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1.
Food Chem ; 366: 130560, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34284183

RESUMO

The colorimetric method can determine the initial results even by the naked eyes, but its main challenge for antibiotics detection in food at present is the relatively low sensitivity. Herein, an ultrasensitive colorimetric biosensor based on G-quadruplex DNAzyme was firstly proposed for the rapid detection of trace tetracycline antibiotics like tetracycline, oxytetracycline, chlortetracycline and doxycycline. DNAzyme composed of hemin and G-quadruplex has peroxidase-like activity, and tetracyclines can combine with hemin to form a stable complex and reduce catalytic activity, making the color of solution changes from yellow to green. The limits of detection (LOD) of the proposed colorimetric biosensor for tetracyclines is determined as low as 3.1 nM, which is lower than most of the other colorimetric methods for antibiotics detection. Moreover, the average recovery range of tetracyclines in actual samples is from 89% to 99%, indicating that such strategy may has bright application prospects for tetracyclines detection in foods.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Tetraciclinas/análise , Antibacterianos , Colorimetria , Quadruplex G , Hemina , Peroxidase , Peroxidases
2.
Talanta ; 237: 122954, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34736679

RESUMO

Herein, a simple microfluidic paper-based analytical device (µPAD) by using platinum nanoparticles (Pt NPs) as highly active peroxidase mimic for simultaneous determination of glucose and uric acid was fabricated. The µPAD consisted of one sample transportation layer, four paper-based detection chips, and two layers of hydrophobic polyethylene terephthalate (PET) films. The four detection chips were immobilized with various chromogenic reagents, Pt NPs, and specific oxidase (glucose oxidase or uricase). H2O2 generated by specific enzymatic reactions could oxidize co-immobilized chromogenic reagents to produce colored products by using Pt NPs as efficient catalyst. The multi-layered structure of µPAD could effectively improve the color uniformity and color intensity. Total color intensity from each two detection chips modified with distinct chromogenic reagents were used for quantitative analysis of glucose and uric acid, respectively, resulting in significantly improved sensitivity. The linear range for glucose and uric acid detection was 0.01-5.0 mM and 0.01-2.5 mM, respectively. Satisfied results were obtained for glucose and uric acid detection in real serum samples. An easy-to-use smartphone APP was developed for convenient and intelligent detection. The developed µPAD integrated with smartphone as detector holds great applicability for simple and portable on-site analysis.


Assuntos
Nanopartículas Metálicas , Técnicas Analíticas Microfluídicas , Colorimetria , Glucose , Peróxido de Hidrogênio , Microfluídica , Papel , Peroxidase , Peroxidases , Platina , Smartphone , Ácido Úrico
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 265: 120348, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34507032

RESUMO

A label-free sensing strategy based on the enzyme-mimicking property of Glutathione-Ag nanoparticles (GSH-AgNPs) was demonstrated for colorimetric detection of vitamin B1 (VB1). Firstly, obvious blue color accompanied with an absorption peak at 652 nm was observed due to the high peroxidase-like activity of GSH-AgNPs towards 3,3',5,5'-tetramethylbenzidine (TMB). Then, in the presence of VB1, the mimetic activity of GSH-AgNPs could be strongly restrained, evidenced as a promiment colorimetric change to colorless, which can be used to achieve the visualization detection VB1. Linear relationship between absorbance response and VB1 concentration from 0 to 0.2 µM were obtained. The detection limit was calculated as low as 40 nM. The inhibition reasons were thoroughly discussed. Considering the advantages of rapid response, easy procedure and high selectivity, the proposed method possesses potential application in environment and biological analysis for VB1 detection.


Assuntos
Colorimetria , Nanopartículas Metálicas , Glutationa , Peroxidase , Peroxidases , Prata , Tiamina
4.
J Colloid Interface Sci ; 607(Pt 1): 470-478, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34509729

RESUMO

Effective electronic interactions between molecular catalysts and supports are critical for heterogeneous enzyme mimics, yet they are frequently neglected in most catalyst designs. Taking the enzyme mimics of hemin immobilized on graphdiyne (Hemin-GDY) as an example, we explicate for the first time the underlying role of GDY as a co-catalyst. Based on the robust conjugation between GDY and hemin, the delocalized π-electrons in GDY act as a ligand for Fe ions so that the orbital interactions including electron transport from GDY â†’ Fe can induce the formation of an electron-rich Fe center and an electron-deficient π-electron conjugated system. This mechanism was validated by electron paramagnetic resonance (EPR), Raman spectroscopy, and DFT calculations. Moreover, both EPR spetra and Lineweaver-Burk plots revealed that Hemin-GDY could efficiently catalyze the decomposition of hydrogen peroxide (H2O2) to produce hydroxyl radical (•OH) and superoxide anion (O2•-) by a ping-pong type catalytic mechanism, and particularly, the catalytic activity was increased by 2.3-fold comparing to that of hemin immobilized on graphene (Hemin-GR). In addition, Hemin-GDY with the exceptional activity and stability was demonstrated for efficient catalytic degradation of organic pollutants under acidic conditions. Collectively, this work provides a theoretical basis for the design of GDY supported catalysts and renders great promises of the GDY based enzyme mimics.


Assuntos
Grafite , Biomimética , Hemina , Peróxido de Hidrogênio , Peroxidase , Peroxidases
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120467, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34637988

RESUMO

A novel Au NPs/GeO2 nanozymes are developed as Surface-Enhanced Raman Scattering (SERS) substrates with the promising prospect for detection ChI. Herein, it is discovered that both Au NPs and GeO2 nanozymes have peroxidase-like activity, catalyzing colorless 3,3',5,5'-tetramethylbenzidine (TMB) to produce blue TMBox. Interestingly, compared with single Au NPs or GeO2 nanozymes, the Au NPs/GeO2 nanozymes show stronger peroxidase-like activity, and significantly ameliorated SERS signal of TMBox. The mentioned two enhancements are ascribed to a positive synergistic function of Au NPs/GeO2 nanozymes. Surprisingly, choline iodide (ChI) can inhibit the positive synergy in Au NPs/GeO2 nanozymes, and slow down the reaction of TMB-H2O2-Au NPs/GeO2 system. On this foundation, a new Au NPs/GeO2 SERS technique with high sensitivity, label-free detection method of choline iodide (ChI) is established, suggesting that Au NPs/GeO2 nanozymes have the potential application of water environment.


Assuntos
Ouro , Nanopartículas Metálicas , Colina , Peróxido de Hidrogênio , Iodetos , Peroxidase , Peroxidases , Análise Espectral Raman
6.
Front Cell Infect Microbiol ; 11: 751232, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34746027

RESUMO

Understanding of the basis for severity and fatal outcome of SARS-CoV-2 infection is of paramount importance for developing therapeutic options and identification of prognostic markers. So far, accumulation of neutrophils and increased levels of pro-inflammatory cytokines are associated with disease severity in COVID-19 patients. In this study, we aimed to compare circulatory levels of neutrophil secretory proteins, alpha-defensins (DEFA1), calprotectin (S100A8/A9), and myeloperoxidase (MPO) in COVID-19 patients with different clinical presentations. We studied 19 healthy subjects, 63 COVID-19 patients with mild (n=32) and severe (n=31) disease, 23 asymptomatic individuals identified through contact tracing programme and 23 recovering patients (1-4 months post-disease). At the time of disease presentation, serum levels of DEFA1 were significantly higher in patients with mild (mean230 ± 17, p<0.0001) and severe (mean452 ± 46, p<0.0001) disease respectively in comparison to healthy subjects (mean113 ± 11). S100A8/A9 proteins were significantly higher in COVID-19 patients (p<0.0001) irrespective of disease severity. The levels of DEFA1, S100A8/A9 and MPO reduced to normal in recovering patients and comparable to healthy subjects. Surprisingly, DEFA1 levels were higher in severe than mild patients in first week of onset of disease (p=0.004). Odds-ratio analysis showed that DEFA1 could act as potential biomarker in predicting disease severity (OR=11.34). In addition, levels of DEFA1 and S100A8/A9 were significantly higher in patients with fatal outcome (p=0.004 and p=0.03) respectively. The rise in DEFA1 levels was independent of secondary infections. In conclusion, our data suggest that induction of elevated levels of alpha-defensins and S100A8/A9 is associated with poor disease outcome in COVID-19 patients.


Assuntos
COVID-19 , alfa-Defensinas , Humanos , Complexo Antígeno L1 Leucocitário , Neutrófilos , Peroxidase , SARS-CoV-2 , Índice de Gravidade de Doença
7.
Anal Chim Acta ; 1187: 339171, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34753561

RESUMO

Nanozyme-mediated 3,3',5,5'-tetramethylbenzidine (TMB) - H2O2 systems have spawned the establishment of multiple colorimetric sensing platforms that are effective but sometimes subject to low sensitivity. Taking temperature as the output signal, photothermal effects lead to new strategies for sensitive detection. In this paper, a colorimetric and photothermal dual-mode immunoassay for diethylstilbestrol (DES) was constructed. It is based on the oxidation reaction of TMB catalyzed by black phosphorus-gold nanoparticle (BP/Au) nanohybrids, and the kinetics as well as catalytic mechanism of the nanohybrids were investigated in detail for the first time. Herein, the nanohybrids playcatalytic and photothermal dual roles. Moreover, the one-electron oxidation product of TMB (oxidized TMB) not only acts as chromogenic agent but also an excellent NIR laser-driven photothermal agent. The temperature (ΔT/°C) was gauged by a portable digital thermometer. Through an indirect competition strategy, a simple, sensitive, and economic immunosensor was proposed. Higher DES content in the sample correlated with less BP/Au nanohybrids conjugated to the surface of ELISA microplate, a weaker color change, and a lower temperature variation when exposed to laser irradiation. This method was applied for DES determination in real samples with gratifying recovery rates, showing great promise in food safety inspection applications.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Colorimetria , Dietilestilbestrol , Ouro , Peróxido de Hidrogênio , Imunoensaio , Peroxidase , Peroxidases , Fósforo
8.
Analyst ; 146(23): 7284-7293, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34749389

RESUMO

Graphdiyne oxide (GDYO) is a novel type of two-dimensional carbon allotrope nanomaterial consisting of a large conjugated system and excellent chemical stability. To date, application of GDYO as a nanozyme in biosensing has been rarely reported. In this study, a novel ultrasensitive colorimetric bioassay was constructed using a hemin/GDYO nanocomposite (H/GDYO) as a new nanozyme with superior peroxidase-like activity for the detection of H2O2 and glucose. It was discovered that H/GDYO exhibited 6-fold higher peroxidase-like activity than pure hemin. Catalytic kinetic analysis showed that H/GDYO had a much higher affinity for H2O2 and glucose than that of hemin. The designed colorimetric bioassay displayed excellent sensitivity for H2O2 and glucose detection with a wide linear range of 0.015-0.5 mM and 0.1-10 mM, respectively, while the limit of detection (LOD) was as low as 4.39 µM and 38 µM, respectively. Moreover, it was successfully applied for the analysis of H2O2 in milk and glucose in real human serum samples with acceptable recoveries. Importantly, the developed colorimetric bioassay shows good agreement with the results obtained from a commercial blood glucose meter. We believe that the proposed method could provide a promising prospect for medical diagnosis and biotechnology.


Assuntos
Técnicas Biossensoriais , Nanocompostos , Bioensaio , Biomimética , Colorimetria , Grafite , Hemina , Humanos , Peróxido de Hidrogênio , Cinética , Óxidos , Peroxidase/metabolismo
9.
Eur Respir Rev ; 30(162)2021 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-34750115

RESUMO

Over the past three decades, an increasing number of publications have reported the association between interstitial lung disease (ILD) and anti-neutrophil cytoplasmic antibody (ANCA) or ANCA-associated vasculitis (AAV). With this increased awareness, we have reviewed the literature to date and provide an update in this narrative review. The vast majority of cases of ILD have been shown to be in the setting of positive anti-myeloperoxidase antibody and can be present in up to 45% of patients of microscopic polyangiitis, though cases of ILD associated with proteinase 3 ANCA have rarely been reported. Pulmonary fibrosis and ANCA positivity can occur with or without systemic involvement. The pathogenetic mechanisms establishing the relationship between ANCA and the development of pulmonary fibrosis remain unclear. Histologic and radiographic features of ANCA-ILD most commonly reveal usual interstitial pneumonia or non-specific interstitial pneumonia patterns, though other atypical features such as bronchiolitis have been described. ILD in the setting of AAV has been associated with worse outcomes, and thus early identification and treatment in these patients is appropriate. We advocate that ANCA antibody testing be performed as a baseline evaluation in patients presenting with idiopathic interstitial pneumonia. Suggested treatment of ANCA-ILD includes immunosuppression and/or antifibrotic agents, though supporting data and clinical trials to substantiate use of these therapies are needed.


Assuntos
Fibrose Pulmonar Idiopática , Doenças Pulmonares Intersticiais , Anticorpos Anticitoplasma de Neutrófilos , Humanos , Pulmão/diagnóstico por imagem , Doenças Pulmonares Intersticiais/diagnóstico , Doenças Pulmonares Intersticiais/terapia , Peroxidase
10.
Front Immunol ; 12: 714833, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34745093

RESUMO

Background: The most severe cases of Coronavirus-Disease-2019 (COVID-19) develop into Acute Respiratory Distress Syndrome (ARDS). It has been proposed that oxygenation may be inhibited by extracellular deoxyribonucleic acid (DNA) in the form of neutrophil extracellular traps (NETs). Dornase alfa (Pulmozyme, Genentech) is recombinant human deoxyribonuclease I that acts as a mucolytic by cleaving and degrading extracellular DNA. We performed a pilot study to evaluate the effects of dornase alfa in patients with ARDS secondary to COVID-19. Methods: We performed a pilot, non-randomized, case-controlled clinical trial of inhaled dornase for patients who developed ARDS secondary to COVID-19 pneumonia. Results: Improvement in arterial oxygen saturation to inhaled fraction of oxygen ratio (PaO2/FiO2) was noted in the treatment group compared to control at day 2 (95% CI, 2.96 to 95.66, P-value = 0.038), as well as in static lung compliance at days 3 through 5 (95% CI, 4.8 to 19.1 mL/cmH2O, 2.7 to 16.5 mL/cmH2O, and 5.3 to 19.2 mL/cmH2O, respectively). These effects were not sustained at 14 days. A reduction in bronchoalveolar lavage fluid (BALF) myeloperoxidase-DNA (DNA : MPO) complexes (95% CI, -14.7 to -1.32, P-value = 0.01) was observed after therapy with dornase alfa. Conclusion: Treatment with dornase alfa was associated with improved oxygenation and decreased DNA : MPO complexes in BALF. The positive effects, however, were limited to the time of drug delivery. These data suggest that degradation of extracellular DNA associated with NETs or other structures by inhaled dornase alfa can be beneficial. We propose a more extensive clinical trial is warranted. Clinical Trial Registration: ClinicalTrials.gov, Identifier: NCT04402970.


Assuntos
COVID-19/tratamento farmacológico , Desoxirribonuclease I/uso terapêutico , Síndrome do Desconforto Respiratório/tratamento farmacológico , SARS-CoV-2/fisiologia , Administração por Inalação , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , DNA/metabolismo , Armadilhas Extracelulares/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio/efeitos dos fármacos , Peroxidase/metabolismo , Projetos Piloto , Proteínas Recombinantes/uso terapêutico , Adulto Jovem
11.
Analyst ; 146(21): 6470-6473, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34609387

RESUMO

A novel and low-cost DNAzyme, Ni/Fe layered double hydroxide (LDH) nanosheet/G-quadruplex (without hemin) with enhanced peroxidase-mimic activity was designed. The catalytic mechanism was investigated. The detection of Cu(II) in actual serum samples could be realized sensitively via this efficient DNAzyme-based method.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Quadruplex G , DNA Catalítico/metabolismo , Hemina , Hidróxidos , Peroxidase , Peroxidases
12.
Int J Mol Sci ; 22(19)2021 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-34638723

RESUMO

The precise synthesis of fine-sized nanoparticles is critical for realizing the advantages of nanoparticles for various applications. We developed a technique for preparing finely controllable sizes of gold nanoparticles (Au NPs) on a silica template, using the seed-mediated growth and interval dropping methods. These Au NPs, embedded on silica nanospheres (SiO2@Au NPs), possess peroxidase-like activity as nanozymes and have several advantages over other nanoparticle-based nanozymes. We confirmed their peroxidase activity; in addition, factors affecting the activity were investigated by varying the reaction conditions, such as concentrations of tetramethyl benzidine and H2O2, pH, particle amount, reaction time, and termination time. We found that SiO2@Au NPs are highly stable under long-term storage and reusable for five cycles. Our study, therefore, provides a novel method for controlling the properties of nanoparticles and for developing nanoparticle-based nanozymes.


Assuntos
Benzidinas/química , Ouro/química , Peróxido de Hidrogênio/química , Nanopartículas Metálicas/química , Nanosferas/química , Peroxidase/química , Dióxido de Silício/química , Concentração de Íons de Hidrogênio
13.
Sensors (Basel) ; 21(19)2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34640646

RESUMO

Hypochlorous acid (HOCl) generates from the reaction between hydrogen peroxide and chloride ions via myeloperoxidase (MPO)-mediated in vivo. As very important reactive oxygen species (ROS), hypochlorous acid (HOCl)/hypochlorite (OCl-) play a crucial role in a variety of physiological and pathological processes. However, excessive or misplaced production of HOCl/OCl- can cause variety of tissue damage and human diseases. Therefore, rapid, sensitive, and selective detection of OCl- is very important. In recent years, the fluorescent probe method for detecting hypochlorous acid has been developed rapidly due to its simple operation, low toxicity, high sensitivity, and high selectivity. In this review, the progress of recently discovered fluorescent probes for the detection of hypochlorous acid was summarized with the aim to provide useful information for further design of better fluorescent probes.


Assuntos
Corantes Fluorescentes , Ácido Hipocloroso , Humanos , Peróxido de Hidrogênio , Peroxidase
14.
J Insect Sci ; 21(5)2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34718645

RESUMO

Radiation is considered as a promising insect pest control strategy for minimizing postharvest yield losses. Among various techniques, irradiation is a method of choice as it induces lethal biochemical or molecular changes that cause a downstream cascade of abrupt physiological abnormalities at the cellular level. In this study, we evaluated the effect of 60Co-γ radiation on various developmental stages of Zeugodacus cucurbitae Coquillett and subsequent carry-over effects on the progeny. For this purpose, we treated eggs with 30- and 50-Gy radiation doses of 60Co-γ. We found that radiation significantly affected cellular antioxidants, insect morphology, and gene expression profiles. Our results indicate that in response to various doses of irradiation reactive oxygen species, catalase, peroxidase, and superoxide dismutase activities were increased along with a significant increase in the malondialdehyde (MDA) content. We observed higher mortality rates during the pupal stage of the insects that hatched from irradiated eggs (50 Gy). Furthermore, the life span of the adults was reduced in response to 50 Gy radiation. The negative effects carried over to the next generation were marked by significantly lower fecundity in the F1 generation of the irradiation groups as compared to control. The radiation induced morphological abnormalities at the pupal, as well as the adult, stages. Furthermore, variations in the gene expression following irradiation are discussed. Taken together, our results signify the utility of 60Co-γ radiation for fruit fly postharvest management.


Assuntos
Apoptose/efeitos da radiação , Raios gama , Expressão Gênica/efeitos da radiação , Tephritidae/efeitos da radiação , Animais , Antioxidantes/metabolismo , Antioxidantes/efeitos da radiação , Apoptose/genética , Catalase/metabolismo , Catalase/efeitos da radiação , Radioisótopos de Cobalto/farmacologia , Controle de Insetos/métodos , Proteínas de Insetos/metabolismo , Proteínas de Insetos/efeitos da radiação , Larva/genética , Larva/metabolismo , Larva/fisiologia , Larva/efeitos da radiação , Longevidade/efeitos da radiação , Malondialdeído/metabolismo , Malondialdeído/efeitos da radiação , Peroxidase/metabolismo , Peroxidase/efeitos da radiação , Controle de Pragas/métodos , Pupa/genética , Pupa/metabolismo , Pupa/fisiologia , Pupa/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Espécies Reativas de Oxigênio/efeitos da radiação , Tephritidae/genética , Tephritidae/metabolismo , Tephritidae/fisiologia
15.
Int J Mol Sci ; 22(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34639208

RESUMO

Bacillus subtilis BsDyP belongs to class I of the dye-decolorizing peroxidase (DyP) family of enzymes and is an interesting biocatalyst due to its high redox potential, broad substrate spectrum and thermostability. This work reports the optimization of BsDyP using directed evolution for improved oxidation of 2,6-dimethoxyphenol, a model lignin-derived phenolic. After three rounds of evolution, one variant was identified displaying 7-fold higher catalytic rates and higher production yields as compared to the wild-type enzyme. The analysis of X-ray structures of the wild type and the evolved variant showed that the heme pocket is delimited by three long conserved loop regions and a small α helix where, incidentally, the mutations were inserted in the course of evolution. One loop in the proximal side of the heme pocket becomes more flexible in the evolved variant and the size of the active site cavity is increased, as well as the width of its mouth, resulting in an enhanced exposure of the heme to solvent. These conformational changes have a positive functional role in facilitating electron transfer from the substrate to the enzyme. However, they concomitantly resulted in decreasing the enzyme's overall stability by 2 kcal mol-1, indicating a trade-off between functionality and stability. Furthermore, the evolved variant exhibited slightly reduced thermal stability compared to the wild type. The obtained data indicate that understanding the role of loops close to the heme pocket in the catalysis and stability of DyPs is critical for the development of new and more powerful biocatalysts: loops can be modulated for tuning important DyP properties such as activity, specificity and stability.


Assuntos
Bacillus subtilis/enzimologia , Proteínas de Bactérias/metabolismo , Heme/química , Mutação , Peroxidase/química , Peroxidase/metabolismo , Proteínas de Bactérias/genética , Catálise , Domínio Catalítico , Corantes/química , Corantes/metabolismo , Estabilidade Enzimática , Heme/metabolismo , Concentração de Íons de Hidrogênio , Oxirredução , Peroxidase/genética , Conformação Proteica
16.
BMJ Case Rep ; 14(10)2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620637

RESUMO

We present a patient with systemic symptoms including 4 months of dyspnoea worsened with exertion, fatigue, rhinorrhoea, intermittent facial swelling, generalised lymphadenopathy and weight loss. Laboratory studies demonstrated proteinuria and eosinophilia. His serology was consistent with Epstein-Barr Virus (EBV) reactivation. A lymph node biopsy was consistent with EBV-associated reactive lymphoid hyperplasia. He was told to continue symptomatic treatment for EBV infection. After several admissions, vasculitis workup and myeloperoxidase-antineutrophil cytoplasmic autoantibody (ANCA) studies were positive. Evolution of clinical symptoms, laboratory parameters and our literature review suggested the diagnosis of EBV-associated ANCA vasculitis. Steroids were started after the patient continued to deteriorate; the viral load started increasing, so we added valganciclovir with favourable clinical response and no relapse during the follow-up for 6 months. This suggests that with evidence of viraemia (primary or reactivation), antiviral treatment likely has clinical benefit while immunosuppression is being considered.


Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos , Infecções por Vírus Epstein-Barr , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/complicações , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/diagnóstico , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/tratamento farmacológico , Anticorpos Anticitoplasma de Neutrófilos , Infecções por Vírus Epstein-Barr/complicações , Infecções por Vírus Epstein-Barr/diagnóstico , Infecções por Vírus Epstein-Barr/tratamento farmacológico , Herpesvirus Humano 4 , Humanos , Masculino , Peroxidase
17.
ACS Nano ; 15(10): 15645-15655, 2021 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-34623130

RESUMO

Enzymes have catalytic turnovers. The field of nanozyme endeavors to engineer nanomaterials as enzyme mimics. However, a discrepancy in the definition of "nanozyme concentration" has led to an unrealistic calculation of nanozyme catalytic turnovers. To date, most of the reported works have considered either the atomic concentration or nanoparticle (NP) concentration as nanozyme concentration. These assumptions can lead to a significant under- or overestimation of the catalytic activity of nanozymes. In this article, we review some classic nanozymes including Fe3O4, CeO2, and gold nanoparticles (AuNPs) with a focus on the reported catalytic activities. We argue that only the surface atoms should be considered as nanozyme active sites, and then the turnover numbers and rates were recalculated based on the surface atoms. According to the calculations, the catalytic turnover of peroxidase Fe3O4 NPs is validated. AuNPs are self-limited when performing glucose-oxidase like activity, but they are also true catalysts. For CeO2 NPs, a self-limited behavior is observed for both oxidase- and phosphatase-like activities due to the adsorption of reaction products. Moreover, the catalytic activity of single-atom nanozymes is discussed. Finally, a few suggestions for future research are proposed.


Assuntos
Ouro , Nanopartículas Metálicas , Catálise , Glucose Oxidase , Peroxidase
18.
PLoS One ; 16(10): e0257777, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34637444

RESUMO

Nitrogen-functionalization is an effective means of improving the catalytic performances of nanozymes. In the present work, plasma-assisted nitrogen modification of nanocolumnar Ni GLAD films was performed using an ammonia plasma, resulting in an improvement in the peroxidase-like catalytic performance of the porous, nanostructured Ni films. The plasma-treated nanozymes were characterized by TEM, SEM, XRD, and XPS, revealing a nitrogen-rich surface composition. Increased surface wettability was observed after ammonia plasma treatment, and the resulting nitrogen-functionalized Ni GLAD films presented dramatically enhanced peroxidase-like catalytic activity. The optimal time for plasma treatment was determined to be 120 s; when used to catalyze the oxidation of the colorimetric substrate TMB in the presence of H2O2, Ni films subjected to 120 s of plasma treatment yielded a much higher maximum reaction velocity (3.7⊆10-8 M/s vs. 2.3⊆10-8 M/s) and lower Michaelis-Menten coefficient (0.17 mM vs. 0.23 mM) than pristine Ni films with the same morphology. Additionally, we demonstrate the application of the nanozyme in a gravity-driven, continuous catalytic reaction device. Such a controllable plasma treatment strategy may open a new door toward surface-functionalized nanozymes with improved catalytic performance and potential applications in flow-driven point-of-care devices.


Assuntos
Peróxido de Hidrogênio/química , Nanoestruturas/química , Nitrogênio/química , Peroxidase/química , Amônia/química , Antioxidantes/química , Biocatálise , Catálise , Colorimetria , Corantes/química , Níquel/química , Oxirredução/efeitos dos fármacos , Oxigênio/química , Espectroscopia Fotoeletrônica , Propriedades de Superfície
19.
Mikrochim Acta ; 188(10): 335, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34505191

RESUMO

A practical colorimetric assay was developed for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For this purpose, magnetic γ Fe2O3 nanoparticles were synthesized and used as a peroxidase-like mimic activity molecule. In the presence of γ Fe2O3 nanoparticles, the color change of H2O2 included 3,3',5,5'-tetramethylbenzidine was monitored at the wavelength of 654 nm when spike protein interacted with angiotensin-converting enzyme 2 receptor. This oxidation-reduction reaction was examined both spectroscopically and by using electrochemical techniques. The experimental parameters were optimized and the analytical characteristics investigated. The developed assay was applied to real SARS-CoV-2 samples, and very good results that were in accordance with the real time polymerase chain reaction were obtained.


Assuntos
Teste para COVID-19/métodos , COVID-19/diagnóstico , Colorimetria/métodos , Nanopartículas Magnéticas de Óxido de Ferro/química , SARS-CoV-2/química , Glicoproteína da Espícula de Coronavírus/química , Enzima de Conversão de Angiotensina 2/metabolismo , Benzidinas/química , Técnicas Biossensoriais/métodos , Teste para COVID-19/instrumentação , Catálise , Compostos Cromogênicos/química , Cisteína/química , Humanos , Peróxido de Hidrogênio/química , Limite de Detecção , Nasofaringe/virologia , Orofaringe/virologia , Oxirredução , Peroxidase/química , Glicoproteína da Espícula de Coronavírus/metabolismo
20.
Anal Chim Acta ; 1179: 338827, 2021 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-34535266

RESUMO

Infectious and inflammatory diseases involve superoxide anion (O2•-) production. Real-time and non-invasive evaluation of O2•- in intact biological systems has been a significant challenge in biology and medicine. Here, I report that an advanced near-infrared chemiluminescent probe, MCLA-800, enables reliable non-invasive optical readout of O2•-ex vivo and in vivo. MCLA-800 allowed highly selective and sensitive monitoring of O2•- in undiluted human whole blood ex vivo. For the first time, the use of MCLA-800 revealed two reproducible types of O2•- production in response to stimulation by unopsonized zymosan particles of Saccharomyces cerevisiae, that is, slow response (S-type) and fast response (F-type), specific to each individual. O2•- production was synchronized with myeloperoxidase (MPO) activation in the former type but not in the latter. Moreover, as new findings, MCLA-800 chemiluminescence demonstrated that the chemiluminescence intensity-time properties of formyl-methionyl-leucyl-phenylalanine (fMLP)- or phorbol 12-myristate 13-acetate (PMA)-induced O2•- production and MPO activity were independent of S- and F-type zymosan-induced MCLA-800 chemiluminescence whole blood and that PMA-induced MPO activation synchronized with PMA-induced O2•- production in S- and F-type zymosan-induced MCLA-800 chemiluminescence whole blood, but fMLP-induced MPO activation did not synchronize with fMLP-induced O2•- production in both of S- and F-type blood. Furthermore, MCLA-800 spatiotemporally allowed non-invasive and clear in vivo imaging of O2•- in animal models of acute dermatitis and focal arthritis. Therefore, MCLA-800 could be possibly applied in various advanced diagnostic techniques.


Assuntos
Medições Luminescentes , Superóxidos , Animais , Humanos , N-Formilmetionina Leucil-Fenilalanina , Peroxidase , Acetato de Tetradecanoilforbol
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