Development of "smart" noninvasive bioimaging probes for trapping specific enzyme activities is highly desirable for cancer therapy in vivo. Given that β-galactosidase (β-gal) is an important biomarker for cell senescence and primary ovarian cancers, we design an enzyme-activatable ratiometric near-infrared (NIR) probe (DCM-βgal) for the real-time fluorescent quantification and trapping of β-gal activity in vivo and in situ. DCM-βgal manifests significantly ratiometric and turn-on NIR fluorescent signals simultaneously in response to β-gal concentration, which makes it favorable for monitoring dynamic β-gal activity in vivo with self-calibration in fluorescent mode. We exemplify DCM-βgal for the ratiometric tracking of endogenously overexpressed β-gal distribution in living 293T cells via the lacZ gene transfection method and OVCAR-3 cells, and further realize real-time in vivo bioimaging of β-gal activity in colorectal tumor-bearing nude mice. Advantages of our system include light-up ratiometric NIR fluorescence with large Stokes shift, high photostability, and pH independency under the physiological range, allowing for the in vivo real-time evaluation of β-gal activity at the tumor site with high-resolution three-dimensional bioimaging for the first time. Our work provides a potential tool for in vivo real-time tracking enzyme activity in preclinical applications.

Solar-driven reduction of CO , which converts inexhaustible solar energy into value-added fuels, has been recognized as a promising sustainable energy conversion technology. However, the overall conversion efficiency is significantly limited by the inefficient charge separation and sluggish interfacial reaction dynamics, which resulted from a lack of sufficient active sites. Herein, Bi O Cl superfine nanotubes with a bilayer thickness of the tube wall are designed to achieve structural distortion for the creation of surface oxygen defects, thus accelerating the carrier migration and facilitating CO activation. Without cocatalyst and sacrificing reagent, Bi O Cl nanotubes deliver high selectivity CO evolution rate of 48.6 μmol g h in water (16.8 times than of bulk Bi O Cl ), while maintaining stability even after 12 h of testing. This paves the way to design efficient photocatalysts with collaborative optimizing charge separation and CO activation towards CO photoreduction.

High‐entropy oxides (HEOs), a new concept of entropy stabilization, exhibit unique structures and fascinating properties, and are thus important class of materials with significant technological potential. However, the conventional high‐temperature synthesis techniques tend to afford micron‐scale HEOs with low surface area, and the catalytic activity of available HEOs is still far from satisfactory because of their limited exposed active sites and poor intrinsic activity. Here we report a low‐temperature plasma strategy for preparing defect‐rich HEOs nanosheets with high surface area, and for the first time employ them for 5‐hydroxymethylfurfural (HMF) electrooxidation. Owing to the nanosheets structure, abundant oxygen vacancies, and high surface area, the quinary (FeCrCoNiCu)3O4 nanosheets deliver improved activity for HMF oxidation with lower onset potential and faster kinetics, outperforming that of HEOs prepared by high‐temperature method. Our method opens new opportunities for synthesizing nanostructured HEOs with great potential applications.

Development of fluorescent probes for on-site sensing and long-term tracking of specific biomarkers is particularly desirable for the early detection of diseases. However, available small-molecule probes tend to facilely diffuse across the cell membrane or remain at the activation site but always suffer from the aggregation-caused quenching (ACQ) effect. Here we report an enzyme-activatable aggregationinduced emission (AIE) probe QM-bgal, which is composed of a hydrophilic b-galactosidase (b-gal)triggered galactose moiety and a hydrophobic AIE-active fluorophore QM-OH. The probe is virtually non-emissive in aqueous media, but when activated by b-gal, specific enzymatic turnover would liberate hydrophobic AIE luminogen (AIEgen) QM-OH, and then highly fluorescent nanoaggregates are in situ generated as a result of the AIE process, allowing for on-site sensing of endogenous b-gal activity in living cells. Notably, taking advantage of the improved intracellular retention of nanoaggregates, we further exemplify QM-bgal for long-term ($12 h) visualization of b-gal-overexpressing ovarian cancer cells with high fidelity, which is essential for biomedicine and diagnostics. Thus, this enzyme-activatable AIE probe not only is a potent tool for elucidating the roles of b-gal in biological systems, but also offers an enzyme-regulated liberation strategy to exploit multifunctional probes for preclinical applications.Scheme 1 Schematic illustration of an enzyme-regulated liberation strategy for on-site sensing and long-term tracking.Scheme 2 Enzyme-activatable probes for b-gal activity sensing.This journal is

Defects have been engineering on the atomically-thin BiOCl nanosheets to tune the electronic structure, build abundant coordination-unsaturated active atoms with dangling bonds acts as active sites and shortens the migration distance of holes to promote holes utilization.

Leucine aminopeptidase (LAP), one of the important proteolytic enzymes, is intertwined with the progress of many pathological disorders as a well-defined biomarker. To explore fluorescent aminopeptidase probe for quantitative detection of LAP distribution and dynamic changes, herein we report a LAP-targeting near-infrared (NIR) fluorescent probe (DCM-Leu) for ratiometric quantitative trapping of LAP activity in different kinds of living cells. DCM-Leu is composed of a NIR-emitting fluorophore (DCM) as a reporter and l-leucine as a triggered moiety, which are linked together by an amide bond specific for LAP cleavage. High contrast on the ratiometric NIR fluorescence signal can be achieved in response to LAP activity, thus enabling quantification of endogenous LAP with "build-in calibration" as well as minimal background interference. Its ratiometric NIR signal can be blocked in a dose-dependent manner by bestatin, an LAP inhibitor, indicating that the alteration of endogenous LAP activity results in these obviously fluorescent signal responses. It is worth noting that DCM-Leu features striking characteristics such as a large Stokes shift (∼205 nm), superior selectivity, and strong photostability responding to LAP. Impressively, not only did we successfully exemplify DCM-Leu in situ ratiometric trapping and quantification of endogenous LAP activity in various types of living cells, but also, with the aid of three-dimensional confocal imaging, the intracellular LAP distribution is clearly observed from different perspectives for the first time, owing to the high signal-to-noise of ratiometric NIR fluorescent response. Collectively, these results demonstrate preclinical potential value of DCM-Leu serving as a useful NIR fluorescent probe for early detection of LAP-associated disease and screening inhibitor.

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Integrating biomass upgrading and hydrogen production in an electrocatalytic system is attractive both environmentally and in terms of sustainability. Conventional electrolyser systems coupling anodic biosubstrate electrooxidation with hydrogen evolution reaction usually require electricity input. Herein, we describe the development of an electrocatalytic system for simultaneous biomass upgrading, hydrogen production, and electricity generation. In contrast to conventional furfural electrooxidation, the employed lowpotential furfural oxidation enabled the hydrogen atom of the aldehyde group to be released as gaseous hydrogen at the anode at a low potential of approximately 0 V RHE (vs. RHE). The integrated electrocatalytic system could generate electricity of about 2 kWh per cubic meter of hydrogen produced. This study may provide a transformative technology to convert electrocatalytic biomass upgrading and hydrogen production from a process requiring electricity input into a process to generate electricity.