In the sensing detection of heavy metal ions (HMIs), the design of probes with specific recognition sites enables the targeting of HMIs through various interactions, in which the coordination interactions exhibit superior selectivity and stability. Additionally, compared to small molecular probes, nanomaterial-based probes possess inherent structural stability, which offers better selectivity, sensitivity, and reliability for the determination of HMIs in complex matrices. Given these significant advantages, sensing strategies based on nanomaterials for HMIs detection, including lead (Pb), mercury (Hg), cadmium (Cd), arsenic (As), copper (Cu), iron (Fe), aluminum (Al), and chromium (Cr), have been extensively studied in recent years. This review focuses on summarizing (from 2020 to 2025) the mechanisms of optical and electrochemical signal changes, such as those in colorimetric, fluorescence, surface-enhanced Raman scattering (SERS), chemiluminescence (CL), and electrochemical responses, resulting from the coordination interactions between HMIs and nanomaterials via M−N, M−O, and M−S (M=metal) binding modes. Furthermore, the limitations and prospects of coordination interaction-guided sensing detection mechanisms are discussed. This review is expected to promote the development and application of nanomaterial-based probes designed for specific HMIs sensing detection based on coordination interactions.

This work presents a novel dual-mode sensing platform based on a hydrogen-bonded organic framework/covalent organic framework heterojunction (Namely HOF/COF) for tannic acid (TA) detection. The platform ingeniously integrates the fluorescence recognition capability of HOF with the photoresponsive nanozyme activity of COF. The HOF component introduces abundant hydrogen-bonding sites, enabling specific TA recognition and modulating fluorescence signal through synergistic mechanisms of dynamic quenching, photoinduced electron transfer (PET), and inner-filter effect (IFE). The COF component provides a stable porous framework and exhibits both photoresponsive oxidase-like and peroxidase-like activities, facilitating colorimetric detection. The formation of heterojunction induces significant interfacial synergy, which enhances both detection sensitivity and selectivity. The dual-mode output of fluorescence and colorimetry allows for mutual signal validation, thereby significantly improving the reliability of the assay. The developed sensor demonstrates good performance in the detection of TA in real Rosa roxburghii, teas, and environmental water samples, with good agreement to HPLC method.

Covalent organic frameworks (COFs), characterized by high specific surface area, tunable pore structures, and excellent stability, provide an ideal platform for developing high-performance ratiometric fluorescence sensors. By measuring the intensity ratio of two emission signals, these sensors offer built-in self-calibration, overcoming the limitations of single-signal probes affected by environmental interference, and thus improving sensitivity, selectivity, and reliability in detecting trace analytes in complex samples. This review systematically outlines construction strategies for dual-emission COF-based ratiometric sensors, such as intrinsic backbone dual-emission, doping-induced dual-emission, and hybrid/heterostructure-induced dual-emission. For each approach, advantages, limitations, and development directions are discussed. Key structural factors (e.g. topology, π–π stacking, donor–acceptor motifs, pore environment, and crystallinity) and their roles in integrating luminescent units are discussed to explain how they collectively influence dual-emission performance and stability. Common construction challenges and corresponding mitigation strategies are also summarized to enhance sensor reliability and efficiency. The review further elaborates on relevant sensing mechanisms, including excited-state intramolecular proton transfer (ESIPT) and Förster resonance energy transfer (FRET), as well as summarizes the interrelationships of construction strategy-response mode-sensing mechanism. Performance advantages and recent applications in environmental monitoring, food safety, and biomedical analysis are highlighted. Despite their promise, practical use of these sensors still faces challenges in signal controllability and environmental adaptability. Based on current limitations, this review suggests future directions: precise control and mechanistic study of dual-emission behavior, enhancing signal reliability in real samples and enabling device integration, and data-driven material design for performance optimization. Through collaborative advances, dual-emission COF-based sensors are expected to evolve into versatile detection platforms for environmental, clinical, and food safety applications, promoting the practical adoption of next-generation sensing technologies.

Acute kidney injury (AKI) represents a global health burden with high mortality and a substantial risk of progression to chronic kidney disease (CKD), underscoring the need for frequent renal function monitoring. Creatinine, the gold-standard endogenous biomarker for renal function, is limited by conventional assays that require complex sample pretreatment processes, precluding real-time point-of-care testing (POCT). Herein, a colorimetric microneedle (MN) platform was constructed using polyvinyl alcohol-chitosan-picric acid (PVA-CSPA) system for minimally invasive, visual POCT of creatinine in interstitial fluid (ISF). The MNs leverage hydrogen bonding and electrostatic interactions between PVA/CS and creatinine for efficient enrichment, followed by a Jaffe reaction between PA and creatinine to generate a colorimetric signal. This design integrates sampling, enrichment, and detection into a single device, with quantitative analysis enabled by a self-developed RGB program. The MNs demonstrated a robust linear response to creatinine (R2 = 0.9910). In AKI mice, ISF sampling via MNs yielded Delta R values of 18-19 at mouse abdomen, back, and head (corresponding to creatinine concentrations of 90.0-98.3 mu g & sdot;mL-1). Concurrently, the Delta R values for plasma and urine from AKI mice were 27 and 24, respectively, demonstrating the feasibility of semi-quantitative creatinine detection in these sample matrices. Notably, normal mice showed significantly lower Delta R values (ISF: 1, plasma: 7, urine: 20), enabling clear diagnosis of physiological states. The PVA-CS-PA MN platform, integrated with smartphone-based RGB analysis, offers a minimally invasive and user-friendly POCT tool for creatinine monitoring with potential for diagnosis and management of AKI and CKD.

The development of integrated technologies capable of simultaneously detecting and degrading pollutants symbolizes a transformational breakthrough in next-generation water treatment strategy, and overcomes the limitations of traditional single-function systems for monitoring and remediation. This study proposes an innovative sodium percarbonate (SPC)/alpha-MnO2/light strategy to establish a dual-functional platform capable of both photoelectrochemical (PEC) detection and advanced oxidation process (AOP) degradation, aiming to achieve precise detection and efficient removal of doxorubicin (DOX). The system strategically adjusts light sources (ultraviolet for detection, visible light for degradation), not only achieves high-sensitivity real-time detection (limit of detection: 0.40 ng center dot mL- 1, 10x lower than conventional methods) but also significantly improves degradation efficiency (37 %-38 % improvement over unitary components), resolving crucial limitation of traditional single-function technologies. The portable PEC platform integrates an alpha-MnO2-modified electrode, SPC-enhanced system, a portable electrochemical workstation and smartphone-based analytical software, which enables rapid on-site quantitative analysis of DOX. Meanwhile, SPC/alpha-MnO2/light system can synergistically generate multiple reactive oxygen species (ROS) including center dot OH, center dot O2- , 1O2 and center dot CO3- , achieve nearly complete mineralization of DOX and generate low-toxicity or even non-toxic byproducts. Mechanistic study reveals that oxygen vacancies and Mn2+/Mn3+/Mn4+ redox cycle in alpha-MnO2 (alpha-MN) jointly serve as core reaction centers, and synergistically interacts with H2O2/CO32- derived from SPC, not only driving efficient separation of photogenerated charge carriers in alpha-MN but also promoting the sustained generation of reactive free radicals. Notably, the system demonstrates excellent salt tolerance and broad pH adaptability in various actual water sources (tap, pond, and river water). Further, achieving 100 % removal of DOX (30 mg center dot L- 1) within 30 min under natural sunlight validates its practicality for solar-driven degradation. This work pioneers a "One-for-Two" strategy, which establishing a novel "detect-to-treat" environmental governance paradigm that provides a sustainable, scalable solution for addressing water pollution.

Novel carbon dots (CDs-1) were synthesized using Sanguisorba officinalis L., as a precursor and a deep eutectic solvent (DES) as both solvent and dopant. For comparison, CDs-2 were prepared under identical conditions but using water as solvent. Chemical analyses reveal that two CDs possess well-defined crystalline structures and are rich in diverse functional groups. Notably, DES-mediated synthesis endows CDs-1 with advantageous features compared to CDs-2, including higher N and Cl contents, enhanced hydrophilicity, and superior optical properties. To evaluate their potential biomedical applications, antioxidant capacities of them were investigated through in vitro and in vivo assays. Results demonstrated that both CDs exhibit potent free radical scavenging activity, strong KMnO4 reduction capability, and notable anti-cellular oxidative damage effects. Importantly, CDs-1 show superior performance in enhancing oxidative stress resistance at nematode level. Furthermore, owing to the exceptional optical characteristics, CDs-1 hold great promise for bioimaging applications and sensitive detection of 2,4,6-trinitrophenol (TNP).

Developing safe and sustainable antimicrobial strategies is critical for postharvest fruit preservation. In this work, corn silk, an abundant agri-food byproduct with a long history of food and medicinal use, was upcycled into fluorescent carbon dots (CS-CDs) via a green hydrothermal route (yield: 27.3%). The resulting CS-CDs were quasi-spherical (∼1.8 nm) and enriched with oxygen-/nitrogen-containing surface groups, exhibiting excitation-dependent blue-green photoluminescence (λ_em ≈ 492 nm at λ_ex = 414 nm). CS-CDs displayed broad-spectrum antibacterial activity against Pseudomonas fluorescens and Staphylococcus aureus, with higher potency against the Gram-negative strain. Mechanistic assays supported a multimodal bactericidal action involving rapid membrane permeabilization (live/dead staining, NPN uptake, and SEM evidence), cytoplasmic leakage, elevated intracellular ROS, and suppressed metabolic activity. CS-CDs also inhibited the postharvest fungal pathogen Penicillium expansum in vitro and reduced decay severity on plums and citrus fruits, as reflected by dose-dependent decreases in lesion area (mm2). When applied as a surface coating (≤1.0 mg/mL), CS-CDs extended the shelf life of jujubes and strawberries by mitigating weight loss and browning, and by lowering microbial loads (CFU/fruit) during storage. Importantly, a practical safety window was supported at functional concentrations, with low cytotoxicity in mammalian cells and no detectable adverse effects on the growth, locomotion, or reproduction of Caenorhabditis elegans. Overall, corn-silk-derived carbon dots provide a promising green antimicrobial platform for postharvest fruit preservation and offer a scalable strategy for valorizing agricultural residues.

This study introduces a highly crystalline yellow fluorescent covalent organic framework, COF-W, and its electrospun nanofiber membrane, COF-W-PP, for the simultaneous detection and adsorption of amphotericin B (AMB). COF-W was synthesized through Schiff-base condensation between 3,6-diaminocarbazole (DAC) and 2,5dimethoxyterephthalaldehyde (DMTP), forming a D-it-A structure that exhibits fluorescence via intramolecular charge transfer (ICT). Its porous framework and imine bonds enable specific AMB capture through hydrogen bonding and it-it interactions, which disrupts the ICT balance and results in fluorescence quenching and color changes, which is establishing a dual-mode fluorescence/colorimetric detection platform. The electrospun COFW-PP membrane, fabricated by incorporating COF-W into a PVP/PVDF polymer matrix on the non-fluorescence filter paper, enhances material stability and usability. COF-W demonstrates high selectivity for AMB, with a detection limit (LOD) of 0.02 & micro;M and a maximum adsorption capacity of 379.98 mg & sdot;g- 1. In real water and plasma samples, detection recoveries range from 79.38% to 114.39%, and adsorption efficiency exceeds 91%. COF-W-PP membrane shows a clear colorimetric response: color gradation intensifies with increasing AMB concentration, enabling rapid on-site detection when paired with smartphone analysis software. Mechanism studies indicate that recognition and quenching are synergistically driven by multiple hydrogen bonds, static quenching, photoinduced electron transfer (PET), and inner filter effect (IFE). Furthermore, COF-W displays good biocompatibility and low cytotoxicity, supporting its potential use in biological samples and in vivo analysis.

The growing interest in natural medicines highlights the need for rapid and accurate analytical methods to identify bioactive compounds. Conventional techniques such as high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance are precise but limited by time, cost, and complexity, restricting their use in high-throughput screening. Biosensor technologies offer real-time, label-free, and highly sensitive detection, emerging as powerful alternatives. This review summarizes recent advances in optical, electrochemical, and microfluidic-integrated biosensors, along with their applications in screening antiviral, anti-inflammatory, anticancer, neuroprotective, and nucleic acid-targeting compounds. Key challenges, including matrix interference, specificity, sensitivity, throughput, and standardization, are discussed. Future directions focus on enhancing sensor performance through surface modifications, improved sample processing, multiplexing, and artificial intelligence-assisted data integration. These strategies aim to fully realize the potential of biosensors in accelerating the discovery of novel and effective therapeutic agents from natural sources.

The persistent presence of refractory organic pollutants in aquatic ecosystems remains a global challenge, owing to their structural stability, bioaccumulation potential, and the toxicity of their transformation products. To address this issue, a hierarchical multilevel synergistic system (denoted as the ZP system) is constructed based on simple single-component ZnS coupled with peroxymonosulfate (PMS) for the efficient degradation of direct black G (DBG). This system integrates three synergistic mechanisms: piezoelectricity-photocatalysis-defect engineering synergy, catalyst-PMS activation synergy, and adsorption-degradation synergy. The cooperative process involves: (i) synergistic separation of photogenerated charges through the piezo-photocatalytic effect and sulfur vacancies (VS) in ZnS; (ii) amplification via a ZnS-VS-PMS interaction, where continuous electron consumption establishes a self-sustaining "excitation-depletion-re-excitation" cycle; and (iii) an adsorption-degradation cycle that enriches pollutants near active sites and regenerates adsorption sites during degradation. ZP system maintains high removal efficiency (>85 %) over a broad pH range (2-8). Moreover, ZP system achieves complete DBG removal within 20 min in various real water matrices (pond, tap, and river water) under the Xenon lamp irradiation, and exhibits a great application potential under natural sunlight and simulated flowing water. Compared with the original DBG, the toxicity of degradation products was significantly reduced, with the cell viability of 96.8 %. Radical trapping experiments and electron paramagnetic resonance spectroscopy identify h+, center dot SO4- , center dot OH, and center dot O-2- as the dominant reactive species. Moreover, the ZP system exhibits excellent biocompatibility with negligible hemolysis, underscoring its environmental friendliness. This work highlights the promise of a simple singlematerial-based multilevel synergy as a scalable, cost-effective, and adaptable strategy for sustainable water purification.

A MXene-based molecularly imprinted polymer (MXMIP) composite was developed for the enrichment and detection of puerarin and its metabolites in complex biological samples. As an ideal substrate material, MXene can make the recognition sites within the MIP matrix more easily exposed compared to conventional MIP. Through the operation of the "dual screening" mechanism, MXMIP combines interaction enhancement with molecular recognition, significantly enhancing the adsorption capacity and efficiency of this material. The successful synthesis of the composite was confirmed by comprehensive characterization of structure and properties. MXMIP achieved a maximum adsorption capacity of 3.70 mg∙g-1, higher than conventional MIP (2.24 mg∙g-1) and MXene alone (1.74 mg∙g-1). The adsorption capacity of MXMIP was 1.65 times that of conventional MIP and 2.12 times that of MXene. In selective adsorption experiments, MXMIP shows excellent specificity toward puerarin, with selectivity factors ranging from 1.33 to 10.4 relative to structural analogs, and achieved an imprinting factor of 6.46. The hydrogen bonding interactions between MXMIP and puerarin were confirmed by ultraviolet spectroscopy, Fourier transform infrared spectroscopy, and density functional theory simulations. MXMIP was successfully applied to enrich and detect puerarin and its metabolites in biological samples. LC-MS/MS analysis showed that the mass charge ratios of MXMIP adsorbed samples were 415.09, 447.13, 253.05 and 255.23, respectively, corresponding to puerarin and its metabolites (dihydroxypuerarin, daidzein and dihydrodaidzein). This study provides a new approach for synthesizing highly selective molecularly imprinted polymers that effectively address the problem of binding site interception.

Introduction: ICG suffers from poor photostability and rapid clearance in PTT. This study constructs an FA-modified, pH/NIR responsive COF nanodelivery system for targeted ICG delivery and precise controlled release. Methods: FA-Lip-IC was prepared by solvent evaporation. TEM and dynamic light scattering characterized morphology and size. Drug release was evaluated under different pH conditions with or without an 808 nm laser. Photothermal properties were assessed by an 808 nm laser. CLSM and flow cytometry analyzed FR-mediated cellular uptake. Biocompatibility was evaluated using an MTT assay, a hemolysis test, and a zebrafish model. Pharmacokinetics was monitored by blood fluorescence intensity in rats. Results: FA-Lip-IC showed uniform spherical morphology with a size of 577.4 ± 9.42 nm. The cumulative drug release reached 92.56 ± 0.81% at pH 5.5 with NIR irradiation. FA modification increased cellular uptake by ID8 and 4T1 cells. Under 808 nm laser irradiation, FA-Lip-IC induced a local temperature increase of > 20°C, with significantly higher cytotoxicity than free ICG. Hemolysis rate was < 3%, normal cell viability > 87%, zebrafish hatching rate > 90%, and blood circulation time was prolonged. Discussion: This platform integrates the high loading capacity of COFs with liposome biocompatibility. FA targeting and pH/NIR-responsive release enhance treatment precision. A limitation is the lack of in vivo efficacy data. Conclusion: FA-Lip-IC combines photothermal stability, active tumor targeting, and stimuliresponsive release, offering a promising strategy to overcome the limitations of conventional PTT and advance precision cancer therapy.

The synthesis of imine-linked covalent organic frameworks (COFs) typically necessitates the use of toxic organic solvents and catalysts. Furthermore, optimizing solvent and catalyst types for creating imine-linked COFs with varied pore structures is often complex and labor-intensive, posing significant challenges to green chemical synthesis. In response, we have developed a green, environmentally-friendly, universal strategy for synthesizing imine-linked COFs using betaine-HFIP-based deep eutectic solvents (DESs) without exploiting an exogenous catalyst. This method diverges from traditional acid-catalyzed solvothermal synthesis, as the dynamic hydrogen bonding network catalyzed by betaine-HFIP-based DESs prevents the reversible hydrolysis of the imine intermediate. Employing this strategy, we have successfully synthesized well-crystallized homopore and heteropore imine-linked COFs in various shapes, confirming the method's general applicability. Notably, COF-3 demonstrates exceptional polarity-dependent fluorescence color change properties and have been developed into a ratiometric fluorescence sensor for monitoring H2O-organic solvent mixtures with high precision. Additionally, the RGB functions are analyzed, leading to the creation of a WeChat applet named "SWMU-AI" for rapid and accurate H2O or organic solvent fraction prediction. Finally, the diverse fluorescence color variations of COF-3 were investigated for their potential in anti-counterfeiting and information encryption applications.

Hydrazone-linked fluorescent covalent organic frameworks (COFs) with high crystallinity exhibit remarkable stability under acid-base conditions and in various organic solvents, maintaining structural integrity for cyclic utilization in sensing and adsorption processes. Consequently, developing new high-crystallinity hydrazonelinked fluorescent COFs is of significant importance. Notably, post-modification can enhance the detection diversity, selectivity, and adsorption performance of these COFs. Herein, a new hydrazone-linked fluorescent COF (namely COF-YYL) with high crystallinity was synthesized using 2,5-bis(allyloxy)terephthalohydrazide (DHzDAll) and 4,4 ',4 ''-(1,3,5-triazine-2,4,6-triyl)tribenzaldehyde (TTB) as precursors at room temperature. COF-YYL demonstrated superior characteristics including a high specific surface area (653.33 m2 center dot g- 1), good chemical and thermal stability, and dual-functionality in detecting methyl orange (MO) and Cu2+ with limits of detection (LODs) of 33 nM (2.1 ng center dot mL-1) and 1 ng center dot mL-1, respectively, and an MO adsorption capacity of 112.81 mg center dot g- 1. To increase functional diversity, COF-YYL underwent post-modification via "click" chemistry between the double bonds on DHzDAll and -SH on 3-mercapto-1-propanesulfonic acid sodium salt (MPS), yielding COFSO3Na. Compared with COF-YYL, COF-SO3Na exhibited a higher specific surface area (815.23 m2 center dot g-1), better dispersion performance, and richer functional group properties. Leveraging these advantages, COF-SO3Na served as a dual-function platform for detecting and adsorbing four cationic dyes including brilliant green (BG), crystal violet (CV), malachite green (MG), and methylene blue (MB), with satisfactory LODs (170 ng center dot mL- 1) and good adsorption capacities ranging from 98.94 to 162.87 mg center dot g-1. Further, COF-YYL and COF-SO3Na were used to analyze related analytes in tap water samples, achieving satisfactory recoveries. This study introduces a new high-crystallinity hydrazone-linked fluorescent COF, along with its sulfonated material, increasing the diversity of detection and adsorption platforms.

Glucocorticoids possess extensive and potent pharmacological effects, but their misuse and overuse are widespread concerns. Consequently, the environmental pollution and health hazards associated with their excessive usage cannot be overlooked. There is an urgent need for enhanced removal and a thorough understanding of the environmental and safety risks arising from the overconsumption of these drugs. In this study, a novel F, Nenriched covalent organic framework (designated as TAPT-COF) with high crystallinity was synthesized. TAPTCOF features numerous active sites, including F-F interaction and hydrogen bond interaction sites, along with a high specific surface area and good thermal stability. These characteristics enable TAPT-COF to serve as an advanced adsorbent for dispersed solid-phase extraction (D-SPE) of glucocorticoids such as fluocinonide acetate, budesonide, and dexamethasone, with adsorption capacities ranging from 146.77 to 228.90 mg & sdot;g-1 . Notably, TAPT-COF exhibits exceptional protein exclusion efficiency, achieving exclusion rates exceeding 95 %. Due to these advantages, TAPT-COF based D-SPE demonstrates strong applicability in the analysis of complex practical samples, including water and plasma, with satisfactory recoveries ranging from 76.48 % to 112.76 %. Compared to a COF (TPB-COF) that lacks a triazine group, TAPT-COF exhibits superior adsorption performance for target glucocorticoids. This is attributed to its ability to provide enhanced electrostatic interactions, as well as the synergistic effects of hydrogen bonding and F-F interactions. Additionally, TAPT-COF displays a low hemolytic activity, indicating its potential for in vivo analysis.

Nitroanilines (NAs) and nitrophenols (NPs), crucial industrial raw materials, are extensively utilized across various sectors. However, the environmental pollution and health hazards stemming from their usage are significant, necessitating urgent monitoring and removal to address environmental and safety concerns. The challenge is further compounded by the presence of NAs/NPs isomers, making the selective analysis of specific isomers crucial. In response, a new post-modified fluorescent covalent organic framework (COF) termed COF@CB, exhibiting dual-emission fluorescence, was synthesized. This synthesis involved coupling a high- crystallinity fluorescent COF (COF-TTDB) with carbazole-9-ethanol (CB) via a "Williamson" reaction. COF@CB featured exceptional dual-emission fluorescence, a high specific surface area (919.4 m2 & sdot;g-1), superior thermal stability, and abundant active sites. These attributes enabled COF@CB to function as a ratiometric fluorescence sensor capable of simultaneous detection and adsorption. The distinct number and arrangement of hydrogen bond sites in NAs/NPs isomers influenced the intramolecular charge transfer (ICT) effects on COF@CB, thereby enabling the COF@CB-ratiometric fluorescence sensor to distinguish and selectively detect p-NA/p-NP from isomers. Analysis of actual water samples further underscored the sensor's effectiveness in detecting p-NA/ p-NP. Furthermore, the presence of multiple active sites on the COF@CB-ratiometric fluorescence sensor facilitated the adsorption of NAs/NPs, promoting the removal of them from actual samples.

This review comprehensively summarizes recent advances (2020-2024) in acetylcholinesterase-based biosensing technologies for detecting organophosphorus pesticides in food and environmental matrices. The critical role of innovative functional materials in enhancing biosensor performance through improved enzyme immobilization, signal amplification, and anti-interference capabilities is highlighted. The principles of acetylcholinesterase inhibition, simplified sample pretreatment, and various immobilization strategies are discussed. Electrochemical, optical, dual-mode, and capillary electrophoresis-based biosensing modalities are compared, emphasizing their respective advantages and limitations. Despite their high sensitivity, portability, and cost-effectiveness, acetylcholinesterase-based biosensing technologies face challenges in terms of specificity, anti-interference capabilities, and reproducibility. Strategies to overcome these limitations include developing engineered enzymes, integrating microfluidic pretreatment, employing eco-friendly nanomaterials, and implementing multisignal calibration and intelligent sensing systems. These advancements support a collaborative "screening-confirmation" framework that combines rapid biosensing with confirmatory liquid chromatography/gas chromatography-mass spectrometry techniques, significantly enhancing capabilities in food safety monitoring and environmental protection.

Diclofenac potassium (DCF-K) is a widely used nonsteroidal anti-inflammatory drug with enhanced therapeutic effects mediated by its bioactive metabolites, particularly 4'-hydroxydiclofenac (4'-OH-DCF) and 5-hydroxydiclofenac (5-OH-DCF). However, the accurate detection of DCF-K and its metabolites in complex biological matrices remains challenging due to trace concentrations and matrix interference. To address this challenge, a chitosan-bentonite molecularly imprinted polymer (CB-MIP) was developed using a dual-role strategy, where chitosan-bentonite (CB) serves as both substrate and functional monomer, combined with a hierarchical functional monomer system (acrylamide as an auxiliary monomer) to enhance binding affinity and selectivity for the specific capture of DCF-K and its metabolites. Comprehensive characterization confirmed the successful synthesis of CB-MIP, revealing improved stability, hydrophilicity, and a mesoporous structure. CB-MIP exhibited good adsorption capacity for DCF-K (17.2× higher than CB), with Langmuir isotherm and pseudo-second-order kinetics indicating monolayer chemisorption. Selectivity studies demonstrated good recognition capability for DCF-K, achieving a selectivity factor up to 77.3 against structural analogs and co-administered drugs. Furthermore, cluster analysis revealed the CB-MIP sensitivity to DCF-K concentration variations as low as 0.3 μg·mL-1 in complex matrices. Mechanistic studies identified electrostatic and hydrogen bonding interactions as the primary binding forces, validated by electrostatic potential simulations, hydrogen-bond modeling, and spectroscopic analyses. Practical application in mouse plasma and liver samples confirmed efficient enrichment and detection of DCF-K and metabolites (4'-OH-DCF, 5-OH-DCF, diclofenac acyl glucuronide) using CB-MIP coupled with HPLC/UPLC-MS/MS, achieving high sensitivity (limit of detection: 0.231 μg·mL-1 in liver) and reproducibility (relative standard deviation: 1.22 %-5.81 %). This work establishes CB-MIP as a robust pretreatment material for targeted drug/metabolite analysis in complex biological systems.

To enhance the fluorescence properties of covalent organic frameworks (COFs) for broader applications, we introduce flexibility-rigidity alternately assembled red fluorescent COFs, named COF-MA. Its uniquely wide layer spacing (7.054 Å) significantly reduces π-π stacking interactions, suppressing fluorescence self-quenching and boosting solid-state emission. With long excitation and emission wavelengths, COF-MA exhibits minimal background interference, enabling highly sensitive detection of rifampicin (RFP) and rifapentine (RPT) in complex biological samples; the detection limits for both are 6.7 ng·mL−1. Combining experimental studies and computational simulations, we elucidated the fluorescence quenching mechanism. Furthermore, COF-MA-based fluorescent powder enabled rapid, high-contrast visualization of latent fingerprints on eight different substrates. This work not only proposes a novel structure-tuning strategy to improve COF fluorescence, but also delivers a stable probe for antibiotic detection and a versatile forensic tool, significantly expanding the practical scope of fluorescent COFs.