hibridização de Ácido Nucleico , Oligonucleotídeos/química , Oligonucleotídeos/genética , Estudo de Prova de Conceito , Compostos de Quinolínio/química
15.
Chemosphere ; 238: 124562, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31442774

RESUMO

Superparamagnetic iron oxide nanoparticles (SPION) have been widely studied for different biomedical and environmental applications. In this study we evaluated the toxicity and potential alterations of relevant physiological parameters caused to the microalga Chlamydomonas reinhardtii (C. reinhardtii) upon exposure to SPION. The results showed dose-dependent toxicity. A mechanistic study combining flow cytometry and physiological endpoints showed a toxic response consisting of a decrease in metabolic activity, increased oxidative stress and alterations in the mitochondrial membrane potential. Additionally, and due to the light absorption of SPION suspensions, we observed a significant shading effect, causing a marked decrease in photosynthetic activity. In this work, we demonstrated for the first time, the internalization of SPION by endocytosis in C. reinhardtii. These results demonstrated that SPION pose a potential risk for the environment if not managed properly.


Assuntos
Chlamydomonas reinhardtii/efeitos dos fármacos , Nanopartículas de Magnetita/toxicidade , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Fotossíntese/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
16.
Chemosphere ; 238: 124694, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524628

RESUMO

Techniques for reutilization of the discarded bischofite are limited while efficient recovery of the Mg(OH)2 nanoparticles from water during the synthesis and reuse processes is a challenge. In this study, the Fe3O4@Mg(OH)2 core-shell magnetic nanoparticles were firstly prepared from discarded bischofite and used as catalyst for improving the ozonation of metronidazole (MNZ). The removal rate constant of MNZ increased by 694.7% using Fe3O4@Mg(OH)2. Compared with the Mg(OH)2 control, the MNZ removal rate constant of Fe3O4@Mg(OH)2 treatment was almost tripled. The persistent high catalytic activity of the Fe3O4@Mg(OH)2 catalyst was observed since the MNZ removal rate constant decreased by just 13.2% in the third reuse run. The Fe3O4@Mg(OH)2 primarily enhanced ozone decomposition through producing hydroxyl radicals. The MNZ removal rate constant increased from 0.075 min-1 to 0.643 min-1 as catalyst dose increased from 0 to 0.6 g L-1 while it decreased by 96.0% when its initial concentration increased from 10 to 200 mg L-1. The maximum removal rate constant was observed at 25 °C when temperature increased from 15 °C to 35 °C. The Cl-, HCO3-, SO42-, Ca2+, Mg2+ ions could jeopardize MNZ degradation. The antibacterial activity of MNZ was eliminated after catalytic ozonation while the mineralization efficiency was almost doubled. The nitro group reduction and the cleavage of hydroxyethyl bond were two main transformation pathways of MNZ. These findings suggest that Fe3O4@Mg(OH)2 nanoparticle made from discarded bischofite is the promising catalyst for the ozonation of antibiotics in the terms of water purification practice and reutilization of the bischofite.


Assuntos
Antibacterianos/análise , Hidróxido de Magnésio/química , Ozônio/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Antibacterianos/metabolismo , Catálise , Fenômenos Magnéticos , Nanopartículas de Magnetita/química , Poluentes Químicos da Água/metabolismo
17.
J Biomed Nanotechnol ; 15(11): 2179-2192, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31847932

RESUMO

Until now, there is no effective method for tracking transplanted stem cells in human. Ruicun (RC) is a new ultra-small SPIONs agent that has been approved by China Food and Drug Administration for iron supplementation but not as a stem cell tracer in clinic. In this study, we demonstrated magnetic resonance imaging-based tracking of RC-labeled human umbilical cord derived mesenchymal stem cells (MSCs) transplanted to locally injured site of rat spinal cords. We then comprehensively evaluated the safety and quality of the RC-labeled MSCs under good manufacturing practicecompliant conditions, to investigate the feasibility of SPIONs for inner tracking in stem cell-based therapy (SCT). Our results showed that RC labeling at appropriate dose (200 µg/mL) did not have evident impacts on characteristics of MSCs in vitro, demonstrating safety, non-carcinogenesis, and non-tissue inflammation in vivo. The systematic assessments of intracellular biocompatibility indicated that the RC labeled MSCs met with mandatory requirements and standards for law-regulation systems regarding SCT, facilitating translation of cell-tracking technologies to clinical trials.


Assuntos
Nanopartículas de Magnetita , Cordão Umbilical , Animais , Rastreamento de Células , Humanos , Imagem por Ressonância Magnética , Transplante de Células-Tronco Mesenquimais , Mesoderma , Ratos
18.
Int J Nanomedicine ; 14: 8421-8432, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31749616

RESUMO

Purpose: Immune activation with T cell tumor infiltration is beneficial for the prognosis of patients suffering from solid cancer. Depending on their immune status, solid tumors can be immunologically classified into three groups: "hot" tumors are infiltrated with T lymphocytes, "cold" tumors are not infiltrated and "immune excluded" tumors are only infiltrated in the peripheral tumor tissue. Checkpoint inhibitors provide new therapeutic options for "hot" tumors by triggering the immune response of T cells. In order to enable this for cold tumors as well, T cells must be enriched in the tumor. Therefore, we use the principle of magnetic targeting to guide T cells loaded with citrate-coated superparamagnetic iron oxide nanoparticles (SPIONCitrate) to the tumor by an externally applied magnetic field. Methods: SPIONCitrate were produced by alkaline coprecipitation of iron(II) and iron(III) chloride and in situ coating with sodium citrate. The concentration-dependent cytocompatibility of the particles was determined by flow cytometry and blood stability assays. Atomic emission spectroscopy was used for the quantification of the particle uptake into T lymphocytes. The attractability of the loaded cells was observed by live-cell imaging in the presence of an externally applied magnetic field. Results: SPIONCitrate displayed good cytocompatibility to T cells and did not show any sign of aggregation in blood. Finally, SPIONCitrate-loaded T cells were strongly attracted by a small external magnet. Conclusion: T cells can be "magnetized" by incorporation of SPIONCitrate for magnetic targeting. The production of the particle-cell hybrid system is straightforward, as the loading process only requires basic laboratory devices and the loading efficiency is sufficient for cells being magnetically controllable. For these reasons, SPIONCitrate are potential suitable candidates for magnetic T cell targeting.


Assuntos
Ácido Cítrico/química , Dextranos/química , Imunoterapia , Magnetismo , Nanopartículas de Magnetita/química , Neoplasias/imunologia , Neoplasias/terapia , Linfócitos T/metabolismo , Linhagem Celular Tumoral , Dextranos/sangue , Dextranos/toxicidade , Dextranos/ultraestrutura , Humanos , Ferro/metabolismo , Nanopartículas de Magnetita/toxicidade , Nanopartículas de Magnetita/ultraestrutura , Neoplasias/sangue , Espécies Reativas de Oxigênio/metabolismo
19.
Environ Monit Assess ; 191(11): 692, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31667640

RESUMO

In this study, a rapid and effective dispersive solid-phase microextraction (d-SPME) method was developed to preconcentrate Pd from aqueous extract of soil samples by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS). The unique properties of magnetic nanoparticles (MNPs) were used to directly isolate Pd from the sample solutions without the need for complexation. Significant parameters of the extraction method such as magnetic nanoparticle type and amount, pH and amount of buffer solution, amount of eluent, and mixing type and period were optimized together with other instrumental parameters to boost the absorbance signal of Pd. An SQT was fitted onto the burner head to boost the interaction between Pd atoms and hollow cathode lamp radiation to enhance absorbance signals. The limit of detection (LOD) and limit of quantification (LOQ) values for Pd determined (d-SPME-MNP-SQT-FAAS) were 6.4 and 21.4 ng/mL, respectively. The percentage relative standard deviation of the developed method was calculated as 6.6%. The method was applied to soil samples taken from the campus area and spiked recovery experiments were performed to evaluate the method's accuracy/applicability. Satisfactory percent recovery results (90-101%) were obtained for different spiked concentrations and this proved the accuracy/applicability of the method.


Assuntos
Paládio/análise , Poluentes do Solo/análise , Monitoramento Ambiental/métodos , Limite de Detecção , Microextração em Fase Líquida/métodos , Magnetismo , Nanopartículas de Magnetita , Quartzo/química , Solo , Microextração em Fase Sólida , Espectrofotometria Atômica/métodos , Água/análise
20.
J Surg Oncol ; 120(8): 1391-1396, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31667855

RESUMO

BACKGROUND: Sentinel lymph node biopsy is a standard staging procedure for early axillary lymph node-negative breast cancer. As an alternative to the currently used radioactive tracers for sentinel lymph node (SLN) detection during the surgical procedure, a number of studies have shown promising results using superparamagnetic iron oxide (SPIO) nanoparticles. Here, we developed a new handheld, cordless, and lightweight magnetic probe for SPIO detection. METHODS: Resovist (SPIO nanoparticles) were detected by the newly developed handheld probe, and the SLN detection rate was compared to that of the standard radioisotope (RI) method using radioactive colloids (99m Tc) and a blue dye (indigo carmine). This was a multicenter prospective clinical trial that included 220 patients with breast cancer scheduled for sentinel node biopsy after a clinical diagnosis of negative axillary lymph node from three facilities in Japan. RESULTS: Of the 210 patients analyzed, SLN was detected in 94.8% (199/210 cases, 90% confidence interval [CI]) with our magnetic method and in 98.1% (206/210 cases, 90% CI) with the RI method. The magnetic method exceeded the threshold identification rate of 90%. CONCLUSION: This was the first clinical study to use a novel handheld magnetometer to detect SLN, which we demonstrate to be not inferior to the RI method.


Assuntos
Compostos Férricos , Nanopartículas de Magnetita , Magnetometria/instrumentação , Biópsia de Linfonodo Sentinela/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/patologia , Corantes , Meios de Contraste , Dextranos , Feminino , Humanos , Índigo Carmim , Pessoa de Meia-Idade , Estudos Prospectivos , Compostos Radiofarmacêuticos , Linfonodo Sentinela/patologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA