Cascade Reaction Research Articles

A substrate-induced dual utilization cascade reaction of N-alkyl anilines: highly site-selective sustainable synthesis of chromeno[4,3-b]quinolin-6-ones.

We describe a novel substrate-induced cascade reaction of N-alkyl anilines via C(sp3)-N bond cleavage and reorganization into chromeno[4,3-b]quinolin-6-ones. N-alkyl anilines are not only used as a carbon source, but also the waste group was trapped by 4-hydroxy coumarin. The calculation of green metrics shows that our protocol is more efficient and green with lower emission than before. Additionally, a gram-scale reaction and one-pot synthesis of bioactive molecules further demonstrate the potential application of our protocol in the pharmaceutical industry.

A Smart Nanomedicine Unleashes a Dual Assault of Glucose Starvation and Cuproptosis to Supercharge αPD-L1 Therapy.

Combination therapy has become a promising strategy for promoting the outcomes of anti-programmed death ligand-1 (αPD-L1) therapy in lung cancer. Among all, emerging strategies targeting cancer metabolism have shown great potency in treating cancers with immunotherapy. Here, alteration in glucose and copper metabolisms is found to synergistically regulate PD-L1 expression in lung cancer cells. Thus, an intelligent biomimetic nano-delivery system is synthesized by camouflaging lung cancer cell membranes onto glucose oxidase-loaded Cu-LDHs (CMGCL) for cancer metabolism targeted interference. Such novel nanomedicine is able to induce lung cancer cell cuproptosis and PD-L1 upregulation significantly via self-amplified cascade reactions. Meanwhile, with a decent cancer cell membrane coating, CMGCL exhibited great biosafety, tumor-targeted efficiency and anti-tumor effects in LLC lung tumor-bearing mice models. Additionally, a combination of CMGCL can sensitize the therapeutic effects of αPD-L1, substantially promoting tumor inhibition in both subcutaneous and lung metastasis LLC-bearing mice models. Overall, these findings highlight the potential connections between glucose metabolism and cell cuproptosis, offering a promising approach for treating lung cancer by integrating starvation, cuproptosis, and immunotherapy.

Inverse Electron Demand Diels-Alder Reaction of Pyrazines with 2,5-Norbornadiene as Acetylene Precursor

Herein, we report the reaction of pyrazines with 2,5-norbornadiene, an acetylene precursor, as a cascade of Diels-Alder reactions yielding substituted pyridines. In contrast to the known examples of intermolecular Diels-Alder type reaction of pyrazines with acetylene, which usually leads to a mixture of products, in our case the formation of a single isomer was observed. The proposed approach allows the conversion of pyrazines with different types of substitution, except those containing methyl and amino donor groups, to pyridines. In addition, highly functionalized aminonicotic esters were obtained, which can be used for the synthesis of bioactive compounds. An unusual course of the Diels-Alder reaction was found in the case of tetrasubstituted pyrazines, which cleave organic nitriles instead of HCN. Quantum-chemical modeling of possible transition states showed that this Diels-Alder reaction proceeds via cycloaddition of 2,5-norbornadiene to pyrazine with sequential elimination of HCN and cyclopentadene; the reaction pathway including initial formation of acetylene from norbornadiene and subsequent Diels-Alder reaction with the acetylene was rejected as kinetically unfavorable.

Synthesis of γ‐Alkenylated δ‐Sultones Via Brønsted Base‐Catalyzed Annulative SuFEx Reaction of Allyl Ketones and Ethenesulfonyl Fluorides

AbstractA tandem annulation reaction of allyl ketones and β‐aryl ethenesulfonyl fluorides has been described. Under the catalysis of Brønsted base, allyl ketones reacted with β‐aryl ethenesulfonyl fluorides through a tandem intermolecular Michael addition‐intramolecular SuFEx process to afford γ‐alkenylated δ‐sultones in good to excellent yields. In this reaction, no additional base was needed, and 4 Å molecular sieves were used as efficient HF scavenger to restrict the neutralization and deactivation of the Brønsted base catalyst.

Efficient and Cost-Effective Synthesis of N-Acetyllactosamine by Sequential Modular Enzymatic Cascade Reactions Involving NTP Regeneration.

Human milk oligosaccharides (HMOs) play important roles in the development of infants, which are the third most abundant component in human milk. N-Acetyllactosamine (LacNAc) is an important intermediate for the biosynthesis of other HMOs and antigens. Since currently appropriate synthetic methods for large-scale production of LacNAc are not available, it is urgently needed to develop an efficient and cost-effective synthetic pathway for LacNAc preparation. In this study, a cost-effective pathway of LacNAc synthesis involving regeneration of adenosine triphosphate (ATP) and uridine 5'-triphosphate (UTP) was established. After optimizing the reaction conditions, LacNAc was synthesized at a yield of >90% via a sequential one-pot multienzyme (OPME) method with crude enzymes at 100 mM substrates. Finally, LacNAc was produced efficiently and cost-effectively at a 5 L scale. This strategy would possibly meet the requirements of potential industrial production of LacNAc and would provide guidance for the production of other structurally complex HMOs or functional oligosaccharides in the future.

Multifunctional Catalysts for Cascade Reactions in Biomass Processing

Multifunctional catalysts have received considerable attention in the cascade reactions of biomass processing. A cascade (or tandem) reaction is realized when multiple reaction steps that require different catalysts are performed in a one-step process. These reactions require bi- or multifunctional catalysts or catalyst mixtures to serve successfully at each reaction step. In this review article, we discuss the major factors of the catalyst design influencing the structure–property relationships, which could differ depending on the catalyst type. The major factors include the amounts and strengths of acidic and basic sites, interactions between those and metal sites, synergetic effects, nanoparticle sizes and morphology, nanostructures, porosity, etc. The catalysts described in this review are based on zeolites, mesoporous solids, MOFs, and enzymes. The importance of continuous cascade processes is also examined.

Design and synthesis of PDSPTCF as an influential Brønsted-Lewis acidic catalyst for the producing benzo[a]benzo[6,7]chromeno[2,3-c]phenazines

Initially, 4,4'-(1,4-phenylene)di(sulfonic)pyridinium tetrachloroferrate (PDSPTCF) as a novel organic–inorganic hybrid salt was synthesized and identified by elemental mapping, energy-dispersive X-ray spectroscopy, inductively coupled plasma atomic emission spectrometer, Raman spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, vibrating-sample magnetometry, and thermal gravimetric (TG) techniques. Then, the catalytic performance of this hybrid salt was assessed for the producing benzo[a]benzo[6,7]chromeno[2,3-c]phenazine derivatives via one-pot multicomponent domino reaction (MDR) of benzene-1,2-diamine, 2-hydroxynaphthalene-1,4-dione and aldehydes under optimal conditions (70 °C, solvent-free, 5 mol% PDSPTCF) in short reaction times and high yields. Highly efficacy of the PDSPTCF for the production of benzo[a]pyrano[2,3-c]phenazines can be assigned to the synergistic effect of Lewis and Brønsted acids, and having two positions of each acid (i.e., FeCl4ˉ and –SO3H). In addition, this catalyst showed good reproducibility with six cycles of recycling.

A Supramolecular Approach to Engineering Living Cells with Enzymes for Adaptive and Recyclable Cascade Synthesis

Biocatalytic transformation in nature is inherently dynamic, spontaneous, and adaptive, enabling complex chemical synthesis and metabolism. These processes often involve supramolecular recognition among cells, enzymes, and biomacromolecules, far surpassing the capabilities of isolated cells and enzymes used in industrial synthesis. Inspired by nature, here we design a supramolecular approach to equip living cells with these capacities, enabling recyclable, efficient cascade reactions. Our two‐step "plug‐and‐play" methodology begins by coating Escherichia coli cells with guest‐containing polymers (SupraBAC) via supramolecular charge interactions, followed by the introduction of β‐cyclodextrin‐functionalized host enzymes through host‐guest chemistry, creating a robust cell‐enzyme complex. This supramolecular coating not only protects cells from various stresses, such as UV radiation, heat, and organic solvents, but also facilitates the overexpression of intracellular enzymes and the attachment of extracellular enzymes within and on SupraBAC. This combination results in efficient multienzyme cascade synthesis, enabling two‐ and three‐step reactions in one pot. Importantly, the multienzyme system can be recycled up to five times without significant loss of activity. Our findings introduce a versatile, adaptive supramolecular coating for whole‐cell catalysts, offering a sustainable and efficient solution for complex synthesis in both chemistry and industrial biotechnology.

Total Alkaloids of Rhizoma Corydalis regulates gut microbiota and restores gut immune barrier to ameliorate cognitive dysfunction in diabetic rats

Background and objectivesGiven the widespread dysbiosis of gut microbiota in patients with T2DM, it has been found that the microbiota-gut-brain axis plays an influential regulatory role in diabetic cognitive dysfunction, and improving gut dysbiosis may be a potential strategy for treating diabetic cognitive dysfunction. Total Alkaloids of Rhizoma Corydalis (TAC) is the main active component extracted from Rhizoma Corydalis. Pharmacological studies have demonstrated its significant pharmacological effects on the cardiovascular and cerebrovascular systems, and berberine, the main component of TAC, has a certain regulatory effect on gut microbiota.Materials and methodsRats were randomly divided into Control group, Model group, TAC-low group, TAC-mid group and TAC-high group. Cognitive function of diabetic rats was evaluated through behavioral testing using the Morris water maze experiment. The relative abundance of gut bacteria in rat feces was determined via 16S rRNA analysis. IHC and Western blot techniques were employed to assess IL-22, IL-23, Reg3g, ZO-1, occludin 1 expression in the colon tissue; GPX4, xCT, NLRP3, Caspase-1 p20, GSDMD-N were detected in the hippocampus.ResultsThe cognitive function of diabetic rats decreased significantly. TAC demonstrated a significant reduction in inflammatory factors in serum, hippocampus, and colon, thus alleviating inflammation. Additionally, it effectively decreased ferroptosis induced by NLRP3 and reduced pathological damage in the hippocampus of diabetic rats. After treatment, the differential microbiota such as Lachnoclotridium and Bacteroides. TAC improved gut barrier permeability and integrity in rats while remodeling gut mucosal homeostasis. Moreover, pyroptosis and ferroptosis caused by the inflammatory cascade in the rat hippocampus were also significantly inhibited.ConclusionThe combination of high lipid and high glucose with STZ can result in gut microbiota disturbance, damage gut immune barrier, decreased gut mucosal permeability and integrity, aggravated gut inflammation, further spread inflammatory factors to brain tissue, cause inflammatory cascade reaction of encephalopathy, and ultimately resulting in neuronal ferroptosis and cognitive dysfunction in diabetes mellitus. Our study suggests that TAC may regulate gut microbiota, restore gut immune homeostasis, improve gut barrier permeability and integrity, inhibit brain tissue inflammatory cascade, reduce neuronal ferroptosis, and thus improve diabetes. This provides new targets for its treatment strategy.

A Supramolecular Approach to Engineering Living Cells with Enzymes for Adaptive and Recyclable Cascade Synthesis

Biocatalytic transformation in nature is inherently dynamic, spontaneous, and adaptive, enabling complex chemical synthesis and metabolism. These processes often involve supramolecular recognition among cells, enzymes, and biomacromolecules, far surpassing the capabilities of isolated cells and enzymes used in industrial synthesis. Inspired by nature, here we design a supramolecular approach to equip living cells with these capacities, enabling recyclable, efficient cascade reactions. Our two‐step "plug‐and‐play" methodology begins by coating Escherichia coli cells with guest‐containing polymers (SupraBAC) via supramolecular charge interactions, followed by the introduction of β‐cyclodextrin‐functionalized host enzymes through host‐guest chemistry, creating a robust cell‐enzyme complex. This supramolecular coating not only protects cells from various stresses, such as UV radiation, heat, and organic solvents, but also facilitates the overexpression of intracellular enzymes and the attachment of extracellular enzymes within and on SupraBAC. This combination results in efficient multienzyme cascade synthesis, enabling two‐ and three‐step reactions in one pot. Importantly, the multienzyme system can be recycled up to five times without significant loss of activity. Our findings introduce a versatile, adaptive supramolecular coating for whole‐cell catalysts, offering a sustainable and efficient solution for complex synthesis in both chemistry and industrial biotechnology.

Super signal-enhancement biosensing platform for precise target recognition based on rolling circle-hybridization chain dual linear cascade amplification technology

This paper presents a self-powered biosensing platform based on graphdiyne@Au (2D GDY@Au) nanoparticles and rolling circle-hybridization chain (RC-HC) dual linear cascade amplification technology, which significantly enhances target recognition and signal amplification efficiency for miRNA-141. Specifically, the target on bioanode outputs a large amount of single-stranded DNA (T1) through the strand displacement amplification (SDA) mechanism. This efficient target recycling process triggers RC-HC dual linear cascade reaction. The RCA product and H2 form the L-Liner/H2 hybridized chain through a hybridization chain reaction, and then are immobilized on a flexible electrode using a Y-DNA capture handle. [Ru(NH3)6]3+ is precisely anchored in the grooves of the DNA double helix. The 2D GDY@Au enhances the electron mobility of the system to form a rich electron-donating center. The [Ru(NH3)6]3+ on the biocathode receives electrons and is reduced to [Ru(NH3)6]2+, producing a significantly amplified open-circuit voltage signal. Dual linear cascade amplification technology realizes precise target recognition, exponential amplification, and efficient conversion of biological signals. This technique displays an extensive linear range (0.0001–10000 pM) with a detection limit of 25.9 aM (S/N = 3), and it provides an innovative method for developing sensors based on nucleic acid amplification and presents a promising novel approach for the sensitive and precise detection of low-abundance target molecules, highlighting a new tactic for the creation of compact and portable analytical devices.

Combining Liposomal Photocatalysts with Whole‐Cell Catalysts for One‐pot Photobiocatalysis

AbstractCooperative photobiocatalytic processes have seen extensive potentials for the synthesis of both bulk and fine chemicals owing to their versatility, eco‐friendliness, and cost‐effectiveness. Nevertheless, developing a universal and effective synthetic strategy compatible with both catalytic systems remains challenging. In this study, we explored cationic liposomes as biocompatible photocatalyst encapsulation systems and combined them with bacteria overexpressing enzymes for two‐step and three‐step cascade reactions. Specifically, the water‐soluble photocatalyst anthraquinone‐2‐sulfonate (AQS), which can oxidize benzyl alcohol, is encapsulated within the core of cationic liposomes composed of dioleoyl‐3‐trimethylammonium propane (DOTAP) and the helper lipid cholesterol. The positive charge on the liposome surface enabled electrostatic interactions with the negative charges on the membrane of Escherichia coli cells. Bacterial cells overexpressing various enzymes, such as Candida antarctica lipase B (CalB) and benzaldehyde lyase (BAL), and coated with liposomes enabled the production of added value compounds through cascade reactions with excellent production. These cascades involve CalB‐catalyzed hydrolysis, BAL‐catalyzed condensation, and AQS‐driven photo‐oxidation reactions. Therefore, the strategy offers more possibilities of combining photocatalysis with biocatalysis for recoverability, enhanced mass transfer, and enhanced compatibility in both industrial biotechnology and synthetic chemistry.

Unprecedented synthesis of indole-linked tetra-substituted alkenes by catalyst-free domino reaction

Herein, we report a simple, efficient catalyst-free green domino reaction of indole, arylglyoxal, and cyclic 1,3-dicarbonyls such as barbituric acid derivatives/dimedone at 100oC in dimethylformamide medium in open air condition. In this reaction, one C-C and one C=C bonds have been formed in one-pot without using any additive or metal based reagent. Considering the presence of indole, benzoyl and cyclic 1,3-dicarbonyl moieties in the products, it is expected that they will exhibit interesting medicinal properties. All the synthesized products were characterized by recording FTIR, 1H NMR, 13C NMR, and HRMS. Moreover, a single crystal XRD of compound 4i was recorded to confirm the structure of the product. Operational simplicity, gram-scale synthesis, mild reaction conditions, good yields, and wide substrate scope are the salient features of this methodology.

Entropy-driven self-assembled enzyme-DNA nanomatrix cascade DNAzyme-CRISPR/cas system for multiplexed enhancement of self-powered sensing platform for protein detection

Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated Proteins (CRISPR/Cas) system can accurately identify and cleave target DNA sequences, while the effective combination of DNA nanomatrix and entropy-driven self-assembled enzymes can significantly enhance the sensitivity, stability, and diversified functionality of sensors through highly ordered molecular arrangement and spontaneous efficient assembly processes. Herein, a carbon-encapsulated MoS2 hollow nanorod (C-MoS2) with excellent conductivity and multiple active sites is used to construct bioanode of biofuel cell by integrating it with an entropy-driven self-assembled enzyme-DNA nanomatrix cascade DNAzyme-CRISPR/Cas system. When thrombin binds aptamer, it exposes the trigger strand on the anode, initiating chain displacement. This activates DNAzyme, triggering a cascade reaction that cleaves and releases the probe strand. The probe then binds CrRNA, forming a multimeric complex with Cas protein.When non-specific cleavage of the single strand occurs, it leads to the release of glucose oxidase (GOD) from the DNA matrix and causes a significant decrease in the value of the system's open-circuit voltage (EOCV). The EOCV values show a good negative correlation with the concentration of thrombin (TB) in the range of 0.00001–100 nM, achieving a limit of detection of 3.55 fM (S/N = 3).

Development of a self-assembled dual-enzyme co-display platform on the surface of the natural “chitosan beads” of yeast spores

Under starvation conditions, Saccharomyces cerevisiae diploid cells initiate meiosis to produce dormant cells called spores. When the DIT1 gene involved in assembling the outermost layer dityrosine is disrupted, the natural “chitosan beads” of yeast spores will be formed. A novel cell surface display system based on “chitosan beads” of dit1Δ yeast spores was previously established. In this study, a self-assembled dual-enzyme co-display platform on the surface of “chitosan beads” of S. cerevisiae spores was developed through the SpyTag/SpyCatcher system. As an example, two polyethylene terephthalate (PET) hydrolases, FAST-PETase (FPETase) and MHETase were self-assembled on the surface of spores. Compared with the unassembled enzymes, the assembled enzymes exhibited higher activity toward bis-hydroxyethyl terephthalate (BHET), achieving the complete degrading of 2 mM BHET within 1 h. Furthermore, the assembly of PETase and MHETase on the surface of spores demonstrated better thermostability (more than 85 % of initial activity after incubation at 30–70 °C for 12 h) and pH tolerance (approximately 80 % of original activity after incubation at pH 5.0 to 9.0 for 12 h). This study provides a novel and practical platform for the co-display and assembly of enzymes, offering a long-term stable enzyme catalyst for multi-enzyme cascade reactions especially conducted in complex environments.

Enzyme-particle Complexes Facilitate Pickering Interfacial Biocatalysis.

Pickering interfacial biocatalysis (PIB), where biocatalysts stabilize emulsions through carrier coupling or polymer grafting, has emerged as a powerful platform for organic synthesis due to its ability to accommodate water-insoluble substrates within enzymatic cascade reactions. PIB provides a large interfacial area for two-phase reactions, reducing diffusional resistance and enhancing transformation efficiency. The performance of PIB relies heavily on enzyme-particle conjugates, which serve a dual function: stabilizing the emulsion and acting as the active biocatalysts in the system. In this Concept, we discuss the latest advancements, current challenges, and future directions in the development of protein-particle conjugates for PIB.

Innovative strategy of ZIF-90 for co-immobilization of whole cells and enzymes in biocatalytic D-phenyllactic acid synthesis.

In this study, we endeavored to catalyze the biosynthesis of D-phenyllactic (D-PLA) from L-Phenylalanine (L-Phe) through a one-pot method. However, the crucial enzymes for the biosynthesis of phenylpyruvate (PPA), amino acid oxidase (L-AAD), is a membrane-bound protein. Herein, we proposed a novel co-immobilization strategy of whole cells and enzymes, integrating them into ZIF-90 to achieve efficient biosynthesis of D-PLA. Consequently, we embarked on integrating both enzyme and E. coli into ZIF-90, ultimately obtaining the novel biocatalyst E. coli/LDH@ZIF-90. This achievement facilitated the cascade reaction between LDH and E. coli, enabling a streamlined one-pot bioconversion process. The morphology and structure of E. coli/LDH@ZIF-90 were thoroughly characterized using a range of methods, including XRD, SEM, FT-IR, CLSM, and XPS, which confirmed that the material had been successfully synthesized. Further activity experiments revealed that E. coli/LDH@ZIF-90 exhibited good stability even under harsh conditions. Additionally, the biocatalyst retained 76% of its initial catalytic activity after completing six cycles. Moreover, when utilized for the biosynthesis of D-PLA, this system demonstrated an impressive conversion rate of 85.2% after 12h. The successful cascade catalysis from L-Phe to D-PLA underscored the potential of the enzyme-cell cascade catalytic system, offering valuable insights for its potential industrial applications.

Significance of the liver arginase activity in the processes of detoxification, formation of thyroid status and dyslipidemia in rats with experimental peritonitis

Peritonitis is a surgical and general pathological problem, the relevance of which does not decrease despite the achievements of modern clinical and experimental medicine. Peritonitis, being one of the most severe complications of various diseases and injuries to the abdominal organs, triggers a complex cascade of pathogenetic reactions with disruption of vital processes. The mortality rate for peritonitis is 20‒30 %, and in its most severe forms it reaches 50–80 %. High mortality is caused by endotoxemia, multiple organ failure and sepsis. To date, sufficient data have been accumulated, indicating the importance of liver arginase in the processes of detoxification and vital activity of the body in normal conditions and in pathology. There were reasons to believe that its activity would be significant in the pathogenesis of peritonitis. However, the elucidation of significance of the liver arginase activity in detoxification processes and in the pathogenesis of septic conditions and peritonitis in particular has been still little studied.The purpose of the study was to determine the significance of the liver arginase activity in the processes of detoxification, the formation of thyroid status and dyslipidemia in rats with experimental peritonitis (CLP-model).In experiments on rats, it was found that liver arginase and nitrogen monoxide are involved in changes in the content of total cholesterol in the liver and lipoproteins in the blood serum, the level of iodine-containing thyroid hormones in the blood plasma and body temperature during CLP-peritonitis. Developing CLP-peritonitis in the conditions of liver argina- se depression by Nω-hydroxy-nor-L-arginine at a dose of 10 mg/kg is accompanied by a more pronounced inhibition of the detoxification function of the liver, worsening changes in the content of total cholesterol in the liver and lipoproteins in the blood serum, and the level of iodine-containing hormones in the blood plasma and contributes to the development of secondary dislipoproteinemia.

Fluidic Membrane-Bound Protocells Enabling Versatile Assembly of Functional Nanomaterials for Biomedical Applications.

The development of membrane-bound protocells, which process cascade biochemical reactions in distinct microcompartments, marks a significant advancement in soft systems. However, many synthesized protocells with cell membrane-like structures are prone to rupturing in biological environments and are challenging to functionalize, limiting their biomedical applications. In this study, we explore the liquid-liquid phase separation of tannic acid (TA) and polyethylene glycol (PEG) to form coacervate droplets. Upon introducing polyvinylpyrrolidone (PVP) molecules, a dense hydrogen bonding network spontaneously forms at the surfaces of the coacervate droplets, resulting in robust fluidic membrane-bound protocells (FMPs). These protocells can be flexibly postfunctionalized to incorporate functional nanomaterials via electrostatic attraction, enabling the design of cascade reactions for biomedical applications. To demonstrate this, nanozymes (Pt/CeO2) are assembled onto Fe3+/FMPs, resulting in functional FMPs (Pt/CeO2@Fe3+/FMPs) capable of catalyzing the degradation of uric acid and its harmful byproduct, H2O2, offering potential treatments for gout.

Biomimetic nanozymes with tunable peroxidase activity based on peptides co-assembly for colorimetric sensing of uric acid

The construction of simple and efficient artificial enzymes is of great importance in the fields of sensing and catalysis. In this work, peptide nanotubes (CA-PNTs) co-assembled from two short peptides were non-covalently combined with hemin to obtain a series of CA-PNTs/hemin composites as biomimetic peroxidase materials. Due to the introduction of histidine and arginine in the short peptides simulating the microenvironment near the hydrophobic cavity in the activity center of the natural enzyme, CA-PNTs/hemin shows enhanced peroxidase activity compared with free hemin and the single short peptide self-assembled peptide nanotubes-supported hemin complex, and the enzyme activity of the material could be regulated by simply adjusting the proportion of co-assembled short peptides. Further investigation of the catalytic mechanism demonstrates that CA-PNTs/hemin can effectively bind to H2O2 to form active intermediates and catalyze the decomposition of H2O2 to generate superoxide radicals (O2•−), thus promoting the whole enzymatic reaction. Combined with an enzyme cascade reaction and enzyme catalytic chromogenic system, a colorimetric method based on CA-PNTs/hemin for uric acid (UA) sensing was constructed. The strategy shows a linear range of 0.5–80 μM with a low limit of detection (0.2 μM) and good selectivity, and has been successfully applied to the determination of UA in human urine. A portable platform for UA detection was further developed by conjugating the strategy with smartphones.