Abstract
•Graphitic carbon nitride (GCN) is explored as a drug carrier.•GCN possess significant therapeutic potential as a drug carrier.•The absorption of curcumin drug on the nanocarrier (GCN) is spontaneous and exothermic.•The hydrogen bonding are responsible for the adsorption of drug (curcumin) on the surface of nanocarrier (GCN).•For visual explanation of different excited-states, PET process and electron-hole theory are used.
The density functional theory (DFT) analysis is used to predict the therapeutic potential of Graphitic carbon nitride (GCN) as a medicinal carrier for curcumin for the treatment of cardiovascular diseases. To evaluate the drug transport capacity of GCN, the electronic, ground, and excited-state properties of curcumin, GCN, and the GCN-curcumin-complex were investigated. The adsorption energy of the GCN-curcumin-complex is higher in the gas phase (−0.25 eV) than in the aqueous phase (−0.09 eV), implying that the GCN-curcumin-complex is more stable in the gas phase. Weak NH bonds anchored the curcumin at GCN surface. The GCN-curcumin-complex has a higher dipole moment in the aqueous medium (2.37 D) than in the gas phase (1.36 D) which aids in the efficient transport of the drug through biological systems. Molecular electrostatic potential and frontier molecular orbitals revealed that during excitation, curcumin behaves as a HOMO, transferring charge to the LUMO (GCN). The charge decomposition analysis, which determines the highest overlap between the curcumin and GCN orbitals, was also employed to investigate the charge transfer process. For several transitions from the donor to the acceptor, Natural bond orbital (NBO) analysis revealed that charge was transferred between the curcumin and GCN molecules. For the GCN-curcumin-complex, excited-state calculations show that λmax is redshifted by 131 nm. The redshift for the GCN-curcumin-complex in the solvent phase is 149 nm. The theoretically generated spectra match experimentally observed spectra quite well. Moreover, the in silico infrared spectra of GCN and Curcumin is also close to the experimental spectra. For the graphical explanation of various excited states, electron-hole and photoinduced electron-transfer analysis are performed. The Photoinduced electron transfer (PET) mechanism perceives quenching of fluorescence because of an interaction. Moreover, GCN +1/−1 showed little structural change and produces stable curcumin complexes. All findings indicated that GCN has substantial therapeutic potential as a carrier for curcumin in cardiovascular disease cure. Researchers will be motivated to investigate alternative 2D nanomaterials for drug delivery applications due to this theoretical study.