title: Mechanically Enhanced Liquid Interfaces at Human Body Temperature Using Thermosensitive Methylated Nanocrystalline Cellulose.
abstract: The mechanical performance of materials at oil/water interfaces after consumption is a key factor affecting hydrophobic drug release. In this study, we methylated the surface of nanocrystalline cellulose (NCC) by mercerization and dimethyl sulfate exposure to produce thermosensitive biopolymers. These methylated NCC (metNCC) were used to investigate interfacial thermogelation at air/water and medium-chain triglyceride (MCT)/water interfaces at body temperature. In contrast to bulk fluid dynamics, elastic layers were formed at room temperature, and elasticity increased significantly at body temperature, which was measured by interfacial shear and dilatational rheology in situ. This unique phenomenon depends on solvent quality, temperature, and polymer concentration at interfaces. Thus, by adjusting the degree of hydrophobicity of metNCC, the interfacial elasticity and thermogelation of the interfaces could be varied. In general, these new materials (metNCC) formed more brittle interfacial layers compared to commercial methylcellulose (MC A15). Thermogelation of methylcellulose promotes attractive intermolecular forces, which were reflected in a change in self-assembly of metNCC at the interface. As a consequence, layer thickness and density increased as a function of temperature. These effects were measured by atomic force microscopy (AFM) images of the displaced interface and confirmed by neutron reflection. The substantial structural and mechanical change of methylcellulose interfaces at body temperature represents a controllable encapsulation parameter allowing optimization of lipid-based drug formulations.
authors.affiliation: Institute of Food Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: N
authors.initials: N
authors.lastname: Scheuble
authors.affiliation: Laboratory of Neutron Scattering and Imaging, Paul Scherrer Institut , 5232 Villigen PSI, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Geue
authors.affiliation: Institute of Food Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Kuster
authors.affiliation: Institute of Food Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Adamcik
authors.affiliation: Institute of Food Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Mezzenga
authors.affiliation: Institute of Food Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: E J
authors.initials: EJ
authors.lastname: Windhab
authors.affiliation: Institute of Food Nutrition and Health, ETH Zurich , 8092 Zurich, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Fischer
mesh_terms: D001831:Body Temperature; D004548:Elasticity; D006801:Humans; D008747:Methylcellulose / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D013499:Surface Properties; D014783:Viscosity
chemical_list: D008747:Methylcellulose