Dataset Information

Augmented COlorimetric NANoplasmonic (CONAN) Method for Grading Purity and Determine Concentration of EV Microliter Volume Solutions.

ABSTRACT: This protocol paper describes how to assign a purity grade and to subsequently titrate extracellular vesicle (EV) solutions of a few microliters in volume by microplate COlorimetric NANoplasmonic (CONAN) assay. The CONAN assay consists of a solution of gold nanoparticles (AuNPs) into which the EV preparation is added. The solution turns blue if the EV preparation is pure, whereas it stays red if soluble exogenous single and aggregated proteins (SAPs; often referred to as protein contaminants) are present. The color change is visible by the naked eye or can be quantified by UV-Vis spectroscopy, providing an index of purity (a unique peculiarity to date). The assay specifically targets SAPs, and not the EV-related proteins, with a detection limit <50 ng/μl (an order of magnitude higher resolution than that of the Bradford protein assay). For pure solutions, the assay also allows for determining the EV number, as the color shift is linearly dependent on the AuNP/EV molar ratio. Instead, it automatically reports if the solution bears SAP contaminants, thus avoiding counting artifacts. The CONAN assay proves to be robust and reliable and displays very interesting performances in terms of cost (inexpensive reagents, run by standard microplate readers), working volumes (1-2 μl of sample required), and time (full procedure takes <1 h). The assay is applicable to all classes of natural and artificial lipid microvesicles and nanovesicles.

SUBMITTER: Zendrini A

PROVIDER: S-EPMC7028770 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Augmented COlorimetric NANoplasmonic (CONAN) Method for Grading Purity and Determine Concentration of EV Microliter Volume Solutions.

Zendrini Andrea A Paolini Lucia L Busatto Sara S Radeghieri Annalisa A Romano Miriam M Wauben Marca H M MHM van Herwijnen Martijn J C MJC Nejsum Peter P Borup Anne A Ridolfi Andrea A Montis Costanza C Bergese Paolo P

Frontiers in bioengineering and biotechnology 20200212

This protocol paper describes how to assign a purity grade and to subsequently titrate extracellular vesicle (EV) solutions of a few microliters in volume by microplate COlorimetric NANoplasmonic (CONAN) assay. The CONAN assay consists of a solution of gold nanoparticles (AuNPs) into which the EV preparation is added. The solution turns blue if the EV preparation is pure, whereas it stays red if soluble exogenous single and aggregated proteins (SAPs; often referred to as protein contaminants) ar ...[more]

PMID: 32117903

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Project description:Experiential and sensory evaluation is an ancient method that remains important in the current quality control system of Traditional Chinese Medicines (TCMs). The process is rapid and convenient when evaluating the quality of crude materials in TCM markets. However, sensory evaluation has been met with skepticism because it is mainly based on experience and lacks a scientific basis. In this study, rhubarb was selected to demonstrate how color-based sensory evaluation could differentiate the quality of herbal medicines objectively. The colors of the rhubarb samples, expressed as RGB values, were obtained from different parts and forms of the plant, including the plant's surface, fracture surface color, and a powdered form with or without treatment with a color-developing reagent. We first divided the rhubarb samples into three grades based on the total content of five hydroxyanthraquinone derivatives, the major pharmacological components in rhubarb. Then, a three-layer back-propagation artificial neural network (BP-ANN), calibrated with selected training samples, was used to correlate the quality of the rhubarb with its color. The color of the rhubarb powder after coloration attained the highest accuracy (92.3%) in predicting the quality grade of the test samples with the established artificial neural networks. Finally, a standardized colorimetric grading scale was created based on the spatial distribution of the rhubarb samples in a two-dimensional chromaticity diagram according to the colors of the powdered rhubarb after color enhancement. By comparing the color between the scale and the tested samples, similar to performing a pH test with indicator paper, subjects without sensory evaluation experience could quickly determine the quality grade of rhubarb. This work illustrates the technical feasibility of the color-based grading of rhubarb quality and offers references for quantifying and standardizing the sensory evaluation of TCMs, foods and other products.

Dataset Information

Augmented COlorimetric NANoplasmonic (CONAN) Method for Grading Purity and Determine Concentration of EV Microliter Volume Solutions.

Publications

Augmented COlorimetric NANoplasmonic (CONAN) Method for Grading Purity and Determine Concentration of EV Microliter Volume Solutions.

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