Functionalizable poly-terthiophene/Cu2O heterojunction constructed in situ for sensitive photoelectrochemical detection of long non-coding RNA markers.

A photoelectrochemical (PEC) sensor based on the poly-2,2,5,2-terthiophene (pTTh)/Cu2O heterojunction was constructed and applied for the detection of long non-coding RNA (lncRNA) TROJAN, a biomarker of triple-negative breast cancer. Cu2O and pTTh were electrodeposited in situ and sequentially onto an indium tin oxide substrate. The bandgap of the resultant type II heterojunction was measured spectroscopically and the morphology was found to effectively separate photogenerated holes from electrons. A photocurrent density as high as 250 µA cm-2 was attained, which is about three times higher than those of only pTTh or Cu2O. Owing to the close contact between pTTh and Cu2O, this PEC sensor is highly stable. Oligonucleotide probes for lncRNA can be cross-linked to carboxyl moieties of mercaptopropionic acid molecules adsorbed on pTTh/Cu2O. The desirable band structure and the high density of probe molecules collectively yielded a linear range of 0.1-10 000 pM. Our PEC sensor has been demonstrated to be amenable for detection of lncRNA markers with excellent analytical performance.

A rapid simultaneous detection of duck hepatitis A virus 3 and novel duck reovirus based on RPA CRISPR Cas12a/Cas13a.

The mixed infection of duck hepatitis A virus 3 (DHAV-3) and novel duck reovirus (NDRV) has caused significant losses to the global duck farming industry. On-site point-of-care testing of viruses plays a crucial role in the early diagnosis, prevention, and disease control. Here, we proposed an RPA-CRISPR Cas12a/Cas13a one-pot strategy (DRCFS) for rapid and simultaneous detection of DHAV-3 and NDRV. This method integrated the reaction of RPA and CRISPR Cas12a/Cas13a in a single tube, eliminating the need to open the lid during the intermediate processes and thereby avoiding aerosol contamination. On this basis, we proposed a dual RPA-CRISPR strategy coupled with a lateral flow analysis platform (DRC-LFA). This circumvented the necessity for complex instruments, enabling direct visual interpretation of results, making the test more accessible and user-friendly. Our findings demonstrated that the DRCFS method could detect DHAV-3 and NDRV at concentrations as low as 100 copy/µL, while DRC-LFA achieved limit of 101 copies/µL within 35 min. Furthermore, when DRCFS, DRC-LFA, and qPCR were employed collectively for clinical samples analysis, all three methods yielded consistent results. The specificity, sensitivity, and user-friendly of these methods rendered them invaluable for on-site virus detection.

Development of a surface plasmon resonance (SPR) assay for rapid detection of Aeromonas hydrophila.

Aquaculture plays an increasingly important if not critical role in the current and future world food supply. Aeromonas hydrophila, a heterotrophic, Gram-negative, bacterium found in fresh or brackish water in warm climates poses a serious threat to the aquaculture industry in many areas, causing significant economic losses. Rapid, portable detection methods of A. hydrophila are needed for its effective control and mitigation. We have developed a surface plasmon resonance (SPR) technique to detect PCR (polymerase chain reaction) products that can replace agarose gel electrophoresis, or otherwise provide an alternative to costlier and more complicated real-time, fluorescence-based detection. The SPR method provides sensitivity comparable to gel electrophoresis, while reducing labor, cross-contamination, and test time, and employs simpler instrumentation with lower cost than real-time PCR.

Visible Light-Driven Self-Powered Device Based on a Straddling Nano-Heterojunction and Bio-Application for the Quantitation of Exosomal RNA.

This paper reports the design and fabrication of a self-powered biosensing device based on TiO2 nanosilks (NSs)@MoS2 quantum dots (QDs) and demonstrates a bioapplication for the quantitative detection of exosomal RNA ( Homo sapiens HOXA distal transcript antisense RNA, HOTTIP). This self-powered device features enhanced power output compared to TiO2 NSs alone. This is attributed to the formation of a heterojunction structure with suitable band offset derived from the hybridization between TiO2 NSs and MoS2 QDs, i.e., the straddling (Type I) band alignment. The sensitization effect and excellent visible light absorption provided by MoS2 QDs can prolong interfacial carrier lifetime and improve energy conversion efficiency. This self-powered biosensing device has been successfully applied in quantitative HOTTIP detection through effective hybridization between a capture probe and HOTTIP. The successful capture of HOTTIP leads to a sequential decrease in power output, which is utilized for ultrasensitive quantitative HOTTIP detection, with a linear relationship of power output change versus the logarithm of HOTTIP concentration ranging from 5 fg/mL to 50 000 ng/mL and a detection limit as low as 5 fg/mL. This TiO2 NSs@MoS2 QDs-based nanomaterial has excellent potential for a superior self-powered device characterized by economical and portable self-powered biosensing. Moreover, this self-powered, visible-light-driven device shows promising applications for cancer biomarker quantitative detection.

Construction of self-powered cytosensing device based on ZnO nanodisks@g-C3N4 quantum dots and application in the detection of CCRF-CEM cells.

We herein report a self-powered and renewable cytosensing device based on ZnO nanodisks(NDs)@g-C3N4 quantum dots. The device features enhanced photoelectrochemical (PEC) activity compared to ZnO NDs or g-C3N4 QDs alone. The enhanced PEC ability is attributed to the synergistic effect of the high visible light sensitivity of g-C3N4 QDs and the staggered band alignment heterojunction structure with suitable band offset, which affords higher photoelectron transfer and separation efficiency. In addition, the hybridization of g-C3N4 QDs further accelerates interfacial electron transfer and blocks recombination between electron donors and photo-generated holes. The device was applied to the detection of CCRF-CEM cells. By conjugation to Sgc8c aptamer, which preferentially interacts with membrane-bound PTK7 on CCRF-CEM membranes, capture of target CCRF-CEM cells resulted in a decrease in apparent power output, which was then exploited for the ultrasensitive detection of the target cells. This decrease in power output can be recovered by simply increasing the temperature to release the cells, thus recycling the cytosensing performance. The device displayed a linear relationship between the change of power output and the logarithm of the cell concentration from 20 to 20,000 cell/mL (R2 = 0.9837) and a detection limit down to 20 cell/mL, as well as excellent selectivity and reproducibility. Thus, this ZnO NDs@g-C3N4 QDs-based device exhibits high potential for the detection of CCRF-CEM cells.

Role of luxS in Stress Tolerance and Adhesion Ability in Lactobacillus plantarum KLDS1.0391.

Lactobacillus plantarum, a probiotic, has a high survival rate and high colonization ability in the gastrointestinal tract. Tolerance to the gastrointestinal environment and adhesion to intestinal epithelial cells by some Lactobacillus species (excluding L. plantarum) are related to luxS/AI-2. Here, the role of luxS in tolerance to simulated digestive juice (SDJ) and adhesion to Caco-2 cells by L. plantarum KLDS1.0391 (hereafter, KLDS1.0391) was investigated. The KLDS1.0391 luxS mutant strain was constructed by homologous recombination. When luxS was deleted, acid and bile salt tolerance and survival rates in SDJ significantly decreased (p < 0.05 for all). The ability of the luxS deletion strain to adhere to Caco-2 cells was markedly lower than that of the wild-type strain (p < 0.05). The ability of the luxS mutant strain to adhere (competition, exclusion, and displacement) to Escherichia coli ATCC 25922 was significantly lower than that of the wild-type strain (p < 0.05 for all). A significant decrease was noted only in the exclusion adhesion inhibition of the luxS mutant strain to Salmonella typhimurium ATCC 14028 (p < 0.05). These results indicate that the luxS gene plays an important role in the gastrointestinal environment tolerance and adhesion ability of KLDS1.0391.

Electrochemiluminescence quenching of luminol by CuS in situ grown on reduced graphene oxide for detection of N-terminal pro-brain natriuretic peptide.

A novel electrochemiluminescence (ECL) signal-off strategy based on CuS in situ grown on reduced graphene oxide (CuS-rGO) quenching luminol/H2O2 system was firstly proposed. Luminol was grafted on the surface of Au@Fe3O4-Cu3(PO4)2 nanoflowers (Luminol-Au@Fe3O4-Cu3(PO4)2) which exhibited excellent catalytic effect towards the reduction of H2O2 to enhance the ECL intensity of luminol. Cu3(PO4)2 nanoflowers showed large surface area which can immobilize more Fe3O4 and Au nanoparticles. The quenching mechanism of CuS-rGO was due to ECL resonance energy transfer (RET). The spectral overlap between fluorescence spectrum of Luminol-Au@Fe3O4-Cu3(PO4)2 and UV-vis absorption spectrum of CuS-rGO revealed that resonance energy transfer was possible. Au nanoparticles were immobilized on the surface of CuS-rGO to capture secondary antibodies. After a sandwich-type immunoreaction, a remarkable decrease of ECL signal was observed. Under the optimal conditions, the immunosensor showed excellent performance for N-terminal pro-brain natriuretic peptide (NT-proBNP) detection with a wide detection range from 0.5 pg mL-1 to 20 ng mL-1 and a low detection limit of 0.12 pg mL-1 (S/N = 3). The prepared NT-proBNP immunosensor displayed high sensitivity, excellent stability and good specificity.

Bioapplications of Cell-SELEX-Generated Aptamers in Cancer Diagnostics, Therapeutics, Theranostics and Biomarker Discovery: A Comprehensive Review.

Currently, functional single-stranded oligonucleotide probes, termed aptamers, generated by an iterative technology, Systematic Evolution of Ligands by Exponential Enrichment (SELEX), are utilized to selectively target molecules or cells with high affinity. Aptamers hold considerable promise as multifunctional molecules or conjugates for challenging nanotechnologies or bioapplications now and in the future. In this review, we first describe recent endeavors to select aptamers towards live cancer cells via cell-SELEX. We then introduce several characteristic applications of selected aptamers, especially in imaging, drug delivery and therapy. In part, these advances have been made possible via synthesis of aptamer-based nanomaterials, which, by their sizes, shapes, and physicochemical properties, allow such aptamer-nanomaterial complexes to function as signal reporters or drug carriers. We also describe how these aptamer-based molecular tools contribute to cancer biomarker discovery through high-affinity recognition of membrane protein receptors.

Sandwich-Type Electrochemiluminescence Sensor for Detection of NT-proBNP by Using High Efficiency Quench Strategy of Fe3O4@PDA toward Ru(bpy)32+ Coordinated with Silver Oxalate.

Heart failure (HF) is a burgeoning public health problem trigged by a heart circulation disorder. N-terminal pro-B-type natriuretic peptide (NT-proBNP) has been acknowledged as a prognostic biomarker for cardiac disease. Herein, a sandwich-type electrochemiluminescence (ECL) immunosensor was introduced for sensitive detection of NT-proBNP. Gold nanoparticle modified graphene oxide-Ru(bpy)32+/Ag2C2O4 was used as a luminophore and a desirable platform for immobilization of the captured antibodies. The more stable immobilization of plentiful Ru(bpy)32+ could be implemented by direct covalent bonding chelation with Ag2C2O4. More importantly, significant quenching can be achieved by introducing polydopamine (PDA) coated Fe3O4 onto the electrode via sandwich immunoreactions. The quenching mechanism mainly showed that the excited states of Ru(bpy)32+ could be annihilated by quinone units in PDA via energy transfer. The ECL quenching efficiency was logarithmically related to the concentration of the NT-proBNP in the range from 0.0005 ng/mL to 100.0 ng/mL with a detection limit of 0.28 pg/mL. Furthermore, this specific immunosensor presented good stability and repeatability as well as selectivity, which offers a guiding significance in both fundamental and clinical diagnosis of NT-proBNP.

Role of the luxS gene in bacteriocin biosynthesis by Lactobacillus plantarum KLDS1.0391: A proteomic analysis.

Certain probiotic species of lactic acid bacteria, especially Lactobacillus plantarum, regulate bacteriocin synthesis through quorum sensing (QS) systems. In this study, we aimed to investigate the luxS-mediated molecular mechanisms of QS during bacteriocin synthesis by L. plantarum KLDS1.0391. In the absence of luxS, the 'spot-on-the-lawn' method showed that the bacteriocin production by L. plantarum KLDS1.0391 significantly decreased upon co-cultivation with L. helveticus KLDS1.9207 (P < 0.01) but did not change significantly when mono-cultivated. Furthermore, liquid chromatography-electrospray ionization tandem mass spectrometry analysis showed that, as a response to luxS deletion, L. plantarum KLDS1.0391 altered the expression level of proteins involved in carbohydrate metabolism, amino acid metabolism, fatty acid synthesis and metabolism, and the two-component regulatory system. In particular, the sensor histidine kinase AgrC (from the two-component system, LytTR family) was expressed differently between the luxS mutant and the wild-type strain during co-cultivation, whereas no significant differences in proteins related to bacteriocin biosynthesis were found upon mono-cultivation. In summary, we found that the production of bacteriocin was regulated by carbohydrate metabolism, amino acid metabolism, fatty acid synthesis and metabolism, and the two-component regulatory system. Furthermore, our results demonstrate the role of luxS-mediated molecular mechanisms in bacteriocin production.

3D Nanostructured Palladium-Functionalized Graphene-Aerogel-Supported Fe3O4 for Enhanced Ru(bpy)32+-Based Electrochemiluminescent Immunosensing of Prostate Specific Antigen.

We developed a novel Ru(bpy)32+-based electrochemiluminescence (ECL) immunosensor utilizing palladium nanoparticle (Pd NP)-functionalized graphene-aerogel-supported Fe3O4 (FGA-Pd) for real-sample analysis of prostate specific antigen (PSA). 3D nanostructured FGA-Pd, as a novel ECL carrier, was prepared by in situ reduction. Large amounts of Ru(bpy)32+ could combine with FGA-Pd via electrostatic interaction to establish a brand-new ECL emitter (Ru@FGA-Pd) for improving ECL efficiency. The obtained Ru@FGA-Pd composite was utilized to label the secondary antibody, which generated strong ECL signals with tripropylamine (TPrA) as a coreactant. Furthermore, we demonstrated that the participation of Pd NPs endowed FGA with favorable electrocatalytic ability in the luminescence process to produce more excited state [Ru(bpy)32+]* for realizing desirable signal amplification. In addition, the primary antibody was captured by gold nanoparticle (Au NP)-functionalized Fe2O3 nanodendrites (Au-FONDs), which possessed good electrical conductivity and favorable biocompatibility. Under optimum conditions, the fabricated sandwich-type ECL immunosensor showed a sensitive response to PSA with a low detection limit of 0.056 pg/mL (S/N = 3) and a calibration range of 0.0001-50 ng/mL. Featuring favorable selectivity, stability, and repeatability, the proposed immunosensor is expected to blaze a novel trail for the real sample detection of PSA and other biomarkers.

Complete genome sequence of bacteriocin-producing Lactobacillus plantarum KLDS1.0391, a probiotic strain with gastrointestinal tract resistance and adhesion to the intestinal epithelial cells.

Lactobacillus plantarum KLDS1.0391 is a probiotic strain isolated from the traditional fermented dairy products and identified to produce bacteriocin against Gram-positive and Gram-negative bacteria. Previous studies showed that the strain has a high resistance to gastrointestinal stress and has a high adhesion ability to the intestinal epithelial cells (Caco-2). We reported the entire genome sequence of this strain, which contains a circular 2,886,607-bp chromosome and three circular plasmids. Genes, which are related to the biosynthesis of bacteriocins, the stress resistance to gastrointestinal tract environment and adhesive performance, were identified. Whole genome sequence of Lactobacillus plantarum KLDS1.0391 will be helpful for its applications in food industry.

Photoelectrochemical Cytosensing of RAW264.7 Macrophage Cells Based on a TiO2 Nanoneedls@MoO3 Array.

We have developed a photoelectrochemical (PEC) cytosensor for ultrasensitive detection of RAW264.7 cells by the signal change of a TiO2 nanoneedles (NNs)@MoO3 array. For the first time, a TiO2 NNs@MoO3 array was adopted for the fabrication of the cytosensor for the signal output. The well-matched alignment of TiO2 NNs and MoO3 efficiently suppresses the recombination of photogenerated electron and hole (e-/h+) pairs for improved photon-to-current conversion efficiency. The RAW264.7 cell and F4/80 antibody could form the biocomplexes because of the specific recognition between each other. The constructed PEC cytosensor based on the TiO2 NNs@MoO3 array displayed good PEC property for detection of RAW264.7 cells. The numbers of RAW264.7 cells are directly detected through the decrement of photocurrent intensity, due to the increased steric hindrance when RAW264.7 cells are captured. The PEC cytosensor showed an ultrasensitive response to RAW264.7 cells with a linear range of 50-15 000 cells/mL and a detection limit of 50 cells/mL. The designed cytosensor based on a TiO2 NNs@MoO3 array offers an ideal platform to detect RAW264.7 cells with excellent stability, reproducibility, and selectivity and served as a model for the fabrication of cytosensors for other cells.

Increased electrocatalyzed performance through high content potassium doped graphene matrix and aptamer tri infinite amplification labels strategy: Highly sensitive for matrix metalloproteinases-2 detection.

Herein, a super-labeled immunoassay was fabricated for matrix metalloproteinases-2 detection. A self-corrosion ITO micro circuit board was designed in this sensing platform to reduce the random error in the same testing condition, and the self-constructed sensing platform is portable with a cheap price. The K-modified graphene (K-GS) was utilized as the matrix material, which was synthesized well by phenylate and phenanthrene through the polar bond of nonpolar molecule phenylate and the π-π interaction for the first time. An aptamer-based labels based on Au nanoparticles (AuNPs), thionine (Th) and horseradish peroxidase (HRP) were applied as the signal source for tri infinite amplification. This fabricated super-labeled immunoassay exhibit excellent performance for MMPs-2 detection. It displayed a broad linear range of 10-4-10ng/mL with a low detection limit of 35 fg/mL, which may have a potential application in the clinical diagnose.

Ultrasensitive Label-free Electrochemical Immunosensor based on Multifunctionalized Graphene Nanocomposites for the Detection of Alpha Fetoprotein.

In this work, a novel label-free electrochemical immunosensor was developed for the quantitative detection of alpha fetoprotein (AFP). Multifunctionalized graphene nanocomposites (TB-Au-Fe3O4-rGO) were applied to modify the electrode to achieve the amplification of electrochemical signal. TB-Au-Fe3O4-rGO includes the advantages of graphene, ferroferric oxide nanoparticles (Fe3O4 NPs), gold nanoparticles (Au NPs) and toluidine blue (TB). As a kind of redox probe, TB can produce the electrochemical signal. Graphene owns large specific surface area, high electrical conductivity and good adsorption property to load a large number of TB. Fe3O4 NPs have good electrocatalytic performance towards the redox of TB. Au NPs have good biocompatibility to capture the antibodies. Due to the good electrochemical performance of TB-Au-Fe3O4-rGO, the effective and sensitive detection of AFP was achieved by the designed electrochemical immunosensor. Under optimal conditions, the designed immunosensor exhibited a wide linear range from 1.0 × 10-5 ng/mL to 10.0 ng/mL with a low detection limit of 2.7 fg/mL for AFP. It also displayed good electrochemical performance including good reproducibility, selectivity and stability, which would provide potential applications in the clinical diagnosis of other tumor markers.

A bio-chemical application of N-GQDs and g-C3N4 QDs sensitized TiO2 nanopillars for the quantitative detection of pcDNA3-HBV.

Herein, TiO2 nanopillars (NPs)/N-doped graphene quantum dots (N-GQDs)/g-C3N4 QDs heterojunction efficiently suppressed the photogenerated charges recombination and improved photo-to-current conversion efficiency. The introduced N-GQDs and g-C3N4 QDs could result in more effective separation of the photogenerated charges, and thus produce a further increase of the photocurrent. TiO2 NPs/N-GQDs/g-C3N4 QDs were firstly applied as the photoactive materials for the fabrication of the biosensors, and the primers of pcDNA3-HBV were then adsorbed on the TiO2 NPs/N-GQDs/g-C3N4 QDs modified electrode under the activation of EDC/NHS. With increase of the pcDNA3-HBV concentration, the photocurrent reduced once the double helix between the primers and pcDNA3-HBV formed. The developed photoelectrochemical (PEC) biosensor showed a sensitive response to pcDNA3-HBV in a linear range of 0.01 fmol/L to 20nmol/L with a detection limit of 0.005 fmol/L under the optimal conditions. The biosensor exhibited high sensitivity, good selectivity, good stability and reproducibility.

Visible-light driven photoelectrochemical immunosensor for insulin detection based on MWCNTs@SnS2@CdS nanocomposites.

In this work, a label-free photoelectrochemical (PEC) immunosensor was developed for ultrasensitive detection of insulin based on MWCNTs@SnS2@CdS nanocomposites. As graphene-like 2D nanomaterial, SnS2 nanosheets loaded on the conducting framework of multi-walled carbon nanotubes (MWCNTs) were adopted for the construction of immunosensor for the first time, providing a favorable substrate for in-situ growth of CdS nanocrystal that had suitable band structure matching well with SnS2. The well-matched band structure of these two metal sulfides effectively inhibited the recombination of photogenerated electron-hole pairs, thus improving the photo-to-current conversion efficiency. Besides, the introduction of MWCNTs facilitated electron transfer across the surface of electrodes, leading to a further increment of photocurrent. The as constructed label-free PEC immunosensor based on MWCNTs@SnS2@CdS nanocomposites exhibited excellent PEC performance for the detection of insulin. The concentrations of insulin could be directly detected based on the decrement of photocurrent that was brought by the increased steric hindrances due to the formation of antigen-antibody immunocomplexes. Under the optimal conditions, the PEC immunosensor had a sensitive response to insulin in a linear range of 0.1pgmL(-1) to 5ngmL(-1) with a detection limit of 0.03pgmL(-1). Meanwhile, good stability and selectivity were achieved as well. The design and fabrication of this PEC immunosensor based on MWCNTs@SnS2@CdS nanocomposites not only provided an ideal platform for the detection of insulin, but also opened up a new avenue for the development of immunosensor for some other biomarkers analysis.

Visible light photoelectrochemical aptasensor for adenosine detection based on CdS/PPy/g-C3N4 nanocomposites.

In this work, a label-free photoelectrochemical (PEC) aptasensor was developed for adenosine detection based on CdS/PPy/g-C3N4 nanocomposites. The CdS/g-C3N4 heterojunction effectively prevented the photogenerated charges recombination of g-C3N4 and self-photocorrosion processes of CdS, improving photo-to-current conversion efficiency. The introduced polypyrrole (PPy) nanoparticles could lead to a more effective separation of photogenerated charges, thus resulting in a further increasing of photocurrent. The CdS/PPy/g-C3N4 was firstly employed as the photoactive materials for fabrication of aptasensor, and SH-aptamer was then adsorbed on the CdS/PPy/g-C3N4 modified electrodes through S-Cd bond. With increasing of adenosine concentration, the photocurrent decreased as the formation of SH-aptamer-adenosine bioaffinity complexes. Under optimal conditions, the PEC aptasensor had a sensitive response to adenosine in a linear range of 0.3nmolL(-1) to 200nmolL(-1) with a detection limit of 0.1nmolL(-1). Besides, the as-proposed aptasensor has also been applied in human serum samples analysis. The aptasensor exhibits high sensitivity and good stability, thus opening up a new promising PEC platform for some other small molecules analysis.

Ultrasensitive photoelectrochemical aptasensing of miR-155 using efficient and stable CH3NH3PbI3 quantum dots sensitized ZnO nanosheets as light harvester.

An ultrasensitive photoelectrochemical (PEC) aptasensor based on a novel signal amplification strategy was developed for the quantitative determination of microRNA (miR)-155. CH3NH3PbI3 quantum dots (QDs) functionalized ZnO nanosheets (NSs) were employed as the light harvester. Owing to the synergetic effect between CH3NH3PbI3 QDs and ZnO NSs, ZnO@CH3NH3PbI3 can provide an obviously increasing PEC signal by forming the heterojunction. Due to the larger steric hindrance, the sensitive decrease of the PEC signal can be achieved by the specific recognition between the primers and ssDNA of miR-155. In this sense, this developed aptasensor can achieve a high sensitivity (especially in the presence of the low concentrations of miR-155) and a wide detection range (0.01fmol/L to 20,000pmol/L). Under the optimal conditions, the proposed aptasensor offered an ultrasensitive and specific determination of miR-155 down to 0.005fmol/L. This aptassay method would open up a new promising platform at ultralow levels for early diagnose of different miRNA.

Facile fabrication of an electrochemical aptasensor based on magnetic electrode by using streptavidin modified magnetic beads for sensitive and specific detection of Hg(2.).

In this work, a novel electrochemical aptasensor was developed for sensitive and specific detection of Hg(2+) based on thymine-Hg(2+)-thymine (T-Hg(2+)-T) structure via application of thionine (Th) as indicator signal. For the fabrication of the aptasensor, streptavidin modified magnetic beads (Fe3O4-SA) was firmly immobilized onto the magnetic glassy carbon electrode (MGCE) benefited from its magnetic character. Then biotin labeled T-riched single stranded DNA (Bio-ssDNA) connected with Fe3O4-SA specifically and steadily because of the specific binding capacity between streptavidin and biotin. The stable structure of T-Hg(2+)-T formed in the present of Hg(2+) provided convenience for the intercalation of Th. The detection of Hg(2+) was achieved by recording the differential pulse voltammetry (DPV) signal of Th. Under optimal experimental conditions, the linear range of the fabricated electrochemical aptasensor was 1-200nmol/L, with a detection limit of 0.33nmol/L. Furthermore, the proposed aptasensor may find a potential application for the detection of Hg(2+) in real water sample analysis.