ABSTRACTPressure-area isotherms and fluorescence microscopy were used to investigate the impact of chitosan on the competitive adsorption between lung surfactant (LS) and serum proteins at the air-liquid interface. Isotherms demonstrate an optimum chitosan concentration to mediate LS adsorption; higher concentrations actually reduce the amount of LS which can adsorb. Fluorescence microscopy images show the transition from a serum protein to LS-covered interface for the optimum chitosan concentration; this transition goes through a sharply phase separated coexistence region. The results suggest that the cationic chitosan molecules mediate adsorption of the negatively charged LS aggregates by reducing the electrostatic barrier imposed by negatively charged interfacial serum proteins.
AbstractThe competitive adsorption of lung surfactant (LS) and albumin at the air-liquid interface and the ability of polyethylene glycol (PEG) to mediate LS adsorption are analyzed using pressure area isotherms and grazing incidence x-ray diffraction (GIXD). The addition of albumin drastically reduces the amount of LS on the interface and slightly increases the LS lattice spacing. The addition of PEG restores the characteristic LS peaks, yielding a slightly more compact lattice. The scattering results are consistent with recent work which proposed that albumin creates a physical barrier which eliminates LS adsorption and that PEG enhances LS adsorption but does not significantly change LS surface ordering.
Toxicological effects of zinc oxide nanoparticle exposure: an in vitro comparison between dry aerosol air-liquid interface and submerged exposure systems