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Graphdiyne oxide quantum dots (GDYO QDs), as derivatives of graphdiyne (GDY), have excellent electroconductibility and luminous properties and can be applied as a new ECL emitter. Herein, an electrochemiluminescence (ECL) biosensor for miRNA-21 ultrasensitive determination is constructed based on AuNPs/GDY, GDYO QD and oligonucleotide signal amplification strategy that integrates DNA walker and hybridization chain reaction (HCR) amplification. As electrode substrate material, AuNPs/GDY can not only bond with the aptamer CP but can also enhance the conductivity of the interface. When miRNA-21 exists, the DNA walker process is initiated, and the signaling probes are introduced on the electrode surface, producing abundant double-stranded H1/H2; then, H3/H4 undergoes complementary base pairing with H1/H2 through HCR. With the increase in miRNA-21, the 3D DNA nanomachine is actively manipulated, resulting in a gradual increase in ECL signal. This ECL biosensor demonstrates outstanding performance in the determination of miRNA-21 in the linear range from 0.1 fM to 1 nM. This study offers a new sensitive idea for the clinical analysis of cancer biomarkers. [ABSTRACT FROM AUTHOR]

Thalassemia is a globally prevalent single-gene blood disorder, with nearly 7% of the world's population being carriers. Therefore, the development of specific and sensitive methods for thalassemia detection holds significant importance. Herein, a sandwich-type electrochemical/colorimetric dual-mode biosensor is developed based on gold nanoparticles (AuNPs)/graphdiyne (GDY) and DNA nanoframeworks for ultra-sensitive detection of CD142 gene associated with sickle cell anemia. Utilizing AuNPs/GDY as the substrate electrode, the fabricated sandwiched DNA nanoframework not only improves selectivity but also introduces numerous signal probes to further amplify the output signal. In the electrochemical mode, glucose oxidase catalyzes the oxidation of glucose, generating electrons that are transferred to the biocathode for a reduction reaction, resulting in an electric signal proportional to the target concentration. In the colorimetric mode, glucose oxidase catalyzes the generation of H 2 O 2 from glucose, and with the aid of horseradish peroxidase, H 2 O 2 oxidizes 3,3′,5,5′-tetramethylbenzidine to produce a colored product, enabling colorimetric detection of the target. The dual-mode biosensor demonstrates a detection range of 0.0001–100 pM in the electrochemical mode and a detection range of 0.0001–10,000 pM in the colorimetric mode. The detection limit in the electrochemical mode is determined to be 30.4 aM (S/N=3), while in the colorimetric mode is of 35.6 aM (S/N=3). This dual-mode detection achieves ultra-sensitive detection of CD142, demonstrating broad prospects for application. [ABSTRACT FROM AUTHOR]

• Smartphone-assisted self-powered sensor is developed for Ultra-sensitive detection of microRNA. • Binary 3D DNA Walkers combined with CRISPR/Cas12a system greatly enhances the sensitivity of biosensor. • Integrated capacitors amplify detection signal, enhancing sensitivity by 20.7-fold. • The dual-mode detection strategy significantly enhances the accuracy of the method. Malignant tumors are significant diseases that pose a threat to human life and health. The advancement of highly sensitive and specific methods is of excellent significance. This study proposes a novel detection platform that employs a smartphone-assisted self-powered sensing system with binary 3D DNA Walkers mediated CRISPR/Cas12a system and ultra-thin 2D graphdiyne for ultrasensitive dual-mode detection of breast cancer biomarker microRNA-let-7a. The binary 3D DNA Walkers possess high efficiency in movement and multifunctional characteristics. When combined with the CRISPR/Cas12a system, they can retain the advantages of 3D DNA Walker while releasing a large of trigger strands complementary to CRISPR RNA, thereby greatly enhancing the sensitivity of the sensor. In addition, capacitors are also integrated into the sensing system to further amplify the detection signal, resulting in a 20.7-fold increase in sensitivity of the method. Additionally, the adoption of an electrochemical/colorimetric dual-mode detection strategy significantly enhances the accuracy of the new approach. The newly developed detection method exhibits a linear range of 0.0001–10000 pM with a detection limit of 8.11 aM (S/N = 3). This work offers a reliable portable sensor for sensitive and accurate detection of tumor biomarkers, enabling remote disease sensing and on-site monitoring applications. [ABSTRACT FROM AUTHOR]

Research has shown that microRNAs exhibit regular dysregulation in cancers, making them potential biomarkers for cancer diagnosis. However, achieving specific and sensitive detection of microRNAs has been a challenging task. To address this issue, two-dimensional networked graphdiyne is used to fabricate a self-powered biosensor and establish a new approach for ultra-responsive dual-mode detection of miRNA-141, a breast cancer biomarker. This method detects miRNA-141 using both electrochemical and colorimetric modes by measuring the output electrical signal of an enzyme-based biofuel cell and the RGB blue value of the electrolyte solution. Tetrahedral DNA and DNA nanorods also are immobilized on the electrode as a biocathode and methylene blue is used as the electron acceptor, which is fixed in the DNA phosphate backbone through electrostatic adsorption. The bioanode catalyzes the oxidation of glucose to produce electrons, which reduces methylene blue to its reduced form, resulting in a high open-circuit voltage (E OCV ) and a highger RGB Blue value, enabling dual-mode detection. A reliable linear correlation is observed between E OCV values and miRNA-141 concentrations ranging from 0.0001 to 100 pM, with a detection limit of 21.9 aM (S/N = 3). Additionally, the colorimetric mode also demonstrates a reliable linear correlation with a concentration range of 0.0001–10000 pM, and this method can detect a concentration of 22.2 aM (S/N = 3). This innovative research realizes sensitive and accurate determination of miRNA-141 and provides an important new method for cancer diagnosis. [Display omitted] • A novel self-powered platform is developed based on graphdiyne and DNA nanorods for ultrasensitive miRNA-141 detection. • Electrochemical/colorimetric dual-mode detection greatly improves reliability and accuracy. • The using of AuNPs/GDY, DNA nanorods and T-DNA enables amplified signal, reducing enzyme consumption and improved stability. [ABSTRACT FROM AUTHOR]

MicroRNA-21 (miRNA-21) is currently the only known oncogenic miRNA that is upregulated in almost all malignant tumors and exhibits a broad spectrum of tumor recognition characteristics. It holds significant value in the early diagnosis, malignant degree assessment, and prognostic evaluation of tumors. In this study, a novel dual-mode self-powered sensing platform is developed using Au nanoparticles/graphdiyne as the electrode substrate and combined with DNA nanoring for highly sensitive and specific detection of miRNA-21. The DNA nanoring structure, which is easy to prepare and contains multiple recognition sites, induces significant electrochemical/colorimetric signal responses of the signaling molecule methylene blue. Under optimal conditions, the linear ranges of the electrochemical and colorimetric detection modes of this self-powered sensor are 0.1 fM-100 pM and 0.1 fM-10 nM, respectively, with the detection limits of 35.1 aM and 61.6 aM (S/N=3). This strategy provides a new reference for the sensitive detection of microRNA and has immense potential for application in the screening and detection of clinical nucleic acid diseases. [ABSTRACT FROM AUTHOR]

Two-dimensional carbon-coated molybdenum disulfide (MoS 2 @C) hollow nanorods are combined with nucleic acid signal amplification strategies and DNA hexahedral nanoframework to construct a novel self-powered biosensing platform for ultra-sensitive dual-mode detection of tumor suppressor microRNA-199a. The nanomaterial is applied on carbon cloth and then modified with glucose oxidase or using as bioanode. A large number of double helix DNA chains are produced on bicathode by nucleic acid technologies including 3D DNA walker, hybrid chain reaction and DNA hexahedral nanoframework to adsorb methylene blue, producing high E OCV signal. Methylene blue also is reduced and an increased RGB Blue value is observed. For microRNA-199a detection, the assay shows a extensive linear range of 0.0001–100 pM with a low detection limit of 4.94 amol/L (S/N = 3). The method has been applied to the detection of actual serum samples, providing a novel method for the accurate and sensitive detection of tumor markers. [Display omitted] • The 2D MoS 2 @C hollow nanorods with good conductivity are prepared. • A smart self-powered sensor with quadruple-signal amplification is fabricated. • A dual-mode strategy with high reliability is developed for miRNA-199a detection. [ABSTRACT FROM AUTHOR]