Mucin Thin Layers: A Model for Mucus-Covered Tissues

Abstract

The fate of macromolecules of biological or pharmacological interest that enter the mucus barrier is a current field of investigation. Studies of the interaction between the main constituent of mucus, mucins, and molecules involved in topical transmucoidal drug or gene delivery is a prerequisite for nanomedicine design. We studied the interaction of mucin with the bio-inspired arginine-derived amphoteric polymer d,l-ARGO7 by applying complementary techniques. Small angle X-ray scattering in bulk unveiled the formation of hundreds of nanometer-sized clusters, phase separated from the mucin mesh. Quartz microbalance with dissipation and neutron reflectometry measurements on thin mucin layers deposited on silica supports highlighted the occurrence of polymer interaction with mucin on the molecular scale. Rinsing procedures on both experimental set ups showed that interaction induces alteration of the deposited hydrogel. We succeeded in building up a new significant model for epithelial tissues covered by mucus, obtaining the deposition of a mucin layer 20 Å thick on the top of a glycolipid enriched phospholipid single membrane, suitable to be investigated by neutron reflectometry. The model is applicable to unveil the cross structural details of mucus-covered epithelia in interaction with macromolecules within the Å discreteness.

Modulation of plant plasma membrane structure by exogenous fatty acid hydroperoxide is a potential perception mechanism for their eliciting activity

“…Errors on parameters values have been estimated from the maximum variation in the acceptable fit subject to the constraints of space‐filling and stoichiometry. NR is a technique suited to collect structural information about the different layers of the studied membrane (Rondelli et al, 2019). Thus, the silicon support and the bulk water are seen as bulk infinite layer, the silicon oxide layer, the water layer between the silicon oxide and the membrane and the diverse hydrophilic/hydrophobic layers of the lipid membranes are modelled as defined layers with a proper thickness, roughness with respect to the previous layer, compactness, composition and consequently contrast.…”

Exogenous Fatty Acid Hydroperoxide Perception as Elicitor Is Related to Modulation of Plant Plasma Membrane Structure

“…Finally, the calculated model profile is compared to the measured profile and the quality of the fit is assessed by using the χ 2 in minimum-squares method. NR is a technique suited to collect structural information about the different layers of the studied membrane (Rondelli et al, 2019). Thus, the silicon support and the bulk water are seen as bulk infinite layer, the silicon oxide layer, the water layer between the silicon oxide and the membrane and the diverse hydrophilic/hydrophobic layers of the lipid membranes are modelled as defined layers with a proper thickness, roughness with respect to the previous layer, compactness, composition and consequently contrast.…”

Is Exogenous Fatty Acid Hydroperoxide Perception as Elicitor Related to Modulation of Plant Plasma Membrane Structure ?

“…Errors on parameters values have been estimated from the maximum variation in the acceptable fit subject to the constraints of space filling and stoichiometry. NR is a technique suited to collect structural information about the different layers of the studied membrane (Rondelli et al , 2019). Thus, the silicon support and the bulk water are seen as bulk infinite layer, the silicon oxide layer, the water layer between the silicon oxide and the membrane and the diverse hydrophilic/hydrophobic layers of the lipid membranes are modelled as defined layers with a proper thickness, roughness with respect to the previous layer, compactness, composition and consequently contrast.…”