scholarly journals Analytical detection methods for diagnosis of COVID-19: developed methods and their performance

2020 ◽  
Vol 35 (1) ◽  
pp. 196-207
Author(s):  
Ibrahim Hotan Alsohaimi
Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 19
Author(s):  
Vicente Antonio Mirón-Mérida ◽  
Yadira González-Espinosa ◽  
Yun Yun Gong ◽  
Yuan Guo ◽  
Francisco M. Goycoolea

Fumonisin B1 (FB1), a mycotoxin commonly produced by Fusarium verticillioides and classified as a group 2B hazard, has been identified in various food products; hence, sensitive and rapid analytical detection methods are needed. Since the first reported aptamer (96 nt ssDNA) for the highly specific molecular recognition of FB1, only 30 aptamer-based biosensors have been published. A critical point, yet commonly overlooked during the design of aptasensors, is the selection of the binding buffer. In this work, a colorimetric assay was designed by incubating a folded aptamer with FB1 and the subsequent addition of gold nanoparticles (AuNPs). The changes in the aggregation profile of AuNPs by a 40 nt aptamer and a 96 nt aptamer were tested after the addition of FB1 under different buffer conditions, where the incubation with Tris-HCl and MgCl2 exhibited the most favorable performances. The assay with the longest aptamer was specific to FB1 and comparable to other aptasensors with a limit of detection (LOD) of 3 ng/mL (A650/520 ratio). Additionally, the application of asymmetric-flow field-flow fractionation (AF4) with multidetection allowed for the analysis of the peak area (λ) and multi-angle light scattering (MALS) with LODs of up to the fg/mL level.


Author(s):  
Anne F. Bushnell ◽  
Sarah Webster ◽  
Lynn S. Perlmutter

Apoptosis, or programmed cell death, is an important mechanism in development and in diverse disease states. The morphological characteristics of apoptosis were first identified using the electron microscope. Since then, DNA laddering on agarose gels was found to correlate well with apoptotic cell death in cultured cells of dissimilar origins. Recently numerous DNA nick end labeling methods have been developed in an attempt to visualize, at the light microscopic level, the apoptotic cells responsible for DNA laddering.The present studies were designed to compare various tissue processing techniques and staining methods to assess the occurrence of apoptosis in post mortem tissue from Alzheimer's diseased (AD) and control human brains by DNA nick end labeling methods. Three tissue preparation methods and two commercial DNA nick end labeling kits were evaluated: the Apoptag kit from Oncor and the Biotin-21 dUTP 3' end labeling kit from Clontech. The detection methods of the two kits differed in that the Oncor kit used digoxigenin dUTP and anti-digoxigenin-peroxidase and the Clontech used biotinylated dUTP and avidinperoxidase. Both used 3-3' diaminobenzidine (DAB) for final color development.


1988 ◽  
Vol 60 (02) ◽  
pp. 133-136 ◽  
Author(s):  
R Schneppenheim ◽  
H Plendl ◽  
U Budde

SummaryA luminescence assay was adapted for detection of von Willebrand factor multimers subsequent to SDS-agarose gel electrophoresis and electroblotting onto nitrocellulose. The method is as fast as chromogenic detection methods and appears to be as sensitive as autoradiography without the disadvantages of the latter.


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