MnO_x In Situ Growth-Induced Luminescence and Oxidase-Like Feature Bimodulation of CePO₄:Tb Nanorods: Toward Ascorbic Acid-Related Bioanalysis in a “One-Stone-Two-Birds” Manner

Abstract

Nanozyme-based multimode detection is a useful means to improve the accuracy and stability of analytical methods. However, both multifunctional nanozymes and related multimodal sensing strategies are still very scarce. Besides, they require complex processes to fabricate and operate. To fill this gap, here we propose a spontaneous interfacial in situ growth strategy to prepare a new bifunctional material (CePO 4 :Tb@MnO x ) featuring good oxidase-like activity and green photoluminescence for the dual-mode colorimetric/luminescence determination of ascorbic acid (AA)-related biomarkers specifically. CePO 4 :Tb@MnO x was gained through the controllable redox reaction between KMnO 4 and CePO 4 :Tb nanorods. It was interestingly found that MnO x in situ growth not only significantly enhanced the enzyme-like activity but also could reversibly regulate the luminescence of CePO 4 :Tb via a dual quenching mechanism. More interestingly, CePO 4 :Tb@MnO x exhibited a distinctive response toward AA against other reducing species. A double-coordination regulation mechanism was further verified to clarify the catalytic activity and luminescence switching behaviors in CePO 4 :Tb@MnO x . Based on these findings, a dual-mode colorimetric/luminescence approach was established for AA sensing in a "one-stone-two-birds" manner, providing excellent selectivity, sensitivity, and practicability. Furthermore, the determination of AA-related biomarkers, including acid phosphatase activity and organophosphorus residue, was also validated by the sensing principle. Our work not only deepens the understanding of the coordinated regulation of the luminescence and enzyme-like features in lanthanide-based materials but also offers a novel way to design and develop multifunctional nanozymes for advanced bioanalytical applications.

Nanozymes: powerful catalytic materials for environmental pollutant detection and degradation

“…190 With low cost, excellent stability, and robust performance, nanomaterials with peroxidase- or oxidase (OXD)-like activities can be integrated with bioenzymes to fabricate natural enzyme–nanozyme cascade systems for pesticide detection. 157–163,165–177,191 Very recently, we explored an Fe-based phosphotungstate (Fe-PTs) with a notable peroxidase-like feature at neutral pH to establish a portable multi-enzyme biosensor for pesticide analysis. 176 The electrostatic interaction between positively charged TMB and negatively charged Fe-PTs as well as the promoted regeneration of Fe 2+ was supposed to play crucial roles in enabling the material to show favorable peroxidase-mimetic activity under neutral conditions.…”