Effect of clay nanoparticles on model lung surfactant: a potential marker of hazard from nanoaerosol inhalation.

Dorota Kondej,Tomasz R Sosnowski

doi:10.1007/s11356-015-5610-4

Abstract

This work investigates influence of different aluminosillicate nanoparticles (NPs) which are found in air in selected workplaces on the properties of the phospholipid (DPPC) monolayer at air–saline interface considered as ex vivo model of the lung surfactant (LS). The measurements were done under physiological-like conditions (deformable liquid interface at 37 °C) for NP concentrations matching the calculated lung doses after exposure in the working environment. Measured surface pressure–area (π–A) isotherms and compressibility curves demonstrated NP-induced changes in the structure and mechanical properties of the lipid monolayer. It was shown that hydrophilic nanomaterials (halloysite and bentonite) induced concentration-dependent impairment of DPPC’s ability of attaining high surface pressures on interfacial compression, suggesting a possibility of reduction of physiological function of natural LS. Hydrophobic montmorillonites affected DPPC monolayer in the opposite way; however, they significantly changed the mechanical properties of the air–liquid interface during compression. The results support the hypothesis of possible reduction or even degradation of the natural function of the lung surfactant induced by particle–phospholipid interactions after inhalation of nanoclays. Presented data do not only supplement the earlier results obtained with another LS model (animal-derived surfactant in oscillating bubble experiments) but also offer an explanation of physicochemical mechanisms responsible for detrimental effects which arise after deposition of inhaled nanomaterials on the surface of the respiratory system.

Highlights

Big concern regarding harmful influence of nanoparticles (NPs) on biological membranes (Donaldson et al 2004; Verma and Stellacci 2006; Shang et al 2014) triggered numerous investigations focused on physicochemical interactions between nanosized particles and lipid layers (e.g., Wang et al 2008; Van Lehn et al 2013; Hoffmann et al 2014)
We investigate the influence of different types of nanoclays on the interfacial properties of a dipalmitoyl phosphatidylcholine (DPPC) monolayer at air–saline interface which can be considered as a basic model of the lung surfactant system and biological membranes
The coexistence region LE-LC exists at molecular areas of 80–105 Å2/molecule which correspond to DPPC surface of 1.58–2.08×10−6 mol/m2

Summary

Introduction

Big concern regarding harmful influence of nanoparticles (NPs) on biological membranes (Donaldson et al 2004; Verma and Stellacci 2006; Shang et al 2014) triggered numerous investigations focused on physicochemical interactions between nanosized particles and lipid layers (e.g., Wang et al 2008; Van Lehn et al 2013; Hoffmann et al 2014). We investigate the influence of different types of nanoclays on the interfacial properties of a dipalmitoyl phosphatidylcholine (DPPC) monolayer at air–saline interface which can be considered as a basic model of the lung surfactant system and biological membranes. These studies extend our earlier research done for the same NPs interacting with a different LS model in the oscillating bubble experimental system (Kondej and Sosnowski 2013)

Materials and methods

Results and discussion

Conclusions