Suitability of ZnO Nanocomposite of Copolymer (PPy-PNVK-ZnO) (PPy = Polypyrrole; PNVK = Poly 9-vinyl carbazole) for the Detection of 6-Thioguanine: A DFT Analysis

Abstract

Conducting polymers have extensively been exploited for the specific drug detection, through diverse drug responses. 6-Thioguanine (6-TG) is commonly used in the treatment of cancer and its level monitoring in the human body is essential to avoid the side effects due to its physiological metabolites. Computational synthesis of a novel sensor material, i.e. ZnO nanocomposite of copolymer (PPy-PNVK-ZnO) using polypyrrole (PPy-ZnO) and poly 9-vinyl carbazole (PNVK-ZnO) polymers, has been performed and investigated its sensing ability for 6-TG drug, using the density functional theory (DFT) based ab initio approach. Generalized gradient approximation (GGA), parameterized with Perdew, Burke and Ernzerhof (PBE) type parameterization furnishes novel resources on the studied molecular model. The molecular interactions have been analyzed in terms of the HOMO-LUMO gap, density of states (DOS), adsorption energy (Eads), recovery time (τ), Mulliken population, electron density plot and quantum molecular descriptors. The calculated negative adsorption energy confirms the stability of these polymers and observes the type of interaction with 6-TG, as physical adsorption, that also confirms the reusability of the prepared sensor and its low operational temperature. It has also been observed that ZnO nanocomposite of copolymer has favourable stability in comparison to its host counterparts, whereas the host PNVK has a better recovery time and PPy has a relatively better range of detection and highly reactive.