Biologic effects of nanoparticle-allergenconjugates: time-resolved uptake using an in vitrolung epithelial co-culture model of A549 andTHP-1 cells
Bettina Grotz, Mark Geppert, Robert Mills-Goodlet, Sabine Hofer, Norbert Hofstätter, Claudia Asam, Andrea Feinle,  Krisztina Kocsis, Thomas Berger, Oliver Diwald, Nicola Hüsing, Michael Wallner,Fatima Ferreira, Albert Duschl and Martin Himly
Abstract:
Nanotechnology is a fast growing field and already a multi-billion dollar market with numerous products available for consumers. TiO2 and SiO2 are by mass the most produced nanomaterials and, thus, of particular interest regarding their biological effects upon inhalation – especially in combination with other inhalable biomolecules such as allergens. We investigated the protein-binding capacity of these two nanomaterials and present detailed uptake profiles of protein-conjugated TiO2 or SiO2 nanoparticles (NPs) in A549 lung epithelial and THP-1 macrophage-like cells. TiO2 and SiO2 NPs (both with a hydrodynamic diameter of about 150 nm) are able to bind bovine serum albumin (BSA), green fluorescent protein (GFP) and the major birch pollen allergen Bet v 1 in substantial amounts that suggest protein monolayers around the particles. GFP-conjugated TiO2 and SiO2 NPs were taken up in A549 and THP-1 cells in a time-dependent manner as demonstrated by confocal laser scanning microscopy, flow cytometry and life cell imaging.
By the aid of fluorescent proteins (GFP or fluorescently labeled Bet v 1) we found that both, the NPs and the conjugated proteins entered the cells. Using A549/THP-1 co-cultures, we showed that the majority of SiO2 NPs is taken up by THP-1 cells; however, also A549 cells take up significant amounts of particles when co-cultured with THP-1 macrophage-like cells. The here discussed data provide valuable insights into protein (allergen) delivery by NPs at the lung epithelial barrier.

The open access article can be found  here.

Reviewed by Angela Risch