title: Colorimetric nanoplasmonic assay to determine purity and titrate extracellular vesicles.
abstract: Extracellular Vesicles (EVs) - cell secreted vesicles that carry rich molecular information of the parental cell and constitute an important mode of intercellular communication - are becoming a primary topic in translational medicine. EVs (that comprise exosomes and microvesicles/microparticles) have a size ranging from 40 nm to 1 μm and share several physicochemical proprieties, including size, density, surface charge, and light interaction, with other nano-objects present in body fluids, such as single and aggregated proteins. This makes separation, titration, and characterization of EVs challenging and time-consuming. Here we present a cost-effective and fast colorimetric assay for probing by eye protein contaminants and determine the concentration of EV preparations, which exploits the synergy between colloidal gold nanoplasmonics, nanoparticle-protein corona, and nanoparticle-membrane interaction. The assay hits a limit of detection of protein contaminants of 5 ng/μL and has a dynamic range of EV concentration ranging from 35 fM to 35 pM, which matches the typical range of EV concentration in body fluids. This work provides the first example of the exploitation of the nanoparticle-protein corona in analytical chemistry.
authors: †Chemistry for Technologies Laboratory and INSTM, Department of Mechanical and Industrial Engineering, University of Brescia, via Branze 38, 25123 Brescia, Brescia, Italy.
authors: Daniele
authors: D
authors: Maiolo
authors: ‡Department of Molecular and Translational Medicine, Faculty of Medicine, University of Brescia, 25123 Brescia, Brescia, Italy.
authors: Lucia
authors: L
authors: Paolini
authors: ‡Department of Molecular and Translational Medicine, Faculty of Medicine, University of Brescia, 25123 Brescia, Brescia, Italy.
authors: Giuseppe
authors: G
authors: Di Noto
authors: ‡Department of Molecular and Translational Medicine, Faculty of Medicine, University of Brescia, 25123 Brescia, Brescia, Italy.
authors: Andrea
authors: A
authors: Zendrini
authors: §Department of Chemistry "Ugo Schiff" and CSGI, University of Florence, via della Lastruccia 3, 50019 Sesto Fiorentino, Florence Italy.
authors: Debora
authors: D
authors: Berti
authors: †Chemistry for Technologies Laboratory and INSTM, Department of Mechanical and Industrial Engineering, University of Brescia, via Branze 38, 25123 Brescia, Brescia, Italy.
authors: Paolo
authors: P
authors: Bergese
authors: ‡Department of Molecular and Translational Medicine, Faculty of Medicine, University of Brescia, 25123 Brescia, Brescia, Italy.
authors: Doris
authors: D
authors: Ricotta
mesh_terms: D003124:Colorimetry / Q000191:economics; D055354:Exosomes / Q000737:chemistry*; D005123:Eye / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000191:economics; D011506:Proteins / Q000032:analysis*
chemical_list: D011506:Proteins; D006046:Gold