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1.
Chemosphere ; 244: 125457, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32050323

RESUMO

The wide range of applications of rare earth elements (REE) is leading to their occurrence in worldwide aquatic environments. Among the most popular REE is Neodymium (Nd), being widely used in permanent magnets, lasers, and glass additives. Neodymium-iron-boron (NdFeB) magnets is the main application of Nd since they are used in electric motors, hard disk drives, speakers and generators for wind turbines. Recent studies have already evaluated the toxic potential of different REE, but no information is available on the effects of Nd towards marine bivalves. Thus, the present study evaluated the biochemical alterations caused by Nd in the mussel Mytilus galloprovincialis exposed to this element for 28 days. The results obtained clearly demonstrated that Nd was accumulated by mussels, leading to mussel's metabolic capacity increase and GLY expenditure, in an attempt to fuel up defense mechanisms. Antioxidant and biotransformation defenses were insufficient in the elimination of ROS excess, resulting from the presence of Nd and increased electron transport system activity, which caused cellular damages (measured by lipid peroxidation) and loss of redox balance (assessed by the ratio between reduced and oxidized glutathione). The results obtained clearly highlight the potential toxicity of REEs and, in particular of Nd, with impacts at cellular level, which may have consequences in mussel's survival, growth and reproduction, affecting mussel's population.


Assuntos
Imãs/química , Metais Terras Raras/toxicidade , Mytilus/efeitos dos fármacos , Neodímio/toxicidade , Animais , Homeostase/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Metais Terras Raras/farmacologia , Mytilus/metabolismo , Oxirredução , Poluentes Químicos da Água/toxicidade
2.
Biomed Chromatogr ; 34(2): e4763, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31770450

RESUMO

Target biomolecule-immobilized magnetic beads could be used as a powerful tool for screening active compounds present in natural products. Low damage rates of the target proteins, associated with the availability of diverse automated online approaches for analysis, make it a valuable tool for affinity studies. RAW264.7 cells (a kind of murine macrophage cell line) were used in this study. These cellular membranes were immobilized onto the surface of MBs and were used for screening the active compounds of Polygonatum sibiricum. Combining this technique with HPLC led to the identification of an active compound and its biological activity was confirmed. This is the first report establishing the use of RAW264.7 cellular membrane-coated magnetic bead fishing followed by HPLC analysis for screening active compounds from natural products.


Assuntos
Membrana Celular/química , Cromatografia Líquida de Alta Pressão/métodos , Imãs/química , Extratos Vegetais , Polygonatum/química , Animais , Membrana Celular/metabolismo , Descoberta de Drogas , Camundongos , Compostos Fitoquímicos , Extratos Vegetais/análise , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/metabolismo , Células RAW 264.7
3.
Talanta ; 207: 120300, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594586

RESUMO

A "signal-on" chemiluminescence biosensor was established for detecting thrombin. The thrombin aptamer1-functionalized magnetic sodium alginate (Malg-Apt1) hydrogel was synthesized by physical interaction between sodium alginate and Ca2+, and it was used in the biosensor for separating and enriching thrombin. Ethylenediamine tetraacetic acid (EDTA) was used to chelate with Ca2+ to dissolve the hydrogel and release thrombin. A metalloporphyrinic metal-organic framework nanosheet, named as Cu-TCPP(Co) MOFs, was prepared as signal amplification strategy. Cu-TCPP(Co) MOFs/Au-ssDNA (ssDNA: single-strand DNA) was synthesized for controllable further amplification of chemiluminescent signal. The thrombin aptamer2-functionalized magnetic carbon nanotubes (MCNTs-Apt2) were used as a matrix, and Cu-TCPP(Co) MOFs/Au-ssDNA was adsorbed on the MCNTs by the complementary pairing of the partial bases between ssDNA and Apt2. Compared with ssDNA, Apt2 has a stronger interaction with thrombin. Therefore, thrombin can trigger the release of Cu-TCPP(Co) MOFs/Au-ssDNA to achieve signal amplification. Under the optimal conditions, the biosensor could detect thrombin as low as 2.178 × 10-13 mol/L with the range from 8.934 × 10-13 to 5.956 × 10-10 mol/L and exhibited excellent selectively. Moreover, the "signal-on" chemiluminescence biosensor showed potential application for the detection of thrombin in body fluids.


Assuntos
Alginatos/química , Técnicas Biossensoriais/métodos , DNA de Cadeia Simples/química , Hidrogéis/química , Estruturas Metalorgânicas/química , Nanotubos de Carbono/química , Trombina/análise , Adsorção , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Aptâmeros de Nucleotídeos/metabolismo , Sequência de Bases , DNA de Cadeia Simples/genética , Medições Luminescentes , Imãs/química , Modelos Moleculares , Conformação Molecular , Porfirinas/química , Trombina/metabolismo
4.
Talanta ; 207: 120290, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594607

RESUMO

Human T-lymphotropic virus type II (HTLV-II) is a crucial retrovirus that is closely associated with a variety of human diseases. Herein, an ultrasensitive fluorescent HTLV-II DNA detection strategy was developed for the first time based on magnetic nanoparticles (MNPs) and atom transfer radical polymerization (ATRP) amplification. In this approach, hairpin DNA probes (pDNA) labelled with 5' thiol and 3' azide group terminally were immobilized on amino group modified MNPs surface through sulfo-N-succinimidyl-4-maleimidobutyrate sodium salt (sulfo-GMBS) cross-linkers. In the presence of target DNAs (tDNA), pDNA hybridized with tDNA to form double-stranded DNA, and therefore its azide group was away from the MNPs surface. Subsequently, to initiate ATRP reaction, initiators were introduced into the pDNA by a Cu (I)-catalyzed alkyne-azide cycloaddition (CuAAC). Then, large numbers of 9-anthracenylmethyl methacrylate polymer (pAMMA) were successfully labelled on the MNPs surface, resulting in significant amplification of the fluorescence signal. Under optimized conditions, the fluorescence signal was proportional to the logarithm of the concentration of tDNA over the range from 1 fM to 1 nM, with a detection limit of 0.22 fM. Moreover, this strategy was capable of discriminating mismatched bases and detecting HTLV-II DNA in human serum samples. By virtue of the high sensitivity, selectivity, simplicity and economy, this ultrasensitive biosensor demonstrates great potential for biomedical research and early clinical diagnosis.


Assuntos
Técnicas Biossensoriais/métodos , DNA Viral/análise , Vírus Linfotrópico T Tipo 2 Humano/genética , Limite de Detecção , Imãs/química , Nanopartículas/química , Polimerização , DNA Viral/sangue , DNA Viral/química , Humanos , Hibridização de Ácido Nucleico , Espectrometria de Fluorescência
5.
Talanta ; 207: 120284, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31594616

RESUMO

Magnetic carbon nanotubes (CNTs) with encapsulated Co nanoparticles (Co@CNTs), was synthesized by exploiting the one-step pyrolysis strategy using ZIF-67 as template. The as-synthesized Co@CNTs is provided with the nanopores, a large specific surface area, and strong magnetic response. The obtained Co@CNTs was used as magnetic solid-phase extraction adsorbents to extract two profens including flurbiprofen and ketoprofen. The parameters of extraction efficiency, involving extraction time, sample solution volume, ionic strength, pH and the conditions of desorption efficiency, were optimized in detail. After determined by high-performance liquid chromatography-ultraviolet (HPLC-UV), the results evinced that Co@CNTs showed a high extraction efficiency with high enrichment factors of 832 and 672. The good linear range of both flurbiprofen and ketoprofen were all 5.0-1000 ng L-1, with the limit of detection were 0.60 ng L-1 and 0.70 ng L-1, respectively. Furthermore, a valid method for the extraction of flurbiprofen and ketoprofen from human serum was established. The spiking recoveries of two profens were between 86.74% and 97.22%, and the relative standard deviation was less than 6.55%. Co@CNTs can be repeatedly used at least 10 times, indicating its excellent regeneration and reusability. The results demonstrated that the Co@CNTs materials exhibits high enrichment ability and extraction efficiency, playing great promise in MSPE.


Assuntos
Flurbiprofeno/isolamento & purificação , Cetoprofeno/isolamento & purificação , Imãs/química , Nanotubos de Carbono/química , Compostos Organometálicos/química , Extração em Fase Sólida/métodos , Adsorção , Cobalto/química , Flurbiprofeno/sangue , Flurbiprofeno/química , Humanos , Imidazóis/química , Cetoprofeno/sangue , Cetoprofeno/química , Nanopartículas Metálicas/química
6.
Carbohydr Polym ; 229: 115512, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826502

RESUMO

In recent decades, increased industrial activities have led to the release of various pollutants, such as toxic heavy metals, inorganic anions, and organics. It is imperative but challenging to develop an eco-friendly treatment technology with easy operation, low cost, and high efficiency. Here, we describe a design of magnetic purifier, which has biomass-based structure by blending attapulgite/chitosan (ATP/CS) composite with bacterial cellulose nanofibrils (BCNs). Compared to similar materials reported previously, our product exhibited efficient adsorption capacities towards various metal ions including Pb2+, Cu2+, and Cr6+, and anionic organic dyes including Congo red. The adsorption process could be well fitted by Langmuir isotherm and pseudo-second order equation. Additionally, the adsorption capacity only decreased less than 8% after five adsorption-desorption cycles. We expect our design will inspire more efforts to build a multifunctional water purifier with simple operation, and hopefully effectively remove pollutants from wastewater in future practical applications.


Assuntos
Bactérias/química , Celulose/química , Corantes/química , Compostos de Magnésio/química , Imãs/química , Metais Pesados/química , Compostos de Silício/química , Poluentes Químicos da Água/química , Adsorção , Corantes/isolamento & purificação , Água Doce/química , Cinética , Metais Pesados/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação
7.
Carbohydr Polym ; 224: 115163, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472828

RESUMO

Efficient procedure for preparation of the novel magnetic nanobiocomposite (MNbC) was successfully established by employing click chemistry protocol. The resulted structure exhibited valuable characteristics from biological viewpoints. The prepared materials and obtained nanobiocomposite were characterized by means of nuclear magnetic resonance (NMR), fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). To assay the antiproliferative effects of the MNbC; as cancerous cells, Hela, MCF-7 and Saos were evaluated by means of MTT assay and compared with normal fibroblast cell line. Promising antiproliferative effects were observed on both epitheloid and mesenchymal cancer cell lines depending on MNbC concentration and time. To detect the apoptosis-associated changes of cell membranes during the process of apoptosis, Acridine Orange/Ethidium Bromide (AO/EB) dual staining fluorescent technique was incorporated. The studies in this article including all of these specifications represent convincing key findings that make MNbC as an appreciable candidate for further bio-applications.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Quitosana/química , Quitosana/farmacologia , Imãs/química , Nanocompostos/química , Química Click , Células HeLa , Humanos , Células MCF-7
8.
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
9.
Chem Commun (Camb) ; 55(69): 10312-10315, 2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31397446

RESUMO

Herein, we report a novel magnet-mediated antibody-boronate sandwich-typed assay (ABSTA) strategy for the ultrasensitive, specific, rapid, and enzyme-free detection of glycoproteins in complex samples. The proposed ABSTA method exhibited ultrahigh sensitivity for HCG with a detection limit of 0.19 mIU mL-1, which is approximately 40-fold lower than that of conventional sandwich enzyme immunoassay.


Assuntos
Anticorpos Imobilizados/química , Ácidos Borônicos/química , Gonadotropina Coriônica/sangue , Corantes Fluorescentes/química , Imãs/química , Anticorpos Monoclonais/química , Gonadotropina Coriônica/análise , Fluorescência , Humanos , Imunoensaio/métodos , Limite de Detecção
10.
Bioelectrochemistry ; 130: 107341, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31400568

RESUMO

Telomerase is considered a pivotal biomarker for early cancer diagnosis and a valuable therapeutic target. However, the current methods to detect telomerase activity have some limitations. Herein, we propose a homogeneous electrochemical strategy to develop a simple, rapid, and highly sensitive assay to detect human telomerase activity from crude cancer cell extracts. Our strategy is based on magnetic bead separation and exonuclease III-aided target recycling amplification. The complementary probes can hybridize with the extended telomeric repeats, which allows exonuclease III to recognize and digest the latter once the hybrid product is separated with magnetic beads. The released complementary probes can hybridize with and open multiple methylene blue (MB)-labeled hairpin (HP) DNA probes, allowing exonuclease III to digest the duplex. Then, the opened hairpin couples with the captured mononucleotides on the surface of the gold electrode. By taking advantage of the exonuclease III-aided target recycling strategy, the present assay enables the detection of telomerase activity at a single-cell level. Furthermore, the assay is carried out in a homogeneous solution achieved by magnetic purification, which removes the interferents present in crude lysates and avoids false negatives, thus, providing a powerful platform to detect telomerase activity in samples of early-stage cancer.


Assuntos
Técnicas Biossensoriais/métodos , Exodesoxirribonucleases/química , Telomerase/análise , Sondas de DNA/química , Técnicas Eletroquímicas/métodos , Ensaios Enzimáticos/métodos , Células HeLa , Humanos , Imãs/química , Neoplasias/enzimologia , Hibridização de Ácido Nucleico
11.
Anal Bioanal Chem ; 411(25): 6583-6590, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31422433

RESUMO

This study reports a follow-up investigation on the capture of specific DNA sequences using ion-tagged oligonucleotides (ITOs) and magnetic ionic liquids (MIL). Five allylimidazolium salts bearing octyl substituents ([AOIM+]-ITOs) were used for the selective extraction of the internal transcribed spacer region (ITS) from Arabidopsis thaliana. In this work, the ability of the [AOIM+]-ITOs to enhance the extraction of longer target sequences (~ 700 bp) of plant origin was shown. Moreover, the independence of the probe binding position and the importance of complementarity to the target region for the extraction performance were demonstrated. To test the specificity of the ITOs, the same experiments were performed using the ITS region from another plant species, with a lower target capture for the probes which were specific for the A. thaliana sequence. Finally, extraction in the presence of interferences (heterogenous DNA, primary and secondary metabolites, proteins) provided interesting and insightful results. This work illustrates the feasibility and versatility of these probes when coupled to MILs for rapid, cost-effective, and environmentally sensitive sample preparation in the extraction of specific target sequences from different origins. Graphical abstract.


Assuntos
Arabidopsis/química , DNA Intergênico/isolamento & purificação , DNA de Plantas/isolamento & purificação , Líquidos Iônicos/química , Imãs/química , Arabidopsis/genética , Sequência de Bases , DNA Intergênico/genética , DNA de Plantas/genética , Imidazóis/química , Sondas de Oligonucleotídeos/química , Sondas de Oligonucleotídeos/genética
12.
Anal Bioanal Chem ; 411(26): 7039-7049, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31428817

RESUMO

Antibiotic compounds in natural waters are normally present at low concentrations. In this paper, an easy and highly sensitive screening method using graphene oxide-functionalized magnetic composites (GO@NH2@Fe3O4) combined with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) was established for twelve quinolone antibiotics. GO@NH2@Fe3O4 composites were utilized as adsorbents for magnetic solid-phase extraction. This method combines the advantages of magnetic solid-phase extraction and MALDI-TOF MS, which allows for fast detection of quinolones at low concentrations. To improve absorption efficiency, the following parameters were individually optimized: sample acidity, extraction time, amount of adsorbent used, eluent used, and desorption time. Under the optimum conditions, the established method gave a low detection limit of 0.010 mg/L and allowed the high-throughput screening of twelve quinolone antibiotics (enoxacin, norfloxacin, ciprofloxacin, pefloxacin, fleroxacin, gatifloxacin, enrofloxacin, levofloxacin, sparfloxacin, danofloxacin, difloxacin, and lomefloxacin). The proposed method, having an easily prepared sorbent with a high affinity for quinolones and a convenient, high-throughput detection step, has been shown to have merit for the detection of antibiotics in water samples. Graphical abstract Schematic illustration of the (A) preparation of GO@NH2@Fe3O4 and (B) operating procedure for the MSPE and MALDI-TOF MS detection of QNs.


Assuntos
Antibacterianos/análise , Grafite/química , Quinolonas/análise , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Antibacterianos/isolamento & purificação , Limite de Detecção , Imãs/química , Modelos Moleculares , Quinolonas/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Água/análise , Poluentes Químicos da Água/isolamento & purificação
13.
Talanta ; 205: 120129, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450438

RESUMO

Self-assembly of building blocks for constructing multifunctional materials has opened prospects for sensing applications in the biomedical fields. In particular, the combination of aptamer with DNA assembly-based nanotechnology has greatly improved the performance of cancer cell detection. Nevertheless, the cancer cell detection strategies of integrating aptamer with protein are relatively sparse. So we have developed a self-assembled aptamer method to realize the efficient capture and rapid detection of cancer cells by ingeniously combining aptamer modified magnetic nanoparticles as capture nanoprobes with self-assembled aptamer/protein hybrid probes (SAPPs) as signal amplification probes. By merely mixing the component materials together simultaneously, the SAPPs, integrating aptamer for cancer cell recognition with protein for amplifying signal, were fabricated by DNA-governed one-step assembly. In addition, the SAPPs-based method exhibits efficient capture, rapid (about 45 min) and specific CCRF-CEM detection performance, with limits of detection down to 75 cells/mL in buffer and 200 cells/mL in whole blood.


Assuntos
Aptâmeros de Nucleotídeos/metabolismo , Separação Celular/métodos , Imãs/química , Células Neoplásicas Circulantes/patologia , Proteínas/metabolismo , Adsorção , Aptâmeros de Nucleotídeos/genética , Sequência de Bases , Linhagem Celular Tumoral , Separação Celular/instrumentação , Humanos , Nanopartículas/química , Fatores de Tempo
14.
Talanta ; 205: 120168, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31450459

RESUMO

Deficiencies in thiamine (vitamin B1) cause a host of neurological and reproductive impairments yielding morbidity and mortality across environmental and clinical realms. In a technique analogous to immunomagnetic separation, we introduce the use of thiamine periplasmic binding protein (TBP)-conjugated magnetic beads to isolate thiamine from complex matrices. TBP expressed in Escherichia coli is highly specific to thiamine and provides an alternative to antibodies for this non-immunogenic target. After incubation with the sample and removal of unbound matrix constituents, thiamine is simultaneously released and converted to its fluorescent oxidation product thiochrome by alkaline potassium ferricyanide. Subsequent measurement of fluorescence at thiochrome-specific wavelengths provides a second layer of specificity for the detection of thiamine. Thiamine could be quantified at concentrations as low as 5 nM ranging up to 240 nM. Within, we apply this technique to selectively capture and quantify thiamine in complex salmonid fish egg and tissue matrices. Our results showed no measurable non-specific binding to the beads by endogenous fluorophores in the fish egg matrix. Thiamine levels as low as 0.2 nmol/g of fish egg can be detected using this approach, which is sufficient to assess deficiencies causing morbidity and mortality in fish that occur at 1.0 nmol/g of egg. This practical method may find application in other resource limited settings for clinical, food, or dietary supplement analyses.


Assuntos
Técnicas Biossensoriais/métodos , Imãs/química , Proteínas Periplásmicas de Ligação/química , Tiamina/análise , Tiamina/isolamento & purificação , Alquil e Aril Transferases/metabolismo , Animais , Ovos/análise , Limite de Detecção , Microesferas , Salmão , Tiamina/metabolismo
15.
Artif Cells Nanomed Biotechnol ; 47(1): 3079-3086, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31352799

RESUMO

The engineering of multifunctional therapeutics in an integrated single platform is demonstrated using three-dimensional SBA-16 (S-16). 10 wt% iron oxide nanoparticles (Fe) were loaded into the cage type of cubic pores through enforced adsorption technique. Fe/S-16 is then functionalized with amine-based silane (A), polyacrylic acid (P) and cisplatin (Cp). The physicochemical textural analysis showed the formation of nano metal oxide distributions at pore walls of S-16 with magnetization of 2.39 emu/g. S-16 based nanoformulations showed high percentage of Cp adsorption (90%) and percentage cumulative release (60%). in vitro study of Fe/S-16-A-Cp showed high toxicity against breast cancer cell line MCF-7 and normal cell line Human foreskin fibroblast (HFF-1) compared to Fe/S-16 indicating cisplatin profusion inside the cells than free cisplatin. While skin fibroblast seems to be resistant to Fe/S-16-AP-Cp with very high LC50 in compare to MCF-7. This indicates the unrelease of cisplatin in skin fibroblast after Fe/S-16-AP-Cp treatment due to effective encapsulation inside the cubic pores and core blockage due to pH-sensitive polyacrylic acid. Also, these treatments resulted in morphological changes in the cells such as DNA condensation and nuclear fragmentation.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Neoplasias da Mama/patologia , Cisplatino/química , Cisplatino/farmacologia , Imãs/química , Dióxido de Silício/química , Resinas Acrílicas/química , Aminas/química , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/patologia , Relação Dose-Resposta a Droga , Portadores de Fármacos/química , Humanos , Células MCF-7 , Nanopartículas/química
16.
Anal Bioanal Chem ; 411(23): 6039-6047, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31304564

RESUMO

Circulating tumor DNA (ctDNA) is a tumor-derived fragmented DNA in the bloodstream that is not associated with cells. It has been greatly focused in the recent decade because of its potential clinical utility for liquid biopsies. Development of ctDNA analytical techniques with high sensitivity and cost-efficiency will undoubtedly promote the clinical spread of ctDNA testing. In this paper, we propose a novel flow cytometry-based ctDNA sensing strategy which combines enzyme-free amplification and magnetic separation. The target DNA is capable of triggering a hybridization chain reaction, producing a fluorescent long linear assembly of DNA, which can be further captured by magnetic beads to present fluorescent signals using flow cytometry. In comparison with some conventional methods, our strategy has the advantages of easy operation and cost-efficiency, and thereby shows a promising application in clinical diagnosis. Graphical abstract.


Assuntos
DNA Tumoral Circulante/sangue , Citometria de Fluxo/métodos , Imãs/química , Técnicas de Amplificação de Ácido Nucleico/métodos , DNA Tumoral Circulante/análise , Humanos , Limite de Detecção , Biópsia Líquida/métodos , Hibridização de Ácido Nucleico/métodos
17.
Biomed Chromatogr ; 33(11): e4647, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31299101

RESUMO

The cytopoxic effect of RL2 lactaptin (the recombinant analog of proteolytic fragment of human kappa-casein) toward tumor cells in vitro and in vivo presents it as a novel promising antitumor drug. The binding of any drug with serum proteins can affect their activity, distribution, rate of excretion and toxicity in the human body. Here, we studied the ability of RL2 to bind to various blood serum proteins. Using magnetic microparticles bearing by RL2 as an affinity matrix, in combination with mass spectrometry and western blot analysis, we found a number of blood serum proteins possessing affinity for RL2. Among them IgA, IgM and IgG subclasses of immunoglobulins, apolipoprotein A1 and various cortactin isoforms were identified. This data suggests that in the bloodstream RL2 lactaptin takes part in complicate protein-protein interactions, which can affect its activity.


Assuntos
Antineoplásicos/metabolismo , Proteínas Sanguíneas/isolamento & purificação , Proteínas Sanguíneas/metabolismo , Caseínas/metabolismo , Imãs/química , Proteínas Sanguíneas/análise , Cromatografia de Afinidade/métodos , Humanos , Microesferas , Ácidos Polimetacrílicos/química , Proteínas Recombinantes/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos
18.
Int J Biol Macromol ; 137: 721-731, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31279890

RESUMO

A novel magnetic chitosan adsorbent (CDF-CS) was synthesized by inserting magnetic particles into the crosslinked compound of chitosan (CS) and cystamine based on one-step method for selectively recovering Au(III) from aqueous solution. The characterization and adsorption mechanism of CDF-CS were studied by SEM-EDS, VSM, FT-IR and XPS, respectively. The experimental results show that the adsorption capacity of CDF-CS is still large in a wide range of pH values (from 1 to 7) and has a higher adsorption capacity for Au(III) than the raw chitosan, the maximum adsorption capacity of CDF-CS for Au(III) was 478.47 mg/g about 6 h at pH = 7.0. The adsorption behavior is most consistent with this pseudo-second-order kinetic model. The adsorption process of gold ions by CDF-CS follows the Langmuir adsorption isotherm. Furthermore, the thermodynamic parameter indicates that the adsorption reaction of gold ions by CDF-CS is an endothermic chemisorption. CDF-CS has great potential for removing gold ions from aqueous solutions due to the excellent repeatability and selectivity. Finally, the adsorption mechanism is that chelation reaction and ion exchange mainly occurred between CDF-CS and Au(III). Therefore, CDF-CS is very promising in recovery of Au(III) from aqueous solutions.


Assuntos
Quitosana/química , Cistamina/química , Ouro/química , Ouro/isolamento & purificação , Imãs/química , Purificação da Água/métodos , Água/química , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Soluções , Temperatura , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
19.
Int J Mol Sci ; 20(13)2019 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-31262026

RESUMO

Magnetorheological elastomer (MRE) is a type of magnetic soft material consisting of ferromagnetic particles embedded in a polymeric matrix. MRE-based devices have characteristics of adjustable stiffness and damping properties, and highly nonlinear and hysteretic force-displacement responses that are dependent on external excitations and applied magnetic fields. To effectively implement the devices in mitigating the hazard vibrations of structures, numerically traceable and computationally efficient models should be firstly developed to accurately present the unique behaviors of MREs, including the typical Payne effect and strain stiffening of rubbers etc. In this study, the up-to-date phenomenological models for describing hysteresis response of MRE devices are experimentally investigated. A prototype of MRE isolator is dynamically tested using a shaking table in the laboratory, and the tests are conducted based on displacement control using harmonic inputs with various loading frequencies, amplitudes and applied current levels. Then, the test results are used to identify the parameters of different phenomenological models for model performance evaluation. The procedure of model identification can be considered as solving a global minimization optimization problem, in which the fitness function is the root mean square error between the experimental data and the model prediction. The genetic algorithm (GA) is employed to solve the optimization problem for optimal model parameters due to its advantages of easy coding and fast convergence. Finally, several evaluation indices are adopted to compare the performances of different models, and the result shows that the improved LuGre friction model outperforms other models and has optimal accuracy in predicting the hysteresis response of the MRE device.


Assuntos
Elastômeros/química , Modelos Teóricos , Reologia/instrumentação , Campos Magnéticos , Imãs/química , Reologia/métodos , Vibração
20.
Int J Mol Sci ; 20(15)2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31357727

RESUMO

Magnetic fluid is a stable colloidal suspension of nano-sized, single-domain ferri/ferromagnetic particles dispersed in a liquid carrier. The liquid can be magnetized by the ferromagnetic particles aligned with the external magnetic field, which can be used as a wavefront corrector to correct the large aberrations up to more than 100 µm in adaptive optics (AO) systems. Since the measuring range of the wavefront sensor is normally small, the application of the magnetic fluid deformable mirror (MFDM) is limited with the WFS based AO system. In this paper, based on the MFDM model and the relationship between the second moment (SM) of the aberration gradients and the far-field intensity distribution, a model-based wavefront sensorless (WFSless) control algorithm is proposed for the MFDM. The correction performance of MFDM using the model-based control algorithm is evaluated in a WFSless AO system setup with a prototype MFDM, where a laser beam with unknown aberrations is supposed to produce a focused spot on the CCD. Experimental results show that the MFDM can be used to effectively compensate for unknown aberrations in the imaging system with the proposed model-based control algorithm.


Assuntos
Coloides/química , Nanopartículas de Magnetita/química , Imãs/química , Algoritmos , Fenômenos Magnéticos , Óptica e Fotônica
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