Grigorios Megariotis graduated from the School of Chemical Engineering at the National Technical University of Athens in 2005 with a grade of 8.41 and at the end of the same year began his PhD in the Computational Materials Science and Engineering Group of Professor Doros Theodorou on Atomistic and Mesoscopic Simulations of Liquid Crystals and Lipid Membranes. In 2009 he was awarded his PhD from the National Technical University of Athens and subsequently, during his military service, was at the Army Research and Technology Center. Next, he worked as a postdoctoral researcher at the Institute of Organic and Pharmaceutical Chemistry of the National Hellenic Research Foundation for two years. There he worked on the calculation of linear and nonlinear optical properties, as well as molecular simulations of drugs and biomolecules, in close collaboration with experimental groups. From 2012 to the present he has been working as a researcher at the National Technical University of Athens. He has 31 publications and has participated in 42 presentations at national and international conferences. His research interests include:
- Multiscale molecular simulations for applications in Chemistry and Chemical Engineering with emphasis on synthetic polymers, liquid crystals and polymer nanocomposites.
- Thermodynamic description of interfacial phenomena of biological interest.
- Computational Biophysics with emphasis on drug interactions with biological systems.
He has also taught in the Departments of Mineral Resources Engineering, Chemical Engineering, and Mathematics at the University of Western Macedonia.
Cyclodextrins as Protective Hosts for Chemical UV Filters
Grigorios Megariotis*, Georgios Mikaelian, Haralambos Sarimveis
School of Chemical Engineering, National Technical University of Athens (NTUA)
UV filter – cyclodextrin complexes are computationally studied in water using all-atom molecular dynamics simulations. The chemical UV filters considered herein are octocrylene and avobenzone, which are widely used in commercial sunscreen products and together provide broad-spectrum skin protection (covering both UV-A and UV-B radiation). The selected host molecules are β-cyclodextrin (β-CD) and 2 hydroxypropyl-β-cyclodextrin (HP-β-CD). In general, cyclodextrins have been assessed for protecting UV filters against photodegradation and oxidation, as well as for their ability to restrict UV filter permeation into deep skin layers. In all molecular dynamics simulations, the starting point involves the UV filters and cyclodextrin molecules in the unbound state to determine whether noncovalent complexation is a spontaneous process. The primary goal is to investigate in detail the complexes from a nanoscopic point of view, as well as the complexation process, with a special focus on the thermodynamic description and the stability of the formed supramolecular complexes. In the framework of our analysis, several properties are calculated and, when possible, comparisons are made with published experimental data. Concerning thermodynamics, the binding free energy is estimated by applying a modified version of the Linear Interaction Energy (LIE) method. This method has low computational cost and has been successfully applied in a number of studies involving complexes formed between cyclodextrins and small organic molecules. With regard to avobenzone, which contains a β-diketone group, both keto and enol forms are studied due to their tautomeric equilibrium and distinct roles in photoprotection and photodegradation mechanisms.