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1.
Anal Chim Acta ; 1139: 198-221, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33190704

RESUMO

The detection of phenolic compounds is relevant not only for their possible benefits to human health but also for their role as chemical pollutants, including as endocrine disruptors. The required monitoring of such compounds on-site or in field analysis can be performed with electrochemical biosensors made with polyphenol oxidases (PPO). In this review, we describe biosensors containing the oxidases tyrosinase and laccase, in addition to crude extracts and tissues from plants as enzyme sources. From the survey in the literature, we found that significant advances to obtain sensitive, robust biosensors arise from the synergy reached with a diversity of nanomaterials employed in the matrix. These nanomaterials are mostly metallic nanoparticles and carbon nanostructures, which offer a suitable environment to preserve the activity of the enzymes and enhance electron transport. Besides presenting a summary of contributions to electrochemical biosensors containing PPOs in the last five years, we discuss the trends and challenges to take these biosensors to the market, especially for biomedical applications.


Assuntos
Técnicas Biossensoriais , Monofenol Mono-Oxigenase , Nanoestruturas , Carbono , Técnicas Eletroquímicas , Lacase
2.
Talanta ; 204: 163-171, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31357278

RESUMO

This work describes the first method using biochar (BC) as carbonaceous platform for immunoassay application. BC is a highly functionalized material obtained through biomass pyrolysis under controlled conditions. Due to the highly functionalized surface, covalent binding between BC and biomolecules can be performed by EDC/NHS conjugation. The application of the modified electrode was done with Hantavirus, that are etiologic agents mainly transmitted by wild rodents. Among its pathologies Hantavirus Cardiopulmonary Syndrome (HCPS) arises at Americas, caused by Hantavirus Araucária and reaches 40% lethality. The diagnostic is based on the presence of specific hantavirus nucleoprotein (Np), under viremic condition or IgG2b antibodies (Ab), during first symptoms. The results presented a device sensitivity of 5.28 µA dec-1 and a LOD of 0.14 ng mL-1 to the Np detection, ranging from 5.0 ng mL-1 to 1.0 µg mL-1, the Ab detection works as qualitative type sensor above 200 ng mL-1. Both sensors were evaluated its selectivity and serum samples; selectivity against Gumboro disease, VP2 protein, and antibody IgG2a against Yellow fever disease (YF), respectively. So, the devices here proposed are promising tool suitable for both rodent and human hantavirus clinical surveys.


Assuntos
Carvão Vegetal/química , Orthohantavírus/isolamento & purificação , Anticorpos Imobilizados/imunologia , Anticorpos Antivirais/imunologia , Sangue/virologia , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Orthohantavírus/química , Humanos , Imunoensaio/métodos , Imunoglobulina G/imunologia , Limite de Detecção , Reprodutibilidade dos Testes , Proteínas Virais/imunologia
3.
Mater Sci Eng C Mater Biol Appl ; 75: 88-94, 2017 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-28415543

RESUMO

The present work describes the synthesis of a new conductive nanocomposite based on polypyrrole (PPy) and silver nanoparticles (PPy-AgNP) based on a facile reverse microemulsion method and its application as a non-enzymatic electrochemical sensor for glucose detection. Focusing on the best sensor performance, all experimental parameters used in the synthesis of nanocomposite were optimized based on its electrochemical response for glucose. Characterization of the optimized material by FT-IR, cyclic voltammetry, and DRX measurements and TEM images showed good monodispersion of semispherical Ag nanoparticles capped by PPy structure, with size average of 12±5nm. Under the best analytical conditions, the proposed sensor exhibited glucose response in linear dynamic range of 25 to 2500µmolL-1, with limit of detection of 3.6µmolL-1. Recovery studies with human saliva samples varying from 99 to 105% revealed the accuracy and feasibility of a non-enzymatic electrochemical sensor for glucose determination by easy construction and low-cost.


Assuntos
Técnicas Eletroquímicas/métodos , Glucose/análise , Nanopartículas Metálicas/química , Nanocompostos/química , Prata/química
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