Binding Mechanism and Surface-Enhanced Raman Scattering of the Antimicrobial Sulfathiazole on Gold Nanoparticles

Tran Ni Kha; Nguyen Thanh Si; Van Man Tran; Khuong Quoc Vo; Minh Tho Nguyen; Pham Vu Nhat

doi:10.1021/acsomega.3c01477

Binding Mechanism and Surface-Enhanced Raman Scattering of the Antimicrobial Sulfathiazole on Gold Nanoparticles

ACS Omega. 2023 Nov 7;8(46):43442-43453. doi: 10.1021/acsomega.3c01477. eCollection 2023 Nov 21.

Authors

Tran Ni Kha¹, Nguyen Thanh Si^{1

2}, Van Man Tran³, Khuong Quoc Vo³, Minh Tho Nguyen^{4

5}, Pham Vu Nhat^{1

6}

Affiliations

¹ Department of Chemistry, Can Tho University, Can Tho City 90000, Vietnam.
² Institute of Environmental Science and Technology, Tra Vinh University, Tra Vinh City 94000, Vietnam.
³ Faculty of Chemistry, University of Science, Vietnam National University, Ho Chi Minh City 70000, Vietnam.
⁴ Laboratory for Chemical Computation and Modeling, Institute for Computational Science and Artificial Intelligence, Van Lang University, Ho Chi Minh City 70000, Vietnam.
⁵ Faculty of Applied Technology, School of Technology, Van Lang University, Ho Chi Minh City 70000, Vietnam.
⁶ Molecular and Materials Modeling Laboratory, Can Tho University, Can Tho City 90000, Vietnam.

Abstract

A combined study using the surface-enhanced Raman scattering (SERS) technique and quantum chemical calculations was carried out to elucidate the adsorption behavior of sulfathiazole, an antibiotic drug, on gold nanoparticles. The tetrahedral Au₂₀ cluster was used as a simple model to mimic a nanostructured gold surface. Computations using density functional theory with the PBE functional were performed in both the gas phase and aqueous medium using a continuum model. The drug is found to bind to the Au metals via the nitrogen of the thiazole ring. The interaction is also partially stabilized by the ring-surface π coupling rather than a sideway adsorption as previously proposed. In an aqueous solution, the drug molecule mainly exists as a deprotonated form, which gives rise to a much greater affinity toward Au nanoparticles as compared to the neutral forms. The drug adsorption further induces a significant alteration on the energy gap of the gold cluster Au_n, which could result in an electrical noise. Notable SERS signals below 1600 cm^-1, which result from a coupling of several vibrations including the ring breathing, C-C stretching, and N-H bending, could be employed for both qualitative and quantitative detection and assessment of sulfathiazole at trace concentrations.