Navegando por Assunto "Magnetic beads"

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    A microbead-enhanced electrochemical platform for β-amyloid peptide (1–42) detection
    (Frontiersin) Razzino, Claudia do Amaral; Sgobbi, Lívia Flório; Cancino-Bernardi, Juliana; Zapata, Angelica Maria Mazuera; Costa, Clara Cardoso; Zucolotto, Valtencir; Vieira, Lucia; Lobo, Anderson Oliveira
    Alzheimer’s disease is the most prevalent form of dementia and is primarily characterized by the accumulation of β-amyloid and phosphorylated tau proteins in the brain, along with the degeneration of nerve cells, which leads to impairment of various cognitive functions. A significant biomarker of Alzheimer’s disease is the decreased level of soluble β-amyloid peptide (1–42) (Aβ1-42) in cerebrospinal fluid (CSF), as pathology progresses when CSF-Aβ1-42 levels drop below 192 pg mL-1 . In this study, we developed an amperometric immunosensor based on magnetic beads as the platform for constructing the immunosensor. Monoclonal antibodies are immobilized on the MBs, enabling selective detection of Aβ1-42. The detection antibody is conjugated with the enzyme horseradish peroxidase, which, in the presence of H2O2 and hydroquinone, catalyzes the decomposition of H2O2 and the oxidation of hydroquinone to p-quinone, generating an electric current measured at a potential of −200 mV (vs. the Ag pseudo-reference electrode) using screen-printed carbon electrodes. The amperometric sandwich-type immunosensor demonstrates a linear response in the concentration range of 10 to 10,000 pg mL-1 , with a detection limit of 7.4 pg mL-1 , exhibiting excellent selectivity against the assessed interferents. These findings suggest the potential application of this immunosensor in the early diagnosis of Alzheimer’s disease, offering a sensitive and specific tool for clinical analysis. Despite its high performance, further studies are required to validate its robustness and applicability in complex clinical samples.
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    Performance of Multiplex Detection Method of IgM Class Antibodies against Toxoplasma gondii, Rubella and Human Cytomegalovirus
    (JSciMed Central) Almeida, Rainara Moreno Sanches de; Ogawa, Guilherme Maerschner; Custódio, Paulo Rogério Siqueira; Sampaio, Maria Alcantara Socorro; Silva, Newton Soares da; Soares, Cristina Pacheco
    Serological diagnosis during neonatal screening is crucial in disease prevention. Among the infectious diseases, the most common are toxoplasmosis, rubella, and cytomegalovirus. Traditional diagnostic methods are used to detect a single infectious agent per test. The use of multiplex detection methods increases productivity and reduces the amount of material used, resulting in a more efficient test from a technical, environmental, and economic point of view. The study’s objective was to evaluate the performance of a new diagnostic method aimed at neonatal screening using the multiplex platform of magnetic microspheres from the company Luminex Corporation. For this, tests were carried out for analytical validation of the diagnostic product developed following the rules of the National Health Surveillance Agency (ANVISA) of Brazil. The parameters evaluated were repeatability, reproducibility, linearity, robustness, high dose, minimum detection limit, and analytical specificity. All data obtained met the acceptance criteria of RDC 166/17 of 2017 for the use of the diagnostic product in the national territory. Repeatability and reproducibility tests showed a CV of less than 15% between replicates of the same operator and different operators. The kit showed linearity throughout the operating range with R2 above 0.990, and no effect of high-efficiency dose was observed in the chosen working dilution. In addition, the kit did not show interference from the matrix with the results, and it was observed that small and deliberate changes in the incubation time of each reagent did not have a significant effect on the data obtained.