No abstract

High‐entropy alloys nanoparticles (HEANPs) are receiving extensive attention due to their broad compositional tunability and unlimited potential in bioapplication. However, developing new methods to prepare ultra‐small high‐entropy alloy nanoparticles (US‐HEANPs) faces severe challenges owing to their intrinsic thermodynamic instability. Furthermore, there are few reports on studying the effect of HEANPs in tumor therapy. Herein, the fabricated PtPdRuRhIr US‐HEANPs act as bifunctional nanoplatforms for the highly efficient treatment of tumors. The US‐HEANPs are engineered by the universal metal‐ligand cross‐linking strategy. This simple and scalable strategy is based on the aldol condensation of organometallics to form the target US‐HEANPs. The synthesized US‐HEANPs exhibit excellent peroxidase‐like (POD‐like) activity and can catalyze the endogenous hydrogen peroxide to produce highly toxic hydroxyl radicals. Furthermore, the US‐HEANPs possess a high photothermal conversion effect for converting 808 nm near‐infrared light into heat energy. In vivo and in vitro experiments demonstrated that under the synergistic effect of POD‐like activity and photothermal action, the US‐HEANPs can effectively ablate cancer cells and treat tumors. It is believed that this work not only provides a new perspective for the fabrication of HEANPs, but also opens the high‐entropy nanozymes research direction and their biomedical application.

The localized surface plasmon resonance (LSPR) property, depending on the structure (morphology and assembly) of nanoparticles, is very sensitive to the environmental fluctuation. Retaining the colorimetric effect derived from the LSPR property while introducing new optical properties (such as fluorescence) that provide supplementary information is an effective means to improve the controllability in structures and reproducibility in optical properties. DNA as a green and low-cost etching agent has been demonstrated to effectively control the morphology and optical properties (the blue shift of the LSPR peak) of the plasmonic nanoparticles. Herein, taking silver nanotriangles (AgNTs) as a proof of concept, we report a novel strategy to induce precisely tunable LSPR and fluorescence-composited dual-mode signals by using mono-DNA first as an etching agent for etching the morphology of AgNTs and later as a template for synthesizing fluorescent silver nanoclusters (AgNCs). In addition, common templates for synthesizing AgNCs, such as L-glutathione and bovine serum albumin, were demonstrated to have the capability to serve as etching agents. More importantly, these biomolecules as dualfunctional capping agents (etching agents and templates) follow the size-dependent rule: as the size of the thiolated biomolecule increases, the blue shift of the LSPR peak increases; at the same time, the fluorescence intensity increases. The enzyme that can change the molecular weight (size) of the biomolecular substrates (DNA, peptides, and proteins) through an enzymatic cleavage reaction was explored to regulate the LSPR and fluorescent properties of the resulting nanoparticles (by etching of AgNTs and synthesis of AgNCs), achieving excellent performance in detection of cancer-related proteases. This study can be expanded to other biopolymers to impact both fundamental nanoscience and applications and provide powerful new tools for bioanalytical biosensors and nanomedicine.