CRISPR/Cas12a-triggered ordered concatemeric DNA probes signal-on/off multifunctional analytical sensing system for ultrasensitive detection of thalassemia.

Based on CRISPR/Cas12a triggered ordered concatemeric DNA probes, a "on/off" self-powered biosensor is developed to achieve highly sensitive detection of thalassemia gene CD142 through open-circuit potential-assisted visual signal output. The ingeniously constructed glucose oxidase (GOD)-functionalized ordered concatemeric DNA probe structure can significantly amplify signal output, while the coupled CRISPR/Cas12a system is served as a "signal switch" with excellent signal-transducing capabilities. When the ordered concatemeric DNA probe structure is anchored on electrode, the response signal of the sensing system is in the "signal on" mode. While, the presence of the target activates the non-specific cleavage activity of the CRISPR/Cas12a system, causing the sensing system to switch to the "signal off" mode. In the detection system, GOD catalyzes the oxidation of glucose to produce hydrogen peroxide, which further catalyzes the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to form a color product, enabling visual signal of the target through naked-eye color contrast. By employing a multifunctional analytical mode combining electrochemical and visual signal outputs, accurate determination of the target is achieved, with linear ranges of 0.0001-100 pM, and detection limits of 48.1 aM (S/N = 3). This work provides a reference method for sensitive detection of thalassemia genes and holds great diagnostic potential in biomedical applications.

A Macrophage Membrane-Coated Cu-WO3-x-Hydro820 Nanoreactor for Treatment and Photoacoustic/Fluorescence Dual-Mode Imaging of Inflamed Liver Tissue.

A disease-targeting nanoplatform that integrates imaging with therapeutic activity would facilitate early diagnosis, treatment, and therapeutic monitoring. To this end, a macrophage membrane-coated Cu-WO3-x-Hydro820 (CWHM) nanoreactor was prepared. This reactor was shown to target inflammatory tissues. The reactive oxygen species (ROS) such as H2O2 and ·OH in inflammatory tissues can react with Hydro820 in the reactor to form the NIR fluorophore IR820. This process allowed photoacoustic/fluorescence dual-mode imaging of H2O2 and ·OH, and it is expected to permit visual diagnosis of inflammatory diseases. The Cu-WO3-x nanoparticles within the nanoreactor shown catalase and superoxide enzyme mimetic activity, allowing the nanoreactor to catalyze the decomposition of H2O2 and ·O2- in inflammatory cells of hepatic tissues in a mouse model of liver injury, thus alleviating the oxidative stress of damaged liver tissue. This nanoreactor illustrates a new strategy for the diagnosis and treatment of hepatitis and inflammatory liver injury.

Multiple signal amplification strategy induced by biomarkers of lung cancer: A self-powered biosensing platform adapted for smartphones.

Lung cancer is a major malignant cancer with low survival rates, and early diagnosis is crucial for effective treatment. Herein, a biosensing platform that is self-powered derived from a capacitor-coupled EBFC has been developed for ultra-sensitive real-time identification of microRNA-21 (miRNA-21) with the assistance of a mobile phone. The flexible substrate of the platform is prepared on a carbon paper modified with graphdiyne and gold nanoparticles. The biosensor employs DNAzyme-mediated dual strand displacement amplification, which enhances the signal output intensity of the EBFC and improves selectivity. The coupling of the capacitor with the EBFC significantly amplifies the sensing signal, causing a 10.6-fold surge in current respond and further improving the sensitivity of the sensing platform. The established detection approach demonstrates a linear relationship varied from 0.0001 to 10,000 pM, with a sensitivity down to 32.3 aM as the minimum detectable limit, which has been effectively utilized for detecting miRNA-21 in practical samples. This sensing system provides strong support for the construction of portable detection devices, and the strategy of the platform construction provides an effective method for ultra-sensitive and accurate detection of miRNA, holding great potential in clinical diagnosis, prognosis evaluation, and drug screening for cancer.

A sandwich-type dual-mode biosensor based on graphdiyne and DNA nanoframework for ultra-sensitive detection of CD142 gene.

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 H2O2 from glucose, and with the aid of horseradish peroxidase, H2O2 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.

Recent Advances in Tailored Fabrication and Properties of Biobased Self-Healing Polyurethane.

With the emergence of challenges in the environmental degradation and resource scarcity fields, the research of biobased self-healing polyurethane (BSPU) has become a prevailing trend in the technology of the polyurethane industry and a promising direction for developing biomass resources. Here, the production of BSPU from lignocellulose, vegetable oil, chitosan, collagen, and coumarin is classified, and the principles of designing polyurethane based on compelling examples using the latest methods and current research are summarized. Moreover, the impact of biomass materials on self-healing and mechanical properties, as well as the tailored performance method, are presented in detail. Finally, the applications of BSPU in biomedicine, sensors, coatings, etc. are also summarized, and the possible challenges and development prospects are explored to helpfully make progress in the development of BSPU. These findings demonstrate valuable references and practical significance for future BSPU research.

Smart enzyme-free amplification dual-mode self-powered platform designed on two-dimensional networked graphdiyne and DNA nanorods for ultra-sensitive detection of breast cancer biomarkers.

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 (EOCV) and a highger RGB Blue value, enabling dual-mode detection. A reliable linear correlation is observed between EOCV 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.

Flexible Self-Powered Sensing System Based on Novel DNA Circuit Strategy and Graphdiyne for Thalassemia Gene by Rapid Naked-Eye Tracking and Open-Circuit Voltage.

Based on the controllable instantaneous self-assembly ability of long-chain branched DNA nanostructures and the synergistic effect between nucleic acid amplification without enzymes, a highly sensitive and highly specific self-powered biosensing platform is developed. Two-dimensional graphdiyne is prepared, modified on flexible carbon cloth, and then functionalized with gold nanoparticles. When DNA mi-tubes are applied on it, target thalassemia gene CD122 triggers a dual-catalytic hairpin assembly reaction. The generated nanoscale DNA is precisely captured by the DNA mi-tube, exposing binding sites and activating the hybridization chain reaction to form long-chain branched DNA. Double-stranded DNA, along with dendritic DNA carrying a large number of guanine bases, precisely captures the signal molecule methylene blue (MB), generating a significant electrochemical signal. The redox reaction of MB also causes a proportional change in the system's color, achieving a colorimetric detection functionality. An efficient dual-mode self-powered sensing platform, therefore, is established for detecting the thalassemia gene CD122. The linear response range of target concentration to open-circuit voltage and RGB Blue value is 0.0001-10,000 pM. The detection limit under electrochemical mode is 36.3 aM (S/N = 3), and under colorimetric mode, it is as low as 12.1 aM (S/N = 3). The new method exhibits high sensitivity, excellent selectivity, and high accuracy, providing a universal strategy for designing novel biosensing platforms that can be extended to the detection of other biomolecules.

Smart Target-Initiated Catalytic DNA Junction Circuit Amplification Strategy for the Ultrasensitive Electrochemiluminescence Detection of MicroRNA.

One of the highly attractive research directions in the electrochemiluminescence (ECL) field is how to regulate and improve ECL efficiency. Quantum dots (QDs) are highly promising ECL materials due to their adjustable luminescence size and strong luminous efficiency. MoS2 NSs@QDs, an ECL emitter, is synthesized via hydrothermal methods, and its ECL mechanism is investigated using cyclic voltammetry and ECL-potential curves. Then, a stable and vertical attachment of a triplex DNA (tsDNA) probe to the MoS2 nanosheets (NSs) is applied to the electrode. Next, an innovative ECL sensor is courageously empoldered for precise and ultrasensitive detection of target miRNA-199a through the agency of ECL-resonance energy transfer (RET) strategy and a dextrous target-initiated catalytic three-arm DNA junction assembly (CTDJA) based on a toehold strand displacement reaction (TSDR) signal amplification approach. Impressively, the ingenious system not only precisely regulates the distance between energy donor-acceptor pairs leave energy less loss and more ECL-RET efficiency, but also simplifies the operational procedure and verifies the feasibility of this self-assembly process without human intervention. This study can expand MoS2 NSs@QDs utilization in ECL biosensing applications, and the proposed nucleic acid amplification strategy can become a miracle cure for ultrasensitive detecting diverse biomarkers, which helps researchers to better study the tumor mechanism, thereby unambiguously increasing cancer cure rates and reducing the risk of recurrence.

A highly sensitive self-powered sensing method designed on DNA circuit strategy and MoS2 hollow nanorods for detection of thalassemia.

Thalassemia is one of the most common monogenic diseases, which seriously affects human growth and development, cardiovascular system, liver, etc. There is currently no effective cure for this disease, making screening for thalassemia particularly important. Herein, a self-powered portable device with high sensitivity and specificity for efficiently screening of low-level thalassemia is developed which is enabled with AuNPs/MoS2@C hollow nanorods and triple nucleic acid amplification technologies. It is noteworthy that AuNPs/MoS2@C electrode shows the advantages of high electrocatalytic activity, fast carrier migration rate and large specific surface area, which can significantly improve the stability and output signal of the platform. Using high-efficiency tetrahedral DNA as the probe, the target CD122 gene associated with thalassemia triggers a catalytic hairpin assembly reaction to achieve CD122 recycling while providing binding sites for subsequent hybridization chain reaction, greatly improving the detection accuracy and sensitivity of the device. A reliable electrochemical/colorimetric dual-mode assay for CD122 is then established, with a linear response range of 0.0001-100 pM for target concentration and open circuit voltage, and the detection limit is 78.7 aM (S/N = 3); a linear range of 0.0001-10000 pM for CD122 level and RGB Blue value, with a detection limit as low as 58.5 aM (S/N = 3). This method achieves ultra-sensitive and accurate detection of CD122, providing a new method for the rapid and accurate screening of thalassemia.

Self-powered dual-mode sensing strategy based on graphdiyne and DNA nanoring for sensitive detection of tumor biomarker.

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.

Fabrication of MIL-101(Cr)/silver nanocomposites as SERS substrate for sensitive determination of malachite green and crystal violet in tilapia.

Nanocomposites with multiple functions have attracted much attention in designing novel SERS substrates. In this report, the enrichment ability of MIL-101(Cr) and the local surface plasma resonance (LSPR) of silver nanoparticles are combined to fabricate a SERS substrate denoted as MIL-101-MA@Ag, which can simultaneously produce high-density and uniformly distributed hot spots. Moreover, the enrichment ability of MIL-101(Cr) can further improve the sensitivity by concentrating and transferring the analytes in the vicinity of hot spots. Under optimal conditions, MIL-101-MA@Ag showed good SERS activity for malachite green (MG) and crystal violet (CV), with detection limits as low as 9.5×10-11 M and 9.2×10-12 M at 1616 cm-1, respectively. The prepared substrate has been successfully applied to detect MG and CV in tilapia, the recovery rate of fish tissue extract was 86.4~102%, and the relative standard deviation (RSD) was 8.9~15%. The results demonstrate that MOF-based nanocomposites are expected to be useful SERS substrates and have a universal applicability for the detection of other hazardous molecules.

Enhancing biosensing with fourfold amplification and self-powering capabilities: MoS2@C hollow nanorods-mediated DNA hexahedral framework architecture for amol-level liver cancer tumor marker detection.

Two-dimensional carbon-coated molybdenum disulfide (MoS2@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 EOCV 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.

Capacitor-parallel-amplified decoupled photoelectrochemical/electrochromic dual-mode bioassay for sensitive detection of microRNA with high reliability.

To achieve sensitive detection of low-content microRNA, photoelectrochemical/electrochromic dual-mode sensor with intrinsically low background signal has been developed, but the two detection modules are usually designed with a series-connected structure, which may cause signal interference and thus affect the detection reliability. To solve the above problems, a decoupled dual-mode bioassay for sensitive miRNA-21 detection with high reliability is constructed in this work, by selecting two capacitors to realize parallel amplification for the two detection modules, supplemented with a 3D DNA nanoring photoelectrode signal amplification strategy. The complete decoupling of the two detection modes, photoelectrochemical and electrochromic, as well as the use of digital multimeter, improves the reliability and accuracy of the sensor, and also frees it from dependence on electrochemical workstation, making detection more intuitive and faster. With simple structure, low cost, good reproducibility, high sensitivity, and easy operation, the capacitor-parallel-amplified decoupled photoelectrochemical/electrochromic dual-mode bioassay has broad application prospect in on-site point-of-care detection of diseases and low-cost clinical diagnosis. The design idea of decoupled dual-mode detector can also be extended to the construction of other dual-mode methods.

Integrating Network Pharmacology, Molecular Docking and Pharmacological Evaluation for Exploring the Polyrhachis vicina Rogers in Ameliorating Depression.

Purpose: To investigate the mechanisms of antidepressant action of active fraction of Polyrhachis vicina Rogers (AFPR) through network pharmacology, molecular docking and experimental validation. Methods: GC-MS was used to predict chemical compounds, corresponding databases were used to predict chemical compound targets and depression targets, Cytoscape software was used to construct and analyze the protein interaction network map, DAVID database was used to analyze gene ontology (GO) and KEGG signaling pathway, and AGFR software was used to perform molecular docking. Subsequently, the underlying action mechanisms of AFPR on depression predicted by network pharmacology analyses were experimentally validated in a CORT-induced depression model in vitro and in vivo. Results: A total of 52 potential targets of AFPR on antidepressant were obtained. GO is mainly related to chemical synaptic transmission, signal transduction and others. KEGG signaling pathways are mainly related to cAMP signaling pathway and C-type lectin receptor signaling pathway. The experiment results showed that AFPR significantly increased the expression of PRKACA, CREB and BDNF in mouse brain tissue and PC12 cells. Furthermore, after interfered of cAMP in PC12 cells, the decreased expression of PRKACA, CREB and BDNF was reversed by AFPR. Conclusion: AFPR may exert antidepressant effects through multiple components, targets and pathways. Furthermore, it could improve neuroplasticity via the cAMP signaling pathway to improve depression-like symptoms.

An all-graphdiyne electrochemiluminescence biosensor for the ultrasensitive detection of microRNA-21 based on target recycling with DNA cascade reaction for signal amplification.

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.

A carbon dot-based nanoscale covalent organic framework as a new emitter combined with a CRISPR/Cas12a-mediated electrochemiluminescence biosensor for ultrasensitive detection of bisphenol A.

Exploring new highly efficient electrochemiluminescence (ECL) luminophores is a necessary condition for developing ultrasensitive ECL biosensors. Therefore, a luminescent carbon dot-based covalent organic framework (CD-COF) was prepared using aldehyde-based carbon dots (CDs) and 1,3,5-tris (4-aminophenyl) benzene (TPB). Because the CD-COF made the regular arrangement of CDs conducive to improving the ECL response, CD-COF had a higher ECL intensity and efficiency than CDs. What's more, the ECL intensity of the CD-COF/S2O82-/Bu4N+ system was about 2.98, 7.50, and 28.08 times higher than those of the CD-COF/S2O82-, CDs/S2O82- and S2O82- systems, respectively. Considering the remarkable ECL performance, the CD-COF/S2O82-/Bu4N+ system was employed combined with the CRISPR/Cas12a trans-cutting strategy to construct an "off-on" ECL biosensor for BPA detection. The proposed ECL biosensor exhibited excellent performance with a wide linear range from 1.0 × 10-14 mol L-1 to 1.0 × 10-5 mol L-1 with a low detection limit of 2.21 fM (S/N = 3) under the optimized conditions. The biosensor demonstrated that CD-COF can be used as an efficient ECL emitter, thus expanding the application field of COFs. In addition, the good stability and specificity of the biosensor enabled the rapid detection of BPA, which will provide valuable insights into promising ultrasensitive ECL biosensors.

Superior graphdiyne self-powered biosensing platform with highly sensitivity and reliability for dual-mode detection of MicroRNA by integrating T7 Exonuclease and 3D DNA walker induced rolling circle amplification.

A highly sensitivity self-powered biosensor is developed based on T7 exonuclease (T7 Exo) and 3D DNA walker induced rolling circle amplification (RCA) for electrochemical/colorimetric dual-mode detection of microRNA-21 (miRNA-21) with improved reliability. Taking its advantage of fascinating properties, such as high structure defects and good conductivity, graphdiyne is prepared and used to prepare high-performance enzyme biofuel cell. T7 Exo-assisted 3D DNA walker target recognition triggers RCA reaction to obtain a significantly amplified signal response. A capacitor is integrated to the enzyme biofuel cell to further amplify the electrochemical output signal of the self-powered biosensor. In detection system, glucose oxidase catalyzes glucose oxidation to produce hydrogen peroxide, and 3,3',5,5'-tetramethylbenzidine (TMB) is then catalyzed to generate colored products, so as to achieve the colorimetric detection of the target. Analysis signals of diverse modes are recorded independently. Consequently, detection of microRNA with improved reliability and wider signal response range are achieved by electrochemical/colorimetric dual-mode with detection limits of 0.15 and 33 fM (S/N = 3) respectively. In addition, the proposed self-powered biosensor successfully applied for the detection of miRNA-21 in human serum samples, confirming its practical applicability in clinical diagnosis. It is powerfully anticipated the proposed self-powered biosensor possesses great potential to be applied to other biomedical domains.

Real-time multiple signal amplification self-powered biosensing platform for ultrasensitive detection of MicroRNA.

A real-time self-powered biosensor is designed for ultrasensitive detection of microRNA-21 based on electrochemical energy device capacitor and target-induced recycling double amplification strategy, which greatly improves the output signal by converting a small number of targets into two glucose oxidase labeled output strand DNAs, and the squeezed-out output strand is recycled by the cathode to fix more signal [Ru(NH3)6]3+ to further improve the detection signal. A digital multimeter (DMM) is connected to computer for real-time displaying the output signal of the self-powered biosensing system, which improves the accuracy of the sensing platform. The sensitivity of the proposed biosensor is 116.15 µA/pM for target microRNA-21, which is 32.26 times higher than that of pure EBFC (3.6 µA/pM). The target concentration is proportional to the open-circuit voltage value in a wide linear range of 0.1-10000 fM with a low detection limit of 0.04 fM (S/N = 3). The method shows high sensitivity and excellent selectivity, and can be applied to detect tumor marker microRNA-21 in biological matrix.

All-carbon sandwich-type self-powered biosensor for ultrasensitive detection of femtomolar miRNA-141.

The latest research shows that the expression level of microRNA-141 can predict the number of prostate cancer cells in the human body and has become an important biomarker. In this paper, an all-carbon sandwich self-powered biosensor based on graphene and carbon cloth is constructed for the highly sensitive detection of the prostate tumor marker miRNA-141. First, gold nanoparticles modified carbon cloth is applied for substrate electrode, and bilirubin oxidase is then immobilized on it to prepare the biocathode of the biofuel cell. Then, aptamer 1 is immobilized on gold nanoparticles-modified carbon cloth as the electrode substrate. The bioconjugate is prepared by immobilizing the aptamer 2-glucose oxidase complex on gold nanoparticles/graphene. In the biofuel cell-based self-powered sensing system, when the target microRNA-141 is present, it undergoes complementary base pairing with aptamer 1 and aptamer 2, and the bioconjugates are immobilized on the anode to form the sandwich structure. The enzyme on the anode undergoes an oxidation reaction to catalyze the reduction of oxygen, and the electrochemical respond of the system increases significantly. The results show that the concentration of microRNA-141 is proportional to the open-circuit voltage value ranging from 0.0001 to 1000 pmol/L with a detection limit of 50 amol/L (S/N = 3). The method has high sensitivity and excellent selectivity and can be applied to sensitively detect tumor marker microRNA-141 in biological matrix.

Superior performance of a graphdiyne self-powered biosensor with exonuclease III-assisted signal amplification for sensitive detection of microRNAs.

Graphdiyne (GDY) is an sp and sp2 co-hydrocarbon allotrope whose particular structure endows it with many fascinating properties, including abundant chemical bonds, high conjugation, natural pores, high carrier mobility, high conductivity and stability, etc. In this work, two-dimensional graphdiyne is prepared as an electrode substrate material coupling with an exonuclease III-assisted amplification strategy to construct a superior-performance self-powered biosensor based on enzymatic biofuel cells for highly sensitive detection of the tumour marker miRNA-21. Glucose oxidase (GOD) is first immobilized on the GDY/AuNP composite to prepare a bioconjugate. GDY/AuNP modified carbon cloth is used as an enzyme biofuel cell electrode, which is then modified with bilirubin oxidase as a biocathode. The bioconjugate binds to GOD through specific binding to the bioanode. When miRNA-21 is present, specific recognition by exonuclease III in the system results in cleavage of the capture probe, and miRNA-21 is recovered and involved in the cycle. The target miRNA-21 then causes corresponding changes in the open-circuit voltage of the self-powered system. Based on this, a sensitive detection method was constructed, within the scope from 0.1 fM to 0.1 nM with a shallow detection limit of 55.2 aM (S/N = 3). The new approach triumphantly has been used to detect miRNA-21 in serum, which provides a compelling new way for early diagnosis of related cancers.