Effect of Rhamnolipids on Pulmonary Surfactant Foam Films

Abstract

The effect of a rhamnolipid biosurfactant on pulmonary surfactant is studied employing the black foam film method. Pulmonary surfactant is modeled by a commercially available lung surfactant preparation (LSP). The effect of rhamnolipid concentration on the formation and stability of films formed from mixtures of LSP and rhamnolipids is experimentally studied by measurements of the probability W of formation of black foam films as a function of both LSP and rhamnolipid concentrations at the physiologically relevant electrolyte concentration C(el) = 0.15 mol dm(-3) NaCl. The obtained curves show that addition of rhamnolipid at a concentration C(RhL) = C(c) (critical concentration of black foam film formation) to LSP suspensions causes destabilization of the foam films. In this case, additional quantities of lung surfactant preparation are needed to obtain black films with probability W = 100%. Rhamnolipid adsorption and formation of mixed adsorbed layers at the solution/air interfaces of foam films formed from mixtures of lung surfactant and rhamnolipids are experimentally studied by monitoring the effect of electrolyte and rhamnolipid concentrations on the thickness h of the foam films. The incorporation of rhamnolipid ions in the adsorbed layers at the film interfaces is evidenced also by direct measurements of the disjoining pressure Pi in the films. The Pi(h) isotherms demonstrate that the added rhamnolipids change the surface electric parameters of the films and their thickness and stability at higher pressures. The obtained results show that the different molecular components in the mixture and the increased surface charge at the film interfaces originating from the rhamnolipid ions have a significant effect on the surface forces operative in the studied films.

Smart and green interfaces: From single bubbles/drops to industrial environmental and biomedical applications

“…These parameters are: film thinning times, critical concentration for black film formation, film stability in terms of probability for stable black foam film formation, film thickness and dependence of its change under applied external pressure, interactions with substances in the bulk, etc. They could be used to direction of optimization and improvement the production technologies as well as development of new generation of therapeutic surfactant preparations [16,17,18,19].…”

PRODUÇÃO DE BIOTENSOATIVO UTILIZANDO Pseudomonas aeruginosa (P.A.) E RESÍDUO AGROINDUSTRIAL (MANIPUEIRA) COMO SUBSTRATO

“…Apesar de altamente poluente, a manipueira pode ser empregada como matéria-prima para outros processos industriais, por apresentar altas concentrações de carboidratos, nitrogênio e sais minerais. Entre as alternativas, encontra-se a produção de biossurfactantes (Costa et (Cohen et al, 2010), de petróleo, de produtos de higiene e de cosméticos (Lourith e Kanlayavattanakul, 2009), de mineração e na indústria agrícola (Banat et al, 2010;Fathabad, 2011). O uso do biotensoativo também se estende a aplicações ambientais, em tratamento de solo e água contaminados por hidrocarbonetos (Cameotra e Makkar, 2010).…”