Molecular dynamics simulation study of curcumin interaction with nano-micelle of PNIPAAm-b-PEG co-polymer as a smart efficient drug delivery system

Drug delivery systems can be designed to safely transfer themedicinal compounds into the body and increase the therapeutic index, consequently. Some useful drug delivery systems such as liposomes, hydrogels, nanoparticles, and polymers are widely used. Polymers mainly block copolymers, smart polymers, and a combination of them are regarded in drug delivery systems by improving controlled release, biocompatibility, bioavailability, and increase the solubility of active pharmaceutical ingredients. For the first time in this study, we thoroughly examined the modified PNIPAAm-b-PEG block-copolymer interaction as a smart nano-drug delivery system with curcumin molecule as a drug, using the molecular dynamics simulation method. We used GROMACS as a molecular dynamic software and Amber99SB as an all-atom force field to investigate the polymer's behavior in the presence of the drug in an aqueous solution. We focused on the encapsulation behaviors of a drug, the intermolecular interactions, the structural properties of drug-polymer nano-micelles, and the capacity of drug-loading in the micelle. Our analysis predicts that PNIPAAm-b-PEG polymer phase change temperature is in the range of 300-305 K and also at the concentration of 9% of the polymer, in 310 K, the effective radius of the formed micelle is equal to 4.36 nm, and it is hydrogel like, in good agreement with the relevant experimental data. Further analysis shows the drug solubility in the presence of the polymer increases by about 88%. The study of the interaction energy between drug and polymer predicts the encapsulation process as favorable. (C) 2021 Elsevier B.V. All rights reserved.