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Fluorescent probes based on fluorescence resonance energy transfer (FRET) are highly promising for diverse bioapplications. The key to constructing FRET probes is to confine the donor and acceptor within a sufficiently close distance. However, the commonly used covalent linkage often requires elaborate design and complex organic synthesis, and sometimes causes changes in the fluorescence properties of the donor and acceptor. Inspired by the binding between small molecules and protein in nature, herein, we propose a protein‐mediated strategy to fabricate FRET probe. In such protein‐mediated FRET (P‐FRET) probe, protein acts as a carrier to simultaneously confine donor and acceptor in its cavity. As a proof of concept, we use bovine serum albumin (BSA) as a model protein, coumarin derivative as a donor and hydroxyl radical (·OH)‐responsive dye fluorescein as an acceptor. Through a series of investigations, including binding parameters, fluorescence properties and detection performance, we prove that the construction of P‐FRET probe is simple and feasible and the detection is sensitive. Our P‐FRET strategy will provide new insights for the design of FRET probes. [ABSTRACT FROM AUTHOR]

Fluorescent probes based on fluorescence resonance energy transfer (FRET) are highly promising for diverse bioapplications. The key to constructing FRET probes is to confine the donor and acceptor within a sufficiently close distance. However, the commonly used covalent linkage often requires elaborate design and complex organic synthesis, and sometimes causes changes in the fluorescence properties of the donor and acceptor. Inspired by the binding between small molecules and protein in nature, herein, we propose a protein‐mediated strategy to fabricate FRET probe. In such protein‐mediated FRET (P‐FRET) probe, protein acts as a carrier to simultaneously confine donor and acceptor in its cavity. As a proof of concept, we use bovine serum albumin (BSA) as a model protein, coumarin derivative as a donor and hydroxyl radical (·OH)‐responsive dye fluorescein as an acceptor. Through a series of investigations, including binding parameters, fluorescence properties and detection performance, we prove that the construction of P‐FRET probe is simple and feasible and the detection is sensitive. Our P‐FRET strategy will provide new insights for the design of FRET probes. [ABSTRACT FROM AUTHOR]

As one of the nanostructures with enzyme-like activity, nanozymes have recently attracted extensive attention for their biomedical applications, especially for bacterial disinfection treatment. Nanozymes with high peroxidase activity are considered to be excellent candidates for building bacterial disinfection systems (nanozyme-H2O2), in which the nanozyme will promote the generation of ROS to kill bacteria based on the decomposition of H2O2. According to this criterion, a cerium oxide nanoparticle (Nanoceria, CeO2, a classical nanozyme with high peroxidase activity)-based nanozyme-H2O2 system would be very efficient for bacterial disinfection. However, CeO2 is a nanozyme with multiple enzyme-like activities. In addition to high peroxidase activity, CeO2 nanozymes also possess high superoxide dismutase activity and antioxidant activity, which can act as a ROS scavenger. Considering the fact that CeO2 nanozymes have both the activity to promote ROS production and the opposite activity for ROS scavenging, it is worth exploring which activity will play the dominating role in the CeO2-H2O2 system, as well as whether it will protect bacteria or produce an antibacterial effect. In this work, we focused on this discussion to unveil the role of CeO2 in the CeO2-H2O2 system, so that it can provide valuable knowledge for the design of a nanozyme-H2O2-based antibacterial system. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are essential oxidative metabolites of organisms, which are closely related to physiological, pathological and pharmacological processes. The accurate detection of ROS/RNS is important for the understanding of biological processes, monitoring of pharmacological effects, and predicting the course of disease. The recently developed NIR nanoprobes based on upconversion nanoparticles (UCNPs) hold great prospects in sensitive and deep-tissue detection of ROS/RNS, and considerable progress has been achieved so far. In this review, we systematically summarize the up-to-date advances of UCNPs-based near-infrared (NIR) probes for ROS/RNS sensing, and the potential challenges and perspectives for further research are also highlighted. We envision that such a research field will have a bright future for modern biomedical applications., (© 2022 Wiley-VCH GmbH.)