AIEgens-based fluorescent covalent organic framework in construction of chemiluminescence resonance energy transfer system for serum uric acid detection

Fluorescence-colorimetric dual detection method for quantitative detection of uric acid in urine based on the competitive oxidation between cerium (IV) and o-phenylenediamine induced by target substances

A dual detection method combining fluorescence and colorimetry used for measuring uric acid (UA) has been developed. Ce4+ can undergo an oxidation reaction with o-phenylenediamine (OPD) to generate 2,3-diaminophenazine (oxOPD), which exhibits a yellow color and has UV-visible light absorption properties. When UA is introduced into the reaction system, it effectively inhibits the oxidation process between Ce4+ and OPD, simultaneously resulting in the emergence of a new emission peak at 500 nm in the solution. It is worth noting that both the degree of enhancement in the fluorescence signal intensity at 500 nm and the decrease in the absorbance of oxOPD in the detection system are directly related to the concentration of UA added. Based on this phenomenon, we have successfully designed and implemented a sensitive, simple, and economically applicable fluorescence and colorimetric dual detection method for UA detection. The linear range of the fluorescence detection method is 160-400 μM, with a limit of detection (LOD) of 11.31 μM, while the colorimetric method exhibits a linear range of 5-150 μM and an LOD of 3.55 μM. The fluorescence and colorimetric dual detection method has been successfully applied to the quantitative detection of UA in spiked human urine samples. The recovery rate of fluorescence detection is 95.32-104.08 %, and the relative standard deviation (RSD) is 1.48-5.37 %. The recovery rate of colorimetric detection is 94.40-103.69 %, and the RSD is 1.30-4.11 %. This achievement indicates that it has broad potential application prospects in the field of clinical testing.

A near-infrared emitting covalent organic framework with AIE characteristics for light-emitting diodes

By incorporating methyl groups to introduce steric hindrance and utilizing hydroxyl groups to establish intramolecular hydrogen bonds, we synthesized a covalent organic framework (COF) with aggregation-induced emission (AIE) behavior and near-infrared (NIR) luminescence (λem = 657 nm). The integration of the innovative COF with LED chips enabled the fabrication of high-quality red and white organic phosphor-converted light-emitting diodes (LEDs). This work provides a new way to explore COFs to construct low-cost, high-performance, and eco-friendly LED devices.

Recent Advances on Integrating Porous Nanomaterials with Chemiluminescence Assays

Advanced porous nanomaterials have recently been the subject of considerable interest due to their high surface areas, tunable pore structures, high porosity, and ease of modification. In the chemiluminescence (CL) domain, the incorporation of additional pores into nanostructures not only enhances the loading capacity for signal amplification but also allows the confinement effect in a nanoscale microreactor and the controlled release of reaction agents. In light of this, increasing efforts have been made to fabricate various porous nanomaterials and explore their potential applications in CL assays. This review therefore aims to highlight the recent advances in preparation strategies and basic attributes of the CL-related porous nanomaterials. Moreover, it offers a comprehensive summary of the emerging CL sensing applications based on these materials. The key challenges and future perspectives of porous nanomaterials in CL assays are finally discussed.

Aggregation-induced emission(AIE)for next-generation biosensing and imaging: A review

Luminescence technology is a powerful analytical tool for biomedical research as well as for marker detection. Luminescent materials with aggregation-induced emission (AIE) properties have attracted extensive research interest, and their unique luminescence characteristics, biocompatibility, and sensitivity make them useful for the development of fluorescence-turn-on biosensors with superior sensitivity. While numerous reviews have focused on the design of AIEgens, comprehensive summaries on the strategies for biosensor preparation and application fields remain limited. In this review, we provide a concise introduction to the discovery and mechanism of the AIE phenomenon and summarize the working principles of classic AIE molecules. We discuss luminescence tuning strategies and functionalization methods for AIEgens, along with the design and preparation of AIE-based biosensors. Typical applications of AIE in biosensing and imaging are outlined, and we analyze the current limitations and future research directions of AIE technology in these fields. We hope this review will serve as a valuable reference for researchers in this rapidly developing field. The insights provided may facilitate the rational design of next-generation biosensors based on AIE technology, exhibiting promising avenues of biomedical applications and vast potential for growth.

Covalent Organic Framework-Involved Sensors for Efficient Enrichment and Monitoring of Food Hazards: A Systematic Review

The food safety issues caused by environmental pollution have posed great risks to human health that cannot be ignored. Hence, the precise monitoring of hazard factors in food has emerged as a critical concern for the food safety sector. As a novel porous material, covalent organic frameworks (COFs) have garnered significant attention due to their large specific surface area, excellent thermal and chemical stability, modifiability, and abundant recognition sites. This makes it a potential solution for food safety issues. In this research, the synthesis and regulation strategies of COFs were reviewed. The roles of COFs in enriching and detecting food hazards were discussed comprehensively and extensively. Taking representative hazard factors in food as the research object, the expression forms and participation approaches of COFs were explored, along with the effectiveness of corresponding detection methods. Finally, the development directions of COFs in the future as well as the problems existing in practical applications were discussed, which was beneficial to promote the application of COFs in food safety and beyond.

Recent advances in emerging nanozymes with aggregation-induced emission

AIE luminogens (AIEgens) are a class of unique fluorescent molecules that exhibit significantly enhanced luminescence properties and excellent photostability in the aggregated state. Recently, it has been found that some AIEgens can produce reactive oxygen species, which means that they may have potential enzyme-like activities and are thus termed "AIEzymes". Consequently, the discovery and design of novel AIEgens with enzyme-like properties have emerged as a new and exciting research direction. Additionally, AIEgens can enhance the catalytic efficiency of traditional nanozymes by direct combination, thereby endowing the nanozymes with multifunctionality. In this regard, nanozymes with aggregation-induced emission (AIE) properties, which represents a win-win integration, not only take full advantage of the low cost and stability of nanozymes, but also incorporate the excellent biocompatibility and fluorescence properties of AIEgens. These synergistic compounds bring about new opportunities for various applications, making AIEzymes of interest in biomedical research, food analysis, environmental monitoring, and especially imaging-guided diagnostics. This review will provide an overview of the latest strategies and achievements in the rational design and preparation of AIEzymes, as well as current research trends, future challenges and prospective solutions. We expect that this work will encourage and motivate more people to study and explore AIEzymes to further promote their applications in various fields.

Review on Uric Acid Recognition by MOFs with a Future in Machine Learning

Uric acid (UA) is produced from purine metabolism and serves as a prevalent biomarker for multiple diseases including cancer. Hyperuricemia or hypouricemia can cause multiple dysfunctions throughout the biological processes. Consequently, there is a pressing need for monitoring UA concentration in body fluid. While clinical methods are known, the availability of a point-of-care testing (PoCT) kit remains conspicuously absent. In the case of electrochemical recognition of UA, the oxidation potential of ascorbic acid closely aligns with that of UA and thus it hinders the detection process, which eventually may result in false positive signals. Several chemosensors are known in the field of supramolecular chemistry, and metal-organic frameworks (MOFs) are one of the best-performing contenders due to their robustness, stability, and versatile structures. In this review, we tried to unbox the up-to-date development of UA sensing by MOFs. We delve into the state of UA recognition by MOFs, exploring both electrochemical and fluorometric pathways and drawing comparisons with structurally similar probes like covalent organic frameworks (COFs) to understand/establish the advantages of MOFs specifically in UA sensing. In the absence of a PoCT kit, we have provided the conceptual outlook for designing a PoCT device termed a "Urimeter" via electrochemical operation. For the first time, we have proposed different methods of how UA sensing can be tied up with artificial intelligence and machine learning (AI-ML).

Noncancerous disease-targeting AIEgens

Noncancerous diseases include a wide plethora of medical conditions beyond cancer and are a major cause of mortality around the world. Despite progresses in clinical research, many puzzles about these diseases remain unanswered, and new therapies are continuously being sought. The evolution of bio-nanomedicine has enabled huge advancements in biosensing, diagnosis, bioimaging, and therapeutics. The recent development of aggregation-induced emission luminogens (AIEgens) has provided an impetus to the field of molecular bionanomaterials. Following aggregation, AIEgens show strong emission, overcoming the problems associated with the aggregation-caused quenching (ACQ) effect. They also have other unique properties, including low background interferences, high signal-to-noise ratios, photostability, and excellent biocompatibility, along with activatable aggregation-enhanced theranostic effects, which help them achieve excellent therapeutic effects as an one-for-all multimodal theranostic platform. This review provides a comprehensive overview of the overall progresses in AIEgen-based nanoplatforms for the detection, diagnosis, bioimaging, and bioimaging-guided treatment of noncancerous diseases. In addition, it details future perspectives and the potential clinical applications of these AIEgens in noncancerous diseases are also proposed. This review hopes to motivate further interest in this topic and promote ideation for the further exploration of more advanced AIEgens in a broad range of biomedical and clinical applications in patients with noncancerous diseases.

Silver Nanoparticle-Functionalised Nitrogen-Doped Carbon Quantum Dots for the Highly Efficient Determination of Uric Acid

The fabrication of efficient fluorescent probes that possess an excellent sensitivity and selectivity for uric acid is highly desirable and challenging. In this study, composites of silver nanoparticles (AgNPs) wrapped with nitrogen-doped carbon quantum dots (N-CQDs) were synthesised utilising N-CQDs as the reducing and stabilising agents in a single reaction with AgNO₃. The morphology and structure, absorption properties, functional groups, and fluorescence properties were characterised by transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, fluorescence spectroscopy, and X-ray diffraction spectroscopy. In addition, we developed a novel method based on AgNPs/N-CQDs for the detection of uric acid using the enzymatic reaction of uric acid oxidase. The fluorescence enhancement of the AgNPs/N-CQDs composite was linear (R² = 0.9971) in the range of 2.0–60 μmol/L, and gave a detection limit of 0.53 μmol/L. Trace uric acid was successfully determined in real serum samples from the serum of 10 healthy candidates and 10 gout patients, and the results were consistent with those recorded by Qianxinan Prefecture People’s Hospital. These results indicate that the developed AgNP/N-CQD system can provide a universal platform for detecting the multispecies ratio fluorescence of H₂O₂ generation in other biological systems.

Potassium Ferricyanide Oxidize Silicon Quantum Dots under Alkaline Condition to Produce Chemiluminescence for Uric Acid Detection in Human Urine

Potassium ferricyanide (K₃ [Fe (CN)₆ ]) could directly oxidize silicon quantum dots (Si QDs) to generate chemiluminescence (CL) under alkaline condition. It was noteworthy that in the Si QDs-K₃ [Fe (CN)₆ ]-NaOH CL system, the Si QDs worked as a new luminescent material. Besides, the signal intensity of this CL system could be weaken with the addition of uric acid (UA). Based on these, we exploited a new painless and convenient determination method of UA. This method only needed to filter and dilute the UA, without other pretreatment. The constructed system exhibited a linear relationship ranged from 0.50 to 4.50 mmol·L^-1 , with 0.24 mmol·L^-1 of detection limit, and this system had been successfully demonstrated the detection of UA in human urine. Meanwhile, this work had also broaden the application of the Si QDs in CL research.

Chemiluminescence resonance energy transfer determination of uric acid with fluorescent covalent organic framework as energy acceptor

A simple and feasible strategy was developed for the preparation of fluorescent covalent organic frameworks (COFs) TpPa-1@FL. The TpPa-1-1@FL was prepared via a self-assembly strategy by soaking non-fluorescent COFs TpPa-1 into strong fluorescent fluorescein (FL) solution. A chemiluminescence resonance energy transfer (CRET) system was constructed by the combination strong fluorescent TpPa-1@FL with TCPO-hydrogen peroxide (H₂O₂) reaction. The chemiluminescence (CL) signal of the system was further improved by the addition of bovine serum albumin (BSA). The CRET system can determine H₂O₂ with a linear range response from 5.0 µmol/L to 20.0 mmol/L and a detection limit of 1.1 µmol/L. The CRET system was further exploited for indirect detection of uric acid with coupling of uricase. A good linear relationship was obtained for uric acid in the 10.0-400.0 µmol/L concentration range with a detection limit of 3.8 µmol/L. The practicability of this method was assessed by the determination of uric acid in real samples of human serum and urine.

State-of-the-art self-luminescence: a win–win situation

The working principles, luminescent mechanisms, versatile integrated approaches and advantages, and future perspectives of AIE-assisted “enhanced” self-luminescence systems are reviewed.