Direct electron transfer: an approach for electrochemical biosensors with higher selectivity and sensitivity

The most promising approach for the development of electrochemical biosensors is to establish a direct electrical communication between the biomolecules and the electrode surface. This review focuses on advances, directions and strategies in the development of third generation electrochemical biosensors. Subjects covered include a brief description of the fundamentals of the electron transfer phenomenon and amperometric biosensor development (different types and new oriented enzyme immobilization techniques). Special attention is given to different redox enzymes and proteins capable of electrocatalyzing reactions via direct electron transfer. The analytical applications and future trends for third generation biosensors are also presented and discussed.A abordagem mais promissora para o desenvolvimento de biossensores eletroquímicos é a busca da comunicação elétrica direta entre as biomoléculas e a superfície do eletrodo. Esta revisão apresenta as principais abordagens, estratégias e avanços no desenvolvimento de biossensores eletroquímicos de terceira geração. Os temas discutidos englobam uma breve descrição sobre os fundamentos do fenômeno de transferência de elétrons e sobre o desenvolvimento de biossensores amperométricos (diferentes tipos e novas técnicas de imobilização orientada de enzimas). Um enfoque especial foi dado para as enzimas e proteínas redox capazes de eletrocatalisar reações via transferência direta de elétrons. Também foram apresentadas e discutidas as aplicações analíticas e tendências futuras dos biossensores de terceira geração.230243Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Direct electron transfer: an approach for electrochemical biosensors with higher selectivity and sensitivity

The most promising approach for the development of electrochemical biosensors is to establish a direct electrical communication between the biomolecules and the electrode surface. This review focuses on advances, directions and strategies in the development of third generation electrochemical biosensors. Subjects covered include a brief description of the fundamentals of the electron transfer phenomenon and amperometric biosensor development (different types and new oriented enzyme immobilization techniques). Special attention is given to different redox enzymes and proteins capable of electrocatalyzing reactions via direct electron transfer. The analytical applications and future trends for third generation biosensors are also presented and discussed

Electrochemical and spectroscopic evidences of the interaction between DNA and Pt(II)(dppf)-complex

The interaction of Pt(II)(dppf)-complex, namely [Pt(dppf)(H2O)(2)](2+) with DNA was investigated by DPV and H-1-NMR techniques. The results showed that the interaction process has been characterized by changes in the electrochemical parameters of both compounds and the formation of a new anodic current peak close to the anodic current peak of the [Pt(dppf)(H2O)(2)](2+). In addition, the H-1-NMR spectra show that the coordination of Pt(II)(dppf)-complex to dsDNA occurs via N(7) of guanine. Others parameters like pH and ionic strength that affect the interaction process were also investigated

Electrochemical And Spectroscopic Characterization Of The Interaction Between Dna And Cu(ii)-naringin Complex.

In this work the interaction of DNA and the flavonoid-transition metal complex (Cu(II)-naringin complex) is characterized. The interaction was evaluated by using electrochemical ssDNA- and dsDNA-based biosensors and the results were supported by UV, CD and (1)H NMR data. In the electrochemical method, changes in the oxidation peak of the guanine and adenine bases obtained by square wave voltammetry (SWV) showed evidence of the interaction. The variations of the spectroscopic characteristics of DNA and Cu(II)-naringin complex in aqueous medium demonstrated that the predominant interaction mode may be by intercalation. Cu(II)-naringin complex interacts to dsDNA probably via N(7) of guanine site.45706-1

In-hospital mortality and severe outcomes after hospital discharge due to COVID-19: A prospective multicenter study from Brazil.

BackgroundWe evaluated in-hospital mortality and outcomes incidence after hospital discharge due to COVID-19 in a Brazilian multicenter cohort.MethodsThis prospective multicenter study (RECOVER-SUS, NCT04807699) included COVID-19 patients hospitalized in public tertiary hospitals in Brazil from June 2020 to March 2021. Clinical assessment and blood samples were performed at hospital admission, with post-hospital discharge remote visits. Hospitalized participants were followed-up until March 31, 2021. The outcomes were in-hospital mortality and incidence of rehospitalization or death after hospital discharge. Kaplan-Meier curves and Cox proportional-hazard models were performed.Findings1589 participants [54.5% male, age=62 (IQR 50-70) years; BMI=28.4 (IQR,24.9-32.9) Kg/m² and 51.9% with diabetes] were included. A total of 429 individuals [27.0% (95%CI,24.8-29.2)] died during hospitalization (median time 14 (IQR,9-24) days). Older age [vs<40 years; age=60-69 years-aHR=1.89 (95%CI,1.08-3.32); age=70-79 years-aHR=2.52 (95%CI,1.42-4.45); age≥80-aHR=2.90 (95%CI 1.54-5.47)]; noninvasive or mechanical ventilation at admission [vs facial-mask or none; aHR=1.69 (95%CI 1.30-2.19)]; SAPS-III score≥57 [vs<57; aHR=1.47 (95%CI 1.13-1.92)] and SOFA score≥10 [vs <10; aHR=1.51 (95%CI 1.08-2.10)] were independently associated with in-hospital mortality. A total of 65 individuals [6.7% (95%CI 5.3-8.4)] had a rehospitalization or death [rate=323 (95%CI 250-417) per 1000 person-years] in a median time of 52 (range 1-280) days post-hospital discharge. Age ≥ 60 years [vs <60, aHR=2.13 (95%CI 1.15-3.94)] and SAPS-III ≥57 at admission [vs <57, aHR=2.37 (95%CI 1.22-4.59)] were independently associated with rehospitalization or death after hospital discharge.InterpretationHigh in-hospital mortality rates due to COVID-19 were observed and elderly people remained at high risk of rehospitalization and death after hospital discharge.FundingFundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Programa INOVA-FIOCRUZ