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1.
Appl Microbiol Biotechnol ; 107(10): 3319-3328, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-37052634

RESUMO

Varicella-zoster virus (VZV) infects more than 90% of the population worldwide and has a high incidence of postherpetic neuralgia in elderly patients, seriously affecting their quality of life. Combined with clustered regularly interspaced short palindromic repeats (CRISPR) system, we develop a quantum dot nanobeads (QDNBs) labeled lateral flow assay for VZV detection. Our assay allows the identification of more than 5 copies of VZV genomic DNA in each reaction. The entire process, from sample preparation to obtaining the results, takes less than an hour. In 86 clinical vesicles samples, the test shows 100% concordance with quantitative real-time PCR for VZV detection. Notably, when vesicles are present in specific areas, such as the genitals, our method outperforms clinical diagnosis. Compared to traditional detection methods, only a minute amount of blister fluid is required for accurate detection. Therefore, we anticipate that our method could be translated to clinical applications for specific and rapid VZV detection. KEY POINTS: • CRISPR/Cas12a and quantum dot nanobead-based lateral flow assay achieved 5 copies per reaction for VZV detection • Specific identification of VZV in atypical skin lesions • Results read by the naked eye within one hour.


Assuntos
Pontos Quânticos , Dermatopatias , Humanos , Idoso , Herpesvirus Humano 3/genética , Qualidade de Vida , Reação em Cadeia da Polimerase em Tempo Real/métodos
2.
Part Fibre Toxicol ; 20(1): 49, 2023 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-38110964

RESUMO

BACKGROUND: Nanoplastics (NPs) are omnipresent in our lives as a new type of pollution with a tiny size. It can enter organisms from the environment, accumulate in the body, and be passed down the food chain. Inflammatory bowel disease (IBD) is a nonspecific intestinal inflammatory disease that is recurrent and prevalent in the population. Given that the intestinal features of colitis may affect the behavior and toxicity of NPs, it is imperative to clarify the risk and toxicity mechanisms of NPs in colitis models. METHODS AND RESULTS: In this study, mice were subjected to three cycles of 5-day dextran sulfate sodium (DSS) exposures, with a break of 7 to 11 days between each cycle. After the first cycle of DSS exposure, the mice were fed gavagely with water containing 100 nm polystyrene nanobeads (PS-NPs, at concentrations of 1 mg/kg·BW, 5 mg/kg·BW and 25 mg/kg·BW, respectively) for 28 consecutive days. The results demonstrated that cyclic administration of DSS induced chronic inflammation in mice, while the standard drug "5-aminosalicylic acid (5-ASA)" treatment partially improved colitis manifestations. PS-NPs exacerbated intestinal inflammation in mice with chronic colitis by activating the MAPK signaling pathway. Furthermore, PS-NPs aggravated inflammation, oxidative stress, as well as hepatic lipid metabolism disturbance in the liver of mice with chronic colitis. CONCLUSION: PS-NPs exacerbate intestinal inflammation and injury in mice with chronic colitis. This finding highlights chronically ill populations' susceptibility to environmental hazards, which urgent more research and risk assessment studies.


Assuntos
Colite , Poliestirenos , Camundongos , Animais , Poliestirenos/toxicidade , Poliestirenos/metabolismo , Metabolismo dos Lipídeos , Colite/induzido quimicamente , Colite/metabolismo , Inflamação/metabolismo , Estresse Oxidativo , Fígado/metabolismo , Doença Crônica , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças
3.
Molecules ; 28(22)2023 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-38005218

RESUMO

Quantum dot nanobeads (QBs) were used as signal source to develop competitive lateral flow immunoassay (LFIA) for the detection of chloramphenicol (CAP). The quantitative detection of CAP was achieved by calculating the total color difference (∆E) values of the test line (T line) using the images of test strips. QB-based LFIA (QBs-LFIA) allowed the effective dynamic linear detection of CAP in the range of 0.1-1.5 ng/mL. The limit of detection (LOD) was 3.0 ng/mL, which was 50 and 667 times lower than those achieved for two different brands of colloidal gold kits. The recoveries of CAP during real-sample detection were 82.82-104.91% at spiked levels of 0.1, 0.7, and 1.5 ng/mL. These results indicate that the developed QBs-LFIA facilitates the sensitive detection of CAP.


Assuntos
Cloranfenicol , Pontos Quânticos , Imunoensaio/métodos , Limite de Detecção , Coloide de Ouro
4.
Anal Biochem ; 659: 114948, 2022 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-36216143

RESUMO

This work established a highly sensitive and specific quantum dot nanobeads-based lateral flow assay for multiplex detection of four respiratory virus markers at point of care. The respiratory virus antigens were detected by fluorescent lateral flow strips within 20 min. The limits of detection for SARS-CoV-2 antigen, IAV antigen, IBV antigen, and ADV antigen were 0.01 ng/mL, 0.05 ng/mL, 0.31 ng/mL, and 0.40 ng/mL, respectively, which were superior to that of conventional AuNPs-based colorimetric lateral flow assay. The coefficients of variation of the test strip were 6.09%, 2.24%, 7.92%, and 12.43% for these four antigens, which indicated that the proposed method had good repeatability. The specificity of the detection system was verified by different combinations of these four respiratory viruses and several other respiratory pathogens. These results indicated that this method could simultaneously detect SARS-CoV-2, IAV, IBV and ADV in a short assay time, showing the remarkable potential for the rapid and multiplex detection of respiratory viruses in resource-limited settings.


Assuntos
COVID-19 , Nanopartículas Metálicas , Vírus , Humanos , Sistemas Automatizados de Assistência Junto ao Leito , Ouro , SARS-CoV-2 , COVID-19/diagnóstico , Sensibilidade e Especificidade
5.
Anal Bioanal Chem ; 414(17): 4963-4975, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35606453

RESUMO

Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) with multiple variants, which may be harmful to human health by absorption and bioaccumulation. To ensure food safety, it is necessary to develop multi-residue immunoassays for broad recognition of PCBs. In this study, by mimicking the generic core structure of PCBs, three haptens have been designed and synthesized for monoclonal antibody (mAb) generation. A carboxylic acid derivative of PCB80 was a hapten that induced a mAb with broad recognition of PCBs. The results of ELISA further identified that the mAb could recognize 11 different kinds of PCBs; half-maximal inhibition concentrations (IC50) ranged from 33.12 to 476.42 ng/mL. Subsequently, using aggregation-induced emission luminogen (AIEgen) nanobeads as the tracer for the output signal, the IC50 value of the various PCBs was improved to 6.38-252.1 ng/mL. The limit of detection (LOD) varied from 0.32 to 42.15 ng/mL. Recoveries of 76.90-95.74% and intra-assay coefficients of variation of 8.5-14.4% were obtained with spiked chicken and crab meat samples. Matrix interference was eliminated by dilution, and no false-positive and false-negative results were observed. The developed assay provides a simple, broad-spectrum, and sensitive tool for detecting PCBs, with high-throughput possibilities for large-scale screening of PCBs in food.


Assuntos
Braquiúros , Bifenilos Policlorados , Animais , Anticorpos Monoclonais , Galinhas , Haptenos , Imunoensaio/métodos , Bifenilos Policlorados/análise , Alimentos Marinhos/análise
6.
Molecules ; 27(23)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36500416

RESUMO

A multicolor immunochromatographic assay platform based on quantum dot nanobeads (QBs) for the rapid and simultaneous detection of nitrofuran metabolites in different aquatic products is documented. These metabolites include 3-amino-2-oxazolidinone (AOZ), 1-aminohydantoin (AHD), semicarbazide (SEM), and 3-amino-5-morpholino-methyl-1,3-oxazolidinone (AMOZ). QBs with emission colors of red, yellow, green, and orange were employed and functionalized with the corresponding antibodies to each analyte to develop a multicolor channel. The visual detection limits (cutoff values) of our method for AOZ, AHD, SEM, and AMOZ reached up to 50 ng/mL, which were 2, 20, 20, and 20 times lower than those of traditional colloidal gold test strips, respectively. The test strip is capable of detection within 10 min in real samples while still achieving good stability and specificity. These results demonstrate that the developed multicolor immunochromatographic assay platform is a promising technique for multiplex, highly sensitive, and on-site detection of nitrofuran metabolites.


Assuntos
Nitrofuranos , Pontos Quânticos , Contaminação de Alimentos/análise , Nitrofuranos/química , Cromatografia de Afinidade/métodos , Semicarbazidas
7.
Anal Biochem ; 633: 114389, 2021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34555369

RESUMO

Rheumatoid arthritis (RA) belongs to the most often occurring autoimmune diseases in the world. For serological diagnosis, IgM auto-antibodies directed against the Fc portion of IgG referred to as rheumatoid factor are used as biomarkers. The autoantibody detection is usually done by ELISA. Such assays are reliable but are not suitable for point-of-care testing in contrast to lateral flow assays. Here, we report the development of a lateral flow assay based on carboxylated fluorescence-encoded poly(methyl methacrylate) nanoparticles. Poly(methyl methacrylate) is a non-toxic plastic with an excellent biocompatibility and high optical transparency which promises especially high sensitive fluorescence detection thereby leading to very sensitive assays. We could detect a positive signal in samples with a nephelometric reading down to 0.4 U/mL. By analyzing 30 sera of patients with a RA diagnosis and 34 sera of healthy test subjects we could confirm positive ELISA results in 72% of all cases and negative ELISA results in 97% of all cases.


Assuntos
Artrite Reumatoide/sangue , Autoanticorpos/sangue , Fluorescência , Imunoglobulina M/sangue , Nanopartículas/química , Polimetil Metacrilato/química , Artrite Reumatoide/diagnóstico , Ensaio de Imunoadsorção Enzimática , Humanos
8.
Sens Actuators B Chem ; 343: 130139, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34035562

RESUMO

Owing to the over-increasing demands in resisting and managing the coronavirus disease 2019 (COVID-19) pandemic, development of rapid, highly sensitive, accurate, and versatile tools for monitoring total antibody concentrations at the population level has been evolved as an urgent challenge on measuring the fatality rate, tracking the changes in incidence and prevalence, comprehending medical sequelae after recovery, as well as characterizing seroprevalence and vaccine coverage. To this end, herein we prepared highly luminescent quantum dot nanobeads (QBs) by embedding numerous quantum dots into polymer matrix, and then applied it as a signal-amplification label in lateral flow immunoassay (LFIA). After covalently linkage with the expressed recombinant SARS-CoV-2 spike protein (RSSP), the synthesized QBs were used to determine the total antibody levels in sera by virtue of a double-antigen sandwich immunoassay. Under the developed condition, the QB-LFIA can allow the rapid detection of SARS-CoV-2 total antibodies within 15 min with about one order of magnitude improvement in analytical sensitivity compared to conventional gold nanoparticle-based LFIA. In addition, the developed QB-LFIA performed well in clinical study in dynamic monitoring of serum antibody levels in the whole course of SARS-CoV-2 infection. In conclusion, we successfully developed a promising fluorescent immunological sensing tool for characterizing the host immune response to SARS-CoV-2 infection and confirming the acquired immunity to COVID-19 by evaluating the SRAS-CoV-2 total antibody level in the crowd.

9.
J Nanobiotechnology ; 19(1): 116, 2021 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-33892737

RESUMO

BACKGROUND: Highly efficient capture and detection of circulating tumor cells (CTCs) remain elusive mainly because of their extremely low concentration in patients' peripheral blood. METHODS: We present an approach for the simultaneous capturing, isolation, and detection of CTCs using an immuno-fluorescent magnetic nanobead system (iFMNS) coated with a monoclonal anti-EpCAM antibody. RESULTS: The developed antibody nanobead system allows magnetic isolation and fluorescent-based quantification of CTCs. The expression of EpCAM on the surface of captured CTCs could be directly visualized without additional immune-fluorescent labeling. Our approach is shown to result in a 70-95% capture efficiency of CTCs, and 95% of the captured cells remain viable. Using our approach, the isolated cells could be directly used for culture, reverse transcription-polymerase chain reaction (RT-PCR), and immunocytochemistry (ICC) identification. We applied iFMNS for testing CTCs in peripheral blood samples from a lung cancer patient. CONCLUSIONS: It is suggested that our iFMNS approach would be a promising tool for CTCs enrichment and detection in one step.


Assuntos
Antígenos de Neoplasias/imunologia , Magnetismo/métodos , Células Neoplásicas Circulantes/imunologia , Pontos Quânticos/química , Anticorpos , Linhagem Celular Tumoral , Separação Celular , Molécula de Adesão da Célula Epitelial , Corantes Fluorescentes , Humanos , Nanopartículas de Magnetita , Maleatos , Nanotecnologia , Células Neoplásicas Circulantes/patologia , Tamanho da Partícula , Poliestirenos
10.
Sensors (Basel) ; 21(19)2021 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-34640926

RESUMO

Sulfamethazine (SMZ) as a broad antibiotic is widely used in livestock and poultry. However, the abuse of SMZ in livestock feed can lead to SMZ residues in food and the resistance of bacteria to drugs. Thus, a method for the detection of SMZ in food is urgently needed. In this study, quantum dot (QD) nanobeads (QBs) were synthesized by encapsulating CdSe/ZnS QDs using a microemulsion technique. The prepared QBs as signal probes were applied in lateral flow immunoassay (LFIA) for the detection of SMZ in chicken and milk. Our proposed method had limits of detection of 0.1138-0.0955 ng/mL and corresponding linear ranges of 0.2-12.5, 0.1-15 ng/mL in chicken and milk samples, respectively. The recovery of LFIA for the detection of SMZ was 80.9-109.4% and 84-101.6% in chicken and milk samples, respectively. Overall, the developed QBs-LFIA had high reliability and excellent potential for rapid and sensitive screening of SMZ in food.


Assuntos
Pontos Quânticos , Animais , Galinhas , Imunoensaio , Leite/química , Reprodutibilidade dos Testes , Sulfametazina/análise
11.
J Sci Food Agric ; 101(2): 684-692, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32705699

RESUMO

BACKGROUND: Sulfamethazine (SMZ), a veterinary drug widely used in animal husbandry, is harmful to human health when excess residues are present in food. In this study, a fast, reliable, and sensitive immunochromatographic assay (ICA) was developed on the basis of the competitive format by using time-resolved fluorescent nanobeads (TRFN) as label for the detection of SMZ in egg, honey, and pork samples. RESULTS: Under optimized working conditions, this method had limits of detection of 0.016, 0.049, and 0.029 ng mL-1 and corresponding linear ranges of 0.05 to 1.00, 0.05 to 5.00, and 0.05 to 1.00 ng mL-1 in egg, honey, and pork samples, respectively. The recovery experiments showed that the average recoveries ranged from 90.5% to 113.9%, 82.4% to 112.0%, and 79.8% to 93.4% with corresponding coefficients of variation of 4.1% to 11.7%, 7.5% to 11.5%, and 4.8% to 8.7% for egg, honey, and pork samples, respectively. The developed TRFN-ICA was also systematically compared with high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) by analyzing 45 actual samples from egg, honey, and pork. CONCLUSION: Overall, the developed TRFN-ICA had high reliability and excellent potential for the ultrasensitive detection of SMZ for food safety monitoring, also providing a universal platform for the on-site detection of other targets. © 2020 Society of Chemical Industry.


Assuntos
Anti-Infecciosos/análise , Ovos/análise , Contaminação de Alimentos/análise , Mel/análise , Imunoensaio/métodos , Carne/análise , Sulfametazina/análise , Drogas Veterinárias/análise , Animais , Galinhas , Imunoensaio/instrumentação , Limite de Detecção , Nanopartículas/análise , Suínos
12.
J Clin Lab Anal ; 34(1): e23015, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31423640

RESUMO

BACKGROUNDS: Shortening of primary cilia in kidney epithelial cells is associated with kidney injury and involved with the induced level of α-tubulin in urine. Therefore, rapid detection and quantification of α-tubulin in the urine samples could be used to the preliminary diagnosis of kidney injury. METHODS: Cellulose-based nanobeads modified with α-tubulin were used for the detection probe of competitive immunochromatographic (IC) assay. The concentration of α-tubulin in the urine samples was determined by IC assay and compared with the amount determined by Western blotting analysis. RESULTS: The relationship between α-tubulin concentration and the colorimetric intensity resulted from IC assay was determined by logistic regression, and the correlation coefficient (R2 ) was 0.9948. When compared to the amount determined by Western blotting analysis, there was a linear relationship between the α-tubulin concentrations measured by the two methods and the R2 value was 0.823. CONCLUSIONS: This method is simple, rapid, and adequately sensitive to detect α-tubulin in patient urine samples, which could be used for the clinical diagnosis of kidney injury.


Assuntos
Imunoensaio/métodos , Rim/lesões , Tubulina (Proteína)/urina , Celulose/química , Humanos , Nanopartículas/química , Padrões de Referência
13.
Mikrochim Acta ; 187(11): 598, 2020 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-33034772

RESUMO

A highly sensitive quantum dot (QD)-based western blot assay with extended dynamic range was developed. Bimodal size distribution QD (BQ) immunoprobes composed of small size single QD (7.3 nm) and big size QD nanobead (QB) (82.9 nm) were employed for fluorescent western blot immunoassay on a membrane. Small size QD immunoprobes contributed to wider dynamic range of assay, while big size QB immunoprobes provided higher detection sensitivity. This BQ-based western blot assay can achieve a wide dynamic range (from 7.8 to 4000 ng IgG) and is nearly as sensitive as commercial available ultrasensitive chemiluminescent methods, just using a simple gel imager with UV light (365 nm) excitation and red light filter (610 nm). The fluorescent signals of BQ western blot were stable for 10 min, while chemiluminescent signals faded after 1 min. Moreover, this BQ immunoprobe was utilized for the detection of housekeeping protein and specific target proteins in complex cell lysate samples. The limit of detection of housekeeping protein is 0.25 µg of cell lysate, and the signal intensities were proportional to loading protein amount in a wide range from 0.61 to 80 µg. We believe that this new strategy of bimodal size distribution nanoparticles can also be expanded for other functional nanoparticle-based biological assays to improve the sensitivity and extend the dynamic range. Graphical abstract.


Assuntos
Imunoensaio/instrumentação , Limite de Detecção , Medições Luminescentes/instrumentação , Nanopartículas , Pontos Quânticos , Western Blotting , Corantes Fluorescentes , Imunoensaio/métodos , Medições Luminescentes/métodos
14.
Mikrochim Acta ; 187(9): 486, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32761391

RESUMO

A novel electrochemical biosensor is reported for simultaneous detection of two of the most common food-borne pathogens: Listeria monocytogenes and Staphylococcus aureus. The biosensor is composed of an array of gold nanoparticles-modified screen-printed carbon electrodes on which magnetic nanoparticles coupled to specific peptides were immobilized via streptavidin-biotin interaction. Taking advantage of the proteolytic activities of the protease enzymes produced from the two bacteria on the specific peptides, the detection was achieved in 1 min. The detection was realized by measuring the percentage increase of the square wave voltammetric peak current at 0.1 V versus a Ag/AgCl reference electrode in ferro/ferricyanide redox couple after incubation with the bacteria protease. The integration of the specificity of the bacterial enzymes towards their peptide substrates with the sensitivity of the electrochemical detection on the sensor array allows the rapid, sensitive and selective quantification of the two bacteria. Outstanding sensitivities were achieved using this biosensor array platform with limit of detection of 9 CFU mL-1 for Listeria monocytogenes and 3 CFU mL-1 for Staphylococcus aureus. The multiplexing capability and selectivity of the array voltammetric biosensor were demonstrated by analysing samples of Staphylococcus aureus, Listeria monocytogenes or E. coli and also containing a mixture of two or three bacteria. Using this biosensor, the two bacteria were successfully quantified simultaneously in one step without the need for DNA extraction or amplification techniques. This platform offers promise for rapid, simple and cost-effective simultaneous detection of various bacteria. Graphical abstract.


Assuntos
Proteínas de Bactérias/análise , Técnicas Biossensoriais/métodos , Listeria monocytogenes/isolamento & purificação , Peptídeo Hidrolases/análise , Peptídeos/química , Staphylococcus aureus/isolamento & purificação , Proteínas de Bactérias/química , Técnicas Biossensoriais/instrumentação , Carbono/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Proteínas Imobilizadas/química , Limite de Detecção , Listeria monocytogenes/enzimologia , Fenômenos Magnéticos , Nanopartículas Metálicas/química , Peptídeo Hidrolases/química , Proteólise , Staphylococcus aureus/enzimologia
15.
Nano Lett ; 19(2): 1275-1281, 2019 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-30681342

RESUMO

An ideal point light source is as small and as bright as possible. For fluorescent point light sources, homogeneity of the light sources is important as well as that the fluorescent units inside the light source maintain their photophysical properties, which is compromised by dye aggregation. Here we propose DNA origami as a rigid scaffold to arrange dye molecules in a dense pixel array with high control of stoichiometry and dye-dye interactions. In order to find the highest labeling density in a DNA origami structure without influencing dye photophysics, we alter the distance of two ATTO647N dyes in single base pair steps and probe the dye-dye interactions on the single-molecule level. For small distances strong quenching in terms of intensity and fluorescence lifetime is observed. With increasing distance, we observe reduced quenching and molecular dynamics. However, energy transfer processes in the weak coupling regime still have a significant impact and can lead to quenching by singlet-dark-state-annihilation. Our study fills a gap of studying the interactions of dyes relevant for superresolution microscopy with dense labeling and for single-molecule biophysics. Incorporating these findings in a 3D DNA origami object will pave the way to bright and homogeneous DNA origami nanobeads.


Assuntos
DNA/química , Corantes Fluorescentes/química , Nanoestruturas/química , Pareamento de Bases , Dimerização , Fluorescência , Microscopia Confocal , Microscopia de Fluorescência , Nanotecnologia , Espectrometria de Fluorescência
16.
Anal Biochem ; 577: 45-51, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31022377

RESUMO

In this study, colloidal gold (CG) and time-resolved fluorescent nanobead (TRFN) probes were used to establish an integrated immunochromatographic assay (ICA) to qualitatively and quantitatively detect clenbuterol (CLE). The best experimental conditions for the two probes in separate ICAs were obtained by optimizing the antibody labeling concentration, the amount of antigen, and the concentration of probe. When the CG and TRFN probes co-existed in the ICA, the latter had no effect on the sensitivity of qualitative detection of the CG probe-based ICA. However, the CG probe optimized the linear range of quantitative detection in the TRFN probe-based ICA. The integrated test strip can be used for qualitative and quantitative detection of CLE in one step. When the amount of antigen reached 0.4 mg/mL, the CG probe concentration reached 1.2 µg/mL, and the TRFN probe concentration reached 0.68 µg/mL. The qualitative sensitivity of the integrated ICA was 0.5 ng/mL and its quantitative limit of detection was 0.04 ng/mL with a detection range of 0.1-2.7 ng/mL. This developed method is of great significance for large-scale samples screening and positive monitoring in the field of food safety testing.


Assuntos
Clembuterol/análise , Inocuidade dos Alimentos/métodos , Imunoensaio/métodos , Corantes Fluorescentes/química , Coloide de Ouro/química , Produtos da Carne , Nanopartículas Metálicas/química , Carne de Porco
17.
Anal Bioanal Chem ; 411(9): 1825-1837, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30627798

RESUMO

Nanomaterials have extensive applications in the life sciences and in clinical diagnosis. We have developed magnetic nanoparticles with high dispersibility and extremely low nonspecific binding to biomolecules and have demonstrated their application in chemical biology (e.g., for the screening of drug receptor proteins). Recently, the excellent properties of nanobeads have made possible the development of novel rapid immunoassay systems and high-precision technologies for exosome detection. For immunoassays, we developed a technology to encapsulate a fluorescent substance in magnetic nanobeads. The fluorescent nanobeads allow the rapid detection of a specific antigen in solution or in tissue specimens. Exosomes, which are released into the blood, are expected to become markers for several diseases, including cancer, but techniques for measuring the absolute quantity of exosomes in biological fluids are lacking. By integrating magnetic nanobead technology with an optical disc system, we developed a novel method for precisely quantifying exosomes in human serum with high sensitivity and high linearity without requiring enrichment procedures. This review focuses on the properties of our magnetic nanobeads, the development of novel biosensors using these nanobeads, and their broad practical applications. Graphical abstract ᅟ.


Assuntos
Técnicas Biossensoriais , Imunoensaio/métodos , Magnetismo , Nanoestruturas , Exossomos , Fluorescência , Limite de Detecção , Nanopartículas
18.
Appl Microbiol Biotechnol ; 102(20): 8931-8942, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30143837

RESUMO

Single-domain antibody (sdAb) or nanobody possesses specific features non-accessible for conventional antibodies that make them suitable for research and biotechnological applications. Porcine epidemic diarrhea virus (PEDV) causes lethal diarrhea in piglets, resulting in great economic losses all over the world. To detect and isolate PEDV rapidly and accurately is important for the control and further research of the clinical PEDV strains. In this study, four sdAb fragments (sdAb-Mc19/29/30/37) targeting the membrane (M) protein of PEDV were selected from sdAb library that was constructed through M protein-immunized Camelus bactrianus. The selected sdAb-Mcs were solubly expressed in Escherichia coli. The functional characteristics analysis revealed that the recombinant sdAb-Mcs have excellent binding activity and specificity to M protein but have no neutralizing activity to PEDV. For further application, sdAb-Mc37 was conjugated with quantum dots to synthesize a nanoprobe for imaging PEDV in vero cells. The observed fluorescence in vero cells clearly reflects that PEDV virions can be reliably recognized and labeled by the nanoprobe. Furthermore, the sdAb-Mc29 was conjugated with superparamagnetic nanobeads to construct immunomagnetic nanobeads (IMNBs) used to isolate PEDV. One PEDV strain was successfully isolated from clinical fecal sample, suggesting IMNBs as a novel and efficient tool suitable for PEDV isolation from clinical samples. This study provided a novel application and substantiated the suitability of sdAb as a specific binder for the isolation of viruses.


Assuntos
Anticorpos Antivirais/química , Infecções por Coronavirus/veterinária , Diarreia/veterinária , Separação Imunomagnética/métodos , Vírus da Diarreia Epidêmica Suína/isolamento & purificação , Anticorpos de Domínio Único/química , Doenças dos Suínos/virologia , Animais , Anticorpos Antivirais/genética , Anticorpos Antivirais/metabolismo , Camelus , Chlorocebus aethiops , Infecções por Coronavirus/virologia , Diarreia/virologia , Fluorescência , Imunização , Separação Imunomagnética/instrumentação , Vírus da Diarreia Epidêmica Suína/genética , Vírus da Diarreia Epidêmica Suína/imunologia , Pontos Quânticos/química , Anticorpos de Domínio Único/genética , Anticorpos de Domínio Único/metabolismo , Suínos , Células Vero
19.
Mikrochim Acta ; 185(3): 164, 2018 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-29594804

RESUMO

The work describes a simple cotton swab-based colorimetric immunoassay as a rapid screening tool for pathogenic bacteria on poultry processing plants. This immunosensing platform can be used for the detection of pathogens present on surfaces such as glass, stainless steel and chicken meat. Unlike the reported assays, here, cotton swab plays dual function: as a sample collector from the solid surfaces and as detection platform. The immunoassay was tested for the detection of 4 different bacteria; Salmonella typhimurium, Salmonella enteritidis, Staphylococcus aureus and Campylobacter jejuni. The immunoassays were fabricated by immobilizing specific antibody for each bacterium on a cotton swab that is used to recover the cells from contaminated surfaces. Then, a sandwich immunoassay was developed by immersing the cotton swab in different colored nanobead-conjugated antibody solutions which corresponds to different bacteria. The immunoassays response was detected colorimetrically by following the change in the color intensity produced by the nanobeads due to the specific binding on the cotton swab. This simple colorimetric assay is very sensitive with a detection limit of 10 cfu.mL-1. Furthermore, no significant cross reactivity of the immunoassays with non specific bacteria was observed indicating good selectivity of the immunoassays. This simple, disposable and easy-to- use colorimetric platform shows great promise as rapid qualitative and semi quantitative detection tool for microorganisms on food processing plants and other surfaces. Graphical abstract Schematic of the sandwich colorimetric immunosensor for the detection of pathogenic bacteria on poultry processing plants using cotton swabs and nanobeads.


Assuntos
Contaminação de Alimentos/análise , Bactérias Gram-Negativas/isolamento & purificação , Imunoensaio/métodos , Aves Domésticas/microbiologia , Animais , Galinhas/microbiologia , Colorimetria/instrumentação , Colorimetria/métodos , Microbiologia de Alimentos/instrumentação , Microbiologia de Alimentos/métodos , Bactérias Gram-Negativas/imunologia , Imunoensaio/instrumentação , Limite de Detecção
20.
Nano Lett ; 17(12): 7478-7486, 2017 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-29116798

RESUMO

Metal nanoparticle arrays are excellent candidates for a variety of applications due to the versatility of their morphology and structure at the nanoscale. Bottom-up self-assembly of metal nanoparticles provides an important complementary alternative to the traditional top-down lithography method and makes it possible to assemble structures with higher-order complexity, for example, nanospheres, nanocubes, and core-shell nanostructures. Here we present a mechanism study of the self-assembly process of 1-D noble metal nanoparticles arrays, composed of Au, Ag, and AuAg alloy nanoparticles. These are prepared within an encapsulated germanium nanowire, obtained by the oxidation of a metal-germanium nanowire hybrid structure. The resulting structure is a 1-D array of equidistant metal nanoparticles with the same diameter, the so-called nanobead (NB) array structure. Atom-probe tomography and transmission electron microscopy were utilized to investigate the details of the morphological and chemical evolution during the oxidation of the encapsulated metal-germanium nanowire hybrid-structures. The self-assembly of nanoparticles relies on the formation of a metal-germanium liquid alloy and the migration of the liquid alloy into the nanowire, followed by dewetting of the liquid during shape-confined oxidation where the liquid column breaks-up into nanoparticles due to the Plateau-Rayleigh instability. Our results demonstrate that the encapsulating oxide layer serves as a structural scaffold, retaining the overall shape during the eutectic liquid formation and demonstrates the relationship between the oxide mechanical properties and the final structural characteristics of the 1-D arrays. The mechanistic details revealed here provide a versatile tool-box for the bottom-up fabrication of 1-D arrays nanopatterning that can be modified for multiple applications according to the RedOx properties of the material system components.

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