DFT study of therapeutic potential of graphitic carbon nitride (g-C3N4) as a new drug delivery system for carboplatin to treat cancer

Abstract

DFT studies were performed to evaluate the chemotherapeutic potential of g-C3N4 as a drug carrier for carboplatin in cancer treatment. The optimized, electronic and excited-state characteristics of g-C3N4, carboplatin, and g-C3N4-carboplatin-complex were determined to evaluate the targeted drug delivery ability of g-C3N4. The Ead values of g-C3N4-carboplatin-complex for the gas phase is −1.39 eV and in the water phase is −0.52 eV. The non-covalent-interaction (NCI) plot revealed that weak forces of interaction are present between g-C3N4 and carboplatin. These weak forces of interactions are responsible for an obvious offloading of the drug from g-C3N4 carrier at its targeted site. Through frontier molecular orbital analysis it was evaluated that during excitation carboplatin behaves as HOMO and delivers the charge towards the LUMO i.e. g-C3N4. Charge-decomposition-analysis (CDA) was also performed to further support the charge transfer process which interprets the maximum overlap between the orbitals of the carboplatin and g-C3N4. In the gas phase, the λmax of g-C3N4- carboplatin-complex is red-shifted by 74 nm. While in the aqueous phase the λmax is blue-shifted. These theoretically obtained spectra are also in good consistency with that of experimental spectra. The PET (photo-induced electron-transfer) process, as well as electron–hole-theory, were also performed for the graphical elucidation of different excited-states. The photo-induced-electron-transfer (PET) process interprets that upon interaction quenching in fluorescence takes place. Furthermore, g-C3N4 with cationic (+1) and anionic (−1) charge-state (g-C3N4+1/−1) represented negligible distortion in structure and forms stable-complexes with carboplatin. All the observed results confirmed that g-C3N4 possesses significant chemo-therapeutic potential as a drug carrier for carboplatin in cancer treatment. This theoretical work will also stimulate the concern of researchers for further exploration of other 2D nanomaterials for drug-delivery applications.