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1.
Phys Rev Lett ; 124(5): 058101, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32083903

RESUMO

We report that trivalent cobalt hexammine cations decrease the persistence length, stretching modulus, helical density, and size of plectonemes formed under torque of DNA but increase those of RNA. Divalent magnesium cations, however, decrease the persistence lengths, contour lengths, and sizes of plectonemes while increasing the helical densities of both DNA and RNA. The experimental results are explained by different binding modes of the cations on DNA and RNA in our all-atom molecular dynamics simulations. The significant variations of the helical densities and structures of DNA and RNA duplexes induced by high-valent cations may affect interactions of the duplexes with proteins.


Assuntos
DNA/química , RNA de Cadeia Dupla/química , Cátions/química , Cobalto/química , Elasticidade , Magnésio/química , Magnetismo/instrumentação , Magnetismo/métodos , Modelos Químicos , Modelos Moleculares , Simulação de Dinâmica Molecular , Pinças Ópticas , RNA/química
2.
J Agric Food Chem ; 68(3): 892-898, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31891506

RESUMO

This study described a simple, specific, and sensitive method using immunoaffinity magnetic purification coupled with high-performance liquid chromatography-fluorescence (HPLC-FL) detection for determination of bovine lactoferrin (bLf) in dairy products. BLf was selectively extracted from dairy products using immunoaffinity beads and then detected by HPLC-FL with its intrinsic fluorescence. During the analysis, standard solutions of bLf were pretreated with Tween 20, an anti-adsorptive agent, for blocking the nonspecific binding of bLf to polypropylene tubes. The calibration curve was linear over the range of 0.8-30 µg mL-1. The validated method was successfully applied to measure bLf at the intact level in dairy products.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Laticínios/análise , Imunoensaio/métodos , Lactoferrina/análise , Lactoferrina/isolamento & purificação , Magnetismo/métodos , Animais , Bovinos , Cromatografia Líquida de Alta Pressão/instrumentação , Fluorescência
4.
J Sci Food Agric ; 100(3): 1048-1055, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31677164

RESUMO

BACKGROUND: Magnetic three-dimensional graphene-based nanoadsorbents have unique characteristics such as large surface area, good thermal and chemical stability, and high adsorption capacity that make them efficient materials in sorbent-based extraction techniques. In this study, four aflatoxins (AFs) were analyzed in bread samples using magnetic three-dimensional graphene as the adsorbent phase in dispersive micro solid-phase extraction. RESULTS AND CONCLUSIONS: In-syringe magnetic sheet solid-phase extraction based on magnetic three-dimensional graphene in tandem with dispersive liquid-liquid microextraction was used for the extraction and preconcentration of the target AFs. The effect of significant parameters of the method was investigated and the optimum conditions were determined as follows: adsorbent dosage, 20 mg; desorption/disperser solvent (methanol) volume, 700 µL; desorption solvent flow rate, 0.7 mL min-1 ; pH, neutral; salt (NaCl) concentration, 10% (w/v); extraction solvent (chloroform) volume, 250 µL; and centrifugation rate (and time), 4000 rpm (5 min). The limits of detection and quantification were in the ranges 0.043-0.083 and 0.14-0.28 µg kg-1 , respectively. The extraction method was followed by the HPLC technique with fluorescence detection and applied to the determination of the AFs in four different Iranian fresh and moldy bread samples. The relative recoveries were in the range 84-107% with relative standard deviations of 3.9-8.6%. © 2019 Society of Chemical Industry.


Assuntos
Aflatoxinas/isolamento & purificação , Pão/análise , Contaminação de Alimentos/análise , Microextração em Fase Líquida/métodos , Magnetismo/métodos , Extração em Fase Sólida/métodos , Adsorção , Aflatoxinas/análise , Cromatografia Líquida de Alta Pressão , Irã (Geográfico) , Extração em Fase Sólida/instrumentação , Seringas
5.
Chemosphere ; 241: 125103, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683438

RESUMO

In this paper, a novel electrode named 2.5D Ti/Sb-SnO2/PANI was developed by magnetically in-situ integration of adsorbent and electrocatalyst, where the green synthetic Fe3O4/polyaniline (PANI) nanoparticles with fair adsorption capability were used as auxiliary electrodes and coated on the surface of Ti/Sb-SnO2 main electrode, to enrich the pollutants in the vicinity of anode and therefore boost the electrochemical oxidation (EO) efficiency. Since the interchangeable auxiliary electrodes can endow the anode with adjustability and versatility, the effect of auxiliary electrodes on the surface structure and electrochemical properties of 2.5D Ti/Sb-SnO2/PANI were extensively investigated. Results showed that a tiny amount of Fe3O4/PANI auxiliary electrodes changed the solid-liquid interface, brought massive less acessible active sites and kept the similar electrode impedance and same EO capability of 2D Ti/Sb-SnO2. In terms of organic elimination and solution biodegradability enhancement, 2.5D Ti/Sb-SnO2/PANI showed a boosted 30%-60% EO efficiency on two typical biorefractory targets, i.e., Acid Red G and lignosulphonate. The specific effectiveness was dependent on the loading amount of magenetic PANI nanoparticles. The operating mechanism of the assembled 2.5D Ti/Sb-SnO2/PANI electrode was further proposed based on many details, as well as a design rule for developing novel electrodes with high efficient EO performance for wastewater treatment. Moreover, the assembled 2.5D electrode was proved to have good sustainability and recyclability, which shows a great potential in the practical applications.


Assuntos
Técnicas Eletroquímicas/métodos , Eletrodos/normas , Nanopartículas/química , Águas Residuárias/química , Purificação da Água/métodos , Compostos de Anilina , Catálise , Magnetismo/métodos , Oxirredução , Compostos de Estanho/química , Titânio/química
6.
Chemosphere ; 238: 124640, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524609

RESUMO

Triclosan (TCS) is a kind of chronic toxicity to aquatic organisms. Due to its highly effective antimicrobial, TCS has been widely applied in personal-care products, which naturally poses a potential risk to the ecological system and human health since its release into water-ecological environment. Therefore, it urgently demands a selective, easily separated, recyclable, and low-cost adsorbent to remove the residues of TCS from aquatic environments. In this study, a novel magnetic molecularly imprinted nano-polymers (TMIPs) were prepared for selective adsorption and convenient collection of TCS in aquatic samples, based on a core-shell technique using TCS as template molecule and SiO2-coated Fe3O4 nanoparticles as the support substrate. The functional groups, particle size, morphology and magnetic property of TMIPs were characterized by Fourier-transform infrared spectroscopy, scanning electron microscope, transmission electron microscopy and vibrating sample magnetometer, respectively. The obtained TMIPs possessed excellent adsorption capacity (Qe = 53.12 mg g-1), speedy adsorption equilibrium time (2 min) and high selectivity (k' = 6.321) for TCS. Moreover, the pH-tolerance and stability tests manifested that the adsorption capacity of TMIPs for TCS was acid-resistance and could retain 94.2% of the maximum Qe after 5 times removal-regeneration cycles. The feature of magnetically susceptibility can simplify the procedures of sample handling in TCS determination, because the TMIPs of TCS are easy to be recycled from aquatic samples. As an application demonstration, the toxicity test in microalgae confirmed that a tiny amount of TMIPs could significantly eliminate the toxic effect of TCS on Chlamydomonas reinhardtii via the efficient binding with TCS.


Assuntos
Magnetismo/métodos , Impressão Molecular , Nanopartículas/química , Triclosan/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Antibacterianos/isolamento & purificação , Antibacterianos/toxicidade , Cosméticos/química , Cosméticos/toxicidade , Impressão Molecular/métodos , Tamanho da Partícula , Polímeros/química , Dióxido de Silício/química , Triclosan/toxicidade
7.
Food Chem ; 306: 125455, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31629968

RESUMO

The present research reported a facile strategy for the synthesis of a novel magnetic covalent organic frameworks (Fe3O4@COF(TpDA)) material and applied it as a sorbent for magnetic solid phase extraction of plant growth regulators from fruits and vegetables. The prepared Fe3O4@COF materials showed many attractive features involving large specific surface area (180.2 m2/g) and high saturation magnetization (62.3 emu/g), which enabled it an ideal sorbent for sample pretreatment. The experimental conditions affecting the extraction performance were optimized systematically, including eluent, amount of sorbent, adsorption time and desorption time. The extracted samples were detected by HPLC-DAD. Under the optimized conditions, the proposed method exhibited good linearity (R ≥ 0.9990) and low limits of detection (4.68-7.51 µg/L). Satisfactory recoveries were calculated to be 83.0-105.0%. Finally, the proposed method was successfully applied to determination of plant growth regulators in fruits and vegetables, indicating the potential prospect of the Fe3O4@COF(TpDA) materials in sample pretreatment.


Assuntos
Frutas/química , Estruturas Metalorgânicas/análise , Reguladores de Crescimento de Planta/análise , Verduras/química , Cromatografia Líquida de Alta Pressão/métodos , Limite de Detecção , Magnetismo/métodos , Imãs , Extração em Fase Sólida/métodos
8.
Chemosphere ; 238: 124690, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31524625

RESUMO

Doxorubicin (DOX) originated from users' urine has been an emerging environmental pollutant due to its significant genotoxicity to mankind. Thus, urine source separation is a potential strategy to isolate DOX at a higher concentration and reduce the burden of downstream wastewater treatment. To develop highly efficient, easy separation and retrievable materials for individual patient to conveniently remove DOX from own urine, magnetic Cu3(PO4)2 nanoflowers were prepared through anchoring amino-functionalized magnetic nanoparticles on the Cu3(PO4)2 nanoflowers. Characterizations revealed the magnetic nanoflowers were spherical in shape with a mean size of 15 µm, and porous and hierarchical in structure. Magnetic nanoparticles located the surface of petals. Multibatch experiments were performed to assess the removal performance of DOX from aqueous solution. The magnetic nanoflowers exhibited excellent removal efficiency of DOX under weakly alkaline condition at ambient temperature. Linear and non-linear analyses were carried out to compare the best fitting kinetics and isotherms. Sorption kinetic data best fitted the pseudo-second order model. The Freundlich isotherm explained equilibrium sorption data with R2 = 0.993 higher than that for the Langmuir isotherm. When the pH of synthetic urine was adjusted to weakly alkaline (pH 8.0-9.0), over 95% of DOX (20 mg L-1) was removed by a little of magnetic nanoflowers (50 mg L-1) within 5 min. Meanwhile, the magnetic nanoflowers could be easily separated and recovered from the synthetic urine by a magnet. So, for individual urine source separation strategy, the magnetic nanoflower seems to be an efficient, convenient and inexpensive approach to remove DOX from human urine.


Assuntos
Cobre/química , Doxorrubicina/análise , Magnetismo/métodos , Urina/química , Purificação da Água/métodos , Adsorção , Humanos , Concentração de Íons de Hidrogênio , Fenômenos Magnéticos , Nanopartículas/química , Fosfatos/química , Águas Residuárias/química
9.
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
10.
J Agric Food Chem ; 67(46): 12936-12944, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31670953

RESUMO

An ultrasensitive bio-barcode competitive immunoassay method based on droplet digital polymerase chain reaction (ddPCR) was developed for the determination of triazophos. Gold nanoparticles (AuNPs) were coated with monoclonal antibodies (mAbs) and complementary double-stranded DNA (dsDNA), which included bio-barcode DNA and thiol-capped DNA. Magnetic nanoparticle (MNP) probes were constructed by modifying the MNPs with ovalbumin-hapten conjugates (OVA-hapten). The target pesticide and OVA-hapten on the surface of the MNP probes competed with the AuNP probes simultaneously, and then the bio-barcode DNA was released for quantification by ddPCR. The concentration of released DNA was inversely proportional to the concentration of pesticide to be tested. Under the optimum conditions, the competitive immunoassay exhibited a wide linear range of 0.01-20 ng/mL and a low detection limit of 0.002 ng/mL. Spike recovery tests were carried out using apple, rice, cabbage, and cucumber samples to verify the feasibility of the method. The recovery and relative standard deviations (RSDs) of the technique ranged from 76.9 to 94.4% and from 10.8 to 19.9%, respectively. To further validate the results, a linear correlation analysis was performed between the proposed method and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Consequently, the bio-barcode immunoassay based on nanoparticles and ddPCR, an ultrasensitive method, showed great potential for the determination of target pesticides in real samples.


Assuntos
Imunoensaio/métodos , Inseticidas/análise , Organotiofosfatos/análise , Reação em Cadeia da Polimerase/métodos , Triazóis/análise , DNA/genética , Ouro/química , Imunoensaio/instrumentação , Limite de Detecção , Magnetismo/métodos , Nanopartículas Metálicas/química
11.
Nat Protoc ; 14(11): 3205-3219, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31628446

RESUMO

To understand and control complex tissues, the ability to genetically manipulate single cells is required. However, current delivery methods for the genetic engineering of single cells, including viral transduction, suffer from limitations that restrict their application. Here we present a protocol that describes a versatile technique that can be used for the targeted viral infection of single cells or small groups of cells in any tissue that is optically accessible. First, cells of interest are selected using optical microscopy. Second, a micropipette-loaded with magnetic nanoparticles to which viral particles are bound-is brought into proximity of the cell of interest, and a magnetic field is applied to guide the viral nanoparticles into cellular contact, leading to transduction. The protocol, exemplified here by stamping cultured neurons with adeno-associated viruses (AAVs), is completed in a few minutes and allows stable transgene expression within a few days, at success rates that approach 80%. We outline how this strategy is applied to single-cell infection in complex tissues, and is feasible both in organoids and in vivo.


Assuntos
Dependovirus/genética , Técnicas de Transferência de Genes , Vetores Genéticos/genética , Magnetismo/métodos , Nanopartículas de Magnetita , Animais , Células Cultivadas , Vetores Genéticos/administração & dosagem , Campos Magnéticos , Nanopartículas de Magnetita/administração & dosagem , Neurônios/metabolismo , Ratos , Transdução Genética , Transgenes
12.
Environ Pollut ; 254(Pt B): 113005, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31473389

RESUMO

Norfloxacin (NOR) is a persistent organic pollutant and can be effectively removed from effluent by adsorption of biochar. However, the presence of other emerging contaminants, such as surfactants, will potentially alter adsorption performance of norfloxacin by biochar and the molecular-scale mechanisms of the interaction between surfactants and biochar remain poorly understood. In this study, adsorption of norfloxacin on magnetic biochar prepared with iron-containing furfural residue (FRMB) in the presence or absence of anionic surfactants was investigated. The adsorption of NOR was significantly affected by the initial pH and anionic surfactants-sodium dodecyl sulfate (SDS) and sodium dodecyl benzene sulfonate (SDBS). In the presence of SDS and SDBS, the maximum sorption capacities of NOR were 2.33 and 1.97 times higher than that in the absence of surfactants, reached to 698.6 mg g-1 and 589.9 mg g-1, respectively. The optimal pH condition which was 4 indicated that electrostatic adsorption played a decisive role in the adsorption process after introduction of SDS/SDBS. The adsorption data were fitted well by the Elovich model and Freundlich model at the optimal conditions in which both SDS and SDBS were hemimicelle (0.8 mM SDS or 0.4 mM SDBS), indicating surface heterogeneity of FRMB and the adsorption mechanism was related to the assembly of surfactants on biochar. FTIR results showed that FRMB and SDS/SDBS interacted through hydrophobic action, and more complex or aggregates were formed between the NOR and biochar/SDS/SDBS. This work highlights the synergistic enhancement effects of tested surfactants on the removal of NOR by magnetic biochar from aqueous systems.


Assuntos
Antibacterianos/química , Carvão Vegetal/química , Resíduos de Drogas/química , Magnetismo/métodos , Norfloxacino/química , Tensoativos/química , Purificação da Água/métodos , Adsorção , Antibacterianos/isolamento & purificação , Benzenossulfonatos/química , Resíduos de Drogas/isolamento & purificação , Magnetismo/instrumentação , Norfloxacino/isolamento & purificação , Dodecilsulfato de Sódio/química , Poluentes Químicos da Água/química , Purificação da Água/instrumentação
13.
Biosensors (Basel) ; 9(3)2019 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-31480476

RESUMO

Inexpensive simple medical devices allowing fast and reliable counting of whole cells are of interest for diagnosis and treatment monitoring. Magnetic-based labs on a chip are one of the possibilities currently studied to address this issue. Giant magnetoresistance (GMR) sensors offer both great sensitivity and device integrability with microfluidics and electronics. When used on a dynamic system, GMR-based biochips are able to detect magnetically labeled individual cells. In this article, a rigorous evaluation of the main characteristics of this magnetic medical device (specificity, sensitivity, time of use and variability) are presented and compared to those of both an ELISA test and a conventional flow cytometer, using an eukaryotic malignant cell line model in physiological conditions (NS1 murine cells in phosphate buffer saline). We describe a proof of specificity of a GMR sensor detection of magnetically labeled cells. The limit of detection of the actual system was shown to be similar to the ELISA one and 10 times higher than the cytometer one.


Assuntos
Técnicas Biossensoriais/instrumentação , Magnetismo/métodos
14.
Mater Sci Eng C Mater Biol Appl ; 104: 109875, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31499988

RESUMO

In this study, the nasopharyngeal carcinoma cell line was cultured in a superparamagnetic iron oxide nanoparticle aqueous solution with a concentration of 1 µg/mL by using magnetic labeling technology. The cells took up superparamagnetic nanoparticles through the endocytosis process, which caused the cells to become magnetic and manipulable by a magnetic field gradient. Each cell contained 5.266 × 106 superparamagnetic nanoparticles, as determined using the magnetophoresis method. A specific domain configuration and its related distribution of magnetic poles in a patterned thin film were obtained after applying a magnetic field in a specific direction. Here, patterned magnetic thin films were designed to form square grid and square ring structures. When the magnetic field of 3000 G was applied along the diagonal of the square (45° direction) and then released, magnetic cells were trapped at the intersection of the square grid and the 45° diagonal corner of the square ring structure. From micromagnetic simulation results, it was determined that head-to-head and tail-to-tail domain walls with a high magnetic pole density formed at the corners of the square ring structure in the 45° diagonal direction, and the attractive force between a head-to-head/tail-to-tail domain wall and a cell at a height of 1 µm above the corner was approximately 2.055 × 10-10 N. In the square grid case, the attractive force between the domain wall at the intersection and a cell at a height of 1 µm above the intersection was approximately 2.245 × 10-10 N. The results of this study demonstrated that cells can simultaneously be arranged at designated locations physically by using patterned magnetic thin films in a noninvasive manner without chemical modification of the substrate.


Assuntos
Imãs/química , Nanopartículas/química , Compostos Férricos/química , Magnetismo/métodos
15.
J Agric Food Chem ; 67(41): 11527-11535, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31536347

RESUMO

A magnetic nanoporous organic polymer (M-NOP) was prepared as a new adsorbent with excellent extraction capacity and rapid adsorption kinetics for 5-nitroimidazoles (5-NDZs). Hence, a rapid and effective method was proposed for determination of 5-NDZs in milk by combining M-NOP-based magnetic solid-phase extraction with high-performance liquid chromatography. Main extraction conditions were investigated. Under optimal conditions, good linear response was achieved in a range of 2.4-100 ng mL-1 with a lower detection limit of 0.8-1.0 ng mL-1. High accuracy with a recovery of 80.0-116.0% for the fortified samples, good repeatability with relative standard deviation below 10%, and a high enrichment factor of 97-111 were obtained. The rapid adsorption of 5-NDZs on M-NOP is mainly driven by H-bonding, π-stacking, and polar interactions. Finally, the M-NOP-based method was successfully used to determine 5-NDZs in milk samples. The M-NOP is expected to present promising application in the extraction and quantitative analysis of other compounds.


Assuntos
Magnetismo/métodos , Leite/química , Nitroimidazóis/isolamento & purificação , Polímeros/química , Adsorção , Animais , Bovinos , Cromatografia Líquida de Alta Pressão , Contaminação de Alimentos/análise , Limite de Detecção , Nanoporos , Nitroimidazóis/química , Polímeros/síntese química , Porosidade
16.
Drug Deliv ; 26(1): 935-943, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31530198

RESUMO

Magnetically guided cell delivery systems would be valuable to achieve effective macrophage-based cell therapy for colonic inflammatory diseases. In the current study, we developed a method for the efficient and simultaneous introduction of superparamagnetic iron oxide nanoparticles (SPIONs) and plasmid DNA (pDNA) into RAW264 murine macrophage-like cells using SPION-incorporated cationic liposome/pDNA complexes (magnetic lipoplexes). SPIONs and pDNA were introduced for magnetization and functionalization of the macrophages, respectively. We also evaluated the adhesive properties of magnetized RAW264 cells using magnetic lipoplexes in the murine colon under a magnetic field. Significant cellular association and gene expression without cytotoxicity were observed when magnetic cationic liposomes and pDNA were mixed at a weight ratio of 10:1, and SPION concentration and magnetic field exposure time was 0.1 mg/mL and 10 min, respectively. We also observed that cytokine production in magnetized RAW264 cells was similar to that in non-treated RAW264 cells, whereas nitric oxide production was significantly increased in magnetized RAW264 cells. Furthermore, magnetized RAW264 cells highly adhered to a Caco-2 cell monolayer and colon in mice, under a magnetic field. These results suggest that this magnetic cell delivery system can improve the colonic delivery of macrophages and its therapeutic efficacy against colonic inflammatory diseases.


Assuntos
Colo/metabolismo , Lipossomos/metabolismo , Macrófagos/metabolismo , Animais , Células CACO-2 , Cátions/metabolismo , Linhagem Celular Tumoral , Citocinas/metabolismo , Feminino , Expressão Gênica/efeitos dos fármacos , Humanos , Campos Magnéticos , Magnetismo/métodos , Camundongos , Camundongos Endogâmicos ICR , Plasmídeos/metabolismo , Células RAW 264.7
17.
Mater Sci Eng C Mater Biol Appl ; 104: 110001, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500023

RESUMO

Paclitaxel is broad-spectrum anticancer drug which has been widely used in clinic. However, traditional drug delivery often suffers from the scarcity of resources and systemic toxic side effects caused by the localization to non-tumor areas, rendering cancer treatment extremely challenging. To address this problem, we developed a novel multifunctional drug delivery system of a poly(lactic-co-glycolic acid) (PLGA) drug-loaded magnetic Janus particles (DMJPs) using electrohydrodynamic (EDH) co-jetting. The DMJPs were loaded with three compartments each with distinct function, i.e. paclitaxel for killing cancer cell, Fe3O4 nanoparticles for target location, and rhodamine B for fluorescence tracing, respectively. The Janus structure of the DMJPs, as demonstrated by the loaded nano-quantum dots CdS/ZnS and CdSe/ZnS in different compartments, enhanced not only the drug loading and encapsulation efficiency but also the cumulative release rate of the loaded drugs from DMJPs in different media. More importantly, DMJPs exhibited specific and high toxicity only to human breast cancer cells (MDA-MB-231), but not to mouse embryonic fibroblasts (NIH-3 T3). Consistently, DMJPs induced the higher lethal effect on cancer cells than paclitaxel suspension of high concentrations. Under guidance of external magnetic field, DMJPs can readily target and accumulate on and inside cancer cells for cell elimination. The specific targetability, selectivity, and toxicity of DMJPs on cancer cells would greatly avoid any potential side effects and reduce the overdose of drugs for conventional drug delivery. This work hopefully provides a new drug delivery system for the development of anticancer drug systems for clinical and precision medicine treatment.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Paclitaxel/química , Paclitaxel/farmacologia , Animais , Linhagem Celular Tumoral , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Humanos , Fenômenos Magnéticos , Magnetismo/métodos , Camundongos , Células NIH 3T3 , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química
18.
Mater Sci Eng C Mater Biol Appl ; 104: 109975, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500037

RESUMO

Sulfonated melamine-formaldehyde including iron oxide nanoparticles were synthesized by sulfonation of melamine-formaldehyde and then Fe3O4 nanoparticles were bounded onto the surface of sulfonated melamine-formaldehyde (SMF). Two different iron oxide nanostructures including nanorods/spheres and nanospheres on sulfonated melamine-formaldehyde (SMF/Fe3O4) were obtained only by modifying the time of radiation from 4 to 8 h in our synthetic method. Furthermore core/shell (Fe3O4@SMF) was prepared by entrapping Fe3O4 magnetic nanoparticles as the core and sulfonated melamine-formaldehyde as the outer shell. The prepared components were characterized via, Fourier transform infrared spectroscopy (FT-IR), titration, X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, Barret-Joyner-Halenda (BJH) analysis, vibrating sample magnetometer (VSM), energy-dispersive X-ray (EDX) spectroscopy, and thermal gravimetric analysis (TGA). According to obtained results, the synthesized products had a thermal stability near 180 °C, particle-size distribution around of 20-140 nm and surface area between 6 and 10 m2/g. In this study, vapor was used as a heat source. These effective and magnetically recoverable catalysts were employed for the synthesis of numerous 3,4-dihydropyrimidin-2(1H)-ones by utilizing aldehydes, ethylacetoacetate and urea. Functional easiness, excellent yields, short reaction time, the simplicity of work-up or filter, and thermal stability of these catalysts created them as appropriate heterogeneous systems and acceptable alternative to different heterogeneous catalysts.


Assuntos
Compostos Férricos/química , Nanotubos/química , Triazinas/química , Catálise/efeitos dos fármacos , Sistemas de Liberação de Medicamentos/métodos , Magnetismo/métodos , Nanopartículas de Magnetita/química , Nanopartículas/química , Nanoestruturas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Inquéritos e Questionários , Ultrassom/métodos , Difração de Raios X/métodos
19.
Mater Sci Eng C Mater Biol Appl ; 104: 109939, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31500062

RESUMO

Folic acid-conjugated magnetic ordered mesoporous carbon nanospheres (FA-MOMCNs) are developed as a targeting delivery vehicle of doxorubicin (DOX) in this work. Investigations on DOX loading mechanism show that the loading capacity of FA-MOMCNs is up to 577.12 mg g-1 by means of both physical porous adsorption and covalent interactions, and the pH-dependent drug release is achieved. Excellent biocompatibility of FA-MOMCNs with blood and cells is confirmed by hemolysis and cytotoxicity assays. With the assistance of effective passive and active targeting, DOX-loading FA-MOMCNs can be readily internalized into cancer cell, where the carried DOX can be efficiently released in the acidic microenvironment of the cancer cell for its proliferation inhibition. This controlled release and targeting vehicle of DOX makes it possible to reduce the toxic effect to normal tissues during circulation in the body and is promising for highly efficient chemotherapy.


Assuntos
Carbono/química , Doxorrubicina/química , Ácido Fólico/química , Nanosferas/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Doxorrubicina/farmacologia , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Liberação Controlada de Fármacos , Células HeLa , Humanos , Células MCF-7 , Fenômenos Magnéticos , Magnetismo/métodos , Porosidade
20.
Can J Microbiol ; 65(11): 851-857, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31404505

RESUMO

Environmentally stable and disinfectant-resistant oocysts of Cryptosporidium spp. shed in the feces of infected humans and animals frequently contaminate water resources and are subsequently spread via potable and recreational waters. The current monoclonal-antibody-based methods for detecting them in water are slow, labor-intensive, and demand skills to interpret the results. We have developed DNA-aptamer-based aptasensors, coupled with magnetic beads, to detect and identify the oocysts of C. parvum for monitoring recreational and drinking water sources. A sensitive and specific electrochemical aptasensor (3'-biotinylated R4-6 aptamer) was used as a secondary ligand to bind the streptavidin-coated magnetic beads. This was incorporated into a probe using gold nanoparticle modified screen-printed carbon electrodes. Square wave voltammetry allowed for specific recognition of C. parvum oocysts. The aptamer-coated probes had an oocyst detection limit of 50. It did not bind to the cysts of Giardia duodenalis, another common waterborne pathogen, thus indicating its high specificity for the target pathogen. The system could successfully detect C. parvum oocysts in spiked samples of the raw lake and river waters. Therefore, the combined use of the aptasensor and magnetic beads has the potential to monitor water quality for C. parvum oocysts in field samples without relying on monoclonal antibodies and skill-demanding microscopy.


Assuntos
Aptâmeros de Nucleotídeos/genética , Cryptosporidium parvum/isolamento & purificação , Água Potável/parasitologia , Magnetismo/métodos , Rios/parasitologia , Animais , Cryptosporidium parvum/classificação , Cryptosporidium parvum/genética , Ouro/química , Humanos , Magnetismo/instrumentação , Nanopartículas Metálicas/química , Oocistos/classificação , Oocistos/genética , Oocistos/isolamento & purificação , Sensibilidade e Especificidade , Recursos Hídricos
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