Pyrazinamide Drug Adsorption on the Pristine and Doped C70 Fullerenes: A DFT/TDDFT Study

The present study evaluated pristine and doped fullerene C70 variations (with Al and Si) in terms of sensitivity and reactivity to PZA drug using the density functional theory (DFT). It was found that the physisorption of PZA drug onto pristine C70 occurred through the O-head of the drug. The energy of such adsorption was obtained to be nearly - 3.11 kcal/mol. The electrical conductivity of the corresponding cluster remained almost unchanged in the adsorption. The Al and Si atoms substituting for C atoms in the fullerene raise the activity of the fullerene. The adsorption energy of Al was predicted to be - 47.95 kcal/mol, whereas that of Si was estimated to be - 29.85 kcal/mol. The LUMO-HOMO energy gap has a large effect on PZA drug. PZA adsorption strongly destabilized LUMOs in the Si-doped fullerene and increased its electrical conductivity. At the same time, electrical signals relating to environmental PZA presence were generated. The results revealed that the Si-doped fullerene is an electronic sensor of PZA with high efficiency. On the other hand, due to the large impacts of PZA adsorption on the Fermi level and functions of the Al-doped fullerene, the Al-doped fullerene is an CYRILLIC CAPITAL LETTER EF-type candidate for use as the sensor of PZA. The time-dependent functional density theory (FDT) results indicated a maximum peak of 784.56 nm for the steady positioning of the PZA/Al-fullerene complex.