Accurate Monitoring Platform for the Surface Catalysis of Nanozyme Validated by Surface-Enhanced Raman-Kinetics Model

Abstract

Surface-enhanced Raman scattering (SERS) is a supersensitive technique for monitoring catalytic reactions. However, building a SERS-kinetics model to investigate catalytic efficiency on the surface or interface of the catalyst remains a great challenge. In the present study, we successfully obtained an excellent semiconducting SERS substrate, reduced MnCo2O4 (R-MnCo2O4) nanotubes, whose favorable SERS sensitivity is mainly related to the promoted interfacial charge transfer caused by the introduction of oxygen vacancies as well as the electromagnetic enhancement effect. Furthermore, the R-MnCo2O4 nanotubes showed a favorable oxidase-like activity toward oxidation with the aid of molecular oxygen. It was also showed the oxidase-like catalytic process could be monitored using the SERS technique. A new SERS-kinetics model to monitor the catalytic efficiency of the oxidase-like reaction was developed, and the results demonstrate that the V m values measured by the SERS-kinetics method are close to that obtained by the UV–vis approach, while the K m values measured by the SERS-kinetics method are much lower, demonstrating the better affinity between the enzyme and the substrate from SERS results and further confirming the high sensitivity of the SERS-kinetics approach and the actual enzyme-like reaction on the surface of nanozymes, which provides guidance in understanding the kinetics process and catalytic mechanism of natural enzymatic and other artificial enzymatic reactions. This work demonstrated the improved SERS sensitivity of defective semiconductors for the application of enzyme mimicking, providing a new frontier to construct highly sensitive biosensors.

Defect engineering in semiconductor-based SERS

“…The SERS technique has been especially favored in monitoring chemical reactions that take place in aqueous environments, as the interference of water signals can be minimized by Raman spectroscopy. The detection of intermediate or product species in a reaction does not usually 8d) 127 . The highlight of the work is the access to in situ monitoring of the oxidization process based on quantitative SERS analysis of the oxidized TMB product (oxTMB) on the surface of oxygen-vacancy-rich MnCo2O4.…”

“…8d ). 127 The highlight of the work is the access to in situ monitoring of the oxidization process based on quantitative SERS analysis of the oxidized TMB product (oxTMB) on the surface of oxygen-vacancy-rich MnCo 2 O 4 . It should be noted that while the CT-induced SERS performance of reduced MnCo 2 O 4 nanotubes improved compared to that of pristine MnCo 2 O 4 , their oxidase-like catalytic activity slightly declined, which shows that the influence of defect engineering on SERS and catalytic activity differs.…”

“…In another example, Wen et al have studied the nanoenzyme properties of reduced MnCo 2 O 4 with the aid of Au NPs to boost its SERS activity 126. They also reported a SERS-kinetic model which monitored the oxidation of tetramethylbenzidine (TMB), based on reduced MnCo 2 O 4 nanotubes, which had the double function of the SERS substrate and oxidase (Fig.8d) 127. The highlight of the work is the access to in situ monitoring of the oxidization process based on quantitative SERS analysis of the oxidized TMB product (oxTMB) on the surface of oxygenvacancy-rich MnCo 2 O 4 .…”

Hollow Multi‐Shelled V2O5 Microstructures Integrating Multiple Synergistic Resonances for Enhanced Semiconductor SERS

“…Raman scattering (SERS) spectroscopy is an ideal surface-sensitive technique that allows for non-destructive molecular analysis. [1][2][3] Semiconductor SERS offers a new possibility to extend its applications in several semiconductor-based fields, [4,5] such as dye-sensitized photovoltaic systems, [6] nanozyme-based catalytic kinetics, [7] redox processes of heme proteins, [8,9] viruses detection, [10] and ion sensing. [11,12] However, the increasing demand for the investigation of various adsorption species on semiconductor surfaces and/or interfaces has triggered the quest for the construction of highly SERS-active semiconductor materials with general applicability.…”

Ag Nanoislands Modified Carbon Fiber Nanostructure: A Versatile and Ultrasensitive Surface-Enhanced Raman Scattering Platform for Antiepileptic Drug Detection

“…As a universal spectral technology with the advantages of high sensitivity [1] and nondestructive detection, surface enhanced Raman scattering (SERS) has a very important application prospect in the fields of analytical chemistry [2], biomedical sensing [3], food safety detection [4] and ultra-trace detection of toxic pollutants [5]. In the past 40 years, people have made great efforts in understanding the origin of the SERS effect and creating more desirable SERS substrates, which have made continuous progress in theory and experiment.…”