Constructing 2D Nanosheet-Assembled MnCo₂O₄ Nanotubes for Pressure and Colorimetric Dual-Signal Readout Detection of Cancer Cells in Serum Samples

Abstract

Developing a facile and reliable strategy for detecting cancer cells in early stages in aqueous systems remains a challenge, although this strategy is crucial in biomedicine. Here, a green approach is proposed for synthesis of MnCo2O4 nanotubes. The resulting nanotubes have been shown to have peroxidase activity that catalyzes the oxidation of 3,3′,5,5′-tertamethylbenzidine (TMB) by O2, resulting in a typical color reaction from colorless to blue. Moreover, such nanotubes exhibit excellent catalytic properties for the decomposition of H2O2 into O2, resulting in a significant increase in pressure in the bottle. Thus, a new sensor system using MnCo2O4 nanotubes as an artificial peroxidase, generating O2 as pressure signal, and TMB as a color change reporter molecule for dual-mode pressure-based (pressuremeter) and colorimetric (naked eye) detection of cancer cells was established. By using folic acid (FA) as a recognition element, a total of 50 folate receptor (FR) positive cancerous cells can be distinguished by naked-eye observation and pressuremeter. The clinical applicability of such a dual-mode strategy has been tested in detecting cancer cells in serum samples. We envisaged that such a dual-signal readout dual-mode strategy based on MnCo2O4 nanotubes offers a promising biosensing platform for early clinical diagnosis.

Preparation of Flower-like NiMnO3 as Oxidase Mimetics for Colorimetric Detection of Hydroquinone

“…The K m value is proven to be an indicator of affinity between enzyme and substrate. The smaller the K m value, the stronger the affinity between the substrate and the enzyme. − The value of K m in NiMnO 3 composites based on TMB as the substrate was much lower than that of Mn 3 O 4 flowers, CuMnO 2 nanoflakes, NiCo 2 O 4 , and rod-like MnOOH/Mn 3 O 4 , as shown in Table . This indicated that, compared with other nanoparticles, NiMnO 3 composites required a lower concentration of TMB to achieve the maximum reaction velocity.…”

Fluorescent Fe3O4 Quantum Dots for H2O2 Detection

“…Visual and colorimetric read-out diagnostic systems enable the introduction of simple and cost-effective medical devices for practical applications. − In contrast to other detection methods (e.g., surface plasmon resonance, electrochemiluminescence (EL), fluorescence (PL), chemiluminescence (CL), and electrochemical methods), colorimetric strategies provide high flexibility and their simple operation enables the general population to visually detect target analytes. Over the last several decades, a number of colorimetric amplification strategies have been explored for biosensor development.…”

Synthesis of dual function Fe3O4@MnO2@HKUST-1 magnetic micromotors for efficient colorimetric detection and degradation of hydroquinone

“…K m was considered to be a most important parameter for evaluating the affinity between the enzyme and the substrate. Briefly speaking, [59][60][61] the smaller the K m value, the stronger the affinity between the enzyme and the substrate. The value of K m for Fe 3 O 4 @MnO 2 @HKUST-1 (0.317 mM) with TMB (Fig.…”