Knowing the thermal relaxation of amino acids as the building blocks of bio-molecules and proteins can provide a better understanding of how a bio-molecule dissipates heat when chemical and photochemical reactions occur at specific spots. In this talk, I will show our recent results about the thermal relaxation of 20 naturally occurring amino acids in water and in lysozyme protein using transient nonequilibrium molecular dynamics [1]. The relationship between the cooling time of amino acids to the solvent-accessible surface area of a sample protein in water is discussed. Our finding might help to analyze the function of water-surrounded amino acids, proteins, and bio-molecules in the face of temperature gradients, which have a wide range of applications, including cancer thermotherapy. I also present how to calculate the interfacial thermal conductance (Kapitza conductance) between different nanoparticles and water by equilibrium and non-equilibrium simulation techniques in both steady and unsteady state conditions [2]. These nanoparticles include gold, silver, graphene flakes and titanium dioxide, and amino acids. The effect of size, hydrophilicity, hydrophobicity, the contribution of van der Waals and polar interactions, as well as the effects of electric charges on nanoparticles and the presence of ions in water are investigated [3-5].

[1] H Hamzi, A Rajabpour, É Roldán, A Hassanali, “Learning the Hydrophobic, Hydrophilic, and Aromatic Character of Amino Acids from Thermal Relaxation and Interfacial Thermal Conductance” J. Phys. Chem. B. 126 (2022) 670-678
 
[2] A Rajabpour, R Seif, S Arabha, MM Heyhat, S Merabia, A Hassanali, “Thermal transport at a nanoparticle-water interface: A molecular dynamics and continuum modeling study” J. of Chem. Phys. 150 (2019) 114701   
 
[3] R Rabani, MH Saidi, L Joly, S Merabia, A Rajabpour, “Enhanced local viscosity around colloidal nanoparticles probed by equilibrium molecular dynamics simulations” J. of Chem. Phys. 155 (2021) 174701
 
[4] F Jabbari, A Rajabpour, S Saedodin, S Wongwises, “Effect of water/carbon interaction strength on interfacial thermal resistance and the surrounding molecular nanolayer of CNT and graphene flake” J. of Molecular Liquids 282 (2019) 197-204.
           
[5] MM Heyhat, M Abbasi, A Rajabpour, “Importance of nanolayer formation in nanofluid properties: Equilibrium molecular dynamic simulations for Ag-water nanofluid” J. Molecular Liquids 333 (2021) 115966