Reduced Graphene Oxide Sheets as Inhibitors of the Photochemical Reactions of α-Lipoic Acid in the Presence of Ag and Au Nanoparticles

N'ghaya Toulbe; Malvina S Stroe; Monica Daescu; Radu Cercel; Alin Mogos; Daniela Dragoman; Marcela Socol; Ionel Mercioniu; Mihaela Baibarac

doi:10.3390/nano10112238

Reduced Graphene Oxide Sheets as Inhibitors of the Photochemical Reactions of α-Lipoic Acid in the Presence of Ag and Au Nanoparticles

Nanomaterials (Basel). 2020 Nov 11;10(11):2238. doi: 10.3390/nano10112238.

Authors

N'ghaya Toulbe^{1

2}, Malvina S Stroe¹, Monica Daescu¹, Radu Cercel¹, Alin Mogos³, Daniela Dragoman⁴, Marcela Socol¹, Ionel Mercioniu⁵, Mihaela Baibarac¹

Affiliations

¹ National Institute of Materials Physics, Laboratory of Optical Processes in Nanostructure Materials, Atomistilor str. 405 A, 77125 Bucharest, Romania.
² Interdisciplinary School of Doctoral Studies, University of Bucharest, Șoseaua Panduri 90, 050663 Bucharest, Romania.
³ S.C. Agilrom Scientific S.R.L., 77190 Bucharest, Romania.
⁴ Faculty of Physics, University of Bucharest, Șoseaua Panduri 90, București 050663, Bucharest, P.O. Box MG-11, 077125 Bucharest-Magurele, Romania.
⁵ National Institute of Materials Physics, Atomic Structures and Defects in Advanced Materials Laboratory, Atomistilor str. 405 A, 77125 Bucharest, Romania.

Abstract

The influence of Ag and Au nanoparticles and reduced graphene oxide (RGO) sheets on the photodegradation of α-lipoic acid (ALA) was determined by UV-VIS spectroscopy. The ALA photodegradation was explained by considering the affinity of thiol groups for the metallic nanoparticles synthesized in the presence of trisodium citrate. The presence of excipients did not induce further changes when ALA interacts with Ag and Au nanoparticles with sizes of 5 and 10 nm by exposure to UV light. Compared to the Raman spectrum of ALA powder, changes in Raman lines' position and relative intensities when ALA has interacted with films obtained from Au nanoparticles with sizes between 5 and 50 nm were significant. These changes were explained by considering the chemical mechanism of surface-enhanced Raman scattering (SERS) spectroscopy. The photodegradation of ALA that had interacted with metallic nanoparticles was inhibited in the presence of RGO sheets.

Keywords: SERS spectroscopy; UV-VIS spectroscopy; α-lipoic acid.

Grants and funding

POC 58/05.09.2016/European Regional Development Fund under the Competitiveness Operational Program 2014-2020 and the National Authority for Scientific Research and Innovation as an Intermediate Body, on behalf of the Ministry of European Funds as Managing Authority for Ope