Silver-loaded graphene as an effective SERS substrate for clotrimazole detection: DFT and spectroscopic studies
Abstract
Vibrational infrared, Raman and surface-enhanced Raman scattering (SERS) spectra of clotrimazole (CTZ) were documented and evaluated. Density-functional theory, B3LYP/6-311++G(d,p), approach was implemented to identify the possible conformations, develop the electrostatic potential map, evaluate frontier molecular orbitals and calculate the vibrational spectra of the target compound. The silver-loaded graphene was shown to be an effective SERS substrate for CTZ trace detection. The SERS spectrum showed two enhanced bands at 670 cm-1 and 700 cm-1 which confirmed the absorption of the silver substrate through chlorine and nitrogen atoms. A detection limit as low as 5 nM could be reached with a determination coefficient of 0.9988 using the band at 670 cm-1. The protein-ligand interaction with Secreted Aspartic Proteinase 2 (SAP2) of C. albicans showed that the four stable forms of CTZ maintain a free energy of binding of 6-7 kcal/mol, which could give insights into the mode of action in treating Candidiasis.
- Publication:
-
Spectrochimica Acta Part A: Molecular Spectroscopy
- Pub Date:
- August 2018
- DOI:
- 10.1016/j.saa.2018.05.018
- Bibcode:
- 2018AcSpA.201..354O
- Keywords:
-
- Clotrimazole;
- Surface-enhanced Raman scattering spectroscopy;
- DFT;
- Candidiasis;
- Molecular docking