Nanoparticle corona artefacts derived from specimen preparation of particle suspensions

Abstract

progress in the implementation of nanoparticles for therapeutic applications will accelerate with an improved understanding of the interface between nanoparticle surfaces and the media they are dispersed in. We examine this interface by analytical scanning transmission electron microscopy and show that incorrect specimen preparation or analysis can induce an artefactual, nanoscale, calcium phosphate-rich, amorphous coating on nanoparticles dispersed in cell culture media. We report that this ionic coating can be induced on five different types of nanoparticles (Au, BaTiO 3 , Zno, tio 2 and fe 2 o 3) when specimen preparation causes a significant rise in pH above physiological levels. Such a pH change reduces ionic solubility in the suspending media to permit precipitation of calcium phosphate. finally, we demonstrate that there is no indication of a calcium-phosphorus-rich coating on Batio 3 nanoparticles suspended in culture media when prepared without alteration of the pH of the suspending media and imaged by cryo-SteM. therefore we recommend that future reports utilising nanoparticles dispersed in cell culture media monitor and report the pH of suspensions during sample preparation.

A functional corona around extracellular vesicles enhances angiogenesis, skin regeneration and immunomodulation

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A Critical Look at Colloid Generation, Stability, and Transport in Redox-Dynamic Environments: Challenges and Perspectives

“…For example, even if oxygen is eliminated, the reduction reaction, if still active, could produce new colloids or change physicochemical properties of existing colloids after sampling, even if collected carefully. Most preservation approaches consist of freezing samples, whether by slowly cooling down to freezing temperatures or flash-freezing (L-N 2 ) the samples immediately. , However, the freezing process itself can facilitate irreversible precipitation of salts, the formation of coatings on colloids, and/or colloid flocculation, altering the colloid concentration and requiring further consideration during analysis. Although, temperatures just above the freezing point (e.g., commonly used 2–5 °C) are believed to minimize reaction kinetics, these have not yet been systematically tested for their efficiency in halting the biogeochemical reactivities completely, particularly in anoxic environments.…”

Mechanistic Understanding of Protein Corona Formation around Nanoparticles: Old Puzzles and New Insights

“…In recent years, awareness has risen that the results of a proteomic analysis can sensitively depend on the sample preparation and further treatment. [190][191][192][193] Typically, NPs are incubated in 1-2 mL of blood plasma (or dilute plasma). Considering the huge total surface area even at low NP concentrations, there is the risk that rare but tightly binding protein species become depleted during NP incubation, so they will be underrepresented in the obtained protein composition.…”