Fabrication of Ag–Cu₂O/Reduced Graphene Oxide Nanocomposites as Surface-Enhanced Raman Scattering Substrates for in Situ Monitoring of Peroxidase-Like Catalytic Reaction and Biosensing

Abstract

Highly sensitive biosensors are essential in medical diagnostics, especially for monitoring the state of an individual's disease. An ideal way to achieve this objective is to analyze human sweat secretions by noninvasive monitoring. Due to low concentrations of target analytes in human secretions, fabrication of ultrasensitive detection devices is a great challenge. In this work, Ag-CuO/reduced graphene oxide (rGO) nanocomposites were prepared by a facile two-step in situ reduction procedure at room temperature. Ag-CuO/rGO nanocomposites possess intrinsic peroxidase-like activity and rapidly catalyze oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of HO. On the basis of the excellent SERS properties and high peroxidase-like activity of the Ag-CuO/rGO nanocomposites, the catalytic oxidation of TMB can be monitored by SERS. This approach can detect HO and glucose with high sensitivity and distinguish between diabetic and normal individuals using glucose levels in fingerprints. Our work provides direction for designing other SERS substrates with high catalytic activity and the potential for application in biosensing, forensic investigation, and medical diagnostics.

Carbon Nanozymes: Enzymatic Properties, Catalytic Mechanism, and Applications

“…Besides their intrinsic enzymatic activity,CNMs and their derivatives can be also utilized as modulators to further improve the catalytic activity and stability of artificial peroxidase.M any classic artificial peroxidases,f or instance, metal oxides (for example,F e 3 O 4 , FeO x H, [94] Fe 2 O 3 , [95][96][97] Co 3 O 4 , [98][99][100] ZnO, [101] CuO, [102][103][104][105] Cu 2 O, [106] CeO 2 , [92] Co-Fe 2 O 4 , [107,108] and WO 3 [109] ), metal hydroxide, [110] metal chalcogenides (for example,C oSe 2 , [111] CuS, [112,113] and MoS 2 [114] ), metal nanoparticles (for example,P t, [92,[115][116][117][118][119][120][121] Pd, [82,88,122,123] Au, [84,88,[124][125][126][127][128][129][130][131][132][133]…”

Irreversible accumulated SERS behavior of the molecule-linked silver and silver-doped titanium dioxide hybrid system

“…Moreover, the additional studies have been carried out to investigate the SERS enhancement from the hybrid system composed of noble metal nanostructure and metal-oxide semiconductor 20,21 . Guo et al fabricated of Au-Cu 2 O/rGO nanocomposites as efficient SERS substrate which origin from the synergistic effect of CE and EE 22 . Liu et al prepared flower-shaped Au-ZnO hybrid nanoparticles with strong charge-transfer-induced SERS property and used as biocompatible and recyclable SERS-active substrate 23 .…”

Kohlenstoff‐Nanozyme: Enzymatische Eigenschaften, Katalysemechanismen und Anwendungen

“…Viele klassische künstliche Peroxidasen, z. B. Metalloxide (Fe 3 O 4 , FeO x H, Fe 2 O 3 , Co 3 O 4 , ZnO, CuO, Cu 2 O, CeO 2 , CoFe 2 O 4 , WO 3 ), Metallhydroxide, Metallchalkogenide (CoSe 2 , CuS, MoS 2 ), Metallnanopartikel (Pt, Pd, Au, Ag, Fe), Legierungen (PtPd, PdNi, AuPd, AuAg, CuAg, FeCo), Metallionen (Cu 2+[152] ), Komplexe (Hämin, chirale metallosupramolekulare Komplexe, Fe‐Phenanthrolin, Preußischblau), wurden verwendet, um Hybride mit CNMs herzustellen. Wegen ihrer großen spezifischen Oberflächen, ihren ausgezeichneten physikalischen Eigenschaften und ihrer vielseitigen Oberflächenchemie spielten CNMs sehr wichtige Rollen in der Regulierung der enzymatischen Aktivität von...…”