Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 60
Filtrar
1.
Int J Infect Dis ; : 107161, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-38992789

RESUMO

OBJECTIVES: To assess safety and immunogenicity of a 4th vaccination (2nd booster) in individuals ≥75 years METHODS: Participants were randomised to BNT162b2 (Comirnaty®, 30µg) or mRNA-1273 (Spikevax®, 100µg). The primary endpoint was the rate of 2-fold antibody titre increase 14 days post-vaccination targeting the receptor binding domain (RBD) region of wild-type SARS-CoV-2. Secondary endpoints included changes in neutralising activity against wild-type and 25 variants. Safety was assessed by monitoring solicited adverse events (AE) for seven days. RESULTS: 269 participants (mean age 81 years, mRNA-1273 n=135/BNT162b2 n=134) were included. 2-fold anti-RBD IgG titre increase was achieved by 101/129 (78%) and 116/133 (87%) subjects in the BNT162b2 and the mRNA-1273 group, respectively (p=0.054). A 2nd booster of mRNA-1273 provided higher anti-RBD IgG geometric mean titre: 21.326 IU/mL (95%-CI: 18.235; 24.940) vs. BNT162b2: 15.181 IU/mL (95%-CI: 13.172; 17.497). Higher neutralising activity was noted for the mRNA-1273 group. The most frequent AE was pain at injection site (51% in mRNA-1273 and 48% in BNT162b2). Participants in the mRNA-1273 group had less vaccine-related AEs (30% vs. 39%). CONCLUSIONS: A 2nd booster of either BNT162b2 or mRNA-1273 provided substantial IgG increase. Full-dose mRNA-1273 provided higher IGG levels and neutralising capacity against SARS-CoV-2 with similar safety profile for subjects of advanced age.

2.
Toxicon ; 247: 107842, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38960287

RESUMO

Poecilotheria spiders are considered theraphosids of underestimated clinical importance, with bites from these species inducing symptoms such as severe pain and intense muscle cramps. However, there is no specific treatment for the envenomation caused by these species, which, while native to India and Sri Lanka, are widely distributed worldwide. The present study reports the case of a 31-year-old man bitten by a Poecilotheria regalis specimen. The patient's clinical presentation was similar to Latrodectus envenomation, and patient was treated with an L. mactans antivenom. Most of patient's symptoms improved (fasciculations, pain, erythema, and local swelling), except muscle cramps. A toxicological study conducted on mice did not show that L. mactans antivenom has a neutralizing effect on the toxicity of P. regalis. The present report discusses the envenoming process of Poecilotheria species and the possible neutralizing effect exerted by L. mactans antivenom.

3.
J. optom. (Internet) ; 17(2): [100492], Abr-Jun, 2024. tab
Artigo em Inglês | IBECS | ID: ibc-231621

RESUMO

Purpose: Given the increase in demand for optometry services by society and the importance of the Optometry profession in Portugal and Spain, the objective of this study was to determine job satisfaction and important factors related to this satisfaction in a sample of Portuguese and Spanish optometrists. Methods: A prospective, cross-sectional, and observational study was carried out from June to December 2021. An adaptation of the 15-item job satisfaction in eye-care personnel (JSEP) questionnaire validated by Paudel et al. was administered to Portuguese and Spanish optometrists. The questionnaire was shared through different social media (Facebook, LinkedIn, WhatsApp, etc.) in a Google form during the months of June to December 2021 in Portugal and Spain. Results: A total of 530 surveys were collected in Portugal (42.3%; n = 224) and Spain (57.7%; n = 306). The factors that most influence overall job satisfaction are salary, career development opportunities, recognition/prestige in society, good work-life balance (all p<0.001), workplace equipment and facilities, and encouragement reward positive feedback (both p = 0.002). When comparing the determinants of job satisfaction of optometrists, it was found that Portuguese professionals were generally more satisfied than Spanish ones (p<0.001). However, Spanish optometrists reported feeling more supported by their colleagues (p<0.001). Conclusion: This study has shown that the level of job satisfaction was higher in Portugal than in Spain. The most important factors influencing job satisfaction were salary, job stability, and support from colleagues.(AU)


Assuntos
Humanos , Masculino , Feminino , Satisfação no Emprego , Visão Ocular , Optometristas , Optometria , Espanha , Portugal , Estudos Prospectivos , Estudos Transversais , Inquéritos e Questionários
4.
Elife ; 122024 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-38634460

RESUMO

Mechanosensory neurons located across the body surface respond to tactile stimuli and elicit diverse behavioral responses, from relatively simple stimulus location-aimed movements to complex movement sequences. How mechanosensory neurons and their postsynaptic circuits influence such diverse behaviors remains unclear. We previously discovered that Drosophila perform a body location-prioritized grooming sequence when mechanosensory neurons at different locations on the head and body are simultaneously stimulated by dust (Hampel et al., 2017; Seeds et al., 2014). Here, we identify nearly all mechanosensory neurons on the Drosophila head that individually elicit aimed grooming of specific head locations, while collectively eliciting a whole head grooming sequence. Different tracing methods were used to reconstruct the projections of these neurons from different locations on the head to their distinct arborizations in the brain. This provides the first synaptic resolution somatotopic map of a head, and defines the parallel-projecting mechanosensory pathways that elicit head grooming.


Assuntos
Drosophila , Neurônios , Animais , Asseio Animal/fisiologia , Vias Aferentes , Neurônios/fisiologia , Encéfalo , Drosophila melanogaster/fisiologia
5.
Int J Mol Sci ; 24(24)2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38139362

RESUMO

The disruption of mitochondrial dynamics has been identified in cardiovascular diseases, including pulmonary hypertension (PH), ischemia-reperfusion injury, heart failure, and cardiomyopathy. Mitofusin 2 (Mfn2) is abundantly expressed in heart and pulmonary vasculature cells at the outer mitochondrial membrane to modulate fusion. Previously, we have reported reduced levels of Mfn2 and fragmented mitochondria in pulmonary arterial endothelial cells (PAECs) isolated from a sheep model of PH induced by pulmonary over-circulation and restoring Mfn2 normalized mitochondrial function. In this study, we assessed the effect of increased expression of Mfn2 on mitochondrial metabolism, bioenergetics, reactive oxygen species production, and mitochondrial membrane potential in control PAECs. Using an adenoviral expression system to overexpress Mfn2 in PAECs and utilizing 13C labeled substrates, we assessed the levels of TCA cycle metabolites. We identified increased pyruvate and lactate production in cells, revealing a glycolytic phenotype (Warburg phenotype). Mfn2 overexpression decreased the mitochondrial ATP production rate, increased the rate of glycolytic ATP production, and disrupted mitochondrial bioenergetics. The increase in glycolysis was linked to increased hypoxia-inducible factor 1α (HIF-1α) protein levels, elevated mitochondrial reactive oxygen species (mt-ROS), and decreased mitochondrial membrane potential. Our data suggest that disrupting the mitochondrial fusion/fission balance to favor hyperfusion leads to a metabolic shift that promotes aerobic glycolysis. Thus, therapies designed to increase mitochondrial fusion should be approached with caution.


Assuntos
Hipertensão Pulmonar , Mitocôndrias , Animais , Trifosfato de Adenosina/metabolismo , Células Endoteliais/metabolismo , Glicólise , Hidrolases/metabolismo , Hipertensão Pulmonar/metabolismo , Mitocôndrias/metabolismo , Dinâmica Mitocondrial , Proteínas Mitocondriais/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Ovinos , GTP Fosfo-Hidrolases/metabolismo
6.
Vaccine ; 41(48): 7166-7175, 2023 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-37919141

RESUMO

BACKGROUND: Vaccination remains crucial for protection against severe SARS-CoV-2 infection, especially for people of advanced age, however, optimal dosing regimens are as yet lacking. METHODS: EU-COVAT-1-AGED Part A is a randomised controlled, adaptive, multicentre phase II trial evaluating safety and immunogenicity of a 3rd vaccination (1st booster) in individuals ≥75 years. Fifty-three participants were randomised to full-doses of either mRNA-1273 (Spikevax®, 100 µg) or BNT162b2 (Comirnaty®, 30 µg). The primary endpoint was the rate of 2-fold circulating antibody titre increase 14 days post-vaccination measured by quantitative electrochemiluminescence (ECL) immunoassay, targeting RBD region of Wuhan wild-type SARS-CoV-2. Secondary endpoints included the changes in neutralising capacity against wild-type and 25 variants of concern at 14 days and up to 12 months. Safety was assessed by monitoring of solicited adverse events (AEs) for seven days after on-study vaccination. Unsolicited AEs were collected until the end of follow-up at 12 months, SAEs were pursued for a further 30 days. RESULTS: Between 08th of November 2021 and 04th of January 2022, 53 participants ≥75 years received a COVID-19 vaccine as 1st booster. Fifty subjects (BNT162b2 n = 25/mRNA-1273 n = 25) were included in the analyses for immunogenicity at day 14. The primary endpoint of a 2-fold anti-RBD IgG titre increase 14 days after vaccination was reached for all subjects. A 3rd vaccination of full-dose mRNA-1273 provided higher anti-RBD IgG titres (Geometric mean titre) D14 mRNA-127310711 IU/mL (95 %-CI: 8003;14336) vs. BNT162b2: 7090 IU/mL (95 %-CI: 5688;8837). We detected a pattern showing higher neutralising capacity of full-dose mRNA-1273 against wild-type as well as for 23 out of 25 tested variants. INTERPRETATION: Third doses of either BNT162b2 or mRNA-1273 provide substantial circulating antibody increase 14 days after vaccination. Full-dose mRNA-1273 provides higher antibody levels with an overall similar safety profile for people ≥75 years. FUNDING: This trial was funded by the European Commission (Framework Program HORIZON 2020).


Assuntos
Vacina de mRNA-1273 contra 2019-nCoV , Vacina BNT162 , Humanos , Adulto , Idoso , Vacinas contra COVID-19/efeitos adversos , RNA Mensageiro , Imunoglobulina G , Imunogenicidade da Vacina , Anticorpos Antivirais , Anticorpos Neutralizantes
7.
Sci Rep ; 13(1): 12420, 2023 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-37528111

RESUMO

One of the major challenges currently faced by global health systems is the prolonged COVID-19 syndrome (also known as "long COVID") which has emerged as a consequence of the SARS-CoV-2 epidemic. It is estimated that at least 30% of patients who have had COVID-19 will develop long COVID. In this study, our goal was to assess the plasma metabolome in a total of 100 samples collected from healthy controls, COVID-19 patients, and long COVID patients recruited in Mexico between 2020 and 2022. A targeted metabolomics approach using a combination of LC-MS/MS and FIA MS/MS was performed to quantify 108 metabolites. IL-17 and leptin were measured in long COVID patients by immunoenzymatic assay. The comparison of paired COVID-19/long COVID-19 samples revealed 53 metabolites that were statistically different. Compared to controls, 27 metabolites remained dysregulated even after two years. Post-COVID-19 patients displayed a heterogeneous metabolic profile. Lactic acid, lactate/pyruvate ratio, ornithine/citrulline ratio, and arginine were identified as the most relevant metabolites for distinguishing patients with more complicated long COVID evolution. Additionally, IL-17 levels were significantly increased in these patients. Mitochondrial dysfunction, redox state imbalance, impaired energy metabolism, and chronic immune dysregulation are likely to be the main hallmarks of long COVID even two years after acute COVID-19 infection.


Assuntos
COVID-19 , Interleucina-17 , Humanos , Espectrometria de Massas em Tandem , Cromatografia Líquida , SARS-CoV-2 , Metaboloma , Metabolômica , Síndrome de COVID-19 Pós-Aguda
8.
FEMS Microbiol Lett ; 3702023 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-37291700

RESUMO

Ubiquinone (UQ) is a fundamental mitochondrial electron transport chain component. This compound is synthesized as the condensation of a p-substituted benzoic acid and a polyisoprenic moiety catalyzed by the enzyme 4-hydroxybenzoate polyprenyltransferase (EC 2.5.1.39). In Plasmodium spp., this enzyme is still uncharacterized. In this work, we expressed the sequence of the Plasmodium falciparum PF3D7_0607500 gene (abbreviated as PfCOQ2) in a coq2Δ mutant strain of Saccharomyces cerevisiae, and studied the functionality of its gene product. This open reading frame could complement S. cerevisiae coq2Δ mutant growth defect on media with glycerol as a carbon source. Further, UQ was unequivocally identified in lipid extracts from this coq2Δ mutant when expressing PfCOQ2. Remarkably, UQ was detected under those conditions when S. cerevisiae cells were metabolically labeled with either [ring-14C(U)]-p-aminobenzoic acid or [ring-14C(U)]-4-hydroxybenzoic acid. However, no UQ was detected in P. falciparum if labeled with p-aminobenzoic acid. These results indicate that PfCOQ2 is a 4-hydroxybenzoate polyprenyltransferase. Further, its substrate profile seems not dissimilar to that of S. cerevisiae, but, as in other organisms, p-aminobenzoic acid does not act as an aromatic precursor in UQ biosynthesis in P. falciparum. The reason for this last feature remains to be established, but may lie upstream of PfCOQ2.


Assuntos
Plasmodium falciparum , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Plasmodium falciparum/genética , Ácido 4-Aminobenzoico
9.
Curr Protoc ; 3(3): e714, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36912580

RESUMO

Primary fibroblasts are a precious resource in the field of translational regenerative medicine. Dermal fibroblasts derived from human subject biopsies are being used as donor tissues for the derivation of patient-specific iPSC lines, which in turn are used for disease modeling, drug screening, tissue engineering, and cell transplantation. We developed a fast and simple protocol to grow dermal fibroblasts from skin biopsies. Using this protocol, we simply and firmly fix the biopsy piece on the surface of a tissue culture-treated plate and allow the fibroblasts to grow. This novel method eliminates any need for enzymatic digestion or mechanical dissociation of the biopsy piece. By using this newly developed protocol, we have successfully established around 100 fibroblast lines characterized by the expression of specific markers [Serpin H1 (Hsp-47), F-actin, and Vimentin]. Finally, we have used many of these fibroblast lines as donor tissues to successfully derive iPSC lines. We have developed a method that is simple, fast, convenient, efficient, and gentle on the cells to derive dermal fibroblasts from human skin biopsies. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Skin biopsy collection and fibroblast derivation Support Protocol 1: Culturing, freezing, and thawing dermal fibroblasts derived from a skin biopsy Support Protocol 2: Characterization of dermal fibroblasts by immunocytochemistry.


Assuntos
Pele , Engenharia Tecidual , Humanos , Pele/patologia , Fibroblastos/metabolismo , Linhagem Celular , Biópsia/métodos
10.
Sensors (Basel) ; 23(3)2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36772400

RESUMO

Zero-emission hydrogen and oxygen production are critical for the UK to reach net-zero greenhouse gasses by 2050. Electrochemical techniques such as water splitting (electrolysis) coupled with renewables energy can provide a unique approach to achieving zero emissions. Many studies exploring electrocatalysts need to "electrically wire" to their material to measure their performance, which usually involves immobilization upon a solid electrode. We demonstrate that significant differences in the calculated onset potential for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) can be observed when using screen-printed electrodes (SPEs) of differing connection lengths which are immobilized with a range of electrocatalysts. This can lead to false improvements in the reported performance of different electrocatalysts and poor comparisons between the literature. Through the use of electrochemical impedance spectroscopy, uncompensated ohmic resistance can be overcome providing more accurate Tafel analysis.

11.
bioRxiv ; 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36798384

RESUMO

Mechanosensory neurons located across the body surface respond to tactile stimuli and elicit diverse behavioral responses, from relatively simple stimulus location-aimed movements to complex movement sequences. How mechanosensory neurons and their postsynaptic circuits influence such diverse behaviors remains unclear. We previously discovered that Drosophila perform a body location-prioritized grooming sequence when mechanosensory neurons at different locations on the head and body are simultaneously stimulated by dust (Hampel et al., 2017; Seeds et al., 2014). Here, we identify nearly all mechanosensory neurons on the Drosophila head that individually elicit aimed grooming of specific head locations, while collectively eliciting a whole head grooming sequence. Different tracing methods were used to reconstruct the projections of these neurons from different locations on the head to their distinct arborizations in the brain. This provides the first synaptic resolution somatotopic map of a head, and defines the parallel-projecting mechanosensory pathways that elicit head grooming.

13.
Trauma Case Rep ; 43: 100756, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36660405

RESUMO

Background: Penetrating chest trauma that is associated with pulmonary injuries can trigger different sequelae, the most frequent being the presence of contusions or pulmonary lacerations that are accompanied by hemopneumothorax. Materials and methods: Description of a clinical case of interest and review of the literature on the topic. Results: In this study, we present an unusual consequence of this type of trauma, a pulmonary infarction secondary to an extensive pulmonary venous thrombosis stemming from a firearm injury. This finding associated with lung tissue necrosis led to the need for right upper pulmonary bilobectomy. Conclusions: The aim of this study is to understand this unusual form of presentation of pulmonary trauma, understand the pathophysiology that triggers lung injury, review the medical literature on the subject, and expand the general knowledge on this topic. Study type: Therapeutic/care management.

14.
Food Chem ; 404(Pt B): 134653, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36327513

RESUMO

Accurate and fast on-site detection of harmful microorganisms in food products is a key preventive step to avoid food-borne illness and product recall. In this study, screen-printed electrodes (SPEs) were functionalized via a facile strategy with surface imprinted polymers (SIPs). The SIP-coated SPEs were used in combination with the heat transfer method (HTM) for the real-time detection of Escherichia coli. The sensor was tested in buffer, with a reproducible and sensitive response that attained a limit of detection of 180 CFU/mL. Furthermore, selectivity was assessed by analyzing the sensor's response to C. sakazakii, K. pneumoniae and S. aureus as analogue strains. Finally, the device was successfully used for the detection of E. coli in spiked milk as proof-of-application, requiring no additional sample preparation. These results suggest the proposed thermal biosensor possesses the potential of becoming a tool for routine, on-site monitoring of E. coli in food safety applications.


Assuntos
Técnicas Biossensoriais , Escherichia coli , Staphylococcus aureus , Eletrodos , Técnicas Biossensoriais/métodos , Laticínios , Limite de Detecção
16.
Sci Transl Med ; 14(666): eabm6391, 2022 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-36223446

RESUMO

The bone marrow microenvironment provides indispensable factors to sustain blood production throughout life. It is also a hotspot for the progression of hematologic disorders and the most frequent site of solid tumor metastasis. Preclinical research relies on xenograft mouse models, but these models preclude the human-specific functional interactions of stem cells with their bone marrow microenvironment. Instead, human mesenchymal cells can be exploited for the in vivo engineering of humanized niches, which confer robust engraftment of human healthy and malignant blood samples. However, mesenchymal cells are associated with major reproducibility issues in tissue formation. Here, we report the fast and standardized generation of human mini-bones by a custom-designed human mesenchymal cell line. These resulting humanized ossicles (hOss) consist of fully mature bone and bone marrow structures hosting a human mesenchymal niche with retained stem cell properties. As compared to mouse bones, we demonstrate superior engraftment of human cord blood hematopoietic cells and primary acute myeloid leukemia samples and also validate hOss as a metastatic site for breast cancer cells. We further report the engraftment of neuroblastoma patient-derived xenograft cells in a humanized model, recapitulating clinically described osteolytic lesions. Collectively, our human mini-bones constitute a powerful preclinical platform to model bone-developing tumors using patient-derived materials.


Assuntos
Leucemia Mieloide Aguda , Nicho de Células-Tronco , Animais , Osso e Ossos , Modelos Animais de Doenças , Hematopoese , Humanos , Camundongos , Reprodutibilidade dos Testes , Microambiente Tumoral
17.
Curr Protoc ; 2(8): e519, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35950852

RESUMO

The CRISPR system is an adaptive defense mechanism used by bacteria and archaea against viruses and plasmids. The discovery of the CRISPR-associated protein Cas9 and its RNA-guided cleavage mechanism marked the beginning of a new era in genomic engineering by enabling the editing of a target region in the genome. Gene-edited cells or mice can be used as models for understanding human diseases. Given its high impact in functional genomic experiments on different model systems, several CRISPR/Cas9 protocols have been generated in the past years. The technique uses a straightforward "cut and stitch" mechanism, but requires an accurate step-by-step design. One of the key points is the use of an efficient programmable guide RNA to increase the rate of success in obtaining gene-specific edited clones. Here, we describe an efficient editing protocol using a ribonucleotide protein (RNP) complex for homology-directed repair (HDR)-based correction of a point mutation in an induced pluripotent stem cell (iPSC) line generated from a 14-year-old patient with severe early-onset obesity carrying a de novo variant of ARNT2. The resulting isogenic iPSC line, named CUIMCi003-A-1, has a normal karyotype, expresses stemness markers, and can be differentiated into progenies from all three germ layers. We provide a detailed workflow for designing a single guide RNA and donor DNA, and for isolating clonal human iPSCs edited with the desired modification. This article also focuses on parameters to consider when selecting reagents for CRISPR/Cas9 gene editing after testing their efficiency with in silico tools. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Design of sgRNAs and PCR primers Basic Protocol 2: Testing the efficiency of sgRNAs Basic Protocol 3: Design of template or donor DNA Basic Protocol 4: Targeted gene editing Basic Protocol 5: Selection of positive clones Basic Protocol 6: Freezing, thawing, and expansion of cells Basic Protocol 7: Characterization of edited cell lines.


Assuntos
Edição de Genes , Células-Tronco Pluripotentes Induzidas , Adolescente , Animais , Sistemas CRISPR-Cas/genética , DNA/metabolismo , Edição de Genes/métodos , Humanos , Camundongos , Obesidade/genética , RNA Guia de Cinetoplastídeos/genética
18.
Front Cell Infect Microbiol ; 12: 869085, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35531326

RESUMO

Malaria is one of the most widespread parasitic diseases, especially in Africa, Southeast Asia and South America. One of the greatest problems for control of the disease is the emergence of drug resistance, which leads to a need for the development of new antimalarial compounds. The biosynthesis of isoprenoids has been investigated as part of a strategy to identify new targets to obtain new antimalarial drugs. Several isoprenoid quinones, including menaquinone-4 (MK-4/vitamin K2), α- and γ-tocopherol and ubiquinone (UQ) homologs UQ-8 and UQ-9, were previously detected in in vitro cultures of Plasmodium falciparum in asexual stages. Herein, we described for the first time the presence of phylloquinone (PK/vitamin K1) in P. falciparum and discuss the possible origins of this prenylquinone. While our results in metabolic labeling experiments suggest a biosynthesis of PK prenylation via phytyl pyrophosphate (phytyl-PP) with phytol being phosphorylated, on the other hand, exogenous PK attenuated atovaquone effects on parasitic growth and respiration, showing that this metabolite can be transported from extracellular environment and that the mitochondrial electron transport system (ETS) of P. falciparum is capable to interact with PK. Although the natural role and origin of PK remains elusive, this work highlights the PK importance in plasmodial metabolism and future studies will be important to elucidate in seeking new targets for antimalarial drugs.


Assuntos
Antimaláricos , Malária Falciparum , Malária , Antimaláricos/farmacologia , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Plasmodium falciparum , Vitamina K 1/metabolismo , Vitamina K 1/farmacologia
19.
Sensors (Basel) ; 22(9)2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35591020

RESUMO

A low-cost, scalable and reproducible approach for the mass production of screen-printed electrode (SPE) platforms that have varying percentage mass incorporations of 2D hexagonal boron nitride (2D-hBN) (2D-hBN/SPEs) is demonstrated herein. These novel 2D-hBN/SPEs are explored as a potential metal-free electrocatalysts towards oxygen reduction reactions (ORRs) within acidic media where their performance is evaluated. A 5% mass incorporation of 2D-hBN into the SPEs resulted in the most beneficial ORR catalysis, reducing the ORR onset potential by ca. 200 mV in comparison to bare/unmodified SPEs. Furthermore, an increase in the achievable current of 83% is also exhibited upon the utilisation of a 2D-hBN/SPE in comparison to its unmodified equivalent. The screen-printed fabrication approach replaces the less-reproducible and time-consuming drop-casting technique of 2D-hBN and provides an alternative approach for the large-scale manufacture of novel electrode platforms that can be utilised in a variety of applications.


Assuntos
Compostos de Boro , Técnicas Eletroquímicas , Eletrodos , Oxigênio
20.
Biosens Bioelectron ; 206: 114123, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35259608

RESUMO

We integrated a magnetohydrodynamic fluid extractor with an amperometric glucose biosensor to develop a wearable device for non-invasive glucose monitoring. Reproducible fluid extraction through the skin and efficient transport of the extracted fluid to the biosensor surface are prerequisites for non-invasive glucose monitoring. We optimized the enzyme immobilization and the interface layer between the sensing device and the skin. The monitoring device was evaluated by extracting fluid through porcine skin followed by glucose detection at the biosensor. The biosensor featured a screen-printed layer of Prussian Blue that was coated with a layer containing glucose oxidase. Both physical entrapment of glucose oxidase in chitosan and tethering of glucose oxidase to electrospun nanofibers were evaluated. Binding of glucose oxidase to nanofibers under mild conditions provided a stable biosensor with analytical performance suitable for accurate detection of micromolar concentrations of glucose. Hydrogels of varying thickness (95-2000 µm) as well as a thin (30 µm) nanofibrous polycaprolactone mat were studied as an interface layer between the biosensor and the skin. The effect of mass transfer phenomena at the biosensor-skin interface on the analytical performance of the biosensor was evaluated. The sensing device detected glucose extracted through porcine skin with an apparent (overall) sensitivity of -0.8 mA/(M·cm2), compared to a sensitivity of -17 mA/(M·cm2) for measurement in solution. The amperometric response of the biosensor correlated with the glucose concentration in the fluid that had been extracted through porcine skin with the magnetohydrodynamic technique.


Assuntos
Técnicas Biossensoriais , Glucose Oxidase , Glicemia , Automonitorização da Glicemia , Enzimas Imobilizadas , Líquido Extracelular , Glucose
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...