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Background: β-lactoglobulin (β-Lg), a major allergen in dairy products, can trigger severe allergic reactions and even fatal outcomes in infants. In this work, we develop a new low background current redox recycling strategy by conjugating the electrochemical mediator to trimetallic hybrid nanoparticles (NPs)-dispersed graphene as the signal tag, which is coupled with DNAzyme amplifications to construct highly catalytic and ultrasensitive β-Lg aptasensor., Results: Target β-Lg molecules bind aptamers in DNAzyme/aptamer duplexes to release active DNAzymes to initiate cyclic cleavage of hairpin substrates. This subsequently leads to confinement of many probes for signal generation on electrode. Assisted by K 3 [Fe(CN) 6 ] in detection buffer, catalytic redox recycling of mediators induced by trimetallic hybrid NPs thus yield considerably magnified currents for detecting β-Lg with detection limit of 5.4 pg/mL. Our results show that attachment of redox mediator to NP-dispersed graphene can effectively and significantly lower the background current compared with its presence in buffer. At the meantime, the coupling of the DNAzyme amplification with catalytic hybrid NPs can enhance the current signal, leading to high signal-to-noise ratio and sensitivity. Such aptasensor also exhibits high selectivity and can achieve detection of low levels of β-Lg in infant rice cereal., Significance: The simultaneous background current reduction and dual catalytic signal amplification of our biosensor strategy leads to highly improved signal-to-noise ratio and sensitivity, which suggesting its promising potential for the monitoring of different trace molecular biomarkers for diverse applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

As a common pollutant, cadmium (Cd) poses a serious threat to the growth and development of plants. Currently, there is no effective method to elucidate the protective mechanism of Cd 2+ in plant cells. For the first time, we designed a Cd 2+ fluorescent probe to observe the adsorption and sequestration of Cd 2+ in rice cell walls and vacuoles. Specifically, Cd 2+ is blocked by the Casparian strip and electrostatically attracted to hemicellulose, which is abundantly adsorbed and fixed to the cell walls of the endodermis. For Cd 2+ that successfully entered the endodermis, one part entered the cells and was compartmentalised and fixed in the vacuoles, while the other part entered the vascular bundles and precipitated in the cell walls of the sclerenchyma through the ion exchange effect. Furthermore, with prolonged exposure to Cd 2+ , compartmentalised bodies that were strongly labelled by fluorescence gradually appeared in the vacuoles, which were assumed to be a new heavy metal protective mechanism activated by plants in response to continuous Cd 2+ exposure. In conclusion, this study provides an innovative and effective method for the detection of adsorption, transportation, and accumulation of Cd 2+ in plant tissues, which can be employed for the rapid identification of crops with low Cd accumulation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Amplified imaging of microRNA (miRNA) in cancer cells is essential for understanding of the underlying pathological process. Synthetic catalytic DNA circuits represent pivotal tools for miRNA imaging. However, most existing catalytic DNA circuits can not achieve the reactant recycling operation in cells and in vivo. Additionally, specificity miRNA imaging in tumor site also is a challenge. Herein, inspired by "turning waste into wealth", we report a DNA sensor for imaging of miRNA in target cells based on apurinic/apyrimidinic endonuclease 1 (APE1)-activated reactant recycling catalytic DNA circuit., Results: The sensing function of the DNA sensor is suppressed firstly through engineering an apurinic/apyrimidinic (AP) site. In the presence of APE1, the AP site undergoes hydrolysis, thereby activating sensing activity and triggering the strand displacement reaction (SDR) under miRNA assistance. In this catalytic DNA circuit, the next reaction cycle can be initiated when the duplex strand waste products are reverted into active components, which allows it to be performed continuously just consuming fuel DNA without depleting the reactant. Noteworthy, the liposome plays important role in overcome biological barriers for nucleic acid delivery. The amplified miRNA imaging strategy is carried out in vivo by this DNA sensor with reducing off-tumor signal under assistance with APE1, and enhances tumor-to-normal tissue contrast compared with traditional catalytic DNA circuit., Significance and Novelty: Firstly, APE1-activated reactant recycling catalytic DNA circuit is developed. Secondly, miRNA image in cell and in animal is achieved with high spatial selectivity. Thirdly, the signal-to-background ratio for imaging is improved in vitro and in vivo. Lastly, our strategy provides an automatic yet versatile approach for the development of more efficient and selective DNA circuits capable of differentiating miRNA in cancer cells from those in normal cells, promising to be valuable in cancer diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Herein, a dual-mode fluorometric and colorimetric biosensor for Pax-5a gene was developed based on zinc-doped molybdenum disulfide quantum dots (Zn-MoS 2 QDs) by coupling exonuclease-assisted recycling amplification and peroxidase-mimic DNAzyme. In the presence of Pax-5a gene, the exonuclease III can cleave the duplexes formed by Pax-5a gene and the hairpin DNA (HP), releasing the output DNA (oDNA). G-rich DNA and magnetic beads (MBs) labeled with capture DNA (cDNA) can hybridize with oDNA to form the MBs-cDNA/oDNA/G-rich DNA sandwich complex. The remaining G-rich DNA in the supernatant through magnetic separation could bind hemin to produce G-quadruplex/hemin peroxidase-mimicking DNAzyme, which catalyzed the oxidization of 3,3'-diaminobenzidine (DAB) by H 2 O 2 . The generated brown oxidation product (oxDAB) had a distinct absorption peak at 464 nm and could quench the fluorescence of Zn-MoS 2 QDs at 406 nm. The high peroxidase activity of DNAzyme, recycling amplification strategy and magnetic separation technique led to excellent sensitivity and specificity of this detection platform. The detection limits of Pax-5a gene by fluorometric and colorimetric methods were 0.52 pM and 1.12 pM, respectively. Furthermore, this sensing system was successfully applied to Pax-5a gene determination in human serum samples, which had promising potential in biochemical analysis and clinical diagnosis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Pb 2+ has numerous sources in cosmetics, industrial pollution and other environments. Therefore, sensitive and accurate detection of Pb 2+ content is extremely important in food safety. In this work, bifunctional nanomaterials Ti 3 C 2 @PtPd NPs with fluorescence quenching effect and peroxidase activity were prepared by in situ growth of platinum‑palladium nanoparticles (PtPd NPs) on the surface of 2D material Ti 3 C 2 . Combining the DNA enzyme recognition element with magnetic separation technology, we constructed a fluorescence/colorimetric dual-channel for the sensitive detection of Pb 2+ . Under the optimal conditions, the detection ranges of this fluorescence/colorimetric bimodal sensing strategy were 0.1-1000 nmol/L and 0.5-1000 nmol/L, respectively. The LOD of the fluorescence method was 23 pmol/L, and that of the colorimetric method was 74 pmol/L, and the results of the detection were visible to the naked eye. This dual-mode sensing method provides a new platform for accurate, reliable and visualized detection of Pb 2+ ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

There is an urgent demand for a simple yet extremely accurate biosensor to analyze tumorigenesis. Herein, we present a novel fluorescent and enzyme-free approach for detecting p53 gene cascading proximity ligation-mediated catalytic hairpin assembly and DNAzyme-assisted signal reaction. When the target p53 gene is present, the interaction between p53 and L1 and L2 chains initiates catalytic hairpin assembly and subsequently exposes DNAzyme in the P3 probe. The exposed DNAzyme binds with the loop region of the P4 probe and generates a nicking site, resulting in the release of a significant amount of ATMND that is conjugated in the stem section of P4. This leads to an amplified fluorescence response, which serves as a fluorescence signal for the detection of the p53 gene. This method allows for the accurate and sensitive identification of the p53 gene, exhibiting a linear reaction range of 1 fM to 1 nM, with a limit of detection as low as 0.23 fM. Furthermore, this fluorescent method has been utilized for the examination of clinical samples with a favorable recovery rate. Crucially, this versatile platform may be expanded to analyze different targets by changing the corresponding recognition unit, showing great potential for point-of-care testing in tumorigenesis analysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The development of intelligent nanotheranostic technology that integrates diagnostic and therapeutic functions holds great promise for personalized nanomedicine. However, most of the nanotheranostic agents exhibit "always-on" properties and do not involve an amplification step, which may largely limit imaging contrast and restrict therapeutic efficacy. Herein, we construct a novel nanotheranostic platform (Hemin/DHPs/PDA@CuS nanocomposite) by assembling DNA hairpin probes (DHPs) and hemin on the surface of PDA@CuS nanosheets that enables amplified fluorescence imaging and activatable chemodynamic therapy (CDT) of tumors. The cancer-relevant APE1 triggers nucleic acid amplification with DHPs to generate activatable and amplified fluorescence signals for discriminating cancer cells from normal cells. Meanwhile, excessive G-quadruplex/hemin-based DNAzyme are also activated, and they function as Fenton-like catalysts to catalyze the production of highly toxic hydroxyl radicals (•OH) for CDT. Moreover, owing to the excellent photothermal conversion efficiency in the near-infrared-II (NIR-II) window, the PDA@CuS not only improves the catalytic performance of CDT but also furnishes PTT. A remarkable antitumor therapeutic effect is demonstrated both in vitro and in vivo . Therefore, the Hemin/DHPs/PDA@CuS nanocomposite is expected to provide a promising avenue for precise imaging-guided antitumor therapy.

DNAzyme-based cascade networks are effective tools to achieve ultrasensitive detection of low-abundance miRNAs. However, their designs are complicated and costly, and the operation is time-consuming. Herein, a novel simple noncascade DNAzyme network is designed and its amplification effect is comparable to or even better than many cascading ones. It is a nonenzymatic, isothermal, bicirculating amplification network consisting of two toehold-mediated strand-displacement reactions and a localized DNAzyme amplification strategy. Taking microRNA-122 as a target model, this ultrasensitive fluorescence biosensor has a detection limit of 84 zmol L -1 , which is 8-orders of magnitude lower than that of the nonamplification one. The ultrasensitivity mainly benefits from the exclusive design and positive self-feedback mechanism of the ingenious bicirculating DNAzyme amplification network. In addition, the utilization of superparamagnetic Fe 3 O 4 @SiO 2 particles not only helps for the localization of DNAzymes but also facilitates the rapid separation of signal probes (output DNA-CdTe QDs). This fluorescent biosensor also has the advantages of specificity, speed, thermal stability, and low cost. This novel design paves a new way to simple and effective bioamplification strategy, which may be very attractive for biosensors, DNA logic gates, and DNA computers.

DNAzyme represents a promising gene silencing toolbox yet is obstructed by the poor substrate accessibility in specific cells. Herein, a compact DNA nanoassembly, incorporating multimeric therapeutic DNAzyme, was prepared for selective delivery of gene-silencing DNAzyme with requisite cofactors and auxiliary chemo-drugs. By virtue of the sequence-conservative duplex-specific nuclease, the endogenous miRNA catalyzes the successive and site-specific cleavage of DNA nanoassembly substrate (nominated as the localized RNA walking machine) and thus ensures the liberation/activation of therapeutic agents with high accuracy and efficacy. The miR-10b-stimulated DNAzyme was designed to downregulate the TWIST transcription factor, an upstream promotor of miR-10b, thus acquiring the self-sufficient downregulation of TWIST/miR-10b signaling nodes (self-adaptive negative feedback loop) for abrogating tumor metastasis and chemo-resistance issues., (© 2024 Wiley-VCH GmbH.)

Enzymes encapsulated in extracellular vesicles (EVs) hold promise as biomarkers for early cancer diagnosis. However, precise measurement of their catalytic activities within EVs remains a notable challenge. Here, we report an enzymatically triggered spherical DNA nanomotor (EDM) that enables one-pot, cascaded, and highly sensitive analysis of the activity of EV-associated or free apurinic/apyrimidinic endonuclease 1 (APE1, a key enzyme in base excision repair) across various biological samples. The EDM capitalizes on APE1-triggered activation of DNAzyme (Dz) and its autonomous cleavage of substrates to achieve nonlinear signal amplification. Using EDM, we demonstrate a strong correlation between APE1 activity in EVs and that of their parental cancer cells. Additionally, EV APE1 mirrors the fluctuation of cellular APE1 activity in response to chemotherapy-induced DNA damage. In a pilot clinical study (n=63), the EDM-based assay reveals that more than 80 % of active APE1 in serum samples is EV-encapsulated. Notably, EV APE1 can differentiate early prostate cancer (PCa) patients from healthy donors (HDs) with an overall accuracy of 92 %, outperforming free APE1 in sera. We anticipate that EDM will become a versatile tool for quantifying EV-associated enzymes., (© 2024 Wiley-VCH GmbH.)

The host-guest recognition system is incorporated into the core region of the 10-23 DNAzyme for precise regulation of its functionality. Biochemical experiments demonstrate reversible and orthogonal control of the DNAzyme function using cucurbit(7)uril and its competitive guests. Furthermore, cellular experiments indicate the gene expression can be effectively manipulated through this ligand-controllable DNAzyme.

Flap endonuclease 1 (FEN1) plays a vital role in cancer by modulating DNA repair mechanisms, inducing genomic instability, and serving as a promising biomarker for cancer diagnosis and prognosis. In this work, we present the development of a novel DNAzyme signal amplification-directed point-of-care sensing system (Dz-PGM) for the sensitive and specific detection of FEN1. The Dz-PGM system utilizes DNAzyme signal amplification in conjunction with a personal glucose meter (PGM) for reporting, capitalizing on a biochemical cascade initiated by FEN1 recognition. Benefiting from enzymatic recognition, magnetic separation, and DNAzyme based signal amplification, this Dz-PGM system demonstrates exceptional specificity and achieves a low detection limit of 3.56× 10 -2 U/mL for FEN1. The versatility of the system is further demonstrated through its ability to screen FEN1 inhibitor drugs and to distinguish FEN1 levels in real cell samples with high accuracy. The article underscores the potential of the Dz-PGM system as a promising tool for early cancer diagnosis, and in constructing sensitive detection platforms for DNA repair enzymes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Although DNAzyme sensors have been widely developed for imaging metal ions, their application in specific subcellular compartments remains challenging due to low spatial controllability. Here we present a locally activatable, DNAzyme-based sensing technology that enables subcellular compartment-specific imaging of metal ions through ribosomal RNA (rRNA) regulated signal amplification. The system leverages a subcellularly encoded rRNA to locally activate DNAzyme-based sensors, and further drives signal amplification via multiple turnover cleavage of molecular beacons, to significantly enhance sensitivity and spatial precision for metal-ion imaging in specific organelles (e.g. mitochondria) or membraneless compartments (e.g. cytosol). Furthermore, we demonstrate that the system allows in situ monitoring of subcellular dynamics of mitochondrial Zn 2+ during ischemia and the drug intervention. This study expands the DNAzyme toolbox for investigating the role of subcellular metal-ion dynamics in disease processes., (© 2024 Wiley-VCH GmbH.)

The detection of pathogens is critical for preventing and controlling health hazards across clinical, environmental, and food safety sectors. Functional nucleic acids (FNAs), such as aptamers and DNAzymes, have emerged as versatile molecular tools for pathogen detection due to their high specificity and affinity. This review focuses on the in vitro selection of FNAs for pathogens, with emphasis on the selection of aptamers for specific biomarkers and intact pathogens, including bacteria and viruses. Additionally, the selection of DNAzymes for bacterial detection is discussed. The integration of these FNAs into colorimetric biosensors has enabled the development of simple, cost-effective diagnostic platforms. Both non-catalytic and catalytic colorimetric biosensors are explored, including those based on gold nanoparticles, polydiacetylenes, protein enzymes, G-quadruplexes, and nanozymes. These biosensors offer visible detection through color changes, making them ideal for point-of-care diagnostics. The review concludes by highlighting current challenges and future perspectives for advancing FNA-based colorimetric biosensing technologies for pathogen detection., (© 2024 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

In this study, we present an intelligent electromagnetic-actuated microfluidic chip integrated with a G-quadruplex DNAzyme-based biocatalysis platform for rapid and sensitive tetracycline (TC) detection. In this sensing system, TC significantly quenches fluorescent magnetic carbon dots (M-CDs) via the internal filtration effect and dynamic quenching (the excitation and emission wavelength at 350 and 440 nm, respectively). Then, the G-quadruplex on the M-CDs-Aptamer is exposed and bound with hemin to form hemin-G-quadruplex DNAzyme, catalyzing the conversion of 3,3',5,5'-tetramethylbenzidine to produce blue color. This enables the fluorescence/colorimetric detection of TC. Importantly, an automatic electromagnet-integrated microfluidic chip was designed to control the shuttling of magnetic materials in each function slot according to a programmed sequence. Under the optimal conditions, the detection limits of TC for fluorescence and colorimetric methods were 11 and 43 μmol/L, respectively. The detection results for tilapia ( Oreochromis nilotica ) were comparable to those of traditional high-performance liquid chromatography. This platform offers excellent performance for TC determination and potential for portable, intelligent detection of trace pollutants in food and the environment.

Herein, an electrochemical aptasensor for highly sensitive detection of acetamiprid (ACE) was constructed based on a one-step cascade amplification strategy. This innovative strategy integrated DNA walker containing DNAzyme sequence into entropy-driven catalysis (EDC) system. The trigger strand was released by aptamer-specific binding to ACE, initiating the EDC amplification circuit and delivering DNA walker strands. The dangling DNA walker continuously bound and cleaved hairpin substrate to form G-quadruplex fragments with the assistance of Mg 2+ . The G-quadruplex fragments folded and captured hemin to form multitudinous G-quadruplex/hemin complexes in the presence of K + , generating significantly enhanced current, enabling enzyme-free, label-free and highly sensitive detection of ACE, with a linear detection range of 100 fM to 50 nM and a detection limit of 68.36 fM (S/N = 3). The constructed aptasensor achieved the reliable detection of ACE in vegetable soil and cucumber samples, demonstrating its potential application prospects in environmental protection and food supervision., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Deoxyribozymes or DNAzymes represent artificial short DNA sequences bearing many catalytic properties. In particular, DNAzymes able to cleave RNA sequences have a huge potential in gene therapy and sequence-specific analytic detection of disease markers. This activity is provided by catalytic cores able to perform site-specific hydrolysis of the phosphodiester bond of an RNA substrate. However, the vast majority of existing DNAzyme catalytic cores have low efficacy in in vivo experiments, whereas SELEX based on in vitro screening offers long and expensive selection cycle with the average success rate of ~ 30%, moreover not allowing the direct selection of chemically modified DNAzymes, which were previously shown to demonstrate higher activity in vivo. Therefore, there is a huge need in in silico approach for exploratory analysis of RNA-cleaving DNAzyme cores to drastically ease the discovery of novel catalytic cores with superior activities., Results: In this work, we develop a machine learning based open-source platform SequenceCraft allowing experimental scientists to perform DNAzyme exploratory analysis via quantitative observed rate constant (k obs ) estimation as well as statistical and clustering data analysis. This became possible with the development of a unique curated database of > 350 RNA-cleaving catalytic cores, property-based sequence representations allowing to work with both conventional and chemically modified nucleotides, and optimized k obs predicting algorithm achieving Q 2  > 0.9 on experimental data published to date., Conclusions: This work represents a significant advancement in DNAzyme research, providing a tool for more efficient discovery of RNA-cleaving DNAzymes. The SequenceCraft platform offers an in silico alternative to traditional experimental approaches, potentially accelerating the development of DNAzymes., Competing Interests: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The concentration elevation of myocardial microRNA (miRNA) biomarker is associated with the pathogenic process of acute myocardial infarction (AMI), and sensitive quantification of myocardial miRNA biomarker plays an important role for early AMI diagnosis and its treatment. In response, this work describes an ultrasensitive and non-label electrochemical biosensor for the assay of myocardial miRNA based on cascade signal amplifications integrated by DNAzyme walker and hemin/G-quadruplex nanowires. The DNAzyme walker is activated by presence of target miRNAs to move along the electrode surface to cyclically cleave the substrate hairpins to release G-quadruplex segments, which further trigger the in situ formation of many hemin/G-quadruplex nanowires. The large amounts of hemin intercalated into the DNA nanowires subsequently generate drastically magnified electrochemical current signals for highly sensitive label-free assay of myocardial miRNAs down to 15.7 fM within dynamic range of 100 fM to 10 nM. Such a biosensor also has high selectivity and can monitor myocardial miRNAs in diluted serums at low levels, providing a sensitive and reliable platform for diagnosing infarct-associated cardiovascular diseases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Hematoma and secondary neuroinflammation continue to pose a significant challenge in the clinical treatment of intracerebral hemorrhage (ICH). This study describes a nanoregulator formed through the self-assembly of Mg 2+ and signal regulatory protein α (SIRPα) DNAzyme (SDz), aimed at enhancing hematoma resolution and inhibiting neuroinflammation in the treatment of ICH. The structure of SDz collapses in response to the acidic endo/lysosomal microenvironment of microglia, releasing Mg 2+ and the SIRPα DNAzyme. The Mg 2+ then acts as a cofactor to activate the SIRPα DNAzyme. By blocking the CD47-SIRPα signaling pathway, microglia can rapidly and effectively phagocytose red blood cells (RBCs), thereby promoting the clearance of the hematoma. Simultaneously, Mg 2+ reset the microglia to the M2 phenotype by inhibiting the MYD88/MAPK/NF-κB signaling pathway, thereby modulating the inflammatory microenvironment of ICH. This co-delivery and synergistic strategy resulted in a significant reduction in hematoma size, decreasing from 11.90 to 5.84 mm 3 , and promoted recovery from ICH with minimal systemic side effects. This simple yet highly effective nanoplatform, which involves complex synergistic mechanisms, proves to be effective for ICH therapy and holds great promise for introducing novel perspectives into clinical and translational approaches for ICH., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

As the most abundant modification in eukaryotic messenger RNA (mRNA) and long noncoding RNA (lncRA), N 6 -methyladenosine (m 6 A) has been shown to play essential roles in various significant biological processes and attracted growing attention in recent years. To investigate its functions and dynamics, there is a critical need to quantitatively determine the m 6 A modification fractions at a precise location. Here, we report a deoxyribozyme mediated CRISPR-Cas12a platform (termed "DCAS") that can directly quantify m 6 A fractions at single-base resolution. DCAS employs a deoxyribozyme (VMC10) to selectively cleave the unmodified adenine (A) in the RNA, allowing only m 6 A-modified RNA amplified by RT-PCR. Leveraging the CRISPR-Cas12a quantify the PCR amplification products, DCAS can directly determine the presence of m 6 A at target sites and its fractions. The combination of CRISPR-Cas12a with RT-PCR has greatly improved the sensitivity and accuracy, enabling the detection of m 6 A-modified RNA as low as 100 aM in 2 fM total target RNA. This robustly represents an improvement of 2-3 orders of magnitude of sensitivity and selectivity compared to traditional standard methods, such as SCARLET and primer extension methods. Therefore, this method can be successfully employed to accurately determine m 6 A fractions in real biological samples, even in low abundance RNA biomarkers., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Non-invasive monitoring of glucose levels in tears and saliva is crucial for diagnosing and predicting various illnesses, such as diabetic nephropathy. However, the capability of the current glucose detection methods to identify small amounts of glucose with a high sensitivity remains a significant obstacle. This study proposes a simple, visual technique for sensitively detecting glucose levels from tears and saliva using glucose oxidase (GOx) to catalyze glucose and pistol-like DNAzyme (PLDz) to enhance the signal. In particular, the β-D-glucose present in the samples serves as the initial molecule that GOx identifies and catalyzes to generate gluconic acid and hydrogen peroxide (H 2 O 2 ). The H 2 O 2 induces the self-cleavage of PLDz, activating the "part b" sequence. This activation initiates catalytic hairpin assembly (CHA) and releases the DNAzyme section in the H1 probe. The DNAzyme acts as a peroxidase analog, facilitating the catalysis of the 3,3',5,5'-tetramethylbenzidine (TMB)-hydrogen peroxide (H 2 O 2 ) system and resulting in color changes. The proposed method exhibits a broad detection range of six orders of magnitude and a low limit of 0.32 μM for glucose detection. Furthermore, the proposed method was highly effective in detecting glucose in saliva and tears, suggesting that it could potentially diagnose hyperglycemia-related disorders in clinical environments., Competing Interests: Declarations. Ethics Approval: Permission from the Institutional Animal Ethical Committee was received before making these experiments (No. SYXK-2023–0014). Consent to Participate: Not applicable. Consent for Publication: All authors agree to publish. Competing Interests: The authors declare that they have no competing interests., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

In situ monitoring microRNA (miRNA) expression in vivo holds immense potential for directly visualizing the occurrence and progression of tumors. However, the significant barrier to developing a probe that can overcome the low abundance of miRNAs while providing an output signal with unlimited tissue penetration depth remains formidable. In this study, we developed a DNA machine-based magnetic resonance imaging nanoprobe (MRINP) for amplified detection of miR-21 in vivo. The MRINP was constructed with superparamagnetic Fe 3 O 4 nanoparticles (NPs), paramagnetic Gd-DOTA complexes, and miR-21-activated DNA machines; the DNA machine was composed of hairpin DNAzyme (HD) strands serving as the DNAzyme walker and hairpin substrate (HS) strands serving as the track. Once uptake into tumor cells, the intracellular miR-21 specifically recognized and hybridized with the HD strand, restoring the activity of DNAzyme. Subsequently, the DNAzyme walker autonomously traveled on the surface of MRINP, and each step movement of the DNAzyme walker resulted in the cleavage of its substrate strands and the ensued release of the Gd-DOTA complex-labeled oligonucleotides, turning on the T 1 signal of Gd-DOTA complexes for in situ imaging of miR-21 in tumor-bearing mice. This strategy would offer a promising approach for mapping tumor-specific biomarkers in vivo with unlimited penetration depth., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Three-dimensional (3D) DNA walking nanomachines have been widely applied in molecular diagnostics and cancer therapy. Specially, DNA dendrimer with 3D nanostructure has gained increasing attention in biomedical applications because of its high biostability, excellent programmability, and outstanding biocompatibility. In this chapter, we developed a 3D DNA walking nanomachine by assembling all nanomachine components (DNAzyme and substrate) onto a DNA dendrimer for miRNA imaging in living cells. In this design, the number of DNAzyme and substrate on the surface of the DNA dendrimer could be precisely regulated to fully implement the function of the DNA nanomachine., (© 2025. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

There is an urgent need for novel strategies to accurately and reliably detect pathogenic bacteria to address the global epidemic of antibiotic resistance. This study proposes an innovative approach combining dual aptamer-based target recognition and proximity ligation assay (PLA) triggered DNAzyme recycling cleavage. This method allows for the precise identification and reliable detection of methicillin-resistant Staphylococcus aureus (MRSA). The fluorescence probe labeled with a fluorophore is modified on gold nanoparticles (AuNPs), resulting in the quenching of the fluorescent signal by the AuNPs. The interaction between MRSA and two aptamers leads to forming a Mg 2+ -dependent DNAzyme. The DNAzyme cleaves the fluorescence probe, causing the fluorescent fragment to detach from the surface of the AuNPs, in which the quenched fluorescence signal in the fluorescence probe reappears. The DNAzyme-assisted cleavage and rebinding process generates a processive strolling along the surface track of AuNPs. Consequently, the fluorescence intensity experiences a substantial recovery. A strong linear correlation is observed between the fluorescence intensity and MRSA concentration within 50 cfu/mL to 10 6  cfu/mL. We believe that implementing the novel integrated strategy will broaden the range of bacterial detection methods in the battlefield environment and stimulate the creation of potential new drugs in the future., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Sugarcane smut is a major disease affecting the yield and quality of sugarcane, and its early detection is crucial for the healthy development of sugarcane industry. In this work, a dual-modal biosensing platform is designed based on Au-V-MOF and 3D DNA walker for highly sensitive and precise detection of the sugarcane smut pathogen. This detection system utilizes the catalytic properties of biocatalysts and the precise cleavage of DNAzymes, along with 3D DNA walker nanotechnology and a designed "walking track", to achieve amplified detection signals and accurate target recognition. The detection platform utilizes catalytic hairpin assembly for target recycling. Output strand T1 interacts with DNAzyme via a 3D transporter, cleaving S1 in Mg 2+ presence. This triggers cascading hybridization chain reaction to form long double-stranded DNA structures that absorb substantial methylene blue (MB). This amplifies the electrical signal and causes a proportional color change due to the redox reaction of MB, which enables electrochemical and colorimetric detection of the target. The method shows a linear response range from 0.0001 to 10,000 pM with a detection limit of 56.76 aM (S/N = 3). It features high sensitivity, specificity, and accuracy, which offers significant potential for early warning and precise detection of sugarcane smut., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2024. Published by Elsevier B.V.)

Developing cost-effective, consumer-accessible platforms for point-of-use environmental and clinical pathogen testing is a priority, to reduce reliance on laborious, time-consuming culturing approaches. Unfortunately, a system offering ultrasensitive detection capabilities in a form that requires little auxiliary equipment or training has remained elusive. Here, a colorimetric DNAzyme-crosslinked hydrogel sensor is presented. In the presence of a target pathogen, DNAzyme cleavage results in hydrogel dissolution, yielding the release of entrapped gold nanoparticles in a manner visible to the naked eye. Recognizing that Escherichia coli holds high relevance within both environmental and clinical environments, an E. coli-responsive DNAzyme is incorporated into this platform. Through the optimization of the hydrogel polymerization process and the discovery of bacteriophage-induced DNAzyme signal amplification, 10 1 CFU mL -1 E. coli is detected within real-world lake water samples. Subsequent pairing with an artificial intelligence model removed ambiguity in sensor readout, offering 96% true positive and 100% true negative accuracy. Finally, high sensor specificity and stability results supported clinical use, where 100% of urine samples collected from patients with E. coli urinary tract infections are accurately identified. No false positives are observed when testing healthy samples. Ultimately, this platform stands to significantly improve population health by substantially increasing pathogen testing accessibility., (© 2024 The Author(s). Advanced Materials published by Wiley‐VCH GmbH.)