1. Cubic and Hexagonal Mesophases for Protein Encapsulation: Structural Effects of Insulin Confinement
- Author
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Francesco Vita, Paola Astolfi, Stefania Pucciarelli, Diego Romano Perinelli, Serena Logrippo, Marco Parlapiano, Giulia Bonacucina, Michela Pisani, Oriano Francescangeli, Lisa Vaccari, Elisabetta Giorgini, and Fabrizio C. Adamo
- Subjects
Diffraction ,Materials science ,Hexagonal phase ,Temperature ,Infrared spectroscopy ,Mesophase ,Surfaces and Interfaces ,Condensed Matter Physics ,Viscoelasticity ,Article ,Protein Structure, Secondary ,Oleic acid ,chemistry.chemical_compound ,Crystallography ,chemistry ,Rheology ,X-Ray Diffraction ,Spectroscopy, Fourier Transform Infrared ,Electrochemistry ,Insulin ,General Materials Science ,Protein secondary structure ,Spectroscopy - Abstract
Monoolein-based cubic and hexagonal mesophases were investigated as matrices for insulin loading, at low pH, as a function of temperature and in the presence of increasing amounts of oleic acid, as a structural stabilizer for the hexagonal phase. Synchrotron small angle X-ray diffraction, rheological measurements, and attenuated total reflection-Fourier transform infrared spectroscopy were used to study the effects of insulin loading on the lipid mesophases and of the effect of protein confinement in the 2D- and 3D-lipid matrix water channels on its stability and unfolding behavior. We found that insulin encapsulation has only little effects both on the mesophase structures and on the viscoelastic properties of lipid systems, whereas protein confinement affects the response of the secondary structure of insulin to thermal changes in a different manner according to the specific mesophase: in the cubic structure, the unfolding toward an unordered structure is favored, while the prevalence of parallel β-sheets, and nuclei for fibril formation, is observed in hexagonal structures.
- Published
- 2021