Bifunctional Mo₂N Nanoparticles with Nanozyme and SERS Activity: A Versatile Platform for Sensitive Detection of Biomarkers in Serum Samples

Abstract

The combined application of nanozymes and surface-enhanced Raman scattering (SERS) provides a promising approach to obtain label-free detection. However, developing nanomaterials with both highly efficient enzyme-like activity and excellent SERS sensitivity remains a huge challenge. Herein, we proposed one-step synthesis of Mo2N nanoparticles (NPs) as a “two-in-one” substrate, which exhibits both excellent peroxidase (POD)-like activity and high SERS activity. Its mimetic POD activity can catalyze the 3,3′,5,5′-tetramethylbenzidine (TMB) molecule to SERS-active oxidized TMB (ox-TMB) with high efficiency. Furthermore, combining experimental profiling with theory, the mechanism of POD-like activity and SERS enhancement of Mo2N NPs was explored in depth. Benefiting from the outstanding properties of Mo2N NPs, a versatile platform for indirect SERS detection of biomarkers was developed based on the Mo2N NPs-catalyzed product ox-TMB, which acts as the SERS signal readout. The feasibility of this platform was validated using glutathione (GSH) and target antigens alpha-fetoprotein antigen (AFP) and carcinoembryonic antigen (CEA) as representatives of small molecules with a hydroxyl radical (·OH) scavenging effect and proteins with a low Raman scattering cross-section, respectively. The limits of detection of GSH, AFP, and CEA were as low as 0.1 μmol/L, 89.1, and 74.6 pg/mL, respectively. Significantly, it also showed application in human serum samples with recoveries ranging from 96.0 to 101%. The acquired values based on this platform were compared with the standard electrochemiluminescence method, and the relative error was less than ±7.3. This work not only provides a strategy for developing highly active bifunctional nanomaterials but also manifests their widespread application for multiple biomarkers analysis.

“Three-in-One” Plasmonic Au@PtOs Nanocluster Driven Lateral Flow Assay for Multimodal Cancer Exosome Biosensing

“…Nanozymes are a type of nanomaterial which possess a similar catalytic ability to natural enzymes; since Fe 3 O 4 NPs with peroxidase (POD)-mimicking activity was reported in 2007, a large amount of engineered nanomaterials based nanozymes have been fabricated with excellent enzyme-mimicking catalytic performance. − Recently, due to the horseradish peroxidase (HRP)-like catalytic signal amplification ability, POD-mimicking nanozymes have been combined with LFA for improved colorimetric detection sensitivity. − On the other hand, for nanozymes coupled with LFA, single-mode colorimetric readout may be affected by the experimental environmental interferences, system errors, and batch-to-batch variations; therefore, nanozymes based multimodal signal readout LFA should be developed to ensure that the multiple signals can complement and mutually confirm with each other to improve the accuracy. − In recent years, several nanozyme based multimodal biosensors obtained by using catalytic colorimetric signals combined with fluorescence, photothermal, chemiluminescent, and surface-enhanced Raman scattering (SERS) , have been reported. Among them, plasmonic nanozymes with LSPR (localized surface plasmon resonance) has been of concern due to both the SERS enhancement and enzyme-mimicking catalytic activity of nanozymes.…”

Nanozyme-Inhibited SERS Multichannel Paper-Based Sensor Array for the Quantification and Identification of Biothiols and Cancer Cells Based on Three Ag-Based Nanomaterials

“…Nanozymes, as nanomaterials with bioenzyme-like characteristics, have drawn extensive interest in biological applications due to their superiorities including low cost, high stability, and easy-to-tailor performance . More importantly, certain nanozymes containing precious metals display superior SERS enhancement capability, which can induce the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to SERS-active reporters (TMBox) and concurrently generate prominent SERS signals . Interestingly, we have found that certain Ag-containing precipitates, such as Ag 3 PO 4 and Ag 3 Cit, possess both oxidase-mimetic and SERS enhancement properties, but these phenomena have been rarely reported.…”