Research Article Issue
Peroxidase-like single Fe atoms anchored on Ti3C2Tx MXene as surface enhanced Raman scattering substrate for the simultaneous discrimination of multiple antioxidants
Nano Research 2023, 16 (7): 10053-10060
Published: 13 May 2023
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Single-atom nanozymes (SAzymes) are emerging as promising alternatives to mimic natural enzyme, which is due to high atomic utilization efficiency, well-defined geometric, and unique electronic structure. Herein, Fe single atoms supported on Ti3C2Tx (Fe-SA/Ti3C2Tx) with intrinsic peroxidase activity is developed, further constructing a sensitive Raman sensor array for sensing of five antioxidants. Fe-SA/Ti3C2Tx shows excellent peroxidase-like performance in catalyzing the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) with colorimetric reactions. X-ray adsorption fine structure (XAFS) reveals that the electron transport between the Ti3C2Tx and Fe atoms occurs along Fe-O-Ti ligands, meanwhile the density functional theory (DFT) calculations confirm the spontaneous dissociation of H2O2 and the formation of OH radicals. Furthermore, the peroxidase-like Fe-SA/Ti3C2Tx was used as surface enhanced Raman scattering (SERS) substrate of oxidized TMB (TMB+) and achieved satisfied signal amplification performance. Using the blocking effects of free radical reactions, one-off identification of 5 antioxidants, including ascorbic acid (AA), uric acid (UA), glutathione (GSH), melatonin (Mel), and tea polyphenols (TPP), could be realized with this high identifiable catalytic property. This principle could realize 100% distinguish accuracy combined with linear discriminant analysis (LDA) and heat map data analysis. A wide detection concentration ranges from 10−8 to 10−3 M for five antioxidants was also achieved.

Research Article Issue
Interface electronic engineering of molybdenum sulfide/MXene hybrids for highly efficient biomimetic sensors
Nano Research 2023, 16 (1): 1158-1164
Published: 24 October 2022
Abstract PDF (18.8 MB) Collect

Interface regulation plays a key role in the electrochemical performance for biosensors. By controlling the interfacial interaction, the electronic structure of active species can be adjusted effectively at micro and nano-level, which results in the optimal reaction energy barrier. Herein, we propose an interface electronic engineering scheme to design a strongly coupled 1T phase molybdenum sulfide (1T-MoS2)/MXene hybrids for constructing an efficient electrocatalytic biomimetic sensor. The local electronic and atomic structures of the 1T-MoS2/Ti3C2TX are comprehensively studied by synchrotron radiation-based X-ray photoelectron spectroscopy (XPS), as well as X-ray absorption spectroscopy (XAS) at atomic level. Experiments and theoretical calculations show that there are interfacial stresses, atomic defects and adjustable bond-length between MoS2/MXene nanosheets, which can significantly promote biomolecular adsorption and rapid electron transfer to achieve excellent electrochemical activity and reaction kinetics. The 1T-MoS2/Ti3C2TX modified electrode shows ultra high sensitivity of 1.198 μA/μM for dopamine detection with low limit of 0.05 μM. We anticipate that the interface electronic engineering investigation could provide a basic idea for guiding the exploration of advanced biosensors with high sensitivity and low detection limit.

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