Adenosine triphosphate (ATP) is a critical intracellular energy currency that plays a key role in various cellular processes and is closely associated with numerous diseases. Similarly, biothiols such as glutathione (GSH), cysteine (Cys), and homocysteine (Hcy) are integral to many physiological and pathological processes due to their strong redox properties. Simultaneous discrimination and detection of ATP and biothiols offer valuable insights into the pathogenesis of conditions such as epilepsy and liver injury. This study introduces the first fluorescent probe, BCR, designed for multifunctional detection of ATP, GSH, Hcy, and Cys. With outstanding optical properties, excellent biocompatibility, high selectivity, and superior sensitivity, probe BCR enables effective imaging of ATP and biothiol dynamics in vivo. Moreover, probe BCR successfully visualizes changes in ATP, GSH, Hcy, and Cys levels in a PTZ-induced epileptic zebrafish model and an APAP-induced mouse liver injury tissue section model. These findings underscore the significant potential of probe BCR for early disease diagnosis and therapeutic applications.

Rapid and robust identification of bacteria is crucial for environmental monitoring and clinical diagnosis. Herein, a bioinspired interface-mediated multichannel sensor array was developed based on three-color-emitting antimicrobial functional carbon dots (FCDs) and concanavalin A doped polydopamine nanoparticles (ConA-PDA) for identification of bacteria. In this sensor, the fluorescence intensity of the three FCDs was quenched by the ConA-PDA. Upon addition different types of bacteria, the fluorescence intensity of the three FCDs was restored or further quenched. Recur to statistical analysis methods, it is employed to accurately discriminate 10 types of bacteria (including three probiotics and seven pathogenic bacteria) in natural water samples and human urine samples. The discrimination ability of the sensor array was highly enhanced via different competing binding of the FCDs and the bacteria toward ConA-PDA. The proposed array-based method offers a rapid, high-throughput, and reliable sensing platform for pathogen diagnosis in the field of environmental monitoring and clinical diagnosis.

Redox imbalance is a key factor in the pathogenesis of diseases such as epilepsy and liver injury. Superoxide anion (O 2 •− ), cysteine (Cys), and homocysteine (Hcy) play central roles in maintaining redox homeostasis, and their dysregulation drives oxidative stress and disease progression. Here, we report a multifunctional fluorescent probe, BPC, capable of simultaneously and selectively detecting Cys, Hcy, and O 2 •− in complex biological environments. BPC shows high sensitivity, selectivity, and biocompatibility, enabling real-time visualization of redox fluctuations in living cells and zebrafish with minimal cytotoxicity. In pentylenetetrazole (PTZ)– and acetaminophen (APAP)–induced models of epilepsy and liver injury, BPC revealed notable alterations in Cys, Hcy, and O 2 •− levels, providing mechanistic insights into redox dysregulation. Moreover, BPC successfully tracked redox restoration following N -acetylcysteine (NAC) treatment. These findings establish BPC as a versatile tool for redox biology and highlight its promise for diagnostic and therapeutic applications.

Lysosomal cysteine (Cys), glutathione (GSH), and homocysteine (Hcy) are vital biothiols essential for maintaining cellular redox homeostasis and regulating critical physiological functions. Aberrant levels of these biothiols are closely linked to various diseases. Understanding the dynamics of lysosomal biothiols is crucial for elucidating their physiological roles and involvement in disease progression. However, the simultaneous and selective detection of Cys, GSH, and Hcy in lysosomes remains challenging due to their structural similarities and dynamic behaviors. In this study, we developed Lyso-FP, a novel coumarin-based fluorescent probe tailored for lysosomal targeting and the simultaneous discrimination of Cys, GSH, and Hcy through three distinct emission channels. By integrating multiple binding sites with a lysosome-targeting moiety, Lyso-FP exhibits high specificity, sensitivity, and subcellular selectivity, enabling precise visualization of biothiol dynamics under oxidative and hyperosmotic stress conditions. Additionally, Lyso-FP was successfully employed for real-time monitoring of biothiol fluctuations in a zebrafish model of oxidative and hyperosmotic stress. This work introduces an innovative tool for studying lysosomal biothiol dynamics, offering critical insights into lysosome-associated processes and their roles in cellular physiology and pathology. Moreover, it presents a promising strategy for diagnosing and investigating lysosome-associated diseases, paving the way for future biomedical and therapeutic advancements.

Single-atom nanozymes (SANzymes) with multi-mimetic activities capable of altering the cellular redox balance demonstrate significant potential in tumor therapy. However, the catalytic treatment provided by SANzymes alone is insufficient to achieve optimal outcomes. Therefore, the combination of nanozyme catalysis with drug therapy is considered a promising alternative. Nonetheless, the leakage of drug molecules is a primary cause of chemotherapy resistance in cancer treatment. Consequently, developing novel drug immobilization methods to attach them to SANzymes is expected to enable multimodal synergistic therapy. Herein, a multifunctional nanoplatform is designed by modifying bioinspired PDA on iron-based SANzyme (Fe SANzyme) and immobilizing doxorubicin (DOX) through Michael addition/Schiff base reaction, which greatly promotes the drug loading efficiency. The Fe SAN-PDA@DOX@HA displays controllable drugs release behavior in the tumor microenvironment (TME), where the Fe SAN-PDA nanozyme can catalyze high level of H2O2 to produce oxygen to alleviate hypoxia, convert H2O2 to the toxic reactive oxygen species (ROS), and deplete intracellular glutathione via the catalase (CAT), peroxidase (POD), and glutathione oxidase (GSHOx)-like activities, respectively. The high drug loading, exceptional nanozyme catalysis, combined with the good photothermal performance of Fe SAN-PDA, resulted in sustained chemodynamic/photothermal/chemotherapy in a mouse mammary carcinoma model. The results reveal the synergistic antitumor potential of the novel conjugation of DOX on Fe SANzyme via PDA, offering a strategy for drug immobilization, TME remodeling and synergistic multimodal therapy.

Acute kidney injury (AKI) is a critical clinical condition characterized by the rapid loss of renal function, requiring timely detection and intervention. Hydrogen sulfide (H2S) and homocysteine (Hcy) have been identified as key biomarkers in AKI, yet their dynamic interplay and coordinated regulation remain elusive. Herein, we report a bifunctional fluorescent probe (Probe 1), based on coumarin derivatives, capable of real-time, simultaneous imaging of H2S and Hcy in distinct fluorescence channels with high sensitivity, selectivity, and rapid response. Probe 1 enables the concurrent detection of H2S and Hcy and was successfully applied to visualize both endogenous and exogenous levels in living cells. Notably, this probe achieved the first dual-channel imaging of H2S and Hcy fluctuations in cisplatin-induced AKI models, both in vitro and in vivo. Furthermore, it was employed to evaluate therapeutic responses to AKI-related drug treatments, demonstrating its value for dynamic monitoring of disease progression and intervention efficacy. This study presents the first chemical tool for investigating the synergistic roles of H2S and Hcy in AKI, offering new insights into sulfur-based signaling pathways and providing a promising platform for early diagnosis and therapeutic evaluation in AKI.

The early diagnosis of diseases largely relies on the monitoring and accurate detection of biomarkers within biological systems. The quantification of chloride ions (Cl-) and glutathione (GSH) can effectively assess the progression of diseases such as cystic fibrosis and cancer, as well as the alterations in the body's internal environment. However, developing reliable sensing platforms with high sensitivity and selectivity poses significant challenges. Based on the dual-functional silver-based metal-organic frameworks (Ag MOF), an electrochemical/electrochemiluminescent (EC/ECL) dual-channel nanoplatform was developed for the detection of Cl- and GSH, aided by graphitic carbon nitride (g-C3N4). In the EC mode, the interaction between Ag MOF and Cl- leads to the formation of silver chloride (AgCl), which is characterized by an increased peak current of AgCl solid-state electrochemistry as Cl- concentration rises. The further introduction of GSH generates a non-electroactive complex through competition with Cl-, resulting in a decrease in the peak current of AgCl. In the ECL mode, the quenching of ECL signals from g-C3N4 by Ag MOF is alleviated by Cl-, due to the etching of the Ag-MOF. The ECL recovery effect is further enhanced with the addition of GSH. For Cl-, both EC and ECL responses exhibit good linear relationships with concentrations ranging from 0.5 to 10 mM, with detection limit (LOD) of 0.4 mM and 0.1 mM, respectively. For GSH, EC and ECL also show good linear relationships in range of 0.01-100 μM, with LOD of 9.8 nM and 1.02 nM. The unique properties of Ag MOF, acting both as an electrochemical sensing component that generates sensitive current outputs for Cl- and GSH, and as a quencher for the ECL of g-C3N4, facilitate the sequential detection of Cl- and GSH, providing mutual validation that significantly enhances accuracy and reliability. The specific interactions of Ag MOF with these analytes offer the innovative platform good selectivity, demonstrating significant potential for advancements in biological analysis and disease diagnosis.

Diabetes is a complex metabolic disorder characterized by persistent hyperglycemia, which causes damage to multiple target organs and triggers a range of complications. Oxidative stress, driven by reactive oxygen species (ROS) such as hypochlorite (HClO) and hydrogen peroxide (H2O2), plays a crucial role in the onset and progression of diabetes and its associated complications. Therefore, the simultaneous and differential detection of HClO, H2O2, and their mixture is essential for accurately assessing oxidative stress status and understanding their synergistic roles in disease progression. In this study, we present a triple-signal fluorescent probe, probe 1, designed to simultaneously and selectively detect HClO, H2O2, and their combination with high specificity and sensitivity. The probe emits three distinct fluorescence signals, enabling precise real-time visualization of oxidative stress dynamics in complex biological systems. Probe 1 has been successfully applied to track both exogenous and endogenous levels of HClO and H2O2 in living cells and zebrafish models. Furthermore, its efficacy has been demonstrated in diabetic mouse models, where it facilitates the spatial and temporal monitoring of oxidative stress across different organs. These findings underscore the potential of probe 1 as a powerful tool for advancing the understanding of oxidative stress mechanisms and developing targeted therapeutic strategies for diabetes and related diseases.

The emergence of various nanozymes has revolutionized approaches to detecting total antioxidant capacity (TAC) in food and biological samples; however, the precise quantification of specific antioxidant species such as ascorbic acid (AA) and glutathione (GSH) continue to present significant challenges. Inspired by the functional characteristics of oxidoreductases, we have developed Cu-CeO2 nanoparticles adorned PCN-224, which exhibit multiple mimetic behaviors, including oxidase (OXD), ascorbate oxidase (AAO), and glutathione peroxidase (GPx)-like activities. This innovative PCN-224@Cu-CeO2 is designed for the quantitative evaluation of TAC in food, pharmaceuticals, and biological samples. Simultaneously, it enables the accurate determination of AA and GSH levels with favorable selectivity. The integration of nanozymes onto metal-organic frameworks significantly enhances both stability and catalytic efficiency. Furthermore, utilizing the multi-mimetics activity of the same materials simplifies the biosensing processes for TAC and individual antioxidants in tablets, beverages, fruits, and cells, thereby considerably diminishing experimental intricacy. Our findings not only advance the development and applications of novel nanozymes with exceptional multi-mimetic properties but also tackle selectivity challenges associated with colorimetric detection platforms that rely on oxidase and peroxidase activities.

The ability to perform simultaneous fluorescence imaging of multiple targets is essential, providing crucial multi-parametric information necessary for understanding complex biological interactions and processes. In this study, TBC, a novel multi-signal fluorescent probe is presented, crafted for simultaneous differentiation and in situ real-time monitoring of homocysteine (Hcy), cysteine (Cys), sulfur dioxide (SO2), and glutathione (GSH), illuminating the dynamic metabolic status of endogenous reactive sulfur species. TBC achieves an ultrahigh signal-to-background ratio, enabling wash-free direct fluorescence imaging of the dynamics and distribution of these entities in living cells and zebrafish. Notably, TBC has revealed distinctive dynamic metabolic features of Hcy/Cys/SO2/GSH during apoptosis and ferroptosis. This innovative probe acts as a key tool for unraveling the conversion networks of multiple reactive sulfur species and assessing the impact of metabolic oscillations during programmed cell death and the progression of diverse diseases, effectively uncovering concurrent biochemical dynamics in various biological settings and cell death events.

Laccase, known as the "green catalyst", holds significant promise for applications in the textile industry and pollutant detection. However, the use of natural laccase is constrained by challenges associated with complex preparation and inherent instability. The emergence of nanozymes provides a pathway for developing laccase-like mimics. This study focuses on the synthesis of copper-manganese oxide (Cu-doped Mn3O4) nanoparticles, which demonstrate significant laccase-like activity through the oxidation coupling reaction between 2,4-dichlorophenol (2,4-DCP) and 4-aminoantipyrine (4-AAP) with observable colorimetric change and an obvious absorption peak at 505 nm. Different copper-manganese oxides were synthesized by varying the proportion of metal salts during the synthesis process. A series of studies have demonstrated that copper doping enhances laccase catalytic activity by increasing the oxygen vacancy. Moreover, the introduction of formaldehyde (FA) results in a decrease of the peak at 505 nm, which is attributed to a condensation reaction between the aldehyde and amino groups under neutral conditions. Based on the laccase-like properties of Cu-doped Mn3O4, FA detection is achievable within the range of 100 nM to 100 μM, with a low detection limit of 39.4 nM. This research not only presents a novel laccase mimic with a simple synthesis route but also establishes a colorimetric method for FA detection, representing significant progress in food safety applications.

Rapid and accurate diagnosis of oral cancer aggressiveness is associated with preoperative guidance and postoperative treatment. However, traditional diagnostic methods are time-consuming and easily misdiagnosed, which makes it challenging to achieve high-precision classification. Herein, we introduce a recognition engineering-mediated multichannel nanosensor for the analysis of tumor metabolites, allowing for sensitive and rapid in vitro and intraoperative cancer malignancy discrimination. This nanosensor system utilizes engineered carbon dots (CDs) with various ratios of amino and carboxyl functional groups, assembled as a “shell” on gold nanoparticles (AuNPs). The multichannel nanosensor displayed distinct fingerprint patterns for fourteen tumor metabolites such as amino acids, nucleic acids, and other metabolites. It offers rapid “turn-on” fluorescence-encoded profiling, generating unique signatures for cancer malignancy within 15 min. The nanosensor demonstrated 100

The integration of reactive oxygen species (ROS) related photodynamic therapy (PDT) with the strategy of reshaping the tumor microenvironment (TME) has emerged as a potential approach for nanodiagnostic and therapeutic interventions. However, the therapeutic efficacy based on ROS treatments may be hindered by intracellular antioxidants such as glutathione (GSH) and tumor hypoxia. To address these challenges, a nano- platform based on GSH-responsive multifunctional porphyrinic metal-organic framework (PCN-224@Au@MnO2@HA, PAMH) was proposed. It was developed through a layer-by-layer in-situ growth method. This method avoids the need for high-temperature calcination and complex modification processes while improving the stability of PCN-224 in a phosphate-rich environment. GSH depletion leads to oxidation-reduction imbalance in TME. With the inactivation of GSH peroxidase 4 (GPX4), the content of hydrogen peroxide (H2O2) increases, ultimately triggering lipid peroxidation (LPO) and promoting ferroptosis. The catalase-like activity of Au nanozymes facilitates the generation of oxygen (O2), thereby mitigating tumor hypoxia and downregulating hypoxia-inducing factors (HIF-1 alpha). Due to the presence of porphyrin ligands in PCN-224, the generated O2 can be further converted to toxic singlet oxygen (1O2) under laser irradiation. Additionally, the platform allows near- infrared (NIR) fluorescence imaging, providing real-time information on intracellular GSH changes during PDT and ferroptosis. The PAMH nanoplatform has shown effective inhibition of tumor growth in subcutaneous models via both intravenous and intratumoral injection, indicating its potential in modulating reactive oxygen/ sulfur species and reshaping TME, thereby facilitating imaging-guided cascaded nanocatalytic therapy.

The gut microbiota and the associated metabolism play a pivotal role in maintaining human health, yet their assessment is challenging due to their inherent diversity, variety, and complexity. Herein, we developed a multichannel sensor array based on a single fluorescent probe, allowing for rapid and robust profiling gut microbiota and their key metabolites including cysteine (Cys), glutathione (GSH), and homocysteine (Hcy). The assay leverages the single fluorescent probe that is with multiple binding sites and the cross-reactive sensing principle to specifically recognize different biological thiols. By analyzing the pattern of biological thiols, the assay is capable of rapidly identifying six gut-derived bacteria including probiotics, neutral, and pathogenic strains based on fluorescent fingerprints within 5 min, and also discriminating bacteria and their mixtures with different composition. Using the assay that enables the simultaneous measurement of multiple gut-derived bacteria and their metabolites, the designed array achieved an accuracy of 0.99 when discriminating colorectal cancer (CRC) patient feces samples from healthy individuals. Remarkably, the as-prepared sensor array can also be used to identify various stages of CRC. The simplicity, rapidness, and cost-effectiveness of our approach render it a robust platform for the analysis of gut microbiota.

Reducing substances play crucial roles in various physiological processes and serve as essential components in the antioxidant defense mechanisms within organisms. Nonetheless, accurately detecting and distinguishing between these substances present a notable challenge due to the presence of potential interferences in complex samples. In response to this challenge, a novel multisignal sensing platform and sensor array have been developed, leveraging fluorescent polydopamine nanoparticles (FPDA) and MnO2 nanozyme. The MnO2/FPDA nanoplatform possesses exceptional catalytic activity and the ability to modulate ratiometric fluorescence in the presence of o-phenylenediamine (OPD), offering a platform with dual-channel output signals in ratiometric fluorescence and UV absorbance. Upon introduction of H2O2, the MnO2 undergoes transformation into Mn2+, thereby reducing the oxidase-like activity of MnO2 and reinstating the fluorescence of FPDA. Notably, this platform exhibits detection ranges for H2O2 from 5 to 500 and 15 to 500 mu M, with corresponding detection limits of 3.18 and 10.67 mu M using fluorescence and colorimetric channels, respectively. This setup has been deployed for quantifying H2O2 in milk and cell lysates, showcasing its versatility as a universal analysis tool for other reducing agents like ascorbic acid. Furthermore, a sensor array has been developed based on MnO2/FPDA/OPD, demonstrating a robust capacity to effectively differentiate and identify five reducing agents effectively. This sensor array also exhibits strong performance in discriminating reducing substances within intricate or authentic samples, such as oranges and cell lysates, underscores its practical utility. This study offers significant insights into the development of sensing platforms for the selectively detecting specific reducing species in real samples or deploying sensor arrays for distinguishing multiple components within authentic samples. Such advancements pave the way for enhanced analysis and screening of reducing substances in cellular and food samples.

The variation in tumor microenvironment, specifically the levels of cellular H2O2/O2/GSH, plays a crucial role in the effectiveness of cancer therapy in nanozyme-drug systems. In this study, bioinspired polydopamine was utilized to surface engineer the rhombic dodecahedron morphology iron-based SANzyme (Fe SANzyme), which exhibited multiple mimetic activities including oxidase (OXD)-like, peroxidase (POD)-like, catalase (CAT)-like, and glutathione peroxidase (GPx)-like activities. The Fe SAN-PDA was intricately designed as a nanoplatform for drug immobilization, remodeling the tumor microenvironment (TME) and enabling synergistic multimodal tumor therapy. The presence of abundant quinone structures on PDA surface facilitated the creation of a conductive microenvironment for the immobilization of doxorubicin (DOX) through Michael addition/Schiff base reaction. The Fe SAN-PDA@DOX can catalyze high level of H2O2 in TME to produce oxygen and alleviate hypoxia, convert the produced oxygen to the toxic ·OH, and deplete intracellular glutathione. Coating with hyaluronic acid (HA) enhanced the biocompatibility and targeting ability of the composite. The exceptional photothermal performance of Fe SAN-PDA@DOX@HA, combined with the nanozyme catalysis, resulted in sustained chemodynamic/photothermal/ chemotherapy is achieved in a mouse mammary carcinoma model. This research highlights the synergistic therapeutic effects resulting from the combination of the multi-enzymatic activities of Fe SAN with multifunctional PDA, offering a novel a novel strategy for doxorubicin immobilization, tumor microenvironment remodeling and synergistic multimodal therapy.

The simultaneous or continuous detection of multiple targets in complex samples is for various applications, notably in medical diagnostics and environmental monitoring. A novel dual-channel colorimetric and fluorescent method has been developed for the continuous detection of adenosine triphosphate (ATP) and copper ions based on PCN-224@Fe2O3, which exhibits both fluorescent and enhanced peroxidase-like (POD-like) properties. The synthesis of PCN-224@Fe2O3 involved the in-situ growth of ferric oxide on Zr-based metal-organic frameworks (PCN-224). Through catalyzing the colorless compound 3,3 ',5,5 '-tetramethylbenzidine (TMB) to produce a blue product (oxTMB) in the presence of H2O2, PCN-224@Fe2O3 allows for the detection of ATP and copper ions. The unique mechanism involves ATP weakening the POD-like activity of PCN-224@Fe2O3 by forming Zr-O-P bonds with Zr in PCN-224, which also leads to fluorescence recovery. Copper ions, through chelating with ATP, counteract the effect of ATP on PCN-224@Fe2O3, resulting in increased POD-like activity and the amount of oxTMB alongside the quenching of the fluorescence of the system. This facilitates colorimetric "on-off-on" and fluorescence "off-on-off" switch sensing for ATP and Cu2+. The application of PCN-224@Fe2O3 in the detection of ATP and Cu2+ in human serum yielded satisfactory results. This innovative approach not only provides a means to regulate the mimic activity of oxides but also presents a convenient, sensitive, and accurate detection method for ATP and Cu2+, significantly broadening the potential application of MOFs and nanozymes in bioanalysis.

Cerebral ischemia-reperfusion injury (CIRI), a cause of cerebral dysfunction during cerebral infarction treatment, is closely associated with mitochondrial viscosity and hydrogen peroxide (H2O2). However, the accurate measurement of mitochondrial viscosity and H2O2 levels in CIRI is challenging because of the lack of sufficient selectivity and blood-brain barrier (BBB) penetration of existing monitoring tools related to CIRI, hampering the exploration of the role of mitochondrial viscosity and H2O2 in CIRI. To address this issue, we designed an activatable fluorescent probe, mitochondria-targeting styryl-quinolin-ium (Mito-IQS), with excellent properties including high selectivity, mitochondrial targeting, and BBB penetration, for the visualization of mitochondrial viscosity and H2O2 in the brain. Based on the real-time monitoring capabilities of the probe, bursts of mitochondrial viscosity and H2O2 levels were visualized during CIRI. This probe can be used to monitor the therapeutic effects of butylphthalein treatment. More importantly, in vivo experiments further confirmed that CIRI was closely associated with the mitochondrial viscosity and H2O2 levels. This discovery provides new insights and tools for the study of CIRI and is expected to accelerate the process of CIRI diagnosis, treatment, and drug design.

As an emerging electrochemiluminescence (ECL) nanomaterial, graphitic carbon nitride (g-C3N4) has attracted considerable attention from the scientific community due to its excellent optical properties, favorable biocompatibility, and tunable bandgap structure. However, the ECL intensity of g-C3N4 is subject to various influencing factors, including conductivity and electrode passivation, which pose notable challenges in improving its ECL performance. In this study, iron single atom nanocatalysts (Fe SAC) were introduced onto g-C3N4 sheets, and a novel approach was proposed to enhance the active sites, modulate the bandgap, and bolster the conductivity through synergistic mechanism. Furthermore, Fe SAC acted as the co-reactant promoter, amplifying the ECL signal significantly. Comparative analysis revealed a visible improvement in the ECL performance of Fe SAC-gC3N4/K2S2O8 in a potential range of 0 to -0.9 V. Via the electron transfer strategy, a copper ion-sensitive ECL sensor based on Fe SAC-g-C3N4 was developed with the linear range of 0.01-100 mu M and a detection limit of 0.75 nM. This sensor has been successfully applied in detecting copper ions in water environment and human serum samples, providing a new strategy for enhancing the ECL performance of g-C3N4 and expanding the utility of Fe SAC in ECL.

The development of efficient, accurate, and high-throughput technology for gut microbiota sensing holds great promise in the maintenance of health and the treatment of diseases. Herein, we developed a rapid fluorescent sensor array based on surface-engineered silver nanoparticles (AgNPs) and vancomycin-modified gold nanoclusters (AuNCs@Van) for gut microbiota sensing. By controlling the surface of AgNPs, the recognition ability of the sensor can be effectively improved. The sensor array was used to successfully discriminate six gut-derived bacteria, including probiotics, neutral, and pathogenic bacteria and even their mixtures. Significantly, the sensing system has also been successfully applied to classify healthy individuals and colorectal cancer (CRC) patients rapidly and accurately within 30 min, demonstrating its clinically relevant specificity.