Multistage pH/H2O2/redox-responsive 3D nanoflowers that fully exploit the tumor microenvironment achieve highly specific guided multimode diagnosis with excellent synergistic chemotherapy and photodynamic therapy effects both in vitro and in vivo.

Metal–organic frameworks (MOFs) are significant useful molecular materials as a result of their high surface area and flexible catalytic activities by tuning the metal centers and ligands. MOFs have attracted great attention as efficient nanozymes recently; however, it is still difficult to understand polymetallic MOFs for enzymatic catalysis because of their complicated structure and interactions. Herein, bimetallic NiFe2 MOF octahedra were well prepared and exhibited enhanced peroxidase-like activities. The synergistic effect of Fe and Ni atoms was systematically investigated by electrochemistry, X-ray photoelectron spectrometry, (XPS) and in situ Raman techniques. The electrons tend to transfer from Ni2+ to Fe3+ in NiFe2 MOFs, and the resulting Fe2+ is ready to decompose H2O2 and generate ·OH by a Fenton-like reaction. After integration with glucose oxidase (GOx), which can downgrade the pH value and generate H2O2 by oxidation of glucose, a self-activated cascade reagent is therefore established for efficiently inducing cell death. The changes of cell morphology, DNA, and protein are also successfully recorded during the cell death process by Raman spectroscopy and fluorescence imaging.

To achieve a highly efficient, dual‐state emission platform for picric acid (PA) detection and latent fingerprint (LFP) visualization, flexible alkyl chains have been facilely attached to the commercial organic dye 3,4,9,10‐perylenetetracarboxylic dianhydride to provide the target perylenetetracarboxylate molecules PTCA‐C4, PTCA‐C6, and PTCA‐C12. Interestingly, all these molecules exhibited impressive fluorescence characteristics with high photoluminescence quantum yields (PLQYs) of around 93.0 % in dilute solution. Also, emissive features were observed in the solid state because close molecular packing is prevented by the alkyl chains, especially for PTCA‐C6, which has a high PLQY value of 49.0 %. Benefiting from its impressive fluorescence performance in both solution and as aggregates, PTCA‐C6 was used as a dual‐state emission platform for PA detection and also LFP visualization. For example, double‐responsive fluorescence quenching in solution was observed in PA detection studies, resulting in high quenching constants (KSV) and also low limit‐of‐detection values. Furthermore, the fingerprint powder based on PTCA‐C6 also presented an impressive performance on various substrates in terms of fluorescence intensity and resolution, clearly providing the specific fine details of latent fingerprints. These results demonstrate that the facilely synthesized PTCA‐C6 with efficient dual‐state emission exhibits great potential in the real‐world applications of PA detection and LFP visualization.