The role of natural processes and surface energy of inhaled engineered nanoparticles on aggregation and corona formation

Abstract

The surface chemistry of engineered nanoparticles (ENPs) becomes more important as their size decreases and enters the nanometer-range. This review explains the fundamental properties of the surface chemistry of nanoparticles, and argues that their agglomeration and the formation of corona around them are natural processes that reduce surface energy. ENP agglomeration and surface corona formation are further discussed in the context of inhaled ENPs, as the lung is a major port of ENP entry to the body. The pulmonary surfactant layer, which the inhaled ENPs first encounter as they land on the lung surface, represents a unique environment with a variety of well-defined biomolecules. Many factors, such as hydrophobicity, surface charge of ENPs, protein/phospholipid concentrations of the alveolar lining fluid, etc. influence the complex processes of ENP agglomeration and corona formation in the alveolar lining fluid, and these events occur even before the ENPs reach the cells. We suggest that molecular dynamic simulations can represent a promising future direction for research of the behavior of inhaled ENPs, complementing the experimental approaches. Moreover, we want to remind biologists working on ENPs of the importance relationship between ENP surface energy and size.

Protein corona: implications for nanoparticle interactions with pulmonary cells

“…It is thought that NPs may aggregate first and then form a corona around the aggregate, or may form coronas around individual particles first and then aggregate. Both aggregation and corona formation are natural processes that lower the surface energy of NPs [ 28 ].…”

Long‐Term Colloidal and Chemical Stability in Aqueous Media of NaYF4‐Type Upconversion Nanoparticles Modified by Ligand‐Exchange

“…Regarding the colloidal stability, the relevant forces within a nanoscopic system must be taken into account. Particles without any surface capping tend to minimize their surface energy by aggregation so that further efforts are inalienable to obtain stable nanoparticles …”

“…Particles without any surface capping tend to minimize their surface energy by aggregation so that further efforts are inalienable to obtain stable nanoparticles. [27] The five different surface ligands attached to UCNPs of identical size consist of three polymers (poly(acrylic acid) (PAA), polyallylamine (PAH), and polyethylene glycol (PEG) and two small ligands (citrate (CIT) and N,N bis(phosphonomethyl)glycine (PG). This set of particles was used to investigate the concentration dependent colloidal and chemical stability in water over time.…”

Inhalation of printer-emitted particles impairs cardiac conduction, hemodynamics, and autonomic regulation and induces arrhythmia and electrical remodeling in rats

“…Exposures to ENMs released across the lifecycle of nano-enabled products have become inevitable. Due to their size, ENMs can bypass biological barriers, become systemic, interfere with cellular processes, and induce adverse health effects [5][6][7][8][9][10][11][12][13][14][15]. Despite that numerous studies have linked exposure to ambient ultrafine particles to cardiovascular dysfunction, autonomic dysregulation, and heart disease [16][17][18][19], there are only limited investigations into the cardiovascular effects of ENMs [20].…”