Deployment of MIL-88B(Fe)/TiO₂ Nanotube-Supported Ti Wires as Reusable Electrochemiluminescence Microelectrodes for Noninvasive Sensing of H₂O₂ from Single Cancer Cells

Abstract

As one of the significant intracellular signaling molecules, hydrogen peroxide (H2O2) regulates some vital biological processes. However, it remains a challenge to develop noninvasive electrodes that can be used for sensing trace H2O2 at the cellular level. Here, we evaluated a high-performance solid-state electrochemiluminescence (ECL) H2O2 sensor based on MIL-88B­(Fe) nanocrystal-anchored Ti microwires. Semiconducting TiO2 nanotubes (TiNTs) vertically grown around a Ti wire via an anodization technique act as an intrinsic ECL luminophore. By integrating with MIL-88B­(Fe), the synergistic effect of the TiO2 luminophore and the remarkable peroxidase-like activity of MIL-88B­(Fe) enable the resulting H2O2 sensor an ultrahigh sensitivity featuring a minimum detection limit of 0.1 nM (S/N = 3), long-term stability, high durativity, and wide-range linear response to a concentration of up to 10 mM. To demonstrate the concept of a MIL-88B­(Fe)@TiO2 microelectrode for single-cell sensing, the electrode was used to detect intracellular H2O2 in a single cell. Moreover, benefiting from the heterojunction of MIL-88B­(Fe)/TiO2, the microelectrode was found to exhibit excellent photocatalytic activity in the visible-light range, that is, the sensor surface can be self-cleaning after a short visible-light treatment. These advanced sensor characteristics involving easy reusability reveal that the MIL-88B­(Fe)@TiO2 microelectrode is a new platform for cytosensing. This study provides a new strategy to design semiconductor materials with arbitrary shape and size, allowing for profound applications in biomedical and clinical analysis.

Biocatalytic Metal‐Organic Frameworks: Promising Materials for Biosensing

“…The remarkable POD‐like attribute of MIL‐88B(Fe) was introduced on ECL electrode, which could directly and quickly decompose H 2 O 2 to hydroxyl radical, leading to an ultrahigh ECL efficiency. This proposed ECL biosensor with the merits of low cost, excellent sensing property and easy production exhibited favorable application prospect in clinical and biomedical analysis [64] …”

“…This proposed ECL biosensor with the merits of low cost, excellent sensing property and easy production exhibited favorable application prospect in clinical and biomedical analysis. [64]…”

In Situ Monitoring of Dynamic Photocatalysis of Metal–Organic Frameworks by Three-Dimensional Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy

“…Conventional disinfection technologies, such as chemical spray inactivation and ultraviolet irradiation inactivation, might produce harmful byproducts, limiting their practical applications. Although heterogeneous photocatalysts can serve as sustained disinfectants since they can generate reactive oxygen species (ROS) against pathogens by photocatalysts, − their antipathogen efficiency is far from meeting demand, especially in the presence of other pollutants [e.g., particulate matter (PM), bioaerosols, etc. ]. , Alternatively, metal–organic frameworks (MOFs), as an up-to-date type of disinfectant, are expected to surpass traditional semiconductors owing to their unique photocatalytic features: (1) the photocatalytic performance of MOFs can be optimized at the molecular level by rationally adjusting metal clusters or organic ligands; (2) the large and well-arranged pore structure of MOFs is conducive to the introduction of guest molecules, which can directly contact the active sites on MOFs, thereby shortening the electron transport distance and improving the transport efficiency of carriers; and (3) the exposed unsaturated metal sites in MOFs serving as active sites could promote the photocatalytic reaction. − Thus, various MOFs have been designed and synthesized to date by changing or modifying metal sites and organic ligands.…”

MnO2 Nanozyme-Mediated CRISPR-Cas12a System for the Detection of SARS-CoV-2

“…Nanozymes have been applied in many fields, including disease diagnosis, − cancer therapy, − pollutant degradation, − and biosensing. − They offer advantages of inexpensiveness, high stability under harsh conditions, and easy preparation. − Nanozyme-mediated colorimetric assays offer an attractive approach for point-of-care detection based on their operational simplicity and easy adaptability for microplate-based high-throughput assays. − Peroxidase-like nanozymes are commonly used for colorimetric assays. − Peroxidase-catalyzed oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) requires H 2 O 2 , which is unstable and corrosive . By contrast, oxidase-like nanozymes can oxidize TMB without H 2 O 2 , which makes the assay simpler and more convenient.…”