Science.gov

Sample records for electrochemical dna biosensor

  1. Electrochemical application of DNA biosensors

    NASA Astrophysics Data System (ADS)

    Mascini, M.; Lucarelli, F.; Palchetti, I.; Marrazza, G.

    2001-09-01

    Disposable electrochemical DNA-based biosensors are reviewed; they have been used for the determination of low- molecular weight compounds with affinity for nucleic acids and for the detection of hybridization reaction. The first application is related to the molecular interaction between surface-linked DNA and pollutants or drugs, in order to develop a simple device for rapid screening of toxic compounds. The determination of such compounds was measured by their effect simple device for rapid screening of toxic compounds. The determination of such compounds was measured by their effect on the oxidation signal of the guanine peak of calf thymus DNA immobilized on the electrode surface and investigated by chronopotentiometric or voltammetric analysis. Applicability to river and wastewater sample is demonstrated. Moreover, disposable electrochemical sensors for the detection of a specific sequence of DNA were realized by immobilizing synthetic single-stranded oligonucleotides onto a graphite screen-printed electrode. The probes because hybridized with different concentrations of complementary sequences present in the sample. The hybrids formed on the electrode surface were evaluated by chronopotentiometric analysis using daunomycin as the indicator of the hybridization reaction. The hybridization was also performed using real samples. Application to apolipoprotein E is described, in this case samples have to be amplified by PCR and then analyzed by the DNA biosensor. The extension of such procedures to samples of environmental interest or to contamination of food is discussed.

  2. Electrochemical uranyl cation biosensor with DNA oligonucleotides as receptor layer.

    PubMed

    Jarczewska, Marta; Ziółkowski, Robert; Górski, Łukasz; Malinowska, Elżbieta

    2014-04-01

    The present study aims at the further development of the uranyl oligonucleotide-based voltammetric biosensor, which takes advantage of strong interaction between UO2(2+) and phosphate DNA backbone. Herein we report the optimization of working parameters of previously elaborated electrochemical DNA biosensor. It is shown that the sensor sensitivity is highly dependent on the oligonucleotide probe length and the incubation time of sensor in a sample solution. Consequently, the highest sensitivity was obtained for 10-nucleotide sequence and 60 min incubation time. The lower detection limit towards uranyl cation for developed biosensor was 30 nM. The influence of mixed monolayers and the possibility of developing a non-calibration device were also investigated. The selectivity of the proposed biosensor was significantly improved via elimination of adenine nucleobases from the DNA probe. Moreover, the regeneration procedure was elaborated and tested to prolong the use of the same biosensor for 4 subsequent determinations of UO2(2+).

  3. Aminated hollow silica spheres for electrochemical DNA biosensor

    NASA Astrophysics Data System (ADS)

    Ariffin, Eda Yuhana; Heng, Lee Yook; Futra, Dedi; Ling, Tan Ling

    2015-09-01

    An electrochemical DNA biosensor for e.coli determination based on aminated hollow silica was successfully developed. Aminated hollow silica spheres were prepared through the reaction of Tween 20 template and silica precursor. The template was removed by the thermal decomposition at 620°C. Hollow silica spheres were modified with (3-Aminopropyl) triethoxysilane (APTS) to form aminated hollow silica spheres.Aminated DNA probe were covalently immobilized on to the amine functionalized hollow silica spheres through glutaradehyde linkers. The formation hollow silica was characterized using FTIR and FESEM. A range of 50-300nm particle size obtained from FESEM micrograph. Meanwhile for the electrochemical study, a quasi-reversible system has been obtain via cyclic voltammetry (CV).

  4. Ultrasensitive electrochemical cocaine biosensor based on reversible DNA nanostructure.

    PubMed

    Sheng, Qinglin; Liu, Ruixiao; Zhang, Sai; Zheng, Jianbin

    2014-01-15

    We proposed an ultrasensitive electrochemical cocaine biosensor based on the three-dimensional (3D) DNA structure conversion of nanostructure from Triangular Pyramid Frustum (TPFDNA) to Equilateral Triangle (ETDNA). The presence of cocaine triggered the aptamer-composed DNA nanostructure change from "Close" to "Open", leading to obvious faradaic impedance changes. The unique properties with excellent stability and specific rigid structure of the 3D DNA nanostructure made the biosensing functions stable, sensitive, and regenerable. The Faradaic impedance responses were linearly related to cocaine concentration between 1.0 nM and 2.0 μM with a correlation coefficient of 0.993. The limit of detection was calculated to be 0.21 nM following IUPAC recommendations (3Sb/b). It is expected that the distinctive features of DNA nanostructure would make it potentially advantageous for a broad range of biosensing, bionanoelectronics, and therapeutic applications.

  5. Electrochemical DNA biosensor based on the BDD nanograss array electrode

    PubMed Central

    2013-01-01

    Background The development of DNA biosensor has attracted considerable attention due to their potential applications, including gene analysis, clinical diagnostics, forensic study and more medical applications. Using electroactive daunomycin as an indicator, the hybridization detection was measured by differential pulse voltammetry in this study. Results Electrochemical DNA biosensor was developed based on the BDD film electrode (fBDD) and BDD nanograss array electrode (nBDD). In comparison with fBDD and AuNPs/CA/fBDD electrode, the lower semicircle diameter of electrochemical impedance spectroscopy obtained on nBDD and AuNPs/CA/nBDD electrode indicated that the presence of nanograss array improved the reactive site, reduced the interfacial resistance, and made the electron transfer easier. Using electroactive daunomycin as an indicator, the hybridization detection was measured by differential pulse voltammetry. Conclusions The experimental results demonstrated that the prepared AuNPs/CA/nBDD electrode was suitable for DNA hybridization with favorable performance of faster response, higher sensitivity, lower detection limit and satisfactory selectivity, reproducibility and stability. PMID:23575250

  6. Genomagnetic Electrochemical Biosensors

    NASA Astrophysics Data System (ADS)

    Wang, Joseph; Erdem, Arzum

    The use of nucleic acid technologies has significantly improved preparation and diagnostic procedures in life sciences. Nucleic acid layers combined with electrochemical or optical transducers produce a new kind of affinity biosensors as DNA Biosensor for small molecular weight molecules. Electrochemical DNA biosensors are attractive devices for converting the hybridization event into an analytical signal for obtaining sequence-specific information in connection with clinical, environmental or forensic investigations. DNA hybridization biosensors, based on electrochemical transduction of hybridization, couple the high specificity of hybridization reactions with the excellent sensitivity and portability of electrochemical transducers. The main goal in all researches is to design DNA biosensors for preparing a basis for the future DNA microarray system. DNA chip has now become a powerful tool in biological research, however the real clinic assay is still under development. Recently, there has been a great interest to the magnetic beads and/or nanoparticles labelled with metals such as gold, cadmium, silver, etc. for designing of novel electrochemical DNA biosensor approaches resulting in efficient separation. The attractive features of this technology include simple approach, rapid results, multi-analyte detection, low-cost per measurument, stable, and non-hazardous reagents, and reduced waste handling. Some of these new approaches and applications of the electrochemical DNA biosensors based on magnetic beads and its combining with nanoparticles labelled with metals are described and discussed.

  7. Electrochemical DNA biosensor for detection of DNA damage induced by hydroxyl radicals.

    PubMed

    Hájková, Andrea; Barek, Jiří; Vyskočil, Vlastimil

    2017-03-01

    A simple electrochemical DNA biosensor based on a glassy carbon electrode (GCE) was prepared by adsorbing double-stranded DNA (dsDNA) onto the GCE surface and subsequently used for the detection of dsDNA damage induced by hydroxyl radicals. Investigation of the mutual interaction between hydroxyl radicals and dsDNA was conducted using a combination of several electrochemical detection techniques: square-wave voltammetry for direct monitoring the oxidation of dsDNA bases, and cyclic voltammetry and electrochemical impedance spectroscopy as indirect electrochemical methods making use of the redox-active indicator [Fe(CN)6](4-/3-). Hydroxyl radicals were generated electrochemically on the surface of a boron-doped diamond electrode and chemically (via the Fenton's reaction or the auto-oxidation of Fe(II)). The extent of dsDNA damage by electrochemically generated hydroxyl radicals depended on the current density applied to the generating electrode: by applying 5, 10, and 50mAcm(-2), selected relative biosensor responses decreased after 3min incubation from 100% to 38%, 27%, and 3%, respectively. Chemically generated hydroxyl radicals caused less pronounced dsDNA damage, and their damaging activity depended on the form of Fe(II) ions: decreases to 49% (Fenton's reaction; Fe(II) complexed with EDTA) and 33% (auto-oxidation of Fe(II); Fe(II) complexed with dsDNA) were observed after 10min incubation.

  8. [Cu(phen)2](2+) acts as electrochemical indicator and anchor to immobilize probe DNA in electrochemical DNA biosensor.

    PubMed

    Yang, Linlin; Li, Xiaoyu; Li, Xi; Yan, Songling; Ren, Yinna; Wang, Mengmeng; Liu, Peng; Dong, Yulin; Zhang, Chaocan

    2016-01-01

    We demonstrate a novel protocol for sensitive in situ label-free electrochemical detection of DNA hybridization based on copper complex ([Cu(phen)2](2+), where phen = 1,10-phenanthroline) and graphene (GR) modified glassy carbon electrode. Here, [Cu(phen)2](2+) acted advantageously as both the electrochemical indicator and the anchor for probe DNA immobilization via intercalative interactions between the partial double helix structure of probe DNA and the vertical aromatic groups of phen. GR provided large density of docking site for probe DNA immobilization and increased the electrical conductivity ability of the electrode. The modification procedure was monitored by electrochemical impedance spectroscopy (EIS). Square-wave voltammetry (SWV) was used to explore the hybridization events. Under the optimal conditions, the designed electrochemical DNA biosensor could effectively distinguish different mismatch degrees of complementary DNA from one-base mismatch to noncomplementary, indicating that the biosensor had high selectivity. It also exhibited a reasonable linear relationship. The oxidation peak currents of [Cu(phen)2](2+) were linear with the logarithm of the concentrations of complementary target DNA ranging from 1 × 10(-12) to 1 × 10(-6) M with a detection limit of 1.99 × 10(-13) M (signal/noise = 3). Moreover, the stability of the electrochemical DNA biosensor was also studied.

  9. Electrochemical DNA biosensor based on avidin-biotin conjugation for influenza virus (type A) detection

    NASA Astrophysics Data System (ADS)

    Chung, Da-Jung; Kim, Ki-Chul; Choi, Seong-Ho

    2011-09-01

    An electrochemical DNA biosensor (E-DNA biosensor) was fabricated by avidin-biotin conjugation of a biotinylated probe DNA, 5'-biotin-ATG AGT CTT CTA ACC GAG GTC GAA-3', and an avidin-modified glassy carbon electrode (GCE) to detect the influenza virus (type A). An avidin-modified GCE was prepared by the reaction of avidin and a carboxylic acid-modified GCE, which was synthesized by the electrochemical reduction of 4-carboxyphenyl diazonium salt. The current value of the E-DNA biosensor was evaluated after hybridization of the probe DNA and target DNA using cyclic voltammetry (CV). The current value decreased after the hybridization of the probe DNA and target DNA. The DNA that was used follows: complementary target DNA, 5'-TTC GAC CTC GGT TAG AAG ACT CAT-3' and two-base mismatched DNA, 5'-TTC GAC AGC GGT TAT AAG ACT CAT-3'.

  10. DNA electrochemical biosensor for metallic drugs at physiological conditions

    PubMed Central

    Santiago-Lopez, Angel J.; Vera, José L.; Meléndez, Enrique

    2014-01-01

    Entrapment of dsSS-DNA into the polypyrrole-polyvinyl sulphonate (dsSS-DNA-PPy-PVS) film over indium-tin-oxide (ITO) coated glass has been designed to detect titanium and platinum drugs, titanocene dichloride and cisplatin. The disposable dsSS-DNA-PPy-PVS/ITO biosensor was characterized by cyclic voltammetry, attenuated total reflectance Infrared spectroscopy and atomic force microscopy. Amperometric studies by cyclic voltammetry using, dsSS-DNA-PPy PVS/ITO biosensor, demonstrated the ability of this biosensor to detect these metallic drugs in millimolar concentration by monitoring the decrease of the guanine oxidation signal as a result of the DNA damage. The concentration range detected for titanocene dichloride is 0.25 to 1.5 mM and for cisplatin is 0.06 to 1.0 mM. PMID:25705144

  11. Indicator Based and Indicator - Free Electrochemical DNA Biosensors

    DTIC Science & Technology

    2007-11-02

    of genomic material from infectious organisms. Methylene blue (MB) is an aromatic heterocycle that binds strongly to DNA via intercalation. MB...detection of disease- related point mutation in the guanine bases of the cyanobacteria . The resulting biosensors offer great promise for mismatch

  12. Electrochemical biosensor for Mycobacterium tuberculosis DNA detection based on gold nanotubes array electrode platform.

    PubMed

    Torati, Sri Ramulu; Reddy, Venu; Yoon, Seok Soo; Kim, CheolGi

    2016-04-15

    The template assisted electrochemical deposition technique was used for the synthesis of gold nanotubes array (AuNTsA). The morphological structure of the synthesized AuNTsA was observed by scanning electron microscopy and found that the individual nanotubes are around 1.5 μm in length with a diameter of 200 nm. Nanotubes are vertically aligned to the Au thick film, which is formed during the synthesis process of nanotubes. The electrochemical performance of the AuNTsA was compared with the bare Au electrode and found that AuNTsA has better electron transfer surface than bare Au electrode which is due to the high surface area. Hence, the AuNTsA was used as an electrode for the fabrication of DNA hybridization biosensor for detection of Mycobacterium Tuberculosis DNA. The DNA hybridization biosensor constructed by AuNTsA electrode was characterized by cyclic voltammetry technique with Fe(CN)6(3-/4-) as an electrochemical redox indicator. The selectivity of the fabricated biosensor was illustrated by hybridization with complementary DNA and non-complementary DNA with probe DNA immobilized AuNTsA electrode using methylene blue as a hybridization indicator. The developed electrochemical DNA biosensor shows good linear range of complementary DNA concentration from 0.01 ng/μL to 100 ng/μL with high detection limit.

  13. Recent advances in DNA-based electrochemical biosensors for heavy metal ion detection: A review.

    PubMed

    Saidur, M R; Aziz, A R Abdul; Basirun, W J

    2017-04-15

    The presence of heavy metal in food chains due to the rapid industrialization poses a serious threat on the environment. Therefore, detection and monitoring of heavy metals contamination are gaining more attention nowadays. However, the current analytical methods (based on spectroscopy) for the detection of heavy metal contamination are often very expensive, tedious and can only be handled by trained personnel. DNA biosensors, which are based on electrochemical transduction, is a sensitive but inexpensive method of detection. The principles, sensitivity, selectivity and challenges of electrochemical biosensors are discussed in this review. This review also highlights the major advances of DNA-based electrochemical biosensors for the detection of heavy metal ions such as Hg(2+), Ag(+), Cu(2+) and Pb(2+).

  14. An electrochemical DNA biosensor for trace amounts of mercury ion quantification.

    PubMed

    Maâtouk, Ferdaous; Maâtouk, Mouna; Bekir, Karima; Barhoumi, Houcine; Maaref, Abderrazak; Ben Mansour, Hedi

    2016-10-01

    In this work we report the development of an electrochemical DNA biosensor with high sensitivity for mercury ion detection. A new matrix based on gold nanoparticles (AuNPs)-glutathione (GSH)/cysteine was investigated. The interaction between DNA oligonucleotides and Hg(2+) ions followed by the formation of Thymine-Hg(2+)-Thymine (T-Hg(2+)-T) structures was quantified using different electrochemical methods. It has been shown that the electrochemical impedance spectroscopy (EIS) measurements and the differential pulse voltammetry (DPV) confirmed the specific interaction between the oligonucleotide receptor layer and the Hg(2+) ions. Besides, the developed sensor exhibited high sensitivity towards mercury among some examined metal ions such as Pb(2+), Cu(2+) and Cd(2+). As a result, a high electrochemical response and low detection limit of 50 pM were estimated in the case of Hg(2+) ions. The developed DNA biosensor was applied successfully to the determination of Hg(2+)ions in wastewater samples.

  15. An electrochemical DNA biosensor based on Oracet Blue as a label for detection of Helicobacter pylori.

    PubMed

    Hajihosseini, Saeedeh; Nasirizadeh, Navid; Hejazi, Mohammad Saeid; Yaghmaei, Parichereh

    2016-10-01

    An innovative method of a DNA electrochemical biosensor based on Oracet Blue (OB) as an electroactive label and gold electrode (AuE) for detection of Helicobacter pylori, was offered. A single-stranded DNA probe with a thiol modification was covalently immobilized on the surface of the AuE by forming an Au-S bond. Differential pulse voltammetry (DPV) was used to monitor DNA hybridization by measuring the electrochemical signals of reduction of the OB binding to double-stranded DNA (ds-DNA). Our results showed that OB-based DNA biosensor has a decent potential for detection of single-base mismatch in target DNA. Selectivity of the proposed DNA biosensor was further confirmed in the presence of non-complementary and complementary DNA strands. Under optimum conditions, the electrochemical signal had a linear relationship with the concentration of the target DNA ranging from 0.3nmolL(-1) to 240.0nmolL(-1), and the detection limit was 0.17nmolL(-1), whit a promising reproducibility and repeatability.

  16. Detection EGFR exon 19 status of lung cancer patients by DNA electrochemical biosensor.

    PubMed

    Xu, Xiong-Wei; Weng, Xiu-Hua; Wang, Chang-Lian; Lin, Wei-Wei; Liu, Ai-Lin; Chen, Wei; Lin, Xin-Hua

    2016-06-15

    Epidermal growth factor receptor (EGFR) exon 19 mutation status is a very important prediction index for tyrosine kinase inhibitors (TKIs) therapy. In this paper, we constructed a superior selective sandwich-type electrochemical biosensor to detect in-frame deletions in exon 19 of EGFR in real samples of patients with non-small cell lung carcinoma. Based on the characteristics of different hybridization efficiency in different hybridization phase conditions, different region around EGFR exon 19 deletion hotspots was selected to design DNA probes to improve biosensor performance. The results confirm that alteration of deletion location in target deliberately according to different hybridization phase is able to improve selectivity of sandwich-type DNA biosensor. Satisfactory discrimination ability can be achieved when the deletions are located in the capture probe interaction region. In order to improve efficiency of ssDNA generation from dsDNA, we introduce Lambda exonuclease (λ-exo) to sandwich-type biosensor system. EGFR exon 19 statuses of clinical real samples from lung cancer patients can be discriminated successfully by the proposed method. Our research would make the electrochemical biosensor be an excellent candidate for EGFR detection for lung cancer patients.

  17. Ultrasensitive cDNA Detection of Dengue Virus RNA Using Electrochemical Nanoporous Membrane-Based Biosensor

    PubMed Central

    Rai, Varun; Hapuarachchi, Hapuarachchige C.; Ng, Lee Ching; Soh, Siew Hwa; Leo, Yee Sin; Toh, Chee-Seng

    2012-01-01

    A nanoporous alumina membrane-based ultrasensitive DNA biosensor is constructed using 5′-aminated DNA probes immobilized onto the alumina channel walls. Alumina nanoporous membrane-like structure is carved over platinum wire electrode of 76 µm diameter dimension by electrochemical anodization. The hybridization of complementary target DNA with probe DNA molecules attached inside the pores influences the pore size and ionic conductivity. The biosensor demonstrates linear range over 6 order of magnitude with ultrasensitive detection limit of 9.55×10−12 M for the quantification of ss-31 mer DNA sequence. Its applicability is challenged against real time cDNA PCR sample of dengue virus serotype1 derived from asymmetric PCR. Excellent specificity down to one nucleotide mismatch in target DNA sample of DENV3 is also demonstrated. PMID:22927927

  18. Specific detection of Mycobacterium sp. genomic DNA using dual labeled gold nanoparticle based electrochemical biosensor.

    PubMed

    Thiruppathiraja, Chinnasamy; Kamatchiammal, Senthilkumar; Adaikkappan, Periyakaruppan; Santhosh, Devakirubakaran Jayakar; Alagar, Muthukaruppan

    2011-10-01

    The present study was aimed at the development and evaluation of a DNA electrochemical biosensor for Mycobacterium sp. genomic DNA detection in a clinical specimen using a signal amplifier as dual-labeled AuNPs. The DNA electrochemical biosensors were fabricated using a sandwich detection strategy involving two kinds of DNA probes specific to Mycobacterium sp. genomic DNA. The probes of enzyme ALP and the detector probe both conjugated on the AuNPs and subsequently hybridized with target DNA immobilized in a SAM/ITO electrode followed by characterization with CV, EIS, and DPV analysis using the electroactive species para-nitrophenol generated by ALP through hydrolysis of para-nitrophenol phosphate. The effect of enhanced sensitivity was obtained due to the AuNPs carrying numerous ALPs per hybridization and a detection limit of 1.25 ng/ml genomic DNA was determined under optimized conditions. The dual-labeled AuNP-facilitated electrochemical sensor was also evaluated by clinical sputum samples, showing a higher sensitivity and specificity and the outcome was in agreement with the PCR analysis. In conclusion, the developed electrochemical sensor demonstrated unique sensitivity and specificity for both genomic DNA and sputum samples and can be employed as a regular diagnostics tool for Mycobacterium sp. monitoring in clinical samples.

  19. DNA Enzyme-Decorated DNA Nanoladders as Enhancer for Peptide Cleavage-Based Electrochemical Biosensor.

    PubMed

    Kou, Bei-Bei; Zhang, Li; Xie, Hua; Wang, Ding; Yuan, Ya-Li; Chai, Ya-Qin; Yuan, Ruo

    2016-09-07

    Herein, we developed a label-free electrochemical biosensor for sensitive detection of matrix metalloproteinase-7 (MMP-7) based on DNA enzyme-decorated DNA nanoladders as enhancer. A peptide and single-stranded DNA S1-modified platinum nanoparticles (P1-PtNPs-S1), which served as recognition nanoprobes, were first immobilized on electrode. When target MMP-7 specifically recognized and cleaved the peptide, the PtNPs-S1 bioconjugates were successfully released from electrode. The remaining S1 on electrode then hybridized with ssDNA1 (I1) and ssDNA2 (I2), which could synchronously trigger two hybridization chain reactions (HCRs), resulting in the in situ formation of DNA nanoladders. The desired DNA nanoladders not only were employed as ideal nanocarriers for enzyme loading, but also maintained its catalytic activity. With the help of hydrogen peroxide (H2O2), manganese porphyrin (MnPP) with peroxidase-like activity accelerated the 4-chloro-1-naphthol (4-CN) oxidation with generation of insoluble precipitation on electrode, causing a very low differential pulse voltammetry (DPV) signal for quantitative determination of MMP-7. Under optimal conditions, the developed biosensor exhibited a wide linear ranging from 0.2 pg/mL to 20 ng/mL, and the detection limit was 0.05 pg/mL. This work successfully realized the combination of DNA signal amplification technique with artificial mimetic enzyme-catalyzed precipitation reaction in peptide cleavage-based protein detection, offering a promising avenue for the detection of other proteases.

  20. Short thio-multi-walled carbon nanotubes and Au nanoparticles enhanced electrochemical DNA biosensor for DNA hybridization detection

    NASA Astrophysics Data System (ADS)

    Guo, Feng; Zhang, Jimei; Dai, Zhao; Zheng, Guo

    2010-07-01

    A novel and sensitive electrochemical DNA biosensor based on multi-walled carbon nanotubes functionalized with a thio group (MWNTs-SH) and gold nanoparticles (GNPs) for covalent DNA immobilization and enhanced hybridization detection is described. The key step for developing this novel DNA biosensor is to cut the pristine MWNT into short and generate lots of active sites simultaneously. With this approach, the target DNA could be quantified in a linear range from 8.5×10-10 to 1.5×10-5 mol/L, with a detection limit of 1.67×10-11 mol/L by 3σ.

  1. Dopamine-loaded liposome and its application in electrochemical DNA biosensor.

    PubMed

    Mahmoudi-Badiki, Tohid; Alipour, Esmaeel; Hamishehkar, Hamed; Golabi, Seyed Mahdi

    2016-08-01

    In this study, disruption and lyophilization-rehydration of dopamine-loaded liposome and its application in electrochemical DNA biosensor was investigated. The liposomes containing soyphosphatidylcholine and cholesterol were prepared through thin-layer hydration. First, an investigation was carried out to find an appropriate lysing agent for disruption of prepared liposomes. Differential pulse voltammetry, as a high sensitive electrochemical technique, was used along with a multi-walled carbon nanotubes modified glassy carbon electrode for sensitive electrochemical detection of released dopamine from disrupted liposomes. Various lysing agents were investigated and finally, the disruption of liposomes using methanol was selected without any surfactant, because of its least fouling effect. Then, lyophilization of dopamine-loaded liposomes was carried out using sucrose as cryoprotectant. The electrochemical studies of lyophilized liposomes showed that the remained dopamine in sucrose-protected liposomes was higher than sucrose-free liposomes. Furthermore, sucrose has no interference in electrochemical studies. Then, with the addition of biotin-X-DHPE to liposome formulation, the lyophilized sucrose protected dopamine-loaded biotin-tagged liposomes were prepared and the feasibility of application of them in electrochemical DNA biosensor was investigated as signal enhancer and verified for detection of oligonucleotides.

  2. Identification of Chinese Herbs Using a Sequencing-Free Nanostructured Electrochemical DNA Biosensor

    PubMed Central

    Lei, Yan; Yang, Fan; Tang, Lina; Chen, Keli; Zhang, Guo-Jun

    2015-01-01

    Due to the nearly identical phenotypes and chemical constituents, it is often very challenging to accurately differentiate diverse species of a Chinese herbal genus. Although technologies including DNA barcoding have been introduced to help address this problem, they are generally time-consuming and require expensive sequencing. Herein, we present a simple sequencing-free electrochemical biosensor, which enables easy differentiation between two closely related Fritillaria species. To improve its differentiation capability using trace amounts of DNA sample available from herbal extracts, a stepwise electrochemical deposition of reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) was adopted to engineer a synergistic nanostructured sensing interface. By using such a nanofeatured electrochemical DNA (E-DNA) biosensor, two Chinese herbal species of Fritillaria (F. thunbergii and F. cirrhosa) were successfully discriminated at the DNA level, because a fragment of 16-mer sequence at the spacer region of the 5S-rRNA only exists in F. thunbergii. This E-DNA sensor was capable of identifying the target sequence in the range from 100 fM to 10 nM, and a detection limit as low as 11.7 fM (S/N = 3) was obtained. Importantly, this sensor was applied to detect the unique fragment of the PCR products amplified from F. thunbergii and F. cirrhosa, respectively. We anticipate that such a direct, sequencing-free sensing mode will ultimately pave the way towards a new generation of herb-identification strategies. PMID:26633399

  3. An Electrochemical DNA Biosensor for the Detection of Salmonella Using Polymeric Films and Electrochemical Labels

    NASA Astrophysics Data System (ADS)

    Diaz Serrano, Madeline

    Waterborne and foodborne diseases are one of the principal public health problems worldwide. Microorganisms are the major agents of foodborne illness: pathogens such as Salmonella, Campylobacter jejuni and Escherichia coli, and parasites such as cryptosporidium. The most popular methods to detect Salmonella are based on culture and colony counting methods, ELISA, Gel electrophoresis and the polymerase chain reaction. Conventional detection methods are laborious and time-consuming, allowing for portions of the food to be distributed, marketed, sold and eaten before the analysis is done and the problem even detected. By these reasons, the rapid, easy and portable detection of foodborne organisms will facilitate the disease treatment. Our particular interest is to develop a nucleic acid biosensor (NAB) for the detection of pathogenic microorganisms in food and water samples. In this research, we report on the development of a NAB prototype using a polymer modified electrode surface together with sequences of different lengths for the OmpC gene from Salmonella as probes and Ferrocene-labeled target (Fc-ssDNA), Ferrocene-labeled tri(ethylene glycol) (Fc-PEG) and Ruthenium-Ferrocene (Ru-Fe) bimetallic complex as an electrochemical labels. We have optimized several PS films and anchored nucleic acid sequences with different lengths at gold and carbon surfaces. Non contact mode AFM and XPS were used to monitor each step of the NAB preparation, from polymer modification to oligos hybridization (conventional design). The hybridization reaction was followed electrochemically using a Fc-ssDNA and Fc-PEG in solution taking advantage of the morphological changes generated upon hybridization. We observed a small current at the potential for the Fe oxidation without signal amplification at +296 mV vs. Ag/AgCl for the Fc-ssDNA strategy and a small current at +524 mV for the Fc-PEG strategy. The immobilization, hybridization and signal amplification of Biotin- OmpC Salmonella genes

  4. Electrochemical DNA biosensors based on thin gold films sputtered on capacitive nanoporous niobium oxide.

    PubMed

    Rho, Sangchul; Jahng, Deokjin; Lim, Jae Hoon; Choi, Jinsub; Chang, Jeong Ho; Lee, Sang Cheon; Kim, Kyung Ja

    2008-01-18

    Electrochemical DNA biosensors based on a thin gold film sputtered on anodic porous niobium oxide (Au@Nb(2)O(5)) are studied in detail here. We found that the novel DNA biosensor based on Au@Nb(2)O(5) is superior to those based on the bulk gold electrode or niobium oxide electrode. For example, the novel method does not require any time-consuming cleaning step in order to obtain reproducible results. The adhesion of gold films on the substrate is very stable during electrochemical biosensing, when the thin gold films are deposited on anodically prepared nanoporous niobium oxide. In particular, the novel biosensor shows enhanced biosensing performance with a 2.4 times higher resolution and a three times higher sensitivity. The signal enhancement is in part attributed to capacitive interface between gold films and nanoporous niobium oxide, where charges are accumulated during the anodic and cathodic scanning, and is in part ascribed to the structural stability of DNA immobilized at the sputtered gold films. The method allows for the detection of single-base mismatch DNA as well as for the discrimination of mismatch positions.

  5. Nanostructured SERS-electrochemical biosensors for testing of anticancer drug interactions with DNA.

    PubMed

    Ilkhani, Hoda; Hughes, Taylor; Li, Jing; Zhong, Chuan Jian; Hepel, Maria

    2016-06-15

    Widely used anti-cancer treatments involving chemotherapeutic drugs result in cancer cell damage due to their strong interaction with DNA. In this work, we have developed laboratory biosensors for screening chemotherapeutic drugs and to aid in the assessment of DNA modification/damage caused by these drugs. The sensors utilize surface-enhanced Raman scattering (SERS) spectroscopy and electrochemical methods to monitor sensory film modification and observe the drug-DNA reactivity. The self-assembled monolayer protected gold-disk electrode (AuDE) was coated with a reduced graphene oxide (rGO), decorated with plasmonic gold-coated Fe2Ni@Au magnetic nanoparticles functionalized with double-stranded DNA (dsDNA), a sequence of the breast cancer gene BRCA1. The nanobiosensors AuDE/SAM/rGO/Fe2Ni@Au/dsDNA were then subjected to the action of a model chemotherapeutic drug, doxorubicin (DOX), to assess the DNA modification and its dose dependence. The designed novel nanobiosensors offer SERS/electrochemical transduction, enabling chemically specific and highly sensitive analytical signals generation. The SERS measurements have corroborated the DOX intercalation into the DNA duplex whereas the electrochemical scans have indicated that the DNA modification by DOX proceeds in a concentration dependent manner, with limit of detection LOD=8 µg/mL (S/N=3), with semilog linearity over 3 orders of magnitude. These new biosensors are sensitive to agents that interact with DNA and facilitate the analysis of functional groups for determination of the binding mode. The proposed nanobiosensors can be applied in the first stage of the drug development for testing the interactions of new drugs with DNA before the drug efficacy can be assessed in more expensive testing in vitro and in vivo.

  6. Electrochemical detection of benzo(a)pyrene and related DNA damage using DNA/hemin/nafion-graphene biosensor.

    PubMed

    Ni, Yongnian; Wang, Pingping; Song, Haiyan; Lin, Xiaoyun; Kokot, Serge

    2014-04-22

    A novel electrochemical biosensor, DNA/hemin/nafion-graphene/GCE, was constructed for the analysis of the benzo(a)pyrene PAH, which can produce DNA damage induced by a benzo(a)pyrene (BaP) enzyme-catalytic product. This biosensor was assembled layer-by-layer, and was characterized with the use of cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and atomic force microscopy. Ultimately, it was demonstrated that the hemin/nafion-graphene/GCE was a viable platform for the immobilization of DNA. This DNA biosensor was treated separately in benzo(a)pyrene, hydrogen peroxide (H2O2) and in their mixture, respectively, and differential pulse voltammetry (DPV) analysis showed that an oxidation peak was apparent after the electrode was immersed in H2O2. Such experiments indicated that in the presence of H2O2, hemin could mimic cytochrome P450 to metabolize benzo(a)pyrene, and a voltammogram of its metabolite was recorded. The DNA damage induced by this metabolite was also detected by electrochemical impedance and ultraviolet spectroscopy. Finally, a novel, indirect DPV analytical method for BaP in aqueous solution was developed based on the linear metabolite versus BaP concentration plot; this method provided a new, indirect, quantitative estimate of DNA damage.

  7. Electrochemical DNA biosensor based on the proximity-dependent surface hybridization assay.

    PubMed

    Zhang, Yanli; Wang, Ying; Wang, Haibo; Jiang, Jian-Hui; Shen, Guo-Li; Yu, Ru-Qin; Li, Jinghong

    2009-03-01

    This paper describes a novel electrochemical DNA (E-DNA) biosensor for simple, rapid, and specific detection of nucleic acids based on the proximity-dependent surface hybridization assay. This E-DNA biosensor was constructed by self-assembly of a 3' short thiolated capture probe on the gold electrode. DNA detection was realized by outputting a remarkable redox current of the 5' ferrocene (Fc) tail labeled probe. When the target DNA was introduced into the system, it was complementary to the 5' Fc labeled probe at the one-half-segment and complementary to the 3' short thiolated capture probe at the other half-segment, resulting in forming a stable duplex complex. As a result, the Fc probe was proximate to the electrode surface, and the Faradaic current was observed. This E-DNA biosensor was proved to have a low detection limit (1 fM) and a wide dynamic range (from 1 fM to 1 nM) due to the stable hybridization mode. In addition, the sensing system could discriminate the complementary sequence from mismatch sequences, with high sensitivity, stability, and reusability.

  8. Tetrahedron-structured DNA and functional oligonucleotide for construction of an electrochemical DNA-based biosensor.

    PubMed

    Bu, Nan-Nan; Tang, Chun-Xia; He, Xi-Wen; Yin, Xue-Bo

    2011-07-21

    Tetrahedron-structured DNA (ts-DNA) in combination with a functionalized oligonucleotide was used to develop a "turn-on" biosensor for Hg(2+) ions. The ts-DNA provided an improved sensitivity and was used to block the active sites.

  9. Electrochemical surface plasmon resonance biosensor for study of DNA desorption and hybridization

    NASA Astrophysics Data System (ADS)

    Ferrari, Luca; Šípová, Hana; Tichý, Ivo; Chadt, Karel; Homola, Jiri

    2013-05-01

    We report a system, which combines electrochemical and surface plasmon resonance (SPR) techniques on the same sensing chip. Each channel of a four-channel laboratory SPR sensor is supplemented with two planar gold electrodes (the reference and the counter electrodes), whereas the gold layer of SPR chip is used as the working electrode. A custom electronics enables to set an arbitrary potential between the reference and working electrodes and to measure the current flow between the counter and the working electrodes. Information from standard electrochemical techniques, i.e. cyclovoltammetry and chronoamperometry can be acquired with the system while simultaneously monitoring the shift in the surface plasmon resonance. The electrochemical SPR biosensor was used to study desorption of thiolated DNA probes with a negative potential. By comparing the acquired electrochemical and SPR signals, we show that DNA probes as well as a monolayer of alkanethiols can be desorbed by applying negative potentials to the SPR chip surface. Moreover, it is shown that the DNA probes can be reabsorbed on the SPR sensor surface and the complementary DNA can be detected without loss in detection sensitivity.

  10. An ultrasensitive electrochemical DNA biosensor based on a copper oxide nanowires/single-walled carbon nanotubes nanocomposite

    NASA Astrophysics Data System (ADS)

    Chen, Mei; Hou, Changjun; Huo, Danqun; Yang, Mei; Fa, Huanbao

    2016-02-01

    Here, we developed a novel and sensitive electrochemical biosensor to detect specific-sequence target DNA. The biosensor was based on a hybrid nanocomposite consisting of copper oxide nanowires (CuO NWs) and carboxyl-functionalized single-walled carbon nanotubes (SWCNTs-COOH). The resulting CuO NWs/SWCNTs layers exhibited a good differential pulse voltammetry (DPV) current response for the target DNA sequences, which we attributed to the properties of CuO NWs and SWCNTs. CuO NWs and SWCNTs hybrid composites with highly conductive and biocompatible nanostructure were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and cyclic voltammetry (CV). Immobilization of the probe DNA on the electrode surface was largely improved due to the unique synergetic effect of CuO NWs and SWCNTs. DPV was applied to monitor the DNA hybridization event, using adriamycin as an electrochemical indicator. Under optimal conditions, the peak currents of adriamycin were linear with the logarithm of target DNA concentrations (ranging from 1.0 × 10-14 to 1.0 × 10-8 M), with a detection limit of 3.5 × 10-15 M (signal/noise ratio of 3). The biosensor also showed high selectivity to single-base mismatched target DNA. Compared with other electrochemical DNA biosensors, we showed that the proposed biosensor is simple to implement, with good stability and high sensitivity.

  11. Recent Updates of DNA Incorporated in Carbon Nanotubes and Nanoparticles for Electrochemical Sensors and Biosensors

    PubMed Central

    Yogeswaran, Umasankar; Thiagarajan, Soundappan; Chen, Shen-Ming

    2008-01-01

    Innovations in the field of electrochemical sensors and biosensors are of much importance nowadays. These devices are designed with probes and micro electrodes. The miniaturized designs of these sensors allow analyses of materials without damaging the samples. Some of these sensors are also useful for real time analysis within the host system, so these sensors are considered to be more advantageous than other types of sensors. The active sensing materials used in these types of sensors can be any material that acts as a catalyst for the oxidation or reduction of particular analyte or set of analytes. Among various kinds of sensing materials, deoxyribonucleic acid (DNA), carbon nanotubes (CNTs) and nanoparticles have received considerable attraction in recent years. DNA is one of the classes of natural polymers, which can interact with CNTs and nanoparticles to form new types of composite materials. These composite materials have also been used as sensing materials for sensor applications. They have advantages in characteristics such as extraordinary low weight and multifunctional properties. In this article, advantages of DNA incorporated in CNT and nanoparticle hybrids for electrochemical sensors and biosensors are presented in detail, along with some key results noted from the literature. PMID:27873923

  12. Recent Updates of DNA Incorporated in Carbon Nanotubes and Nanoparticles for Electrochemical Sensors and Biosensors.

    PubMed

    Yogeswaran, Umasankar; Thiagarajan, Soundappan; Chen, Shen-Ming

    2008-11-13

    Innovations in the field of electrochemical sensors and biosensors are of much importance nowadays. These devices are designed with probes and micro electrodes. The miniaturized designs of these sensors allow analyses of materials without damaging the samples. Some of these sensors are also useful for real time analysis within the host system, so these sensors are considered to be more advantageous than other types of sensors. The active sensing materials used in these types of sensors can be any material that acts as a catalyst for the oxidation or reduction of particular analyte or set of analytes. Among various kinds of sensing materials, deoxyribonucleic acid (DNA), carbon nanotubes (CNTs) and nanoparticles have received considerable attraction in recent years. DNA is one of the classes of natural polymers, which can interact with CNTs and nanoparticles to form new types of composite materials. These composite materials have also been used as sensing materials for sensor applications. They have advantages in characteristics such as extraordinary low weight and multifunctional properties. In this article, advantages of DNA incorporated in CNT and nanoparticle hybrids for electrochemical sensors and biosensors are presented in detail, along with some key results noted from the literature.

  13. Electrochemical biosensor modified with dsDNA monolayer for restriction enzyme activity determination.

    PubMed

    Zajda, Joanna; Górski, Łukasz; Malinowska, Elżbieta

    2016-06-01

    A simple and cost effective method for the determination of restriction endonuclease activity is presented. dsDNA immobilized at a gold electrode surface is used as the enzymatic substrate, and an external cationic redox probe is employed in voltammetric measurements for analytical signal generation. The assessment of enzyme activity is based on a decrease of a current signal derived from reduction of methylene blue which is present in the sample solution. For this reason, the covalent attachment of the label molecule is not required which significantly reduces costs of the analysis and simplifies the entire determination procedure. The influence of buffer components on utilized dsDNA/MCH monolayer stability and integrity is also verified. Electrochemical impedance spectroscopy measurements reveal that due to pinhole formation during enzyme activity measurement the presence of any surfactants should be avoided. Additionally, it is shown that the sensitivity of the electrochemical biosensor can be tuned by changing the restriction site location along the DNA length. Under optimal conditions the proposed biosensor exhibits a linear response toward PvuII activity within a range from 0.25 to 1.50 U/μL.

  14. Electrochemical functionalization of polypyrrole through amine oxidation of poly(amidoamine) dendrimers: Application to DNA biosensor.

    PubMed

    Miodek, Anna; Mejri-Omrani, Nawel; Khoder, Rabih; Korri-Youssoufi, Hafsa

    2016-07-01

    Electrochemical patterning method has been developed to fabricate composite based on polypyrrole (PPy) film and poly(amidoamine) dendrimers of fourth generation (PAMAM G4). PPy layer was generated using electrochemical polymerization of pyrrole on a gold electrode. PPy film was then modified with PAMAM G4 using amines electro-oxidation method. Covalent bonding of PAMAM G4 and the formation of PPy-PAMAM composite was characterized using Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS). Ferrocenyl groups were then attached to such surface as a redox marker. Electrochemical properties of the modified nanomaterial (PPy-PAMAM-Fc) were studied using both amperometric and impedimetric methods to demonstrate the efficiency of electron transfer through the modified PPy layer. The obtained electrical and electrochemical properties were compared to a composite where PPy bearing carboxylic acid functions was chemically modified with PAMAM G4 by covalent attachment through formation of amid bond (PPy-CONH-PAMAM). The above mentioned studies showed that electrochemical patterning does not disturb the electronic properties of PPy. The effect of the number of functional groups introduced by the electrochemical patterning was demonstrated through the association of various compounds (ethylenediamine, PAMAM G2 and PAMAM G6). We demonstrated that such compounds could be applied in the biosensors technology. The modified PPy-PAMAM-Fc was evaluated as a platform for DNA sensing. High performance in the DNA detection by variation of the electrochemical signal of ferrocene was obtained with detection limit of 0.4 fM. Furthermore, such approach of electrochemical patterning by oxidation of amines could be applied for chemical modification of PPy and open a new way in various biosensing application involving functionalized PPy.

  15. Electrochemical DNA biosensor for detection of porcine oligonucleotides using ruthenium(II) complex as intercalator label redox

    NASA Astrophysics Data System (ADS)

    Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Ahmad, Haslina; Heng, Lee Yook; Karim, Nurul Huda Abd; Harun, Siti Norain

    2014-09-01

    A DNA biosensor detection of oligonucleotides via the interactions of porcine DNA with redox active complex based on the electrochemical transduction is described. A ruthenium(II) complex, [Ru(bpy)2(PIP)]2+, (bpy = 2,2'bipyridine, PIP = 2-phenylimidazo[4,5-f[[1,10-phenanthroline]) as DNA label has been synthesized and characterized by 1H NMR and mass spectra. The study was carried out by covalent bonding immobilization of porcine aminated DNA probes sequences on screen printed electrode (SPE) modified with succinimide-acrylic microspheres and [Ru(bpy)2(PIP)]2+ was used as electrochemical redox intercalator label to detect DNA hybridization event. Electrochemical detection was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over the potential range where the ruthenium (II) complex was active. The results indicate that the interaction of [Ru(bpy)2(PIP)]2+ with hybridization complementary DNA has higher response compared to single-stranded and mismatch complementary DNA.

  16. An Electrochemical DNA Biosensor Developed on a Nanocomposite Platform of Gold and Poly(propyleneimine) Dendrimer

    PubMed Central

    Arotiba, Omotayo; Owino, Joseph; Songa, Everlyne; Hendricks, Nicolette; Waryo, Tesfaye; Jahed, Nazeem; Baker, Priscilla; Iwuoha, Emmanuel

    2008-01-01

    An electrochemical DNA nanobiosensor was prepared by immobilization of a 20mer thiolated probe DNA on electro-deposited generation 4 (G4) poly(propyleneimine) dendrimer (PPI) doped with gold nanoparticles (AuNP) as platform, on a glassy carbon electrode (GCE). Field emission scanning electron microscopy results confirmed the co-deposition of PPI (which was linked to the carbon electrode surface by C-N covalent bonds) and AuNP ca 60 nm. Voltammetric interrogations showed that the platform (GCE/PPI-AuNP) was conducting and exhibited reversible electrochemistry (E°′ = 235 mV) in pH 7.2 phosphate buffer saline solution (PBS) due to the PPI component. The redox chemistry of PPI was pH dependent and involves a two electron, one proton process, as interpreted from a 28 mV/pH value obtained from pH studies. The charge transfer resistance (Rct) from the electrochemical impedance spectroscopy (EIS) profiles of GCE/PPI-AuNP monitored with ferro/ferricyanide (Fe(CN)63-/4-) redox probe, decreased by 81% compared to bare GCE. The conductivity (in PBS) and reduced Rct (in Fe(CN)63-/4-) values confirmed PPI-AuNP as a suitable electron transfer mediator platform for voltammetric and impedimetric DNA biosensor. The DNA probe was effectively wired onto the GCE/PPI-AuNP via Au-S linkage and electrostatic interactions. The nanobiosensor responses to target DNA which gave a dynamic linear range of 0.01 - 5 nM in PBS was based on the changes in Rct values using Fe(CN)63-/4- redox probe. PMID:27873900

  17. Electrochemical biosensors for hormone analyses.

    PubMed

    Bahadır, Elif Burcu; Sezgintürk, Mustafa Kemal

    2015-06-15

    Electrochemical biosensors have a unique place in determination of hormones due to simplicity, sensitivity, portability and ease of operation. Unlike chromatographic techniques, electrochemical techniques used do not require pre-treatment. Electrochemical biosensors are based on amperometric, potentiometric, impedimetric, and conductometric principle. Amperometric technique is a commonly used one. Although electrochemical biosensors offer a great selectivity and sensitivity for early clinical analysis, the poor reproducible results, difficult regeneration steps remain primary challenges to the commercialization of these biosensors. This review summarizes electrochemical (amperometric, potentiometric, impedimetric and conductometric) biosensors for hormone detection for the first time in the literature. After a brief description of the hormones, the immobilization steps and analytical performance of these biosensors are summarized. Linear ranges, LODs, reproducibilities, regenerations of developed biosensors are compared. Future outlooks in this area are also discussed.

  18. Development of an electrochemical biosensor methods based on acrylic microsphere for the determination of Arowana DNA hybridization

    NASA Astrophysics Data System (ADS)

    Rahman, Mahbubur; Heng, Lee Yook; Futra, Dedi; Chiang, Chew Poh

    2015-09-01

    An electrochemical method of Arowana DNA determination based of N-acrylosuccinimide (NAS) modified acrylic microsphere was fabricated. Hydrophobic succinimide functional group containing poly(n-butylacrylate-N-acryloxysuccinimide) microspheres were synthesized with a simple one-step photopolymerization pocedure. Aminated DNA probe was covalently bonded to the succinimde functional group of the acrylic microspheres. The hybridization of the immobilized DNA probe with the complementary DNA was determined by the differential pulse voltametry using anthraquninone-2-sulfonic acid monohydrate sodium salt (AQMS) as the electroactive hybridization label. The influences of many factors such as duration of DNA probe immobilization and hybridization, operational temperature and non-complementary DNA on the biosensor performance were evaluated. Under optimized conditions, the DNA microbiosensor demonstrated a wide linear response range to target DNA is 1.0 × 10-16 and 1.0 × 10-8 M with a lower limit of detection (LOD) of 9.46 × 10-17 M (R2 = 0.99) were calculated. This biosensor had improved the overall analytical performance of the resultant DNA microbiosensor when compared with other reported DNA biosensors using other nano-materials for membranes and microspheres as DNA immobilization matrices.

  19. Electrochemical biosensors and nanobiosensors

    PubMed Central

    Hammond, Jules L.; Formisano, Nello; Carrara, Sandro; Tkac, Jan

    2016-01-01

    Electrochemical techniques have great promise for low-cost miniaturised easy-to-use portable devices for a wide range of applications–in particular, medical diagnosis and environmental monitoring. Different techniques can be used for biosensing, with amperometric devices taking the central role due to their widespread application in glucose monitoring. In fact, glucose biosensing takes an approximately 70% share of the biosensor market due to the need for diabetic patients to monitor their sugar levels several times a day, making it an appealing commercial market. In this review, we present the basic principles of electrochemical biosensor devices. A description of the different generations of glucose sensors is used to describe in some detail the operation of amperometric sensors and how the introduction of mediators can enhance the performance of the sensors. Electrochemical impedance spectroscopy is a technique being increasingly used in devices due to its ability to detect variations in resistance and capacitance upon binding events. Novel advances in electrochemical sensors, due to the use of nanomaterials such as carbon nanotubes and graphene, are presented as well as future directions that the field is taking. PMID:27365037

  20. Homogeneous Electrochemical Biosensor for Melamine Based on DNA Triplex Structure and Exonuclease III-Assisted Recycling Amplification.

    PubMed

    Fu, Caili; Liu, Chang; Li, Ying; Guo, Yajing; Luo, Fang; Wang, Peilong; Guo, Longhua; Qiu, Bin; Lin, Zhenyu

    2016-10-03

    Abasic site (AP site) in the triplex structure can recognize specific target with high selectivity. In this study, this character was first applied to develop a simple, sensitive, and selective homogeneous electrochemical biosensor for melamine determination. The assay combines the advantage of the high selectivity of the DNA triplex structure containing an AP site to melamine and high efficiency of exonuclease (Exo) III-assisted recycling amplification. DNA-1 (T1), DNA-2 (T2), poly[dA] probe containing an AP site (8A) and methylene blue-labeled DNA probe (dMB probe) were carefully designed. Melamine can specifically locate in the AP site through hydrogen bonding interaction between thymine and melamine to make T1, T2, and 8A close to each other, therefore, forming a stable T-melamine-T DNA triplex structure. Under the optimal conditions, the differential pulse voltammetric (DPV) response had a linear relationship with the logarithm of melamine concentration in the range of 1 nM∼0.5 μM. The developed biosensor has been successfully applied to detect the migration of melamine from melamine bowl. Result showed that the migration in 4% acetic acid solvent was the largest, which is similar to that detected by high performance liquid chromatography. This homogeneous electrochemical sensor may have a potential prospect in detecting melamine in dairy products and migration of melamine from multicategory food packaging or application materials.

  1. An electrochemical DNA biosensor based on nitrogen-doped graphene/Au nanoparticles for human multidrug resistance gene detection.

    PubMed

    Chen, Mei; Hou, Changjun; Huo, Danqun; Bao, Jing; Fa, Huanbao; Shen, Caihong

    2016-11-15

    Multidrug resistance (MDR) has become a major obstacle to the adequate treatment of cancer patients; thus, there is an urgent need for exploring new strategies for early diagnosis of MDR in clinic. Here, we report a novel electrochemical biosensor based on nitrogen-doped graphene nanosheets functionalized with Au nanoparticles (N-G/Au) for sensitive and selective DNA detection. The highly conductive nanocomposite layer was characterized by using scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, and cyclic voltammetry. DNA with thiol groups at the 5' end was immobilized on the N-G/Au surface via the strong Au-S bond. Differential pulse voltammetry was applied to monitor the target DNA hybridization event using methylene blue as an electrochemical indicator. Under optimal conditions, the biosensor could detect target DNA down to 3.12×10(-15)M with a linear range from 1.0×10(-14) to 1.0×10(-7)M, showing high sensitivity. Further, the sensing strategy was successfully used for detecting MDR1 DNA in real clinical samples. These results will aid in developing a new portable detection system for MDR that will allow effective diagnosis in the early stages of related cancer.

  2. Studies on the Interaction Mechanism of 1,10-Phenanthroline Cobalt(II) Complex with DNA and Preparation of Electrochemical DNA Biosensor

    PubMed Central

    Niu, Shuyan; Li, Feng; Zhang, Shusheng; Wang, Long; Li, Xuemei; Wang, Shiying

    2006-01-01

    Fluorescence spectroscopy and ultraviolet (UV) spectroscopy techniques coupled with cyclic voltammetry (CV) were used to study the interaction between salmon sperm DNA and 1,10-Phenanthroline cobalt(II) complex, [Co(phen)2(Cl)(H2O)]Cl·H2O, where phen = 1,10-phenanthroline. The interaction between [Co(phen)2(Cl)(H2O)]+ and double-strand DNA (dsDNA) was identified to be intercalative mode. An electrochemical DNA biosensor was developed by covalent immobilization of probe single-strand DNA (ssDNA) related to human immunodeficiency virus (HIV) on the activated glassy carbon electrode (GCE). With [Co(phen)2(Cl)(H2O)]+ being the novel electrochemical hybridization indicator, the selectivity of ssDNA-modified electrode was investigated and selective detection of complementary ssDNA was achieved using differential pulse voltammetry (DPV).

  3. Electrochemical DNA biosensor for detection of porcine oligonucleotides using ruthenium(II) complex as intercalator label redox

    SciTech Connect

    Halid, Nurul Izni Abdullah; Hasbullah, Siti Aishah; Heng, Lee Yook; Karim, Nurul Huda Abd; Ahmad, Haslina; Harun, Siti Norain

    2014-09-03

    A DNA biosensor detection of oligonucleotides via the interactions of porcine DNA with redox active complex based on the electrochemical transduction is described. A ruthenium(II) complex, [Ru(bpy){sub 2}(PIP)]{sup 2+}, (bpy = 2,2′bipyridine, PIP = 2-phenylimidazo[4,5-f[[1,10-phenanthroline]) as DNA label has been synthesized and characterized by 1H NMR and mass spectra. The study was carried out by covalent bonding immobilization of porcine aminated DNA probes sequences on screen printed electrode (SPE) modified with succinimide-acrylic microspheres and [Ru(bpy){sub 2}(PIP)]{sup 2+} was used as electrochemical redox intercalator label to detect DNA hybridization event. Electrochemical detection was performed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) over the potential range where the ruthenium (II) complex was active. The results indicate that the interaction of [Ru(bpy){sub 2}(PIP)]{sup 2+} with hybridization complementary DNA has higher response compared to single-stranded and mismatch complementary DNA.

  4. A Sensitive and Selective Label-Free Electrochemical DNA Biosensor for the Detection of Specific Dengue Virus Serotype 3 Sequences

    PubMed Central

    Oliveira, Natália; Souza, Elaine; Ferreira, Danielly; Zanforlin, Deborah; Bezerra, Wessulla; Borba, Maria Amélia; Arruda, Mariana; Lopes, Kennya; Nascimento, Gustavo; Martins, Danyelly; Cordeiro, Marli; Lima-Filho, José

    2015-01-01

    Dengue fever is the most prevalent vector-borne disease in the world, with nearly 100 million people infected every year. Early diagnosis and identification of the pathogen are crucial steps for the treatment and for prevention of the disease, mainly in areas where the co-circulation of different serotypes is common, increasing the outcome of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Due to the lack of fast and inexpensive methods available for the identification of dengue serotypes, herein we report the development of an electrochemical DNA biosensor for the detection of sequences of dengue virus serotype 3 (DENV-3). DENV-3 probe was designed using bioinformatics software and differential pulse voltammetry (DPV) was used for electrochemical analysis. The results showed that a 22-m sequence was the best DNA probe for the identification of DENV-3. The optimum concentration of the DNA probe immobilized onto the electrode surface is 500 nM and a low detection limit of the system (3.09 nM). Moreover, this system allows selective detection of DENV-3 sequences in buffer and human serum solutions. Therefore, the application of DNA biosensors for diagnostics at the molecular level may contribute to future advances in the implementation of specific, effective and rapid detection methods for the diagnosis dengue viruses. PMID:26140346

  5. Specific and Sensitive Isothermal Electrochemical Biosensor for Plant Pathogen DNA Detection with Colloidal Gold Nanoparticles as Probes.

    PubMed

    Lau, Han Yih; Wu, Haoqi; Wee, Eugene J H; Trau, Matt; Wang, Yuling; Botella, Jose R

    2017-01-17

    Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV). Our method was 10,000 times more sensitive than conventional polymerase chain reaction (PCR)/gel electrophoresis and could readily identify P. syringae infected plant samples even before the disease symptoms were visible. On the basis of the speed, sensitivity, simplicity and portability of the approach, we believe the method has potential as a rapid disease management solution for applications in agriculture diagnostics.

  6. Specific and Sensitive Isothermal Electrochemical Biosensor for Plant Pathogen DNA Detection with Colloidal Gold Nanoparticles as Probes

    NASA Astrophysics Data System (ADS)

    Lau, Han Yih; Wu, Haoqi; Wee, Eugene J. H.; Trau, Matt; Wang, Yuling; Botella, Jose R.

    2017-01-01

    Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV). Our method was 10,000 times more sensitive than conventional polymerase chain reaction (PCR)/gel electrophoresis and could readily identify P. syringae infected plant samples even before the disease symptoms were visible. On the basis of the speed, sensitivity, simplicity and portability of the approach, we believe the method has potential as a rapid disease management solution for applications in agriculture diagnostics.

  7. Specific and Sensitive Isothermal Electrochemical Biosensor for Plant Pathogen DNA Detection with Colloidal Gold Nanoparticles as Probes

    PubMed Central

    Lau, Han Yih; Wu, Haoqi; Wee, Eugene J. H.; Trau, Matt; Wang, Yuling; Botella, Jose R.

    2017-01-01

    Developing quick and sensitive molecular diagnostics for plant pathogen detection is challenging. Herein, a nanoparticle based electrochemical biosensor was developed for rapid and sensitive detection of plant pathogen DNA on disposable screen-printed carbon electrodes. This 60 min assay relied on the rapid isothermal amplification of target pathogen DNA sequences by recombinase polymerase amplification (RPA) followed by gold nanoparticle-based electrochemical assessment with differential pulse voltammetry (DPV). Our method was 10,000 times more sensitive than conventional polymerase chain reaction (PCR)/gel electrophoresis and could readily identify P. syringae infected plant samples even before the disease symptoms were visible. On the basis of the speed, sensitivity, simplicity and portability of the approach, we believe the method has potential as a rapid disease management solution for applications in agriculture diagnostics. PMID:28094255

  8. Nanomaterial-Based Electrochemical Biosensors and Bioassays

    SciTech Connect

    Liu, Guodong; Mao, Xun; Gurung, Anant; Baloda, Meenu; Lin, Yuehe; He, Yuqing

    2010-08-31

    This book chapter summarizes the recent advance in nanomaterials for electrochemical biosensors and bioassays. Biofunctionalization of nanomaterials for biosensors fabrication and their biomedical applications are discussed.

  9. Electrochemical DNA Biosensor Based on a Tetrahedral Nanostructure Probe for the Detection of Avian Influenza A (H7N9) Virus.

    PubMed

    Dong, Shibiao; Zhao, Rongtao; Zhu, Jiangong; Lu, Xiao; Li, Yang; Qiu, Shaofu; Jia, Leili; Jiao, Xiong; Song, Shiping; Fan, Chunhai; Hao, RongZhang; Song, HongBin

    2015-04-29

    A DNA tetrahedral nanostructure-based electrochemical biosensor was developed to detect avian influenza A (H7N9) virus through recognizing a fragment of the hemagglutinin gene sequence. The DNA tetrahedral probe was immobilized onto a gold electrode surface based on self-assembly between three thiolated nucleotide sequences and a longer nucleotide sequence containing complementary DNA to hybridize with the target single-stranded (ss)DNA. The captured target sequence was hybridized with a biotinylated-ssDNA oligonucleotide as a detection probe, and then avidin-horseradish peroxidase was introduced to produce an amperometric signal through the interaction with 3,3',5,5'-tetramethylbenzidine substrate. The target ssDNA was obtained by asymmetric polymerase chain reaction (PCR) of the cDNA template, reversely transcribed from the viral lysate of influenza A (H7N9) virus in throat swabs. The results showed that this electrochemical biosensor could specifically recognize the target DNA fragment of influenza A (H7N9) virus from other types of influenza viruses, such as influenza A (H1N1) and (H3N2) viruses, and even from single-base mismatches of oligonucleotides. Its detection limit could reach a magnitude of 100 fM for target nucleotide sequences. Moreover, the cycle number of the asymmetric PCR could be reduced below three with the electrochemical biosensor still distinguishing the target sequence from the negative control. To the best of our knowledge, this is the first report of the detection of target DNA from clinical samples using a tetrahedral DNA probe functionalized electrochemical biosensor. It displays that the DNA tetrahedra has a great potential application as a probe of the electrochemical biosensor to detect avian influenza A (H7N9) virus and other pathogens at the gene level, which will potentially aid the prevention and control of the disease caused by such pathogens.

  10. Ultrasensitive electrochemical DNA biosensor based on functionalized gold clusters/graphene nanohybrids coupling with exonuclease III-aided cascade target recycling.

    PubMed

    Wang, Wei; Bao, Ting; Zeng, Xi; Xiong, Huayu; Wen, Wei; Zhang, Xiuhua; Wang, Shengfu

    2017-05-15

    In this work, a novel and ultrasensitive electrochemical biosensor was constructed for DNA detection based on functionalized gold clusters/graphene nanohybrids (AuNCs/GR nanobybrids) and exonuclease III (Exo III)-aided cascade target recycling. By utilizing the capacity of GR as universal template, different metal nanoclusters including AuNCs/GR nanobybrids and PtNCs/GR nanohybrids were synthesized through convenient ultrasonic method. Exo III-aided cascade recycling was initiated by target DNA, generating the final cleavage product (S2), which acted as a linkage between capture probe and the functionalized metal nanoclusters/GR conjugates in the construction of the biosensor. The AuNCs/GR-DNA-enzyme conjugates acted as interfaces of enzyme-catalyzed silver deposition reaction, achieving DNA detection ranging from 0.02 fM to 20 pM with a detection limit of 0.057 fM. In addition, PtNCs/GR-DNA conjugates presented peroxidase-like activity and the functionalized PtNCs/GR nanohybrids-based electrochemical biosensor also realized DNA detection by catalyzing the 3,3',5,5'-tetramethylbenzidine-hydrogen peroxide (TMB-H2O2) system to produce electrochemical signal. This metal clusters/GR-based multiple-amplified electrochemical biosensor provided an universal method for DNA detection.

  11. Biosensors for DNA sequence detection

    NASA Technical Reports Server (NTRS)

    Vercoutere, Wenonah; Akeson, Mark

    2002-01-01

    DNA biosensors are being developed as alternatives to conventional DNA microarrays. These devices couple signal transduction directly to sequence recognition. Some of the most sensitive and functional technologies use fibre optics or electrochemical sensors in combination with DNA hybridization. In a shift from sequence recognition by hybridization, two emerging single-molecule techniques read sequence composition using zero-mode waveguides or electrical impedance in nanoscale pores.

  12. Single bead-based electrochemical biosensor

    PubMed Central

    Liu, Changchun; Schrlau, Michael G.; Bau, Haim H.

    2009-01-01

    A simple, robust, single bead-based electrochemical biosensor was fabricated and characterized. The sensor’s working electrode consists of an electrochemically-etched platinum wire, with a nominal diameter of 25 μm, hermetically heat-fusion sealed in a pulled glass capillary (micropipette). The sealing process does not require any epoxy or glue. A commercially available, densely functionalized agarose bead was mounted on the tip of the etched platinum wire. The use of a pre-functionalized bead eliminates the tedious and complicated surface functionalization process that is often the bottleneck in the development of electrochemical biosensors. We report on the use of a biotin agarose bead-based, micropipette, electrochemical (Bio-BMP) biosensor to monitor H2O2 concentration and the use of a streptavidin bead-based, micropipette, electrochemical (SA-BMP) biosensor to detect DNA amplicons. The Bio-BMP biosensor’s response increased linearly as the H2O2 concentration increased in the range from 1×10−6 to 1.2×10−4 M with a detection limit of 5×10−7 M. The SA-BMP was able to detect the amplicons of 1 pg DNA template of B. Cereus bacteria, thus providing better detection sensitivity than conventional gel-based electropherograms. PMID:19767195

  13. Developing an electrochemical deoxyribonucleic acid (DNA) biosensor on the basis of human interleukine-2 gene using an electroactive label.

    PubMed

    Pournaghi-Azar, M H; Hejazi, M S; Alipour, E

    2006-06-16

    Development of an electrochemical DNA biosensor based on a human interleukine-2 (IL-2) gene probe, using a pencil graphite electrode (PGE) as transducer and methylene blue (MB) as electroactive label is described. The sensor relies on the immobilization of a 20-mer single stranded oligonucleotide probe (hIL-2) related to the IL-2 gene on the electrode. The hybridization between the probe and its complementary sequence (chIL-2) as the target was studied by square wave voltammetry (SWV) of MB accumulated on the PGE. In this approach the extent of hybridization is evaluated on the basis of the difference between SWV signals of MB accumulated on the probe-PGE and MB accumulated on the probe-target-PGE. Some hybridization experiments with non-complementary oligonucleotides were carried out to assess whether the suggested DNA sensor responds selectively to the target. Some experimental variables affecting the performance of the biosensor including: polishing of PGE, its electrochemical activation conditions (i.e., activation potential and activation time) and probe immobilization conditions on the electrodes (i.e., immobilization potential and time) were investigated and the optimum values of 1.80 V and 300 s for PGE activation, and -0.5 V and 400s for the probe immobilization on the electrode were suggested.

  14. Electrochemical Biosensor: Multistep functionalization of thiolated ssDNA on gold-coated microcantilever

    NASA Astrophysics Data System (ADS)

    Dulanto Carbajal, Jorge

    Bio-chemical sensors are an emerging and vibrant area of research. The use of micromechanical cantilevers is relatively new as biomechanical recognition detectors. Reactions on a gold coated and chemically functionalized surface produce a mechanical deflection of the cantilever which is used as the input signal of the detector. Within the area of biosensors, DNA-sensors have a wide range of applications such as DNA hybridization detectors, DNA mismatch sequence detectors and protein detectors. We designed and built a microcantilever sensor system which allows for control and characterization of surface conditions. This includes controlled functionalization which can be a dominant factor in signal generation and reproducibility in these systems. Additionally, we developed a multistep functionalization protocol which consists of a sequence of short incubations and characterizations of thiolated ssDNA on a gold-coated cantilever. Multistep functionalization is a new protocol that is used to control the ssDNA surface density on a gold-coated cantilever. Repeatable responses and feasible biosensors are obtained using this protocol.

  15. Electrochemical study of quinone redox cycling: A novel application of DNA-based biosensors for monitoring biochemical reactions.

    PubMed

    Ensafi, Ali A; Jamei, Hamid Reza; Heydari-Bafrooei, Esmaeil; Rezaei, B

    2016-10-01

    This paper presents the results of an experimental investigation of voltammetric and impedimetric DNA-based biosensors for monitoring biological and chemical redox cycling reactions involving free radical intermediates. The concept is based on associating the amounts of radicals generated with the electrochemical signals produced, using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). For this purpose, a pencil graphite electrode (PGE) modified with multiwall carbon nanotubes and poly-diallydimethlammonium chloride decorated with double stranded fish sperm DNA was prepared to detect DNA damage induced by the radicals generated from a redox cycling quinone (i.e., menadione (MD; 2-methyl-1,4-naphthoquinone)). Menadione was employed as a model compound to study the redox cycling of quinones. A direct relationship was found between free radical production and DNA damage. The relationship between MD-induced DNA damage and free radical generation was investigated in an attempt to identify the possible mechanism(s) involved in the action of MD. Results showed that DPV and EIS were appropriate, simple and inexpensive techniques for the quantitative and qualitative comparisons of different reducing reagents. These techniques may be recommended for monitoring DNA damages and investigating the mechanisms involved in the production of redox cycling compounds.

  16. DNA-wrapped multi-walled carbon nanotube modified electrochemical biosensor for the detection of Escherichia coli from real samples.

    PubMed

    Ozkan-Ariksoysal, Dilsat; Kayran, Yasin Ugur; Yilmaz, Fethiye Ferda; Ciucu, Anton Alexandru; David, Iulia Gabriela; David, Vasile; Hosgor-Limoncu, Mine; Ozsoz, Mehmet

    2017-05-01

    This paper introduces DNA-wrapped multi-walled carbon nanotube (MWCNT)-modified genosensor for the detection of Escherichia coli (E. coli) from polymerase chain reaction (PCR)-amplified real samples while Staphylococcus aureus (S. aureus) was used to investigate the selectivity of the biosensor. The capture probe specifically recognizing E. coli DNA and it was firstly interacted with MWCNTs for wrapping of single-stranded DNA (ssDNA) onto the nanomaterial. DNA-wrapped MWCNTs were then immobilised on the surface of disposable pencil graphite electrode (PGE) for the detection of DNA hybridization. Electrochemical behaviors of the modified PGEs were investigated using Raman spectroscopy and differential pulse voltammetry (DPV). The sequence selective DNA hybridization was determined and evaluated by changes in the intrinsic guanine oxidation signal at about 1.0V by DPV. Numerous factors affecting the hybridization were optimized such as target concentration, hybridization time, etc. The designed DNA sensor can well detect E. coli DNA in 20min detection time with 0.5pmole of detection limit in 30µL of sample volume.

  17. Electrochemical DNA sandwich biosensor based on enzyme amplified microRNA-21 detection and gold nanoparticles.

    PubMed

    Mandli, Jihane; Mohammadi, Hasna; Amine, Aziz

    2017-03-14

    In this work, a novel electrochemical biosensor for miRNA-21 determination, involving a sandwich hybridization assay onto gold nanoparticles modified pencil graphite electrode (PGE) and enzyme signal amplification was reported. The thiol terminated capture probe 1 (SH-P1) was immobilized on the electrode through AuS interaction. In the presence of target miRNA-21, SH-P1 hybridized with the first part of the target, however, the second part hybridizes with a biotinylated probe P2 (B-P2). Then, a streptavidin-conjugated alkaline phosphatase was immobilized by a specific binding of avidin-B-P2. The enzyme catalyzed the electro-inactive α-naphtyl phosphate to an electro-active α-naphtol. The miRNA-21 detection was achieved through the changes of α-naphtol oxidation signals observed at +0.12V vs Ag/AgCl with Differential Pulse Voltammetry. Under the optimal detection conditions, the biosensor exhibited selective and sensitive detection with a linear range from 200pM to 388nM and the detection limit was 100pM (10fmol in 100μL).

  18. A sandwich-type DNA biosensor based on electrochemical co-reduction synthesis of graphene-three dimensional nanostructure gold nanocomposite films.

    PubMed

    Liu, Ai-Lin; Zhong, Guang-Xian; Chen, Jin-Yuan; Weng, Shao-Huang; Huang, Hong-Nan; Chen, Wei; Lin, Li-Qing; Lei, Yun; Fu, Fei-Huan; Sun, Zhou-liang; Lin, Xin-Hua; Lin, Jian-Hua; Yang, Shu-Yu

    2013-03-12

    A novel electrochemical DNA biosensor based on graphene-three dimensional nanostructure gold nanocomposite modified glassy carbon electrode (G-3D Au/GCE) was fabricated for detection of survivin gene which was correlated with osteosarcoma. The G-3D Au film was prepared with one-step electrochemical coreduction with graphite oxide and HAuCl4 at cathodic potentials. The active surface area of G-3D Au/GCE was 2.629cm(2), which was about 3.8 times compared to that of a Au-coated GCE under the same experimental conditions, and 8.8 times compared to a planar gold electrode with a similar geometric area. The resultant nanocomposites with high conductivity, electrocatalysis and biocompatibility were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A "sandwich-type" detection strategy was employed in this electrochemical DNA biosensor and the response of this DNA biosensor was measured by CV and amperometric current-time curve detection. Under optimum conditions, there was a good linear relationship between the current signal and the logarithmic function of complementary DNA concentration in a range of 50-5000fM with a detection limit of 3.4fM. This new biosensor exhibited a fast amperometric response, high sensitivity and selectivity and has been used in a polymerase chain reaction assay of real-life sample with a satisfactory result.

  19. Development of an Advanced Electrochemical DNA Biosensor for Bacterial Pathogen Detection

    PubMed Central

    Liao, Joseph C.; Mastali, Mitra; Li, Yang; Gau, Vincent; Suchard, Marc A.; Babbitt, Jane; Gornbein, Jeffrey; Landaw, Elliot M.; McCabe, Edward R.B.; Churchill, Bernard M.; Haake, David A.

    2007-01-01

    Electrochemical sensors have the capacity for rapid and accurate detection of a wide variety of target molecules in biological fluids. We have developed an electrochemical sensor assay involving hybridization of bacterial 16S rRNA to fluorescein-modified detector probes and to biotin-modified capture probes anchored to the sensor surface. Signal is generated by an oxidation-reduction current produced by the action of horseradish peroxidase conjugated to an anti-fluorescein monoclonal Fab. A previous study found that this electrochemical sensor strategy could identify uropathogens in clinical urine specimens. To improve assay sensitivity, we examined the key steps that affect the current amplitude of the electrochemical signal. Efficient lysis and release of 16S rRNA from both gram-negative and -positive bacteria was achieved with an initial treatment with Triton X-100 and lysozyme followed by alkaline lysis, resulting in a 12-fold increase in electrochemical signal compared with alkaline lysis alone. The distance in nucleotides between the target hybridization sites of the detector and capture probes and the location of fluorescein modification on the detector probe contributed to a 23-fold change in signal intensity. These results demonstrate the importance of target-probe and probe-probe interactions in the detection of bacterial 16S rRNA using an electrochemical DNA sensor approach. PMID:17384207

  20. Enzyme-based electrochemical biosensor for sensitive detection of DNA demethylation and the activity of DNA demethylase.

    PubMed

    Zhou, Yunlei; Li, Bingchen; Wang, Mo; Yang, Zhiqing; Yin, Huanshun; Ai, Shiyun

    2014-08-20

    A novel electrochemical method is developed for detection of DNA demethylation and assay of DNA demethylase activity. This method is constructed by hybridizing the probe with biotin tagged hemi-methylated complementary DNA and further capturing streptavidin tagged alkaline phosphatase (SA-ALP) to catalyze the hydrolysis reaction of p-nitrophenyl phosphate. The hydrolysate of p-nitrophenol (PNP) is then used as electrochemical probe for detecting DNA demethylation and assaying the activity of DNA demethylase. Demethylation of target DNA initiates a degradation reaction of the double-stranded DNA (dsDNA) by restriction endonuclease of BstUI. It makes the failed immobilization of ALP, resulting in a decreased electrochemical oxidation signal of PNP. Through the change of this electrochemical signal, the DNA demethylation is identified and the activity of DNA demethylase is analyzed with low detection limit of 1.3 ng mL(-1). This method shows the advantages of simple operation, cheap and miniaturized instrument, high selectivity. Thus, it provides a useful platform for detecting DNA demethylation, analyzing demethylase activity and screening inhibited drug.

  1. Fabrication of an electrochemical DNA-based biosensor for Bacillus cereus detection in milk and infant formula.

    PubMed

    Izadi, Zahra; Sheikh-Zeinoddin, Mahmoud; Ensafi, Ali A; Soleimanian-Zad, Sabihe

    2016-06-15

    This paper describes fabrication of a DNA-based Au-nanoparticle modified pencil graphite electrode (PGE) biosensor for detection of Bacillus cereus, causative agent of two types of food-borne disease, i.e., emetic and diarrheal syndrome. The sensing element of the biosensor was comprised of gold nanoparticles (GNPs) self-assembled with single-stranded DNA (ssDNA) of nheA gene immobilized with thiol linker on the GNPs modified PGE. The size, shape and dispersion of the GNPs were characterized by field emission scanning electron microscope (FESEM). Detection of B. cereus was carried out based on an increase in the charge transfer resistance (Rct) of the biosensor due to hybridization of the ss-DNA with target DNA. An Atomic force microscope (AFM) was used to confirm the hybridization. The biosensor sensitivity in pure cultures of B. cereus was found to be 10(0) colony forming units per milliliter (CFU/mL) with a detection limit of 9.4 × 10(-12) mol L(-1). The biosensor could distinguish complementary from mismatch DNA sequence. The proposed biosensor exhibited a rapid detection, low cost, high sensitivity to bacterial contamination and could exclusively and specifically detect the target DNA sequence of B. cereus from other bacteria that can be found in dairy products. Moreover, the DNA biosensor exhibited high reproducibility and stability, thus it may be used as a suitable biosensor to detect B. cereus and to become a portable system for food quality control.

  2. A label-free, PCR-free and signal-on electrochemical DNA biosensor for Leishmania major based on gold nanoleaves.

    PubMed

    Moradi, M; Sattarahmady, N; Rahi, A; Hatam, G R; Sorkhabadi, S M Rezayat; Heli, H

    2016-12-01

    Detection of leishmaniasis is important in clinical diagnoses. In the present study, identification of Leishmania parasites was performed by a label-free, PCR-free and signal-on ultrasensitive electrochemical DNA biosensor. Gold nanoleaves were firstly electrodeposited by an electrodeposition method using spermidine as a shape directing agent. The biosensor was fabricated by immobilization of a Leishmania major specific DNA probe onto gold nanoleaves, and methylene blue was employed as a marker. Hybridization of the complementary single stranded DNA sequence with the biosensor under the selected conditions was then investigated. The biosensor could detect a synthetic DNA target in a range of 1.0×10(-10) to 1.0×10(-19)molL(-1) with a limit of detection of 1.8×10(-20)molL(-1), and genomic DNA in a range of 0.5-20ngμL(-1) with a limit of detection of 0.07ngμL(-1). The biosensor could distinguish Leishmania major from a non-complementary-sequence oligonucleotide and the tropica species with a high selectivity. The biosensor was applicable to detect Leishmania major in patient samples.

  3. A sensitive electrochemical DNA biosensor for antineoplastic drug 5-fluorouracil based on glassy carbon electrode modified with poly(bromocresol purple).

    PubMed

    Koyuncu Zeybek, Derya; Demir, Burcu; Zeybek, Bülent; Pekyardımcı, Şule

    2015-11-01

    This paper describes an electrochemical sensor for the first time based on poly(bromocresol purple) (P(BCP)) developed to observe the interaction between 5-fluorouracil (5-FU) and fish sperm double strand DNA (dsDNA). The P(BCP) film was electrosynthesized by cyclic voltammetry method on the glassy carbon electrode (GCE). The dsDNA was electrochemically immobilized on the surface of P(BCP) modified GCE and the DNA biosensor was prepared. The interaction mechanism of dsDNA with 5-FU was investigated by differential pulse voltammetry using this biosensor. A decrease in the guanine oxidation peak current of the biosensor was observed after the interaction of dsDNA and 5-FU in 0.5 mol L(-1) acetate buffer (pH 4.8) containing 0.02 mol L(-1) NaCl. The accumulation time and dsDNA concentration were optimized to obtain the best peak current response. Under optimum conditions, the linear response on the guanine signal decreasing curve was observed in the 5-FU concentration range of 1.0-50 mg L(-1). The interaction mechanism between dsDNA and 5-FU was further investigated by UV-vis spectroscopy and viscometer. The results reveal that intercalation is the primary mode of interaction between 5-FU and dsDNA.

  4. Ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon mediated circular strand displacement polymerization and hyperbranched rolling circle amplification.

    PubMed

    Li, Xiaolu; Guo, Jing; Zhai, Qian; Xia, Jing; Yi, Gang

    2016-08-31

    Using a cascade signal amplification strategy, an ultrasensitive electrochemical biosensor for specific detection of DNA based on molecular beacon (MB) mediated circular strand displacement polymerization (CSDP) and hyperbranched rolling circle amplification (HRCA) was proposed. The hybridization of MB probe to target DNA resulted in a conformational change of the MB and triggered the CSDP in the presence of bio-primer and Klenow fragment (KF exo(-)), leading to multiple biotin-tagged DNA duplex. Furthermore, the HRCA was implemented to product amounts of double-stranded DNA (ds-DNA) fragments using phi29 DNA polymerase via biotin-streptavidin interaction. After the product of HRCA binded numerous biotinylated detection probes, an ultrasensitive electrochemical readout by further employing the streptavidin-alkaline phosphatase. The proposed biosensor exhibited excellent detection sensitivity and specificity with a log-linear response to target DNA from 0.01 fM to 10 pM as low as 8.9 aM. The proposed method allowed DNA detection with simplicity, rapidness, low cost and high specificity, which might have the potential for application in clinical molecular diagnostics and environmental monitoring.

  5. A novel electrochemical DNA biosensor based on a modified magnetic bar carbon paste electrode with Fe3O4NPs-reduced graphene oxide/PANHS nanocomposite.

    PubMed

    Jahanbani, Shahriar; Benvidi, Ali

    2016-11-01

    In this study, we have designed a label free DNA biosensor based on a magnetic bar carbon paste electrode (MBCPE) modified with nanomaterial of Fe3O4/reduced graphene oxide (Fe3O4NP-RGO) as a composite and 1- pyrenebutyric acid-N- hydroxysuccinimide ester (PANHS) as a linker for detection of DNA sequences. Probe (BRCA1 5382 insC mutation detection) strands were immobilized on the MBCPE/Fe3O4-RGO/PANHS electrode for the exact incubation time. The characterization of the modified electrode was studied using different techniques such as scanning electron microscopy (SEM), infrared spectroscopy (IR), vibrating sample magnetometer (VSM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry methods. Some experimental parameters such as immobilization time of probe DNA, time and temperature of hybridization process were investigated. Under the optimum conditions, the immobilization of the probe and its hybridization with the target DNA (Complementary DNA) were tested. This DNA biosensor revealed a good linear relationship between ∆Rct and logarithm of the complementary target DNA concentration ranging from 1.0×10(-18)molL(-1) to 1.0×10(-8)molL(-1) with a correlation coefficient of 0.9935 and a detection limit of 2.8×10(-19)molL(-1). In addition, the mentioned biosensor was satisfactorily applied for discriminating of complementary sequences from non-complementary sequences. The constructed biosensor (MBCPE/Fe3O4-RGO/PANHS/ssDNA) with high sensitivity, selectivity, stability, reproducibility and low cost can be used for detection of BRCA1 5382 insC mutation.

  6. Detection of Single-Nucleotide Polymorphism on uidA Gene of Escherichia coli by a Multiplexed Electrochemical DNA Biosensor with Oligonucleotide-Incorporated Nonfouling Surface

    PubMed Central

    Liu, Gang; Lao, Ruojun; Xu, Li; Xu, Qin; Li, Lanying; Zhang, Min; Shen, Hao; Mathur, Sanjay; Fan, Chunhai; Song, Shiping

    2011-01-01

    We report here a practical application of a multiplexed electrochemical DNA sensor for highly specific single-nucleotide polymorphism (SNP) detection. In this work, a 16-electrode array was applied with an oligonucleotide-incorporated nonfouling surfaces (ONS) on each electrode for the resistance of unspecific absorption. The fully matched target DNA templated the ligation between the capture probe assembled on gold electrodes and the tandem signal probe with a biotin moiety, which could be transduced to peroxidase-based catalyzed amperometric signals. A mutant site (T93G) in uidA gene of E. coli was analyzed in PCR amplicons. 10% percentage of single mismatched mutant gene was detected, which clearly proved the selectivity of the multiplexed electrochemical DNA biosensor when practically applied. PMID:22164059

  7. Electrochemical DNA biosensor based on poly(2,6-pyridinedicarboxylic acid) modified glassy carbon electrode for the determination of anticancer drug gemcitabine.

    PubMed

    Tığ, Gözde Aydoğdu; Zeybek, Bülent; Pekyardımcı, Şule

    2016-07-01

    In this study, a simple methodology was used to develop a new electrochemical DNA biosensor based on poly(2,6-pyridinedicarboxylic acid) (P(PDCA)) modified glassy carbon electrode (GCE). This modified electrode was used to monitor for the electrochemical interaction between the dsDNA and gemcitabine (GEM) for the first time. A decrease in oxidation signals of guanine after the interaction of the dsDNA with the GEM was used as an indicator for the selective determination of the GEM via differential pulse voltammetry (DPV). The guanine oxidation peak currents were linearly proportional to the concentrations of the GEM in the range of 1-30mgL(‒1). Limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.276mgL(‒1) and 0.922mgL(‒1), respectively. The reproducibility, repeatability, and applicability of the analysis to pharmaceutical dosage forms and human serum samples were also examined. In addition to DPV method, UV-vis and viscosity measurements were utilized to propose the interaction mechanism between the GEM and the dsDNA. The novel DNA biosensor could serve for sensitive, accurate and rapid determination of the GEM.

  8. Electrochemical Performances of Electroactive Nano-Layered Organic-Inorganic Perovskite Containing Trivalent Iron Ion and its Use for a DNA Biosensor Preparation

    PubMed Central

    Wu, Jing; Liu, Hanxing; Lin, Zhidong; Cao, Minghe

    2010-01-01

    A steady nano organic-inorganic perovskite hybrid with [H23-AMP]3/2Fe(CN)6 (3-AMP = 3-methylaminopyridine) was prepared in the air. The structure is an unusual layered organic-inorganic type. The resulting hybrid enveloped in paraffin to prepare [H23-AMP]3/2Fe(CN)6 paste electrode (HPE) shows good electrochemical activity and a couple of oxidation and reduction peaks with potential of cyclic voltammometry (CV) at around 440 mV and 30 mV. Compared with that on CPE, oxidation potential of Fe(CN)63− on HPE shifts negatively 259.7 mV and that of reduction shifts positively 338.7 mV, which exhibits that [H23-AMP]3/2Fe(CN)6 can accelerate the electron-transfer to improve the electrochemical reaction reversibility. Such characteristics of [H23-AMP]3/2Fe(CN)6 have been employed to prepare the DNA biosensor. The single-strand DNA (ssDNA) and double-strand DNA (dsDNA) immobilized on HPE, respectively, can improve the square wave voltammometry (SWV) current and SWV potential shifts positively. The effect of pH was evaluated. And there is hybridization peak on SWV curve using HPE immobilized ssDNA in the complementary ssDNA solution. And HPE immobilized ssDNA can be utilized to monitor the DNA hybridization and detect complementary ssDNA, covering range from 3.24 × 10−7 to 6.72 × 10−5 g/mL with detection limit of 1.57 × 10−7 g/mL. The DNA biosensor exhibits a good stability and reproducibility. PMID:20671970

  9. Recent advances in electrochemical biosensors based on graphene two-dimensional nanomaterials.

    PubMed

    Song, Yang; Luo, Yanan; Zhu, Chengzhou; Li, He; Du, Dan; Lin, Yuehe

    2016-02-15

    Graphene as a star among two-dimensional nanomaterials has attracted tremendous research interest in the field of electrochemistry due to their intrinsic properties, including the electronic, optical, and mechanical properties associated with their planar structure. The marriage of graphene and electrochemical biosensors has created many ingenious biosensing strategies for applications in the areas of clinical diagnosis and food safety. This review provides a comprehensive overview of the recent advances in the development of graphene based electrochemical biosensors. Special attention is paid to graphene-based enzyme biosensors, immunosensors, and DNA biosensors. Future perspectives on high-performance graphene-based electrochemical biosensors are also discussed.

  10. A sandwich-type DNA electrochemical biosensor for hairpin-stem-loop structure based on multistep temperature-controlling method

    PubMed Central

    Hong, Guolin; Liu, Yinhuan; Chen, Wei; Weng, Shaohuang; Liu, Qicai; Liu, Ailin; Zheng, Daoxin; Lin, Xinhua

    2012-01-01

    A highly sensitive and selective method for amplified electrochemical detection for hairpin-stem-loop structured target sequences was developed based on the temperature regulation of DNA hybrids on a sandwich-type electrochemical DNA sensor. Multistep hybridization was applied to promote the hybridization efficiency of each section of sandwich structure. The results showed that both multistep and temperature-controlling hybridization techniques were both especially made to fabricate the sensor for the tendency of internal hybridization of target gene sequences. This strategy provides significantly enhanced hybridization efficiency and sequence specificity of electrochemical detection. PMID:23028223

  11. DNA Generated Electric Current Biosensor.

    PubMed

    Hu, Lanshuang; Hu, Shengqiang; Guo, Linyan; Shen, Congcong; Yang, Minghui; Rasooly, Avraham

    2017-02-21

    In addition to its primary function as a genetic material, deoxyribonucleic acid (DNA) is also a potential biologic energy source for molecular electronics. For the first time, we demonstrate that DNA can generate a redox electric current. As an example of this new functionality, DNA generated redox current was used for electrochemical detection of human epidermal growth factor receptor 2 (HER2), a clinically important breast cancer biomarker. To induce redox current, the phosphate of the single stranded DNA aptamer backbone was reacted with molybdate to form redox molybdophosphate precipitate and generate an electrochemical current of ∼16.8 μA/μM cm(2). This detection of HER2 was performed using a sandwich detection assay. A HER2 specific peptide was immobilized onto a gold electrode surface for capturing HER2 in buffer and serum. The HER2 specific aptamer was used as both ligand to bind the captured HER2 and to generate a redox current signal. When tested for HER2 detection, the electrochemical current generated by the aptasensor was proportional to HER2 concentration in the range of 0.01 to 5 ng/mL, with a current generated in the range of ∼6.37 to 31.8 μA/cm(2) in both buffer and serum. This detection level is within the clinically relevant range of HER2 concentrations. This method of electrochemical signal amplification greatly simplifies the signal transduction of aptasensors, broadening their use for HER2 analysis. This novel approach of using the same aptamer as biosensor ligand and as transducer can be universally extended to other aptasensors for a wide array of biodetection applications. Moreover, electric currents generated by DNA or other nucleic acids can be used in molecular electronics or implanted devices for both power generation and measurement of output.

  12. An electrochemical DNA biosensor for evaluating the effect of mix anion in cellular fluid on the antioxidant activity of CeO2 nanoparticles.

    PubMed

    Zhai, Yanwu; Zhang, Yan; Qin, Fei; Yao, Xin

    2015-08-15

    CeO2 nanoparticles are of particular interest as a novel antioxidant for scavenging free radicals. However, some studies showed that they could cause cell damage or death by generating reactive oxygen species (ROS). Up to now, it is not well understood about these paradoxical phenomena. Therefore, many attentions have been paid to the factors that could affect the antioxidant activity of CeO2 nanoparticles. CeO2 nanoparticles would inevitably encounter body fluid environment for its potential medical application. In this work the antioxidant activity behavior of CeO2 nanoparticles is studied in simulated cellular fluid, which contains main body anions (HPO4(2-), HCO3(-), Cl(-) and SO4(2-)), by a method of electrochemical DNA biosensor. We found that in the solution of Cl(-) and SO4(2-), CeO2 nanoparticles can protect DNA from damage by hydroxyl radicals, while in the presence of HPO4(2-) and HCO3(-), CeO2 nanoparticles lose the antioxidant activity. This can be explained by the cerium phosphate and cerium carbonate formed on the surface of the nanoparticles, which interfere with the redox cycling between Ce(3+) and Ce(4+). These results not only add basic knowledge to the antioxidant activity of CeO2 nanoparticles under different situations, but also pave the way for practical applications of nanoceria. Moreover, it also shows electrochemical DNA biosensor is an effective method to explore the antioxidant activity of CeO2 nanoparticles.

  13. Pd-Au@carbon dots nanocomposite: Facile synthesis and application as an ultrasensitive electrochemical biosensor for determination of colitoxin DNA in human serum.

    PubMed

    Huang, Qitong; Lin, Xiaofeng; Zhu, Jie-Ji; Tong, Qing-Xiao

    2017-03-22

    In this study, a green and fast method was developed to synthesize high-yield carbon dots (CDs) via one-pot microwave treatment of banana peels without using any other surface passivation agents. Then the as-prepared CDs was used as the reducing agent and stabilizer to synthesize a Pd-Au@CDs nanocomposite by a simple sequential reduction strategy. Finally, Pd-Au@CDs nanocomposite modified glassy carbon electrode (Pd-Au@CDs/GCE) was obtained as a biosensor for target DNA after being immobilized a single-stranded probe DNA by a carboxyl ammonia condensation reaction. Under the optimal conditions, the sensor could detect target DNA concentrations in the range from 5.0×10(-16) to 1.0×10(-1)°molL(-1). The detection limit (LD) was estimated to be 1.82×10(-17)molL(-1), which showed higher sensitivity than other electrochemical biosensors reported. In addition, the DNA sensor was also successfully applied to detect colitoxin DNA in human serum.

  14. Real-time, multiplexed electrochemical DNA detection using an active complementary metal-oxide-semiconductor biosensor array with integrated sensor electronics.

    PubMed

    Levine, Peter M; Gong, Ping; Levicky, Rastislav; Shepard, Kenneth L

    2009-03-15

    Optical biosensing based on fluorescence detection has arguably become the standard technique for quantifying extents of hybridization between surface-immobilized probes and fluorophore-labeled analyte targets in DNA microarrays. However, electrochemical detection techniques are emerging which could eliminate the need for physically bulky optical instrumentation, enabling the design of portable devices for point-of-care applications. Unlike fluorescence detection, which can function well using a passive substrate (one without integrated electronics), multiplexed electrochemical detection requires an electronically active substrate to analyze each array site and benefits from the addition of integrated electronic instrumentation to further reduce platform size and eliminate the electromagnetic interference that can result from bringing non-amplified signals off chip. We report on an active electrochemical biosensor array, constructed with a standard complementary metal-oxide-semiconductor (CMOS) technology, to perform quantitative DNA hybridization detection on chip using targets conjugated with ferrocene redox labels. A 4 x 4 array of gold working electrodes and integrated potentiostat electronics, consisting of control amplifiers and current-input analog-to-digital converters, on a custom-designed 5 mm x 3 mm CMOS chip drive redox reactions using cyclic voltammetry, sense DNA binding, and transmit digital data off chip for analysis. We demonstrate multiplexed and specific detection of DNA targets as well as real-time monitoring of hybridization, a task that is difficult, if not impossible, with traditional fluorescence-based microarrays.

  15. Real-time, multiplexed electrochemical DNA detection using an active complementary metal-oxide-semiconductor biosensor array with integrated sensor electronics

    PubMed Central

    Levine, Peter M.; Gong, Ping; Levicky, Rastislav; Shepard, Kenneth L.

    2009-01-01

    Optical biosensing based on fluorescence detection has arguably become the standard technique for quantifying extents of hybridization between surface-immobilized probes and fluorophore-labeled analyte targets in DNA microarrays. However, electrochemical detection techniques are emerging which could eliminate the need for physically bulky optical instrumentation, enabling the design of portable devices for point-of-care applications. Unlike fluorescence detection, which can function well using a passive substrate (one without integrated electronics), multiplexed electrochemical detection requires an electronically-active substrate to analyze each array site and benefits from the addition of integrated electronic instrumentation to further reduce platform size and eliminate the electromagnetic interference that can result from bringing non-amplified signals off chip. We report on an active electrochemical biosensor array, constructed with a standard complementary metal-oxide-semiconductor (CMOS) technology, to perform quantitative DNA hybridization detection on chip using targets conjugated with ferrocene redox labels. A 4×4 array of gold working electrodes and integrated potentiostat electronics, consisting of control amplifiers and current-input analog-to-digital converters, on a custom-designed 5×3 mm2 CMOS chip drive redox reactions using cyclic voltammetry, sense DNA binding, and transmit digital data off chip for analysis. We demonstrate multiplexed and specific detection of DNA targets as well as real-time monitoring of hybridization, a task that is difficult, if not impossible, with traditional fluorescence-based microarrays. PMID:19054661

  16. Electrochemical spectroscopic investigations on the interaction of an ytterbium complex with DNA and their analytical applications such as biosensor.

    PubMed

    Ilkhani, Hoda; Ganjali, Mohamad Reza; Arvand, Majid; Hejazi, Mohammad Saeid; Azimi, Fateme; Norouzi, Parviz

    2011-12-01

    Metal ion-DNA interactions are important in nature, often changing the genetic material's structure and function. A new Yb complex of YbCl(3) (tris(8-hydroxyquinoline-5-sulfonic acid) ytterbium) was synthesized and utilized as an electrochemical indicator for the detection of DNA oligonucleotide based on its interaction with Yb(QS)(3). Cyclic voltammetry (CV) and fluorescence spectroscopy were used to investigate the interaction of Yb(QS)(3) with ds-DNA. It was revealed that Yb(QS)(3) presented an excellent electrochemical activity on glassy carbon electrode (GCE) and could intercalate into the double helix of double-stranded DNA (ds-DNA). The binding mechanism of interaction was elucidated on glassy carbon electrode dipped in DNA solution and DNA modified carbon paste electrode by using differential pulse voltammetry and cyclic voltammetry. The binding ratio between this complex and ds-DNA was calculated to be 1:1. The extent of hybridization was evaluated on the basis of the difference between signals of Yb(QS)(3) with probe DNA before and after hybridization with complementary DNA. With this approach, this DNA could be quantified over the range from 1 × 10(-8) to 1.1 × 10(-7)M. The interaction mode between Yb(QS)(3) and DNA was found to be mainly intercalative interaction. These results were confirmed with fluorescence experiments.

  17. DNA biosensors that reason.

    PubMed

    Sainz de Murieta, Iñaki; Rodríguez-Patón, Alfonso

    2012-08-01

    Despite the many designs of devices operating with the DNA strand displacement, surprisingly none is explicitly devoted to the implementation of logical deductions. The present article introduces a new model of biosensor device that uses nucleic acid strands to encode simple rules such as "IF DNA_strand(1) is present THEN disease(A)" or "IF DNA_strand(1) AND DNA_strand(2) are present THEN disease(B)". Taking advantage of the strand displacement operation, our model makes these simple rules interact with input signals (either DNA or any type of RNA) to generate an output signal (in the form of nucleotide strands). This output signal represents a diagnosis, which either can be measured using FRET techniques, cascaded as the input of another logical deduction with different rules, or even be a drug that is administered in response to a set of symptoms. The encoding introduces an implicit error cancellation mechanism, which increases the system scalability enabling longer inference cascades with a bounded and controllable signal-noise relation. It also allows the same rule to be used in forward inference or backward inference, providing the option of validly outputting negated propositions (e.g. "diagnosis A excluded"). The models presented in this paper can be used to implement smart logical DNA devices that perform genetic diagnosis in vitro.

  18. A novel electrochemical DNA biosensor based on HRP-mimicking hemin/G-quadruplex wrapped GOx nanocomposites as tag for detection of Escherichia coli O157:H7.

    PubMed

    Li, Yan; Deng, Jun; Fang, Lichao; Yu, Kangkang; Huang, Hui; Jiang, Lili; Liang, Wenbin; Zheng, Junsong

    2015-01-15

    A novel sensitive electrochemical DNA biosensor was developed for amperometric detection of Escherichia coli O157:H7 (E. coli O157:H7). The graphene oxide (GOx) was utilized as nanocarrier to immobilize thionine (Thi) and the Au nanoparticles coated SiO2 nanocomposites (Au-SiO2) by electrostatic adsorption and the adsorption among nanomaterials. Then a large amounts of signal DNA (S2) and G-quadruplex were immobilized on the GOx-Thi-Au@SiO2 nanocomposites. Finally, hemin was intercalated into the G-quadruplex to obtain the hemin/G-quadruplex structure as HRP-mimicking DNAzyme. On the basis of the signal amplification strategy of GOx-Thi-Au@SiO2 nanocomposites and DNAzyme, the developed DNA biosensor could respond to 0.01 nM (S/N=3) with a linear calibration range from 0.02 to 50.0 nM E. coli O157:H7, which could be well accepted for early clinical detection. The studied system provides new opportunities, and might speed up disease diagnosis, treatment and prevention with pathogen.

  19. A microfluidic electrochemical biosensor based on multiwall carbon nanotube/ferrocene for genomic DNA detection of Mycobacterium tuberculosis in clinical isolates

    PubMed Central

    Zribi, B.; Roy, E.; Pallandre, A.; Chebil, S.; Koubaa, M.; Mejri, N.; Magdinier Gomez, H.; Sola, C.; Korri-Youssoufi, H.; Haghiri-Gosnet, A.-M.

    2016-01-01

    Herein we present a microfluidic-multiplexed platform that integrates electrochemical sensors based on carbon nanotubes associated with ferrocene as redox marker (carbon nanotube (CNT)/ferrocene) for direct detection of pathogenic viral DNA from Hepatitis C and genomic DNA from Mycobacterium tuberculosis in clinical isolates. By operating the fluidic device under high flow (150 μl/min), the formation of a very thin depletion layer at the sensor surface (δS = 230 nm) enhances the capture rate up to one DNA strand per second. By comparison, this capture rate is only 0.02 molecule/s in a static regime without flow. This fluidic protocol allows thus enhancing the limit of detection of the electrochemical biosensor from picomolar in bulk solution to femtomolar with a large dynamic range from 0.1 fM to 1 pM. Kinetics analysis also demonstrates an enhancement of the rate constant of electron transfer (kS) of the electrochemical process from 1 s−1 up to 6 s−1 thanks to the geometry of the miniaturized fluidic electrochemical cell. This microfluidic device working under high flow allows selective direct detection of a Mycobacterium tuberculosis (H37Rv) rpoB allele from clinical isolate extracted DNA. We envision that a microfluidic approach under high flow associated with a multiwall CNT/ferrocene sensor could find useful applications as the point-of-care for multi-target diagnostics of biomarkers in real samples. PMID:26865908

  20. DNA nanotechnology-enabled biosensors.

    PubMed

    Chao, Jie; Zhu, Dan; Zhang, Yinan; Wang, Lianhui; Fan, Chunhai

    2016-02-15

    Biosensors employ biological molecules to recognize the target and utilize output elements which can translate the biorecognition event into electrical, optical or mass-sensitive signals to determine the quantities of the target. DNA-based biosensors, as a sub-field to biosensor, utilize DNA strands with short oligonucleotides as probes for target recognition. Although DNA-based biosensors have offered a promising alternative for fast, simple and cheap detection of target molecules, there still exist key challenges including poor stability and reproducibility that hinder their competition with the current gold standard for DNA assays. By exploiting the self-recognition properties of DNA molecules, researchers have dedicated to make versatile DNA nanostructures in a highly rigid, controllable and functionalized manner, which offers unprecedented opportunities for developing DNA-based biosensors. In this review, we will briefly introduce the recent advances on design and fabrication of static and dynamic DNA nanostructures, and summarize their applications for fabrication and functionalization of DNA-based biosensors.

  1. Graphene Based Electrochemical Sensors and Biosensors: A Review

    SciTech Connect

    Shao, Yuyan; Wang, Jun; Wu, Hong; Liu, Jun; Aksay, Ilhan A.; Lin, Yuehe

    2010-05-01

    Graphene, emerging as a true 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, high mechanical strength, and ease of functionalization and mass production). This article selectively reviews recent advances in graphene-based electrochemical sensors and biosensors. In particular, graphene for direct electrochemistry of enzyme, its electrocatalytic activity toward small biomolecules (hydrogen peroxide, NADH, dopamine, etc.), and graphene-based enzyme biosensors have been summarized in more detail; Graphene-based DNA sensing and environmental analysis have been discussed. Future perspectives in this rapidly developing field are also discussed.

  2. An immobilization free DNAzyme based electrochemical biosensor for lead determination.

    PubMed

    Tan, Yue; Qiu, Jiazhi; Cui, Meiying; Wei, Xiaofeng; Zhao, Mengmeng; Qiu, Bin; Chen, Guonan

    2016-02-07

    DNAzyme based electrochemical biosensors have the characteristics of high sensitivity and selectivity, but traditional DNAzyme based electrochemical biosensors need the immobilization of DNAzyme on the electrode surface first, and the procedures are time consuming and tedious, which limit their real application. In this study, a simple but sensitive immobilization free DNAzyme based electrochemical biosensor has been proposed and lead has been chosen as a model target because of the severe effects of lead toxicity. The different diffusivity and electrostatic repulsion between long and short DNA on the negatively charged ITO electrode can be used to discriminate the short and long DNA. Lead dependent DNAzyme was hybridized with its substrate (which was modified with methylene blue at the 3' terminal) beforehand. Since the DNAzyme/substrate complex contains a large negative charge, it cannot diffuse easily to the negatively charged ITO electrode surface and little electrochemical signal has been detected. The presence of lead would trigger the cleavage of the DNAzyme/substrate complex and cause the release of a methylene blue-labeled short-oligonucleotide into the solution. The methylene blue-labeled short-oligonucleotide can diffuse easily to the surface of the negatively charged ITO electrode and results in the enhanced electrochemical response being detected. Each lead can cleave a lot of DNAzyme/substrate complex to realize signal amplification. The enhanced electrochemical signal has a linear relationship with the Pb(2+) concentration in the range of 0.05-1 μM with a detection limit of 0.018 μM (S/N = 3). The proposed biosensor has been applied to detect Pb(2+) in water samples with satisfactory results.

  3. Development of a novel electrochemical DNA biosensor based on elongated hexagonal-pyramid CdS and poly-isonicotinic acid composite film.

    PubMed

    Zheng, Delun; Wang, Qingxiang; Gao, Feng; Wang, Qinghua; Qiu, Weiwei; Gao, Fei

    2014-10-15

    Three CdS materials with different shapes (i.e., irregular, rod-like, and elongated hexagonal-pyramid) were hydrothermally synthesized through controlling the molar ratio of Cd(2+) to thiourea. Electrochemical experiments showed that the elongated hexagonal-pyramid CdS (eh-CdS) modified on glassy carbon electrode (GCE) had the higher electrical conductivity than the other two forms. Then the eh-CdS modified GCE was further modified with a layer of poly-isonicotinic acid (PIA) through electro-polymerization in IA solution to enhance the stability and functionality of the interface. The layer-by-layer modification process was characterized by atomic force microscopy and electrochemistry. Then 5'-amino functionalized DNA was immobilized on the electrode surface through coupling with the carboxylic groups derived from PIA-eh-CdS composite film. The hybridization performance of the developed biosensor was evaluated using methylene blue as redox indicator, and the results showed that the peak currents of methylene blue varied with target concentrations in a wide linear range from 1.0 × 10(-14)M to 1.0 × 10(-9)M with a low detection limit of 3.9 × 10(-15)M. The biosensor also showed high stability and good discrimination ability to the one-base, three-base mismatched and non-complementary sequence.

  4. Bioapplications of Electrochemical Sensors and Biosensors.

    PubMed

    Dumitrescu, Eduard; Andreescu, Silvana

    2017-01-01

    Recent progress in the electrochemical field enabled development of miniaturized sensing devices that can be used in biological settings to obtain fundamental and practical biochemically relevant information on physiology, metabolism, and disease states in living systems. Electrochemical sensors and biosensors have demonstrated potential for rapid, real-time measurements of biologically relevant molecules. This chapter provides an overview of the most recent advances in the development of miniaturized sensors for biological investigations in living systems, with focus on the detection of neurotransmitters and oxidative stress markers. The design of electrochemical (bio)sensors, including their detection mechanism and functionality in biological systems, is described as well as their advantages and limitations. Application of these sensors to studies in live cells, embryonic development, and rodent models is discussed.

  5. Electrochemical biosensors: recommended definitions and classification.

    PubMed

    Thévenot, D R; Toth, K; Durst, R A; Wilson, G S

    2001-01-01

    Two Divisions of the International Union of Pure and Applied Chemistry (IUPAC), namely Physical Chemistry (Commission 1.7 on Biophysical Chemistry formerly Steering Committee on Biophysical Chemistry) and Analytical Chemistry (Commission V.5 on Electroanalytical Chemistry) have prepared recommendations on the definition, classification and nomenclature related to electrochemical biosensors: these recommendations could, in the future, be extended to other types of biosensors. An electrochemical biosensor is a self-contained integrated device, which is capable of providing specific quantitative or semi-quantitative analytical information using a biological recognition element (biochemical receptor) which is retained in direct spatial contact with an electrochemical transduction element. Because of their ability to be repeatedly calibrated, we recommend that a biosensor should be clearly distinguished from a bioanalytical system, which requires additional processing steps, such as reagent addition. A device that is both disposable after one measurement, i.e. single use, and unable to monitor the analyte concentration continuously or after rapid and reproducible regeneration, should be designated a single use biosensor. Biosensors may be classified according to the biological specificity-conferring mechanism or, alternatively, to the mode of physico-chemical signal transduction. The biological recognition element may be based on a chemical reaction catalysed by, or on an equilibrium reaction with macromolecules that have been isolated, engineered or present in their original biological environment. In the latter cases. equilibrium is generally reached and there is no further, if any, net consumption of analyte(s) by the immobilized biocomplexing agent incorporated into the sensor. Biosensors may be further classified according to the analytes or reactions that they monitor: direct monitoring of analyte concentration or of reactions producing or consuming such analytes

  6. An electrochemical biosensor based on DNA tetrahedron/graphene composite film for highly sensitive detection of NADH.

    PubMed

    Li, Zonglin; Su, Wenqiong; Liu, Shuopeng; Ding, Xianting

    2015-07-15

    Dihydronicotinamide adenine dinucleotide (NADH) is a major biomarker correlated with lethal diseases such as cancers and bacterial infection. Herein, we report a graphene-DNA tetrahedron-gold nanoparticle modified gold disk electrode for highly sensitive NADH detection. By assembling the DNA tetrahedron/graphene composite film on the gold disk electrode surface which prior harnessed electrochemical deposition of gold nanoparticles to enhance the effective surface area, the oxidation potential of NADH was substantially decreased to 0.28V (vs. Ag/AgCl) and surface fouling effects were successfully eliminated. Furthermore, the lower detection limit of NADH by the presented platform was reduced down to 1fM, with an upper limit of 10pM. Both the regeneration and selectivity of composite film-modified electrode are investigated and proved to be robust. The novel sensor developed here could serve as a highly sensitive probe for NADH detection, which would further benefit the field of NADH related disease diagnostics.

  7. CMOS Electrochemical Instrumentation for Biosensor Microsystems: A Review.

    PubMed

    Li, Haitao; Liu, Xiaowen; Li, Lin; Mu, Xiaoyi; Genov, Roman; Mason, Andrew J

    2016-12-31

    Modern biosensors play a critical role in healthcare and have a quickly growing commercial market. Compared to traditional optical-based sensing, electrochemical biosensors are attractive due to superior performance in response time, cost, complexity and potential for miniaturization. To address the shortcomings of traditional benchtop electrochemical instruments, in recent years, many complementary metal oxide semiconductor (CMOS) instrumentation circuits have been reported for electrochemical biosensors. This paper provides a review and analysis of CMOS electrochemical instrumentation circuits. First, important concepts in electrochemical sensing are presented from an instrumentation point of view. Then, electrochemical instrumentation circuits are organized into functional classes, and reported CMOS circuits are reviewed and analyzed to illuminate design options and performance tradeoffs. Finally, recent trends and challenges toward on-CMOS sensor integration that could enable highly miniaturized electrochemical biosensor microsystems are discussed. The information in the paper can guide next generation electrochemical sensor design.

  8. CMOS Electrochemical Instrumentation for Biosensor Microsystems: A Review

    PubMed Central

    Li, Haitao; Liu, Xiaowen; Li, Lin; Mu, Xiaoyi; Genov, Roman; Mason, Andrew J.

    2016-01-01

    Modern biosensors play a critical role in healthcare and have a quickly growing commercial market. Compared to traditional optical-based sensing, electrochemical biosensors are attractive due to superior performance in response time, cost, complexity and potential for miniaturization. To address the shortcomings of traditional benchtop electrochemical instruments, in recent years, many complementary metal oxide semiconductor (CMOS) instrumentation circuits have been reported for electrochemical biosensors. This paper provides a review and analysis of CMOS electrochemical instrumentation circuits. First, important concepts in electrochemical sensing are presented from an instrumentation point of view. Then, electrochemical instrumentation circuits are organized into functional classes, and reported CMOS circuits are reviewed and analyzed to illuminate design options and performance tradeoffs. Finally, recent trends and challenges toward on-CMOS sensor integration that could enable highly miniaturized electrochemical biosensor microsystems are discussed. The information in the paper can guide next generation electrochemical sensor design. PMID:28042860

  9. Aptamer-based Electrochemical Biosensor for Interferon Gamma Detection

    PubMed Central

    Liu, Ying; Tuleouva, Nazgul; Ramanculov, Erlan; Revzin, Alexander

    2010-01-01

    In this paper, we describe the development of an electrochemical DNA aptamer-based biosensor for detection of IFN-γ. A DNA hairpin containing IFN-γ-binding aptamer was thiolated, conjugated with Methylene Blue (MB) redox tag and immobilized on a gold electrode by self-assembly. Binding of IFN-γ caused the aptamer hairpin to unfold, pushing MB redox molecules away from the electrode and decreasing electron-transfer efficiency. The change in redox current was quantified using Square Wave Voltammetry (SWV) and was found to be highly sensitive to IFN-γ concentration. The limit of detection for optimized biosensor was 0.06 nM with linear response extending to 10 nM. This aptasensor was specific to IFN-γ in the presence of overabundant serum proteins. Importantly, the same aptasensor could be regenerated by disrupting aptamer-IFN-γ complex in urea buffer and re-used multiple times. Unlike standard sandwich immunoassays, the aptasensor described here allowed to detect IFN-γ binding directly without the need for multiple washing steps and reagents. An electrochemical biosensor for simple and sensitive detection of IFN-γ demonstrated in this paper will have future applications in immunology, cancer research and infectious disease monitoring. PMID:20815336

  10. Recent Progress in Electrochemical Biosensors for Glycoproteins

    PubMed Central

    Akiba, Uichi; Anzai, Jun-ichi

    2016-01-01

    This review provides an overview of recent progress in the development of electrochemical biosensors for glycoproteins. Electrochemical glycoprotein sensors are constructed by combining metal and carbon electrodes with glycoprotein-selective binding elements including antibodies, lectin, phenylboronic acid and molecularly imprinted polymers. A recent trend in the preparation of glycoprotein sensors is the successful use of nanomaterials such as graphene, carbon nanotube, and metal nanoparticles. These nanomaterials are extremely useful for improving the sensitivity of glycoprotein sensors. This review focuses mainly on the protocols for the preparation of glycoprotein sensors and the materials used. Recent improvements in glycoprotein sensors are discussed by grouping the sensors into several categories based on the materials used as recognition elements. PMID:27916961

  11. Synthesis and characterization of nanoparticles for electrochemical biosensor applications

    NASA Astrophysics Data System (ADS)

    Won, Yu-Ho

    Biosensors have been developed for detection, quantification, and monitoring of specific biomolecules or chemical species for environmental, clinical, and industrial fields. Nanoparticles, which can be functionalized by various materials, have attracted research interest in the electrochemical biosensors field due to their versatile physical and chemical properties. Thus, nanoparticles and nanocomposites have been widely investigated as a matrix for the electrochemical biosensors of the detection of various molecules. In this work, nanoparticles, including Fe3O4/silica core/shell nanocomposites, CaCO3-CdSe/ZnS/silica composites, Au nanocrystals, and Cu2O & Cu2O/Au particles, were synthesized and applied for the design of electrochemical biosensors. The goal of this research is to investigate novel nanoparticle-based platforms for the design of highly sensitive and stable biosensors. Biosensors can be categorized into enzyme-based biosensors and enzyme-free biosensors depending on whether or not enzymes are present in the system. Fe3O 4/silica core/shell nanocomposites and CaCO3-CdSe/ZnS/silica composites were used as material platforms to immobilize enzymes and fabricate enzyme-based electrochemical biosensors. On the other hand, Au nanocrystals, Cu2O, and Cu2O/Au particles, which display significant catalytic and electron transfer properties, were investigated in enzyme-free biosensor configurations. In addition, the morphology-dependent biosensing properties of Au nanocrystals, Cu2O, and Cu2O/Au particles were investigated.

  12. Optimization of printing techniques for electrochemical biosensors

    NASA Astrophysics Data System (ADS)

    Zainuddin, Ahmad Anwar; Mansor, Ahmad Fairuzabadi Mohd; Rahim, Rosminazuin Ab; Nordin, Anis Nurashikin

    2017-03-01

    Electrochemical biosensors show great promise for point-of-care applications due to their low cost, portability and compatibility with microfluidics. The miniature size of these sensors provides advantages in terms of sensitivity, specificity and allows them to be mass produced in arrays. The most reliable fabrication technique for these sensors is lithography followed by metal deposition using sputtering or chemical vapor deposition techniques. This technique which is usually done in the cleanroom requires expensive masking followed by deposition. Recently, cheaper printing techniques such as screen-printing and ink-jet printing have become popular due to its low cost, ease of fabrication and mask-less method. In this paper, two different printing techniques namely inkjet and screen printing are demonstrated for an electrochemical biosensor. For ink-jet printing technique, optimization of key printing parameters, such as pulse voltages, drop spacing and waveform setting, in-house temperature and cure annealing for obtaining the high quality droplets, are discussed. These factors are compared with screen-printing parameters such as mesh size, emulsion thickness, minimum spacing of lines and curing times. The reliability and reproducibility of the sensors are evaluated using scotch tape test, resistivity and profile-meter measurements. It was found that inkjet printing is superior because it is mask-less, has minimum resolution of 100 µm compared to 200 µm for screen printing and higher reproducibility rate of 90% compared to 78% for screen printing.

  13. Electrochemical Biosensors - Sensor Principles and Architectures

    PubMed Central

    Grieshaber, Dorothee; MacKenzie, Robert; Vörös, Janos; Reimhult, Erik

    2008-01-01

    Quantification of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. However, converting the biological information to an easily processed electronic signal is challenging due to the complexity of connecting an electronic device directly to a biological environment. Electrochemical biosensors provide an attractive means to analyze the content of a biological sample due to the direct conversion of a biological event to an electronic signal. Over the past decades several sensing concepts and related devices have been developed. In this review, the most common traditional techniques, such as cyclic voltammetry, chronoamperometry, chronopotentiometry, impedance spectroscopy, and various field-effect transistor based methods are presented along with selected promising novel approaches, such as nanowire or magnetic nanoparticle-based biosensing. Additional measurement techniques, which have been shown useful in combination with electrochemical detection, are also summarized, such as the electrochemical versions of surface plasmon resonance, optical waveguide lightmode spectroscopy, ellipsometry, quartz crystal microbalance, and scanning probe microscopy. The signal transduction and the general performance of electrochemical sensors are often determined by the surface architectures that connect the sensing element to the biological sample at the nanometer scale. The most common surface modification techniques, the various electrochemical transduction mechanisms, and the choice of the recognition receptor molecules all influence the ultimate sensitivity of the sensor. New nanotechnology-based approaches, such as the use of engineered ion-channels in lipid bilayers, the encapsulation of enzymes into vesicles, polymersomes, or polyelectrolyte capsules provide additional possibilities for signal amplification. In particular, this review highlights the importance of the precise control over the delicate

  14. Printable Electrochemical Biosensors: A Focus on Screen-Printed Electrodes and Their Application

    PubMed Central

    Yamanaka, Keiichiro; Vestergaard, Mun’delanji C.; Tamiya, Eiichi

    2016-01-01

    In this review we present electrochemical biosensor developments, focusing on screen-printed electrodes (SPEs) and their applications. In particular, we discuss how SPEs enable simple integration, and the portability needed for on-field applications. First, we briefly discuss the general concept of biosensors and quickly move on to electrochemical biosensors. Drawing from research undertaken in this area, we cover the development of electrochemical DNA biosensors in great detail. Through specific examples, we describe the fabrication and surface modification of printed electrodes for sensitive and selective detection of targeted DNA sequences, as well as integration with reverse transcription-polymerase chain reaction (RT-PCR). For a more rounded approach, we also touch on electrochemical immunosensors and enzyme-based biosensors. Last, we present some electrochemical devices specifically developed for use with SPEs, including USB-powered compact mini potentiostat. The coupling demonstrates the practical use of printable electrode technologies for application at point-of-use. Although tremendous advances have indeed been made in this area, a few challenges remain. One of the main challenges is application of these technologies for on-field analysis, which involves complicated sample matrices. PMID:27775661

  15. Printable Electrochemical Biosensors: A Focus on Screen-Printed Electrodes and Their Application.

    PubMed

    Yamanaka, Keiichiro; Vestergaard, Mun'delanji C; Tamiya, Eiichi

    2016-10-21

    In this review we present electrochemical biosensor developments, focusing on screen-printed electrodes (SPEs) and their applications. In particular, we discuss how SPEs enable simple integration, and the portability needed for on-field applications. First, we briefly discuss the general concept of biosensors and quickly move on to electrochemical biosensors. Drawing from research undertaken in this area, we cover the development of electrochemical DNA biosensors in great detail. Through specific examples, we describe the fabrication and surface modification of printed electrodes for sensitive and selective detection of targeted DNA sequences, as well as integration with reverse transcription-polymerase chain reaction (RT-PCR). For a more rounded approach, we also touch on electrochemical immunosensors and enzyme-based biosensors. Last, we present some electrochemical devices specifically developed for use with SPEs, including USB-powered compact mini potentiostat. The coupling demonstrates the practical use of printable electrode technologies for application at point-of-use. Although tremendous advances have indeed been made in this area, a few challenges remain. One of the main challenges is application of these technologies for on-field analysis, which involves complicated sample matrices.

  16. An electrochemical biosensor to simultaneously detect VEGF and PSA for early prostate cancer diagnosis based on graphene oxide/ssDNA/PLLA nanoparticles.

    PubMed

    Pan, Lung-Hsuan; Kuo, Shin-Hung; Lin, Tzu-Yang; Lin, Chih-Wen; Fang, Po-Yu; Yang, Hung-Wei

    2017-03-15

    Early diagnosis of prostate cancer (PCa) is critical for the prevention of metastasis and for early treatment; therefore, a simple and accurate device must be developed for this purpose. In this study, we reported a novel fabrication method for producing a dual-modality biosensor that can simultaneously detect vascular endothelial growth factor (VEGF) and prostate-specific antigen (PSA) in human serum for early diagnosis of PCa. This biosensor was constructed by coating graphene oxide/ssDNA (GO-ssDNA) on an Au-electrode for VEGF detection, and incorporated with poly-L-lactide nanoparticles (PLLA NPs) for signal amplification and PSA detection. The results showed that this biosensor has wide liner detection ranges (0.05-100ng/mL for VEGF and 1-100ng/mL for PSA), as well as high levels of sensitivity and selectivity (i.e., resisting interference from external factors, such as glucose, ascorbic acid human serum protein, immunoglobulin G, and immunoglobulin M), and demonstrated a high correlation with an enzyme-linked immunosorbent assay for sample detection in patients. Therefore, this biosensor could be utilized for early clinical diagnosis of PCa in the future.

  17. Utilization of nanoparticle labels for signal amplification in ultrasensitive electrochemical affinity biosensors: a review.

    PubMed

    Ding, Liang; Bond, Alan M; Zhai, Jianping; Zhang, Jie

    2013-10-03

    Nanoparticles with desirable properties not exhibited by the bulk material can be readily synthesized because of rapid technological developments in the fields of materials science and nanotechnology. In particular their highly attractive electrochemical properties and electrocatalytic activity have facilitated achievement of the high level of signal amplification needed for the development of ultrasensitive electrochemical affinity biosensors for the detection of proteins and DNA. This review article explains the basic principles of nanoparticle based electrochemical biosensors, highlights the recent advances in the development of nanoparticle based signal amplification strategies, and provides a critical assessment of the likely drawbacks associated with each strategy. Finally, future perspectives for achieving advanced signal simplification in nanoparticles based biosensors are considered.

  18. Immobilization free electrochemical biosensor for folate receptor in cancer cells based on terminal protection.

    PubMed

    Ni, Jiancong; Wang, Qingxiang; Yang, Weiqiang; Zhao, Mengmeng; Zhang, Ying; Guo, Longhua; Qiu, Bin; Lin, Zhenyu; Yang, Huang-Hao

    2016-12-15

    The determination of folate receptor (FR) that over expressed in vast quantity of cancerous cells frequently is significant for the clinical diagnosis and treatment of cancers. Many DNA-based electrochemical biosensors have been developed for FR detection with high selectivity and sensitivity, but most of them need complicated immobilization of DNA on the electrode surface firstly, which is tedious and therefore results in the poor reproducibility. In this study, a simple, sensitive, and selective electrochemical FR biosensor in cancer cells has been proposed, which combines the advantages of the convenient immobilization-free homogeneous indium tin oxide (ITO)-based electrochemical detection strategy and the high selectivity of the terminal protection of small molecule linked DNA. The small molecule of folic acid (FA) and an electroactive molecule of ferrocence (Fc) were tethered to 3'- and 5'-end of an arbitrary single-stranded DNA (ssDNA), respectively, forming the FA-ssDNA-Fc complex. In the absence of the target FR, the FA-ssDNA-Fc was degraded by exonuclease I (Exo I) from 3'-end and produced a free Fc, diffusing freely to the ITO electrode surface and resulting in strong electrochemical signal. When the target FR was present, the FA-ssDNA-Fc was bound to FR through specific interaction with FA anchored at the 3'-end, effectively protecting the ssDNA strand from hydrolysis by Exo I. The FR-FA-ssDNA-Fc could not diffuse easily to the negatively charged ITO electrode surface due to the electrostatic repulsion between the DNA strand and the negatively charged ITO electrode, so electrochemical signal reduced. The decreased electrochemical signal has a linear relationship with the logarithm of FR concentration in range of 10fM to 10nM with a detection limit of 3.8fM (S/N=3). The proposed biosensor has been applied to detect FR in HeLa cancer cells, and the decreased electrochemical signal has a linear relationship with the logarithm of cell concentration ranging

  19. Carbon nanomaterial-based electrochemical biosensors: an overview

    NASA Astrophysics Data System (ADS)

    Wang, Zhaoyin; Dai, Zhihui

    2015-04-01

    Carbon materials on the nanoscale exhibit diverse outstanding properties, rendering them extremely suitable for the fabrication of electrochemical biosensors. Over the past two decades, advances in this area have continuously emerged. In this review, we attempt to survey the recent developments of electrochemical biosensors based on six types of carbon nanomaterials (CNs), i.e., graphene, carbon nanotubes, carbon dots, carbon nanofibers, nanodiamonds and buckminsterfullerene. For each material, representative samples are introduced to expound the different roles of the CNs in electrochemical bioanalytical strategies. In addition, remaining challenges and perspectives for future developments are also briefly discussed.

  20. Electrochemical sensors and biosensors based on less aggregated graphene.

    PubMed

    Bo, Xiangjie; Zhou, Ming; Guo, Liping

    2017-03-15

    As a novel single-atom-thick sheet of sp(2) hybridized carbon atoms, graphene (GR) has attracted extensive attention in recent years because of its unique and remarkable properties, such as excellent electrical conductivity, large theoretical specific surface area, and strong mechanical strength. However, due to the π-π interaction, GR sheets are inclined to stack together, which may seriously degrade the performance of GR with the unique single-atom layer. In recent years, an increasing number of GR-based electrochemical sensors and biosensors are reported, which may reflect that GR has been considered as a kind of hot and promising electrode material for electrochemical sensor and biosensor construction. However, the active sites on GR surface induced by the irreversible GR aggregations would be deeply secluded inside the stacked GR sheets and therefore are not available for the electrocatalysis. So the alleviation or the minimization of the aggregation level for GR sheets would facilitate the exposure of active sites on GR and effectively upgrade the performance of GR-based electrochemical sensors and biosensors. Less aggregated GR with low aggregation and high dispersed structure can be used in improving the electrochemical activity of GR-based electrochemical sensors or biosensors. In this review, we summarize recent advances and new progress for the development of electrochemical sensors based on less aggregated GR. To achieve such goal, many strategies (such as the intercalation of carbon materials, surface modification, and structural engineering) have been applied to alleviate the aggregation level of GR in order to enhance the performance of GR-based electrochemical sensors and biosensors. Finally, the challenges associated with less aggregated GR-based electrochemical sensors and biosensors as well as related future research directions are discussed.

  1. Electrochemical Glucose Biosensor of Platinum Nanospheres Connected by Carbon Nanotubes

    PubMed Central

    Claussen, Jonathan C.; Kim, Sungwon S.; Haque, Aeraj ul; Artiles, Mayra S.; Porterfield, D. Marshall; Fisher, Timothy S.

    2010-01-01

    Background Glucose biosensors comprised of nanomaterials such as carbon nanotubes (CNTs) and metallic nanoparticles offer enhanced electrochemical performance that produces highly sensitive glucose sensing. This article presents a facile biosensor fabrication and biofunctionalization procedure that utilizes CNTs electrochemically decorated with platinum (Pt) nanospheres to sense glucose amperometrically with high sensitivity. Method Carbon nanotubes are grown in situ by microwave plasma chemical vapor deposition (MPCVD) and electro-chemically decorated with Pt nanospheres to form a CNT/Pt nanosphere composite biosensor. Carbon nanotube electrodes are immobilized with fluorescently labeled bovine serum albumin (BSA) and analyzed with fluorescence microscopy to demonstrate their biocompatibility. The enzyme glucose oxidase (GOX) is immobilized onto the CNT/Pt nanosphere biosensor by a simple drop-coat method for amperometric glucose sensing. Results Fluorescence microscopy demonstrates the biofunctionalization capability of the sensor by portraying adsorption of fluorescently labeled BSA unto MPCVD-grown CNT electrodes. The subsequent GOX–CNT/Pt nanosphere biosensor demonstrates a high sensitivity toward H2O2 (7.4 μA/mM/cm2) and glucose (70 μA/mM/cm2), with a glucose detection limit and response time of 380 nM (signal-to-noise ratio = 3) and 8 s (t90%), respectively. The apparent Michaelis–Menten constant (0.64 mM) of the biosensor also reflects the improved sensitivity of the immobilized GOX/nanomaterial complexes. Conclusions The GOX–CNT/Pt nanosphere biosensor outperforms similar CNT, metallic nanoparticle, and more conventional carbon-based biosensors in terms of glucose sensitivity and detection limit. The biosensor fabrication and biofunctionalization scheme can easily be scaled and adapted for microsensors for physiological research applications that require highly sensitive glucose sensing. PMID:20307391

  2. Electroactive crown ester-Cu(2+) complex with in-situ modification at molecular beacon probe serving as a facile electrochemical DNA biosensor for the detection of CaMV 35s.

    PubMed

    Zhan, Fengping; Liao, Xiaolei; Gao, Feng; Qiu, Weiwei; Wang, Qingxiang

    2017-06-15

    A novel electrochemical DNA biosensor has been facilely constructed by in-situ assembly of electroactive 4'-aminobenzo-18-crown-6-copper(II) complex (AbC-Cu(2+)) on the free terminal of the hairpin-structured molecule beacon. The 3'-SH modified molecule beacon probe was first immobilized on the gold electrode (AuE) surface through self-assembly chemistry of Au-S bond. Then the crow ester of AbC was covalently coupled with 5'-COOH on the molecule beacon, and served as a platform to attach the Cu(2+) by coordination with ether bond (-O-) of the crown cycle. Thus, an electroactive molecule beacon-based biosensing interface was constructed. In comparison with conventional methods for preparation of electroactive molecule beacon, the approach presented in this work is much simpler, reagent- and labor-saving. Selectivity study shows that the in-situ fabricated electroactive molecule beacon remains excellent recognition ability of pristine molecule beacon probe to well differentiate various DNA fragments. The target DNA can be quantatively determined over the range from 0.10pM to 0.50nM. The detection limit of 0.060pM was estimated based on signal-to-noise ratio of 3. When the biosensor was applied for the detection cauliflower mosaic virus 35s (CaMV 35s) in soybean extraction samples, satisfactory results are achieved. This work opens a new strategy for facilely fabricating electrochemical sensing interface, which also shows great potential in aptasensor and immurosensor fabrication.

  3. Electrochemical affinity biosensors for detection of mycotoxins: A review.

    PubMed

    Vidal, Juan C; Bonel, Laura; Ezquerra, Alba; Hernández, Susana; Bertolín, Juan R; Cubel, Carlota; Castillo, Juan R

    2013-11-15

    This review discusses the current state of electrochemical biosensors in the determination of mycotoxins in foods. Mycotoxins are highly toxic secondary metabolites produced by molds. The acute toxicity of these results in serious human and animal health problems, although it has been only since early 1960s when the first studied aflatoxins were found to be carcinogenic. Mycotoxins affect a broad range of agricultural products, most important cereals and cereal-based foods. A majority of countries, mentioning especially the European Union, have established preventive programs to control contamination and strict laws of the permitted levels in foods. Official methods of analysis of mycotoxins normally requires sophisticated instrumentation, e.g. liquid chromatography with fluorescence or mass detectors, combined with extraction procedures for sample preparation. For about sixteen years, the use of simpler and faster analytical procedures based on affinity biosensors has emerged in scientific literature as a very promising alternative, particularly electrochemical (i.e., amperometric, impedance, potentiometric or conductimetric) affinity biosensors due to their simplicity and sensitivity. Typically, electrochemical biosensors for mycotoxins use specific antibodies or aptamers as affinity ligands, although recombinant antibodies, artificial receptors and molecular imprinted polymers show potential utility. This article deals with recent advances in electrochemical affinity biosensors for mycotoxins and covers complete literature from the first reports about sixteen years ago.

  4. Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures

    SciTech Connect

    Zhu, Chengzhou; Yang, Guohai; Li, He; Du, Dan; Lin, Yuehe

    2014-10-29

    We report that considerable attention has been devoted to the integration of recognition elements with electronic elements to develop electrochemical sensors and biosensors.Various electrochemical devices, such as amperometric sensors, electrochemical impedance sensors, and electrochemical luminescence sensors as well as photoelectrochemical sensors, provide wide applications in the detection of chemical and biological targets in terms of electrochemical change of electrode interfaces. Here, this review focuses on recent advances in electrochemical sensors and biosensors based on nanomaterials and nanostructures during 2013 to 2014. The aim of this effort is to provide the reader with a clear and concise view of new advances in areas ranging from electrode engineering, strategies for electrochemical signal amplification, and novel electroanalytical techniques used in the miniaturization and integration of the sensors. Moreover, the authors have attempted to highlight areas of the latest and significant development of enhanced electrochemical nanosensors and nanobiosensors that inspire broader interests across various disciplines. Electrochemical sensors for small molecules, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are reviewed herein (Figure 1). Such novel advances are important for the development of electrochemical sensors that open up new avenues and methods for future research. In conclusion, we recommend readers interested in the general principles of electrochemical sensors and electrochemical methods to refer to other excellent literature for a broad scope in this area.(3, 4) However, due to the explosion of publications in this active field, we do not claim that this Review includes all of the published works in the past two years and we apologize to the authors of excellent work, which is unintentionally left out.

  5. Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures

    DOE PAGES

    Zhu, Chengzhou; Yang, Guohai; Li, He; ...

    2014-10-29

    We report that considerable attention has been devoted to the integration of recognition elements with electronic elements to develop electrochemical sensors and biosensors.Various electrochemical devices, such as amperometric sensors, electrochemical impedance sensors, and electrochemical luminescence sensors as well as photoelectrochemical sensors, provide wide applications in the detection of chemical and biological targets in terms of electrochemical change of electrode interfaces. Here, this review focuses on recent advances in electrochemical sensors and biosensors based on nanomaterials and nanostructures during 2013 to 2014. The aim of this effort is to provide the reader with a clear and concise view of new advancesmore » in areas ranging from electrode engineering, strategies for electrochemical signal amplification, and novel electroanalytical techniques used in the miniaturization and integration of the sensors. Moreover, the authors have attempted to highlight areas of the latest and significant development of enhanced electrochemical nanosensors and nanobiosensors that inspire broader interests across various disciplines. Electrochemical sensors for small molecules, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are reviewed herein (Figure 1). Such novel advances are important for the development of electrochemical sensors that open up new avenues and methods for future research. In conclusion, we recommend readers interested in the general principles of electrochemical sensors and electrochemical methods to refer to other excellent literature for a broad scope in this area.(3, 4) However, due to the explosion of publications in this active field, we do not claim that this Review includes all of the published works in the past two years and we apologize to the authors of excellent work, which is unintentionally left out.« less

  6. Electrochemical biosensor based on immobilized enzymes and redox polymers

    DOEpatents

    Skotheim, Terje A.; Okamoto, Yoshiyuki; Hale, Paul D.

    1992-01-01

    The present invention relates to an electrochemical enzyme biosensor for use in liquid mixtures of components for detecting the presence of, or measuring the amount of, one or more select components. The enzyme electrode of the present invention is comprised of an enzyme, an artificial redox compound covalently bound to a flexible polymer backbone and an electron collector.

  7. Beyond graphene: Electrochemical sensors and biosensors for biomarkers detection.

    PubMed

    Bollella, Paolo; Fusco, Giovanni; Tortolini, Cristina; Sanzò, Gabriella; Favero, Gabriele; Gorton, Lo; Antiochia, Riccarda

    2017-03-15

    Graphene's success has stimulated great interest and research in the synthesis and characterization of graphene-like 2D materials, single and few-atom-thick layers of van der Waals materials, which show fascinating and technologically useful properties. This review presents an overview of recent electrochemical sensors and biosensors based on graphene and on graphene-like 2D materials for biomarkers detection. Initially, we will outline different electrochemical sensors and biosensors based on chemically derived graphene, including graphene oxide and reduced graphene oxide, properly functionalized for improved performances and we will discuss the various strategies to prepare graphene modified electrodes. Successively, we present electrochemical sensors and biosensors based on graphene-like 2D materials, such as boron nitride (BN), graphite-carbon nitride (g-C3N4), transition metal dichalcogenides (TMDs), transition metal oxides and graphane, outlining how the new modified 2D nanomaterials will improve the electrochemical performances. Finally, we will compare the results obtained with different sensors and biosensors for the detection of important biomarkers such as glucose, hydrogen peroxide and cancer biomarkers and highlight the advantages and disadvantages of the use of graphene and graphene-like 2D materials in different sensing platforms.

  8. Electrochemical paper-based peptide nucleic acid biosensor for detecting human papillomavirus.

    PubMed

    Teengam, Prinjaporn; Siangproh, Weena; Tuantranont, Adisorn; Henry, Charles S; Vilaivan, Tirayut; Chailapakul, Orawon

    2017-02-01

    A novel paper-based electrochemical biosensor was developed using an anthraquinone-labeled pyrrolidinyl peptide nucleic acid (acpcPNA) probe (AQ-PNA) and graphene-polyaniline (G-PANI) modified electrode to detect human papillomavirus (HPV). An inkjet printing technique was employed to prepare the paper-based G-PANI-modified working electrode. The AQ-PNA probe baring a negatively charged amino acid at the N-terminus was immobilized onto the electrode surface through electrostatic attraction. Electrochemical impedance spectroscopy (EIS) was used to verify the AQ-PNA immobilization. The paper-based electrochemical DNA biosensor was used to detect a synthetic 14-base oligonucleotide target with a sequence corresponding to human papillomavirus (HPV) type 16 DNA by measuring the electrochemical signal response of the AQ label using square-wave voltammetry before and after hybridization. It was determined that the current signal significantly decreased after the addition of target DNA. This phenomenon is explained by the rigidity of PNA-DNA duplexes, which obstructs the accessibility of electron transfer from the AQ label to the electrode surface. Under optimal conditions, the detection limit of HPV type 16 DNA was found to be 2.3 nM with a linear range of 10-200 nM. The performance of this biosensor on real DNA samples was tested with the detection of PCR-amplified DNA samples from the SiHa cell line. The new method employs an inexpensive and disposable device, which easily incinerated after use and is promising for the screening and monitoring of the amount of HPV-DNA type 16 to identify the primary stages of cervical cancer.

  9. Enzyme catalytic amplification of miRNA-155 detection with graphene quantum dot-based electrochemical biosensor.

    PubMed

    Hu, Tianxing; Zhang, Le; Wen, Wei; Zhang, Xiuhua; Wang, Shengfu

    2016-03-15

    A specific and sensitive method was developed for quantitative detection of miRNA by integrating horseradish peroxidase (HRP)-assisted catalytic reaction with a simple electrochemical RNA biosensor. The electrochemical biosensor was constructed by a double-stranded DNA structure. The structure was formed by the hybridization of thiol-tethered oligodeoxynucleotide probes (capture DNA), assembled on the gold electrode surface, with target DNA and aminated indicator probe (NH2-DNA). After the construction of the double-stranded DNA structure, the activated carboxyl groups of graphene quantum dots (GQDs) assembled on NH2-DNA. GQDs were used as a new platform for HRP immobilization through noncovalent assembly. HRP modified biosensor can effectively catalyze the hydrogen peroxide (H2O2)-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), accompanied by a change from colorless to blue in solution color and an increased electrochemical current signal. Due to GQDs and enzyme catalysis, the proposed biosensor could sensitively detect miRNA-155 from 1 fM to 100 pM with a detection limit of 0.14 fM. High performance of the biosensor is attributed to the large surface-to-volume ratio, excellent compatibility of GQDs. For these advantages, the proposed method holds great potential for analysis of other interesting tumor makers.

  10. A signal-amplified electrochemical DNA biosensor incorporated with a colorimetric internal control for Vibrio cholerae detection using shelf-ready reagents.

    PubMed

    Low, Kim-Fatt; Zain, Zainiharyati Mohd; Yean, Chan Yean

    2017-01-15

    A novel enzyme/nanoparticle-based DNA biosensing platform with dual colorimetric/electrochemical approach has been developed for the sequence-specific detection of the bacterium Vibrio cholerae, the causative agent of acute diarrheal disease in cholera. This assay platform exploits the use of shelf-stable and ready-to-use (shelf-ready) reagents to greatly simplify the bioanalysis procedures, allowing the assay platform to be more amenable to point-of-care applications. To assure maximum diagnosis reliability, an internal control (IC) capable of providing instant validation of results was incorporated into the assay. The microbial target, single-stranded DNA amplified with asymmetric PCR, was quantitatively detected via electrochemical stripping analysis of gold nanoparticle-loaded latex microspheres as a signal-amplified hybridization tag, while the incorporated IC was analyzed using a simplified horseradish peroxidase enzyme-based colorimetric scheme by simple visual observation of enzymatic color development. The platform showed excellent diagnostic sensitivity and specificity (100%) when challenged with 145 clinical isolate-spiked fecal specimens. The limits of detection were 0.5ng/ml of genomic DNA and 10 colony-forming units (CFU)/ml of bacterial cells with dynamic ranges of 0-100ng/ml (R(2)=0.992) and log10 (1-10(4) CFU/ml) (R(2)=0.9918), respectively. An accelerated stability test revealed that the assay reagents were stable at temperatures of 4-37°C, with an estimated ambient shelf life of 200 days. The versatility of the biosensing platform makes it easily adaptable for quantitative detection of other microbial pathogens.

  11. FIBER OPTIC BIOSENSOR FOR DNA DAMAGE

    EPA Science Inventory

    This paper describes a fiber optic biosensor for the rapid and sensitive detection of radiation-induced or chemically-induced oxidative DNA damage. The assay is based on the hybridization and temperature-induced dissociation (melting curves) of synthetic oligonucleotides. The...

  12. Bioelectrochemical interface engineering: toward the fabrication of electrochemical biosensors, biofuel cells, and self-powered logic biosensors.

    PubMed

    Zhou, Ming; Dong, Shaojun

    2011-11-15

    Over the past decade, researchers have devoted considerable attention to the integration of living organisms with electronic elements to yield bioelectronic devices. Not only is the integration of DNA, enzymes, or whole cells with electronics of scientific interest, but it has many versatile potential applications. Researchers are using these ideas to fabricate biosensors for analytical applications and to assemble biofuel cells (BFCs) and biomolecule-based devices. Other research efforts include the development of biocomputing systems for information processing. In this Account, we focus on our recent progress in engineering at the bioelectrochemical interface (BECI) for the rational design and construction of important bioelectronic devices, ranging from electrochemical (EC-) biosensors to BFCs, and self-powered logic biosensors. Hydrogels and sol-gels provide attractive materials for the immobilization of enzymes because they make EC-enzyme biosensors stable and even functional in extreme environments. We use a layer-by-layer (LBL) self-assembly technique to fabricate multicomponent thin films on the BECI at the nanometer scale. Additionally, we demonstrate how carbon nanomaterials have paved the way for new and improved EC-enzyme biosensors. In addition to the widely reported BECI-based electrochemical impedance spectroscopy (EIS)-type aptasensors, we integrate the LBL technique with our previously developed "solid-state probe" technique for redox probes immobilization on electrode surfaces to design and fabricate BECI-based differential pulse voltammetry (DPV)-type aptasensors. BFCs can directly harvest energy from ambient biofuels as green energy sources, which could lead to their application as simple, flexible, and portable power sources. Porous materials provide favorable microenvironments for enzyme immobilization, which can enhance BFC power output. Furthermore, by introducing aptamer-based logic systems to BFCs, such systems could be applied as self

  13. Layered double hydroxides: an attractive material for electrochemical biosensor design.

    PubMed

    Shan, Dan; Cosnier, Serge; Mousty, Christine

    2003-08-01

    Electrochemical biosensors for phenol determination were developed based on the immobilization of polyphenol oxidase (PPO) within two different clay matrixes, one anionic (layered double hydroxide, LDH) and the other cationic (Laponite). The biosensor based on the enzyme immobilized in [Zn-Al-Cl] LDH shows greater sensitivity (7807 mA M(-1) cm(-2)) and maximum current (492 microA cm(-2)). Biosensor characteristics, such as Michaelis-Menten constant, recycling constant, activation energy, and permeability highlight the advantages of LDH matrixes to immobilize PPO. It appears that LDH provides a favorable environment to PPO activity. The best PPO/[Zn-Al-Cl] configuration was used to determine five different phenol derivatives reaching extremely sensitive detection limits (< or = 1 nM).

  14. Tin Oxide Nanorod Array-Based Electrochemical Hydrogen Peroxide Biosensor

    PubMed Central

    2010-01-01

    SnO2 nanorod array grown directly on alloy substrate has been employed as the working electrode of H2O2 biosensor. Single-crystalline SnO2 nanorods provide not only low isoelectric point and enough void spaces for facile horseradish peroxidase (HRP) immobilization but also numerous conductive channels for electron transport to and from current collector; thus, leading to direct electrochemistry of HRP. The nanorod array-based biosensor demonstrates high H2O2 sensing performance in terms of excellent sensitivity (379 μA mM−1 cm−2), low detection limit (0.2 μM) and high selectivity with the apparent Michaelis–Menten constant estimated to be as small as 33.9 μM. Our work further demonstrates the advantages of ordered array architecture in electrochemical device application and sheds light on the construction of other high-performance enzymatic biosensors. PMID:20596358

  15. Tin Oxide Nanorod Array-Based Electrochemical Hydrogen Peroxide Biosensor

    NASA Astrophysics Data System (ADS)

    Liu, Jinping; Li, Yuanyuan; Huang, Xintang; Zhu, Zhihong

    2010-07-01

    SnO2 nanorod array grown directly on alloy substrate has been employed as the working electrode of H2O2 biosensor. Single-crystalline SnO2 nanorods provide not only low isoelectric point and enough void spaces for facile horseradish peroxidase (HRP) immobilization but also numerous conductive channels for electron transport to and from current collector; thus, leading to direct electrochemistry of HRP. The nanorod array-based biosensor demonstrates high H2O2 sensing performance in terms of excellent sensitivity (379 μA mM-1 cm-2), low detection limit (0.2 μM) and high selectivity with the apparent Michaelis-Menten constant estimated to be as small as 33.9 μM. Our work further demonstrates the advantages of ordered array architecture in electrochemical device application and sheds light on the construction of other high-performance enzymatic biosensors.

  16. Development of an electrochemical biosensor for alkylphenol detection.

    PubMed

    Belkhamssa, Najet; da Costa, João P; Justino, Celine I L; Santos, Patrícia S M; Cardoso, Susana; Duarte, Armando C; Rocha-Santos, Teresa; Ksibi, Mohamed

    2016-09-01

    In this work, electrochemical biosensors based on field effect transistors (FET) with single-walled carbon nanotubes (SWCNT) were constructed as disposable analytical devices to detect alkylphenols through immunoreaction using 4-nonylphenol (NP) as model analyte, and validated by comparison with enzyme-linked immunosorbent assay (ELISA). The calibration curve displays a working range with five concentrations between 5 and 500µgL(-1), and for each concentration, five biosensors were analysed for reproducibility estimation and two analytical measurements were performed for each biosensor for repeatability estimation. The accuracy of the biosensors was validated by analyzing NP contents in ten spiked artificial seawater samples and comparing these results to those obtained with the traditional ELISA methodology. Excellent analytical performance was obtained with reproducibility of 0.56±0.08%, repeatability of 0.5±0.2%, limit of detection for NP as low as 5µgL(-1), and average recovery between 97.8% and 104.6%. This work demonstrates that simple biosensors can be used to detect hazardous priority substances in seawater samples, even at low concentrations.

  17. A reduced graphene oxide based electrochemical biosensor for tyrosine detection.

    PubMed

    Wei, Junhua; Qiu, Jingjing; Li, Li; Ren, Liqiang; Zhang, Xianwen; Chaudhuri, Jharna; Wang, Shiren

    2012-08-24

    In this paper, a 'green' and safe hydrothermal method has been used to reduce graphene oxide and produce hemin modified graphene nanosheet (HGN) based electrochemical biosensors for the determination of l-tyrosine levels. The as-fabricated HGN biosensors were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FTIR) spectra and thermogravimetric analysis (TGA). The experimental results indicated that hemin was successfully immobilized on the reduced graphene oxide nanosheet (rGO) through π-π interaction. TEM images and EDX results further confirmed the attachment of hemin on the rGO nanosheet. Cyclic voltammetry tests were carried out for the bare glass carbon electrode (GCE), the rGO electrode (rGO/GCE), and the hemin-rGO electrode (HGN/GCE). The HGN/GCE based biosensor exhibits a tyrosine detection linear range from 5 × 10(-7) M to 2 × 10(-5) M with a detection limitation of 7.5 × 10(-8) M at a signal-to-noise ratio of 3. The sensitivity of this biosensor is 133 times higher than that of the bare GCE. In comparison with other works, electroactive biosensors are easily fabricated, easily controlled and cost-effective. Moreover, the hemin-rGO based biosensors demonstrate higher stability, a broader detection linear range and better detection sensitivity. Study of the oxidation scheme reveals that the rGO enhances the electron transfer between the electrode and the hemin, and the existence of hemin groups effectively electrocatalyzes the oxidation of tyrosine. This study contributes to a widespread clinical application of nanomaterial based biosensor devices with a broader detection linear range, improved stability, enhanced sensitivity and reduced costs.

  18. A reduced graphene oxide based electrochemical biosensor for tyrosine detection

    NASA Astrophysics Data System (ADS)

    Wei, Junhua; Qiu, Jingjing; Li, Li; Ren, Liqiang; Zhang, Xianwen; Chaudhuri, Jharna; Wang, Shiren

    2012-08-01

    In this paper, a ‘green’ and safe hydrothermal method has been used to reduce graphene oxide and produce hemin modified graphene nanosheet (HGN) based electrochemical biosensors for the determination of l-tyrosine levels. The as-fabricated HGN biosensors were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FTIR) spectra and thermogravimetric analysis (TGA). The experimental results indicated that hemin was successfully immobilized on the reduced graphene oxide nanosheet (rGO) through π-π interaction. TEM images and EDX results further confirmed the attachment of hemin on the rGO nanosheet. Cyclic voltammetry tests were carried out for the bare glass carbon electrode (GCE), the rGO electrode (rGO/GCE), and the hemin-rGO electrode (HGN/GCE). The HGN/GCE based biosensor exhibits a tyrosine detection linear range from 5 × 10-7 M to 2 × 10-5 M with a detection limitation of 7.5 × 10-8 M at a signal-to-noise ratio of 3. The sensitivity of this biosensor is 133 times higher than that of the bare GCE. In comparison with other works, electroactive biosensors are easily fabricated, easily controlled and cost-effective. Moreover, the hemin-rGO based biosensors demonstrate higher stability, a broader detection linear range and better detection sensitivity. Study of the oxidation scheme reveals that the rGO enhances the electron transfer between the electrode and the hemin, and the existence of hemin groups effectively electrocatalyzes the oxidation of tyrosine. This study contributes to a widespread clinical application of nanomaterial based biosensor devices with a broader detection linear range, improved stability, enhanced sensitivity and reduced costs.

  19. Design of electrochemical biosensor systems for the detection of specific DNA sequences in PCR-amplified nucleic acids related to the catechol-O-methyltransferase Val108/158Met polymorphism based on intrinsic guanine signal.

    PubMed

    Ozkan-Ariksoysal, Dilsat; Tezcanli, Burcin; Kosova, Buket; Ozsoz, Mehmet

    2008-02-01

    Psychiatric disorders are common and complex diseases that show polygenic and multifactorial heredity. A single nucleotide polymorphism (Val108/158Met) in the catechol-O-methyl transferase (COMT) gene is related to many psychiatric disorders such as schizophrenia, alcoholism, bipolar disorder, and obsessive-compulsive disorder. Schizophrenia is a complex disorder and a single nucleotide polymorphism (Val108/158Met) at the COMT gene is related to schizophrenia susceptibility. A novel hybridization-based disposable electrochemical DNA biosensor for the detection of a common functional polymorphism in the COMT gene from polymerase chain reaction (PCR) amplicons has been described without using an external label. This developed technology combined with a disposable carbon graphite electrode and differential pulse voltammetry was performed by using short synthetic oligonucleotides and PCR amplicons in length 203 bp to measure the change of guanine oxidation signal obtained at approximately +1.0 V after DNA hybridization between probe and target (synthetic target or denatured PCR samples). COMT-specific oligonucleotides were immobilized onto the carbon surface with a simple adsorption method in two different modes: (a) Guanine-containing targets were attached or (b) inosine-substituted probes were attached onto an electrode. By controlling the surface coverage of the target DNA, the hybridization event between the probes and their synthetic targets or specific PCR products was optimized. The wild-type or polymorphic allele-specific probes/targets were also interacted with an equal amount of noncomplementary and one-base mismatch-containing DNAs in order to measure the sensor selectivity. The decrease or appearance in the intrinsic guanine signal simplified the detection procedure and shortened the assay time because protocol eliminates the label-binding step. The nonspecific binding effects were minimized by using sodium dodecyl sulfate with different washing methods

  20. Enzyme-gelatin electrochemical biosensors: scaling down.

    PubMed

    De Wael, Karolien; De Belder, Stijn; Pilehvar, Sanaz; Van Steenberge, Geert; Herrebout, Wouter; Heering, Hendrik A

    2012-03-15

    In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC) in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix.

  1. Enzyme-Gelatin Electrochemical Biosensors: Scaling Down

    PubMed Central

    Wael, Karolien De; Belder, Stijn De; Pilehvar, Sanaz; Steenberge, Geert Van; Herrebout, Wouter; Heering, Hendrik A.

    2012-01-01

    In this article we investigate the possibility of scaling down enzyme-gelatin modified electrodes by spin coating the enzyme-gelatin layer. Special attention is given to the electrochemical behavior of the selected enzymes inside the gelatin matrix. A glassy carbon electrode was used as a substrate to immobilize, in the first instance, horse heart cytochrome c (HHC) in a gelatin matrix. Both a drop dried and a spin coated layer was prepared. On scaling down, a transition from diffusion controlled reactions towards adsorption controlled reactions is observed. Compared to a drop dried electrode, a spin coated electrode showed a more stable electrochemical behavior. Next to HHC, we also incorporated catalase in a spin coated gelatin matrix immobilized on a glassy carbon electrode. By spincoating, highly uniform sub micrometer layers of biocompatible matrices can be constructed. A full electrochemical study and characterization of the modified surfaces has been carried out. It was clear that in the case of catalase, gluteraldehyde addition was needed to prevent leaking of the catalase from the gelatin matrix. PMID:25585635

  2. Novel immobilization techniques in the fabrication of efficient electrochemical biosensors

    NASA Astrophysics Data System (ADS)

    Alva, Shridhara; Marx, Kenneth A.; Samuelson, Lynne A.; Kumar, Jayant; Tripathy, Sukant K.; Kaplan, David L.

    1996-02-01

    The development of enzyme electrodes plays a major role in the performance of an electrochemical biosensor. In this paper, we describe two generic methods for efficient immobilization of enzymes or biomolecules at the electrode surface. These methods are based on physical entrapment of the enzymes during biochemical polymerization of phenols and electrochemical copolymerization of aromatic diamines with enzymes that are covalently coupled to the monomer. Both of these techniques have proven to be chemically mild and provide efficient polymer matrices for the fabrication of enzyme electrodes. Enzymes including horseradish peroxidase, alkaline phosphatase and glucose oxidase have been immobilized in these polymeric matrices and used for electrochemical as well as colorimetric detection of various substrates. Response times of the order of 5 - 10 seconds and sensitivities of the order of mM have been achieved with these electrodes. The use of these immobilization techniques towards the development of microelectrode arrays for multianalyte sensors is also discussed.

  3. Ultrasensitive Electrochemical Biosensor for HIV Gene Detection Based on Graphene Stabilized Gold Nanoclusters with Exonuclease Amplification.

    PubMed

    Wang, Yijia; Bai, Xiaoning; Wen, Wei; Zhang, Xiuhua; Wang, Shengfu

    2015-08-26

    Because human immunodeficiency virus (HIV) has been one of the most terrible viruses in recent decades, early diagnosis of the HIV gene is of great importance for all scientists around the world. In our work, we developed a novel electrochemical biosensor based on one-step ultrasonic synthesized graphene stabilized gold nanocluster (GR/AuNC) modified glassy carbon electrode (GCE) with an exonuclease III (Exo III)-assisted target recycling amplification strategy for the detection of HIV DNA. It is the first time that GR/AuNCs have been used as biosensor platform and aptamer with cytosine-rich base set as capture probe to construct the biosensor. With the combination of cytosine-rich capture probe, good conductivity and high surfaces of GR/AuNCs, and Exo III-assisted target recycling amplification, we realized high sensitivity and good selectivity detection of target HIV DNA with a detection limit of 30 aM (S/N = 3). Furthermore, the proposed biosensor has a promising potential application for target detection in human serum analysis.

  4. Engineering the bioelectrochemical interface using functional nanomaterials and microchip technique toward sensitive and portable electrochemical biosensors.

    PubMed

    Jia, Xiaofang; Dong, Shaojun; Wang, Erkang

    2016-02-15

    Electrochemical biosensors have played active roles at the forefront of bioanalysis because they have the potential to achieve sensitive, specific and low-cost detection of biomolecules and many others. Engineering the electrochemical sensing interface with functional nanomaterials leads to novel electrochemical biosensors with improved performances in terms of sensitivity, selectivity, stability and simplicity. Functional nanomaterials possess good conductivity, catalytic activity, biocompatibility and high surface area. Coupled with bio-recognition elements, these features can amplify signal transduction and biorecognition events, resulting in highly sensitive biosensing. Additionally, microfluidic electrochemical biosensors have attracted considerable attention on account of their miniature, portable and low-cost systems as well as high fabrication throughput and ease of scaleup. For example, electrochemical enzymetic biosensors and aptamer biosensors (aptasensors) based on the integrated microchip can be used for portable point-of-care diagnostics and environmental monitoring. This review is a summary of our recent progress in the field of electrochemical biosensors, including aptasensors, cytosensors, enzymatic biosensors and self-powered biosensors based on biofuel cells. We presented the advantages that functional nanomaterials and microfluidic chip technology bring to the electrochemical biosensors, together with future prospects and possible challenges.

  5. The Application of DNA-Biosensors and Differential Scanning Calorimetry to the Study of the DNA-Binding Agent Berenil.

    PubMed

    De Abreu, Fabiane C; De Paula, Francine S; Ferreira, Danielle C M; Nascimento, Valberes B; Lopes, Julio C D; Santos, Alexandre M C; Santoro, Marcelo M; Salas, Carlos E; Goulart, Marília O F

    2008-03-03

    The in situ DNA-damaging capacity of berenil (1) has been investigated usingan electrochemical approach employing double stranded (ds) DNA-modified glassy carbonelectrode biosensors. Electrochemical voltammetric sensing of damage caused by 1 todsDNA was monitored by the appearance of peaks diagnostic of the oxidation of guanineand adenine. When 1 was incorporated directly onto the biosensor surface, DNA damagecould be observed at concentrations of additive as low as 10 μM. In contrast, when thedsDNA-modified biosensor was exposed to 1, in acetate buffer solution, the method wasmuch less sensitive and DNA damage could be detected only in the presence of 100 μMberenil. When mixed solutions of 1 and single stranded (ss) DNA, polyguanylic acid orpolyadenylic acid were submitted to voltammetric study, the oxidation signals of therespective bases decreased in a concentration-dependent manner and the major variation ofthe adenine current peak indicated preferential binding of 1 to adenine. The electrochemical results were in close agreement with those deriving from a differentialscanning calorimetric study of the DNA-berenil complex.

  6. Recent Development of Nano-Materials Used in DNA Biosensors

    PubMed Central

    Xu, Kai; Huang, Junran; Ye, Zunzhong; Ying, Yibin; Li, Yanbin

    2009-01-01

    As knowledge of the structure and function of nucleic acid molecules has increased, sequence-specific DNA detection has gained increased importance. DNA biosensors based on nucleic acid hybridization have been actively developed because of their specificity, speed, portability, and low cost. Recently, there has been considerable interest in using nano-materials for DNA biosensors. Because of their high surface-to-volume ratios and excellent biological compatibilities, nano-materials could be used to increase the amount of DNA immobilization; moreover, DNA bound to nano-materials can maintain its biological activity. Alternatively, signal amplification by labeling a targeted analyte with nano-materials has also been reported for DNA biosensors in many papers. This review summarizes the applications of various nano-materials for DNA biosensors during past five years. We found that nano-materials of small sizes were advantageous as substrates for DNA attachment or as labels for signal amplification; and use of two or more types of nano-materials in the biosensors could improve their overall quality and to overcome the deficiencies of the individual nano-components. Most current DNA biosensors require the use of polymerase chain reaction (PCR) in their protocols. However, further development of nano-materials with smaller size and/or with improved biological and chemical properties would substantially enhance the accuracy, selectivity and sensitivity of DNA biosensors. Thus, DNA biosensors without PCR amplification may become a reality in the foreseeable future. PMID:22346713

  7. Recent development of nano-materials used in DNA biosensors.

    PubMed

    Xu, Kai; Huang, Junran; Ye, Zunzhong; Ying, Yibin; Li, Yanbin

    2009-01-01

    As knowledge of the structure and function of nucleic acid molecules has increased, sequence-specific DNA detection has gained increased importance. DNA biosensors based on nucleic acid hybridization have been actively developed because of their specificity, speed, portability, and low cost. Recently, there has been considerable interest in using nano-materials for DNA biosensors. Because of their high surface-to-volume ratios and excellent biological compatibilities, nano-materials could be used to increase the amount of DNA immobilization; moreover, DNA bound to nano-materials can maintain its biological activity. Alternatively, signal amplification by labeling a targeted analyte with nano-materials has also been reported for DNA biosensors in many papers. This review summarizes the applications of various nano-materials for DNA biosensors during past five years. We found that nano-materials of small sizes were advantageous as substrates for DNA attachment or as labels for signal amplification; and use of two or more types of nano-materials in the biosensors could improve their overall quality and to overcome the deficiencies of the individual nano-components. Most current DNA biosensors require the use of polymerase chain reaction (PCR) in their protocols. However, further development of nano-materials with smaller size and/or with improved biological and chemical properties would substantially enhance the accuracy, selectivity and sensitivity of DNA biosensors. Thus, DNA biosensors without PCR amplification may become a reality in the foreseeable future.

  8. Zeolitic imidazolate framework-based electrochemical biosensor for in vivo electrochemical measurements.

    PubMed

    Ma, Wenjie; Jiang, Qin; Yu, Ping; Yang, Lifen; Mao, Lanqun

    2013-08-06

    This study demonstrates the first exploitation of zeolitic imidazolate frameworks (ZIFs) as the matrix for constructing integrated dehydrogenase-based electrochemical biosensors for in vivo measurement of neurochemicals, such as glucose. In this study, we find that ZIFs are able to serve as a matrix for coimmobilizing electrocatalysts (i.e., methylene green, MG) and dehydrogenases (i.e., glucose dehydrogenase, GDH) onto the electrode surface and an integrated electrochemical biosensor is readily formed. We synthesize a series of ZIFs, including ZIF-7, ZIF-8, ZIF-67, ZIF-68, and ZIF-70 with different pore sizes, surface areas, and functional groups. The adsorption capabilities toward MG and GDH of these ZIFs are systematically studied with UV-vis spectroscopy, confocal laser scanning microscopy, and Fourier transfer-infrared spectroscopy. Among all the ZIFs demonstrated here, ZIF-70 shows excellent adsorption capacities toward both MG and GDH and is thus employed as the matrix for our glucose biosensor. To construct the biosensor, we first drop-coat a MG/ZIF-70 composite onto a glassy carbon electrode and then coat GDH onto the MG/ZIF-70 composite. In a continuous-flow system, the as-prepared ZIF-based biosensor is very sensitive to glucose with a linear range of 0.1-2 mM. Moreover, the ZIF-based biosensor is more highly selective on glucose than on other endogenous electroactive species in the cerebral system. In the end, we demonstrate that our biosensor is capable of monitoring dialysate glucose collected from the brain of guinea pigs selectively and in a near real-time pattern.

  9. Electrochemical biosensors for rapid detection of Escherichia coli O157:H7.

    PubMed

    Xu, Meng; Wang, Ronghui; Li, Yanbin

    2017-01-01

    Electrochemical biosensors have shown great promise in the development of rapid methods for the detection of foodborne pathogens and have been intensively studied over the past two decades. The scope of this review is to summarize the advancements made in the development of electrochemical biosensors for the rapid detection of one of the most common foodborne pathogens, Escherichia coli O157:H7. The article is intended to include different configurations of electrochemical biosensors based on the sensing principles and measured electrical parameters, as well as the latest improvements of technology in the progress of electrochemical biosensor development to detect E. coli O157:H7. By discussing the current and future trend based on some of excellent published literatures and reviews, this survey is hoped to illustrate a broad and comprehensive understanding of electrochemical biosensors for the detection of foodborne pathogens.

  10. Electrochemical enzymatic biosensors using carbon nanofiber nanoelectrode arrays

    NASA Astrophysics Data System (ADS)

    Li, Jun; Li, Yi-fen; Swisher, Luxi Z.; Syed, Lateef U.; Prior, Allan M.; Nguyen, Thu A.; Hua, Duy H.

    2012-10-01

    The reduction of electrode size down to nanometers could dramatically enhance detection sensitivity and temporal resolution. Nanoelectrode arrays (NEAs) are of particular interest for ultrasensitive biosensors. Here we report the study of two types of biosensors for measuring enzyme activities using NEAs fabricated with vertically aligned carbon nanofibers (VACNFs). VACNFs of ~100 nm in average diameter and 3-5 μm in length were grown on conductive substrates as uniform vertical arrays which were then encapsulated in SiO2 matrix leaving only the tips exposed. We demonstrate that such VACNF NEAs can be used in profiling enzyme activities through monitoring the change in electrochemical signals induced by enzymatic reactions to the peptides attached to the VACNF tip. The cleavage of the tetrapeptide with a ferrocene tag by a cancerrelated protease (legumain) was monitored with AC voltammetry. Real-time electrochemical impedance spectroscopy (REIS) was used for fast label-free detection of two reversible processes, i.e. phosphorylation by c-Src tyrosine kinase and dephosphorylation by protein tyrosine phosphatase 1B (PTP1B). The REIS data of phosphorylation were slow and unreliable, but those of dephosphorylation showed large and fast exponential decay due to much higher activity of phosphatase PTP1B. The kinetic data were analyzed with a heterogeneous Michaelis-Menten model to derive the "specificity constant" kcat/Km, which is 8.2x103 M-1s-1 for legumain and (2.1 ± 0.1) x 107 M-1s-1 for phosphatase (PTP1B), well consistent with literature. It is promising to develop VACNF NEA based electrochemical enzymatic biosensors as portable multiplex electronic techniques for rapid cancer diagnosis and treatment monitoring.

  11. DNA biosensors based on self-assembled carbon nanotubes.

    PubMed

    Wang, S G; Wang, Ruili; Sellin, P J; Zhang, Qing

    2004-12-24

    DNA biosensors based on self-assembled multi-walled carbon nanotubes (MWNTs) were described in this paper, in which the probe DNA oligonucleotides were immobilized by forming covalent amide bonds between carboxyl groups at the nanotubes and amino groups at the ends of the DNA oligonucleotides. Hybridization between the probe and target DNA oligonucleotides was confirmed by the changes in the voltammetric peak of the indicator of methylene blue. Our results demonstrate that the DNA biosensors based on self-assembled MWNTs had a higher hybridization efficiency compared to those based on random MWNTs. In addition, the developed DNA biosensors also had a high selectivity of hybridization detection.

  12. Biosensors based on DNA-Functionalized Graphene

    NASA Astrophysics Data System (ADS)

    Vishnubhotla, Ramya; Ping, Jinglei; Vrudhula, Amey; Johnson, A. T. Charlie

    Since its discovery, graphene has been used for sensing applications due to its outstanding electrical properties and biocompatibility. Here, we demonstrate the capabilities of field effect transistors (FETs) based on CVD-grown graphene functionalized with commercially obtained DNA oligomers and aptamers for detection of various biomolecular targets (e.g., complementary DNA and small molecule drug targets). Graphene FETs were created with a scalable photolithography process that produces arrays consisting of 50-100 FETs with a layout suitable for multiplexed detection of four molecular targets. FETs were characterized via AFM to confirm the presence of the aptamer. From the measured electrical characteristics, it was determined that binding of molecular targets by the DNA chemical recognition element led to a reproducible, concentration-dependent shift in the Dirac voltage. This biosensor class is potentially suitable for applications in drug detection. This work is funded by NIH through the Center for AIDS Research at the University of Pennsylvania.

  13. Immobilization techniques in the fabrication of nanomaterial-based electrochemical biosensors: a review.

    PubMed

    Putzbach, William; Ronkainen, Niina J

    2013-04-11

    The evolution of 1st to 3rd generation electrochemical biosensors reflects a simplification and enhancement of the transduction pathway. However, in recent years, modification of the transducer with nanomaterials has become increasingly studied and imparts many advantages. The sensitivity and overall performance of enzymatic biosensors has improved tremendously as a result of incorporating nanomaterials in their fabrication. Given the unique and favorable qualities of gold nanoparticles, graphene and carbon nanotubes as applied to electrochemical biosensors, a consolidated survey of the different methods of nanomaterial immobilization on transducer surfaces and enzyme immobilization on these species is beneficial and timely. This review encompasses modification of enzymatic biosensors with gold nanoparticles, carbon nanotubes, and graphene.

  14. An electrochemical biosensor for ultratrace terbium based on Tb3+ promoted conformational change of human telomeric G-quadruplex.

    PubMed

    Zhang, Jing; Chen, Jinghua; Chen, Rongchun; Chen, Guonan; Fu, Fengfu

    2009-10-15

    A new electrochemical biosensor for the monitoring of ultratrace terbium based on the conformational change of DNA containing a single guanine (G)-rich stretch was described here. The biosensor was fabricated by immobilizing a thiolated DNA containing a single G-rich stretch on the gold surface as probe surface. The G-rich DNA probe was found to be capable of changing its configuration from flexible single-stranded structures to rigid tetramolecular G-quadruplex in the presence of terbium III, which provided a switchable charge transport path for the oxidation of [Fe(CN)(6)](4-). The switchable surface provided a sensing platform for the single-step and reagentless detection of Tb(3+). Using this reusable electrochemical sensing platform, a simple, rapid, and selective biosensor for the determination of ultratrace terbium ions with a detection limit of 6.0 x 10(-11)M has been developed. The success in the present biosensor served as a significant step toward the development of monitoring ultratrace Tb(3+) in river water or seawater.

  15. Nanopillar based electrochemical biosensor for monitoring microfluidic based cell culture

    NASA Astrophysics Data System (ADS)

    Gangadharan, Rajan

    In-vitro assays using cultured cells have been widely performed for studying many aspects of cell biology and cell physiology. These assays also form the basis of cell based sensing. Presently, analysis procedures on cell cultures are done using techniques that are not integrated with the cell culture system. This approach makes continuous and real-time in-vitro measurements difficult. It is well known that the availability of continuous online measurements for extended periods of time will help provide a better understanding and will give better insight into cell physiological events. With this motivation we developed a highly sensitive, selective and stable microfluidic electrochemical glucose biosensor to make continuous glucose measurements in cell culture media. The performance of the microfluidic biosensor was enhanced by adding 3D nanopillars to the electrode surfaces. The microfluidic glucose biosensor consisted of three electrodes---Enzyme electrode, Working electrode, and Counter electrode. All these electrodes were enhanced with nanopillars and were optimized in their respective own ways to obtain an effective and stable biosensing device in cell culture media. For example, the 'Enzyme electrode' was optimized for enzyme immobilization via either a polypyrrole-based or a self-assembled-monolayer-based immobilization method, and the 'Working electrode' was modified with Prussian Blue or electropolymerized Neutral Red to reduce the working potential and also the interference from other interacting electro-active species. The complete microfluidic biosensor was tested for its ability to monitor glucose concentration changes in cell culture media. The significance of this work is multifold. First, the developed device may find applications in continuous and real-time measurements of glucose concentrations in in-vitro cell cultures. Second, the development of a microfluidic biosensor will bring technical know-how toward constructing continuous glucose

  16. Tetrahedral DNA nanostructure-based microRNA biosensor coupled with catalytic recycling of the analyte.

    PubMed

    Miao, Peng; Wang, Bidou; Chen, Xifeng; Li, Xiaoxi; Tang, Yuguo

    2015-03-25

    MicroRNAs are not only important regulators of a wide range of cellular processes but are also identified as promising disease biomarkers. Due to the low contents in serum, microRNAs are always difficult to detect accurately . In this study, an electrochemical biosensor for ultrasensitive detection of microRNA based on tetrahedral DNA nanostructure is developed. Four DNA single strands are engineered to form a tetrahedral nanostructure with a pendant stem-loop and modified on a gold electrode surface, which largely enhances the molecular recognition efficiency. Moreover, taking advantage of strand displacement polymerization, catalytic recycling of microRNA, and silver nanoparticle-based solid-state Ag/AgCl reaction, the proposed biosensor exhibits high sensitivity with the limit of detection down to 0.4 fM. This biosensor shows great clinical value and may have practical utility in early diagnosis and prognosis of certain diseases.

  17. Electrochemical impedimetric biosensor based on a nanostructured polycarbonate substrate

    PubMed Central

    Chen, Yu-Shan; Wu, Chia-Che; Tsai, Jaw-Ji; Wang, Gou-Jen

    2012-01-01

    This study integrates the techniques of nanoelectroforming, hot-embossing, and electrochemical deposition to develop a disposable, low-cost, and high sensitivity nanostructure biosensor. A modified anodic aluminum oxide barrier-layer surface was used as the template for thin nickel film deposition. After etching the anodic aluminum oxide template off, a three-dimensional mold of the concave nanostructure array was created. The fabricated three-dimensional nickel mold was further used for replica molding of a nanostructure polycarbonate substrate by hot-embossing. A thin gold film was then sputtered onto the polycarbonate substrate to form the electrode, followed by deposition of an orderly and uniform gold nanoparticle layer on the three-dimensional gold electrode using electrochemical deposition. Finally, silver nanoparticles were deposited on the uniformly deposited gold nanoparticles to enhance the conductivity of the sensor. Electrochemical impedance spectroscopy analysis was then used to detect the concentration of the target element. The sensitivity of the proposed scheme on the detection of the dust mite antigen, Der p2, reached 0.1 pg/mL. PMID:22275829

  18. Biotin determination in food supplements by an electrochemical magneto biosensor.

    PubMed

    Kergaravat, Silvina V; Gómez, Gabriel A; Fabiano, Silvia N; Laube Chávez, Tamara I; Pividori, María I; Hernández, Silvia R

    2012-08-15

    An electrochemical magneto biosensor for the rapid determination of biotin in food samples is reported. The affinity reaction was performed on streptavidin-modified magnetic microbeads as a solid support in a direct competitive format. The biotinylated horseradish peroxidase enzyme (biotin-HRP) competes with free biotin in the sample for the binding sites of streptavidin on the magnetic microbeads. The modified magnetic beads were then easily captured by a magneto graphite-epoxy composite electrode and the electrochemical signal was based on the enzymatic activity of the HRP enzyme under the addition of H(2)O(2) as the substrate and o-phenilendiamine as cosubstrate. The response was electrochemically detected by square wave voltammetry. The limit of detection was 8.4×10(-8) mol L(--1) of biotin (20 μg L(--1)) with a dynamic range from 0.94 to 2.4×10(-7) mol L(--1). Biotin-fortified commercial dietary supplement and infant formula samples were evaluated obtaining good performances in the results. Total time of analysis was 40 min per 20 assays.

  19. Engineering a novel self-powering electrochemical biosensor

    PubMed Central

    Gu, X.; Ramsay, S.; Jensen, M.; Fulton, R.; Rosser, S.; Gilbert, D.

    2010-01-01

    This paper records the efforts of a multi-disciplinary team of undergraduate students from Glasgow University to collectively design and carry out a 10 week project in Synthetic Biology as part of the international Genetic Engineered Machine competition (iGEM). The aim of the project was to design and build a self-powering electrochemical biosensor called ‘ElectrEcoBlu’. The novelty of this engineered machine lies in coupling a biosensor with a microbial fuel cell to transduce a pollution input into an easily measurable electrical output signal. The device consists of two components; the sensor element which is modular, allowing for customisation to detect a range of input signals as required, and the universal reporter element which is responsible for generating an electrical signal as an output. The genetic components produce pyocyanin, a competitive electron mediator for microbial fuel cells, thus enabling the generation of an electrical current in the presence of target chemical pollutants. The pollutants tested in our implementation were toluene and salicylate. ElectrEcoBlu is expected to drive forward the development of a new generation of biosensors. Our approach exploited a range of state-of-the-art modelling techniques in a unified framework of qualitative, stochastic and continuous approaches to support the design and guide the construction of this novel biological machine. This work shows that integrating engineering techniques with scientific methodologies can provide new insights into genetic regulation and can be considered as a reference framework for the development of biochemical systems in synthetic biology. PMID:21189841

  20. Nanocoax-based molecular imprint polymer for electrochemical biosensor

    NASA Astrophysics Data System (ADS)

    Rizal, Binod; Archibald, Michelle; Simko, Laura; Connolly, Timothy; Shepard, Stephen; Burns, Michael; Chiles, Thomas; Naughton, Michael

    2013-03-01

    We have used molecular imprint polymerization (MIP) on planar, nanopillar, and nanocoax structures to fabricate label-free, all-electronic electrochemical biosensors with high selectivity and sensitivity. MIP-based films of ~ 7 nm thickness are formed on gold-coated surfaces by electropolymerization of a solution containing phenol and a target protein (streptavidin, at 100 μg/ml, or 1 nanomole concentration) and subsequent removal of exposed target protein, leaving behind its molecular imprint. With its molecular memory, MIP subsequently specifically recognizes and binds target protein with attomolar sensitivity, detected via differential pulse voltammetry. We will discuss and compare the results of MIP for different proteins on planar, nanopillar, and nanocoax structures, along with their respective ultimate sensitivities. Supported by the NIH grants NCI CA137681 and NIAID AI100216.

  1. Preparation of Electrochemical Biosensor for Detection of Organophosphorus Pesticides

    PubMed Central

    Gothwal, Ashish; Beniwal, Puneet; Dhull, Vikas

    2014-01-01

    Polyvinyl chloride (PVC) can be used to develop reaction beaker which acts as electrochemical cell for the measurement of OP pesticides. Being chemically inert, corrosion resistant, and easy in molding to various shapes and size, PVC can be used for the immobilization of enzyme. Organophosphorus hydrolase was immobilized covalently onto the chemically activated inner surface of PVC beaker by using glutaraldehyde as a coupling agent. The carbon nanotubes paste working electrode was constructed for amperometric measurement at a potential of +0.8 V. The biosensor showed optimum response at pH 8.0 with incubation temperature of 40°C. Km and Imax for substrate (methyl parathion) were 322.58 µM and 1.1 µA, respectively. Evaluation study showed a correlation of 0.985, which was in agreement with the standard method. The OPH biosensor lost 50% of its initial activity after its regular use for 25 times over a period of 50 days when stored in 0.1 M sodium phosphate buffer, pH 8.0 at 4°C. No interference was observed by interfering species. PMID:25667593

  2. Electrochemical aptamer scaffold biosensors for detection of botulism and ricin toxins.

    PubMed

    Fetter, Lisa; Richards, Jonathan; Daniel, Jessica; Roon, Laura; Rowland, Teisha J; Bonham, Andrew J

    2015-10-21

    Protein toxins present considerable health risks, but detection often requires laborious analysis. Here, we developed electrochemical aptamer biosensors for ricin and botulinum neurotoxins, which display robust and specific signal at nanomolar concentrations and function in dilute serum. These biosensors may aid future efforts for the rapid diagnosis of toxins.

  3. Utilization of Electrochemical Sensors and Biosensors in Biochemistry and Molecular Biology

    PubMed Central

    Adam, Vojtech; Kizek, Rene

    2008-01-01

    A special issue of Sensors entitled “Utilization of Electrochemical Sensors and Biosensors in Biochemistry and Molecular Biology” has been prepared over a period of three years. In this Editorial Note we would like to highlight one of the possible directions for electrochemical sensor and biosensor research resulting from the ideas of Czechoslovakian Nobel Prize winner Jaroslav Heyrovsky and his colleague Rudolf Brdicka. PMID:27873861

  4. High specific surface gold electrode on polystyrene substrate: Characterization and application as DNA biosensor.

    PubMed

    Yang, Zhiliu; Liu, Yichen; Lu, Wei; Yuan, Qingpan; Wang, Wei; Pu, Qiaosheng; Yao, Bo

    2016-05-15

    In the past decades, many efforts have been made to improve the sensitivity and specificity of electrochemical DNA biosensors. However, it is still strongly required to develop disposable and reliable DNA biosensors for wide and practical application. In this article, we reported superior electrochemical properties of an integrated plastic-gold electrode (PGE) fabricated in-house by chemical plating on polystyrene substrate. PGEs were found having extremely high capacity of DNA immobilization compared with gold electrodes fabricated by standard sputtering based photolithography. Unique nano-structured surface was observed on PGEs through morphology techniques, which would to some extend give an explanation to higher capacity of DNA immobilization on PGEs. A probable mechanism of carboxylic acid produced on polystyrene substrate after exposure to UV irradiation was proposed and discussed for the first time. This biosensor was applied to detection and manipulate of DNA hybridization. Detection limit of 7.2×10(-11) M and 1-500 nM of linearity range was obtained.

  5. A microfluidic paper-based electrochemical biosensor array for multiplexed detection of metabolic biomarkers

    NASA Astrophysics Data System (ADS)

    Zhao, Chen; Thuo, Martin M.; Liu, Xinyu

    2013-10-01

    Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to that of the existing commercial and paper-based platforms. The paper-based biosensor array and its electrochemical reader will enable the acquisition of high-density, statistically meaningful diagnostic information at the point of care in a rapid and cost-efficient way.

  6. A microfluidic paper-based electrochemical biosensor array for multiplexed detection of metabolic biomarkers

    PubMed Central

    Zhao, Chen; Thuo, Martin M; Liu, Xinyu

    2013-01-01

    Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to that of the existing commercial and paper-based platforms. The paper-based biosensor array and its electrochemical reader will enable the acquisition of high-density, statistically meaningful diagnostic information at the point of care in a rapid and cost-efficient way. PMID:27877606

  7. Papers Based Electrochemical Biosensors: From Test Strips to Paper-Based Microfluidics

    SciTech Connect

    Liu, Bingwen; Du, Dan; Hua, Xin; Yu, Xiao-Ying; Lin, Yuehe

    2014-05-08

    Papers based biosensors such as lateral flow test strips and paper-based microfluidic devices (or paperfluidics) are inexpensive, rapid, flexible, and easy-to-use analytical tools. An apparent trend in their detection is to interpret sensing results from qualitative assessment to quantitative determination. Electrochemical detection plays an important role in quantification. This review focuses on electrochemical (EC) detection enabled biosensors. The first part provides detailed examples in paper test strips. The second part gives an overview of paperfluidics engaging EC detections. The outlook and recommendation of future directions of EC enabled biosensors are discussed in the end.

  8. Graphene as a signal amplifier for preparation of ultrasensitive electrochemical biosensors.

    PubMed

    Filip, Jaroslav; Kasák, Peter; Tkac, Jan

    2015-01-01

    Early diagnostics of diseases performed with minimal money and time consumption has become achievable due to recent advances in development of biosensors. These devices use biorecognition elements for selective interaction with an analyte and signal readout is obtained via different types of transducers. Operational characteristics of biosensors have been reported to improve substantially, when a diverse range of nanomaterials was employed. This review presents construction of electrochemical biosensors based on graphene, atomically thin 2D carbon crystals, which is currently intensively studied nanomaterial. The most attractive directions of graphene applications in biosensor preparation are discussed here including novel detection and amplification schemes exploiting graphene's unique electrochemical, physical and chemical properties. The future of graphene-based biosensors is most likely bright, but there is still a lot of work to do to fulfill high expectations.

  9. Graphene as a signal amplifier for preparation of ultrasensitive electrochemical biosensors

    PubMed Central

    Filip, Jaroslav; Kasák, Peter; Tkac, Jan

    2016-01-01

    Early diagnostics of diseases performed with minimal money and time consumption has become achievable due to recent advances in development of biosensors. These devices use biorecognition elements for selective interaction with an analyte and signal readout is obtained via different types of transducers. Operational characteristics of biosensors have been reported to improve substantially, when a diverse range of nanomaterials was employed. This review presents construction of electrochemical biosensors based on graphene, atomically thin 2D carbon crystals, which is currently intensively studied nanomaterial. The most attractive directions of graphene applications in biosensor preparation are discussed here including novel detection and amplification schemes exploiting graphene’s unique electrochemical, physical and chemical properties. The future of graphene-based biosensors is most likely bright, but there is still a lot of work to do to fulfill high expectations. PMID:27242391

  10. Detection of femtomolar level osteosarcoma-related gene via a chronocoulometric DNA biosensor based on nanostructure gold electrode.

    PubMed

    Zhong, Guangxian; Liu, Ailin; Xu, Xiongwei; Sun, Zhouliang; Chen, Jinyuan; Wang, Kun; Liu, Qicai; Lin, Xinhua; Lin, Jianhua

    2012-01-01

    In this paper, a sensitive chronocoulometric deoxyribonucleic acid (DNA) biosensor based on a nanostructure gold electrode was fabricated for detection of the femtomolar level survivin gene which was correlated with osteosarcoma by using hexaamine-ruthenium III complexes, [Ru(NH(3))(6)](3+), as the electrochemical indicator. The effect of different frequencies on the real surface area of the nanostructure gold electrode obtained by repetitive square-wave oxidation reduction cycle was investigated. At the optimal frequency of 8000 Hz, the real surface of the developed nanostructure gold electrode was about 42.5 times compared with that of the bare planar gold electrode. The capture probe DNA was immobilized on the nanostructure gold electrode and hybridized with target DNA. Electrochemical signals of hexaamine-ruthenium III bound to the anionic phosphate of DNA strands via electrostatic interactions were measured by chronocoulometry before and after hybridization. The increase of the charges of hexaamine-ruthenium III was observed upon hybridization of the probe with target DNA. Results indicate that this DNA biosensor could detect the femtomole (fM) concentration of the DNA target quantitatively in the range of 50 fM to 250 fM; the detection limit of this DNA biosensor was 5.6 fM (signal to noise = 3). This new biosensor exhibits excellent sensitivity and selectivity and has been used for an assay of polymerase chain reaction (PCR) with a satisfactory result.

  11. An Evolution Based Biosensor Receptor DNA Sequence Generation Algorithm

    PubMed Central

    Kim, Eungyeong; Lee, Malrey; Gatton, Thomas M.; Lee, Jaewan; Zang, Yupeng

    2010-01-01

    A biosensor is composed of a bioreceptor, an associated recognition molecule, and a signal transducer that can selectively detect target substances for analysis. DNA based biosensors utilize receptor molecules that allow hybridization with the target analyte. However, most DNA biosensor research uses oligonucleotides as the target analytes and does not address the potential problems of real samples. The identification of recognition molecules suitable for real target analyte samples is an important step towards further development of DNA biosensors. This study examines the characteristics of DNA used as bioreceptors and proposes a hybrid evolution-based DNA sequence generating algorithm, based on DNA computing, to identify suitable DNA bioreceptor recognition molecules for stable hybridization with real target substances. The Traveling Salesman Problem (TSP) approach is applied in the proposed algorithm to evaluate the safety and fitness of the generated DNA sequences. This approach improves efficiency and stability for enhanced and variable-length DNA sequence generation and allows extension to generation of variable-length DNA sequences with diverse receptor recognition requirements. PMID:22315543

  12. Electrochemical biosensors based on nanofibres for cardiac biomarker detection: A comprehensive review.

    PubMed

    Rezaei, Babak; Ghani, Mozhdeh; Shoushtari, Ahmad Mousavi; Rabiee, Mohammad

    2016-04-15

    The vital importance of early and accurate diagnosis of cardiovascular diseases (CVDs) to prevent the irreversible damage or even death of patients has driven the development of biosensor devices for detection and quantification of cardiac biomarkers. Electrochemical biosensors offer rapid sensing, low cost, portability and ease of use. Over the past few years, nanotechnology has contributed to a tremendous improvement in the sensitivity of biosensors. In this review, the authors summarise the state-of-the-art of the application of one particular type of nanostructured material, i.e. nanofibres, for use in electrochemical biosensors for the ultrasensitive detection of cardiac biomarkers. A new way of classifying the nanofibre-based electrochemical biosensors according to the electrical conductance and the type of nanofibres is presented. Some key data from each article reviewed are highlighted, including the mechanism of detection, experimental conditions and the response range of the biosensor. The primary aim of this review is to emphasise the prospects for nanofibres for the future development of biosensors in diagnosis of CVDs as well as considering how to improve their characteristics for application in medicine.

  13. Developing a miniaturized continuous flow electrochemical cell for biosensor applications

    NASA Astrophysics Data System (ADS)

    Ilie, M.; Ovreiu, E.; Dejana, R.; Foglietti, V.; Nardi, L.; Masci, A.; Lanza, B.; Della Seta, L.; Montereali, M.-R.; Vastarella, W.; Pilloton, R.

    2009-01-01

    The development of a miniaturized electrochemical cell for biosensor application regards both the structuring of an array of electrodes in a fluidic chamber and their connections to the control & processing unit The sensitivity of the chrono-amperometric measurement performed with the cell is increased by: (a) integrating the reference electrode on the same chip with the counter- and working- electrodes, (b) designing a specific pattern of the gold electrodes and (c) serially distributing them along the pipeline reservoir. Borosilicate glass is used as substrate for the electrodes, allowing, due to its transparency, an accurate and easy pad to pad alignment of the up-side-down chip versus a PCB soldered on a standard DIL 40 socket. This alignment is necessary to accomplish the elastomer-based-solderless electric contact, between chip and PCB. The solderless contact significantly improves both reliability and signal processing accuracy. The reservoir and its cover are micromachined out of silicone rubber respectively photosensitive glass in order to easy disassemble the fluidic chamber without any damage. Both thickness and elasticity of the photosensitive glass rend the device less brittle. A plug-in -plug-flow device with improved characteristics has been obtained with a modular structure that allows further extension of the number of electrodes.

  14. First paraben substituted cyclotetraphosphazene compounds and DNA interaction analysis with a new automated biosensor.

    PubMed

    Çiftçi, Gönül Yenilmez; Şenkuytu, Elif; İncir, Saadet Elif; Yuksel, Fatma; Ölçer, Zehra; Yıldırım, Tuba; Kılıç, Adem; Uludağ, Yıldız

    2016-06-15

    Cancer, as one of the leading causes of death in the world, is caused by malignant cell division and growth that depends on rapid DNA replication. To develop anti-cancer drugs this feature of cancer could be exploited by utilizing DNA-damaging molecules. To achieve this, the paraben substituted cyclotetraphosphazene compounds have been synthesized for the first time and their effect on DNA (genotoxicity) has been investigated. The conventional genotoxicity testing methods are laborious, take time and are expensive. Biosensor based assays provide an alternative to investigate this drug/compound DNA interactions. Here for the first time, a new, easy and rapid screening method has been used to investigate the DNA damage, which is based on an automated biosensor device that relies on the real-time electrochemical profiling (REP™) technology. Using both the biosensor based screening method and the in vitro biological assay, the compounds 9 and 11 (propyl and benzyl substituted cyclotetraphosphazene compounds, respectively), have resulted in higher DNA damage than the others with 65% and 80% activity reduction, respectively.

  15. A multifunctional label-free electrochemical impedance biosensor for Hg(2+), adenosine triphosphate and thrombin.

    PubMed

    Chen, Lifen; Chen, Zhong-Ning

    2015-01-01

    A multifunctional label-free biosensor for the detection of Hg(2+), adenosine triphosphate and thrombin has been developed based on the changing of the electrochemical impedance spectroscopy (EIS) from the modified electrodes when nucleic acid subunits interacting with different targets. The modified electrode consists of three interaction sections, including DNA with T-T mismatch recognizing Hg(2+) to form T-Hg(2+)-T complex, split DNA chip against ATP, and DNA domin against thrombin to form G-quadruplex. Upon DNA interaction with thrombin or ATP, an increased charge transfer resistance (Rct) had been detected. However, a decreased Rct against Hg(2+) was obtained. The Rct difference (ΔRct) has relationship with the concentration of the different targets, Hg(2+), ATP and thrombin can be selectively detected with the detection limit of 0.03, 0.25, and 0.20 nmol L(-1), respectively. To separately detect the three analytes existing in the same sample, ATP aptamer, G-rich DNA strands and EDTA were applied to mask ATP, Hg(2+) or thrombin separately.

  16. Online electrochemical systems for continuous neurochemical measurements with low-potential mediator-based electrochemical biosensors as selective detectors.

    PubMed

    Zhang, Zipin; Hao, Jie; Xiao, Tongfang; Yu, Ping; Mao, Lanqun

    2015-08-07

    This study demonstrates a new strategy to develop online electrochemical systems (OECSs) for continuously monitoring neurochemicals by efficiently integrating in vivo microdialysis with an oxidase-based electrochemical biosensor with low-potential electron mediators to shuttle the electron transfer of the oxidases. By using thionine and xanthine oxidase (XOD) as examples of low-potential mediators and oxidases, respectively, we demonstrate that the use of low-potential mediators to shuttle the electron transfer of oxidases would offer a new approach to the development of oxidase-based biosensors with theoretical and technical simplicity. To construct the XOD-based biosensor, thionine was adsorbed onto carbon nanotubes and used to shuttle the electron transfer of XOD. The XOD-based biosensor was positioned into an electrochemical cell that was directly coupled with in vivo microdialysis to form an online electrochemical system (OECS) for continuous and selective measurements of the substrate of XOD (with hypoxanthine as an example). The OECS based on the low-potential mediators is highly selective against the species endogenously existing in the brain system, which is attributed to the low operation potential benefited from the low redox potentials of the mediators. Moreover, the OECS demonstrated here is stable and reproducible and could thus be envisaged to find some interesting applications in physiological and pathological investigations. This study essentially offers a new strategy to develop online electrochemical systems, which is of great importance in understanding the molecular basis of physiological and pathological events.

  17. DNA Diagnostics: Nanotechnology-enhanced Electrochemical Detection of Nucleic Acids

    PubMed Central

    Wei, Fang; Lillehoj, Peter B.; Ho, Chih-Ming

    2010-01-01

    The detection of mismatched base pairs in DNA plays a crucial role in the diagnosis of genetic-related diseases and conditions, especially for early stage treatment. Among the various biosensors that have been employed for DNA detection, electrochemical sensors show great promise since they are capable of precise DNA recognition and efficient signal transduction. Advancements in micro- and nanotechnologies, specifically fabrication techniques and new nanomaterials, have enabled for the development of highly sensitive, highly specific sensors making them attractive for the detection of small sequence variations. Furthermore, the integration of sensors with sample preparation and fluidic processes enables for rapid, multiplexed DNA detection for point-of-care (POC) clinical diagnostics. PMID:20075759

  18. Synthesis and utilization of carbon nanotubes for fabrication of electrochemical biosensors

    SciTech Connect

    Lawal, Abdulazeez T.

    2016-01-15

    Graphical abstract: Carbon nanotubes. - Highlights: • This review discusses synthesis and applications of carbon nanotubes sensors. • The review summarizes contributions of carbon nanotube to electrochemical biosensor. • Good electrical conductivity makes carbon nanotubes a good material for biosensors. • Carbon nanotubes promotes electron transfer that aids biosensing of biomolecules. - Abstract: This review summarizes the most recent contributions in the fabrication of carbon nanotubes-based electrochemical biosensors in recent years. It discusses the synthesis and application of carbon nanotubes to the assembly of carbon nanotube-based electrochemical sensors, its analytical performance and future expectations. An increasing number of reviews and publications involving carbon nanotubes sensors have been reported ever since the first design of carbon nanotube electrochemical biosensors. The large surface area and good electrical conductivity of carbon nanotubes allow them to act as “electron wire” between the redox center of an enzyme or protein and an electrode's surface, which make them very excellent material for the design of electrochemical biosensors. Carbon nanotubes promote the different rapid electron transfers that facilitate accurate and selective detection of cytochrome-c, β-nicotinamide adenine dinucleotide, hemoglobin and biomolecules, such as glucose, cholesterol, ascorbic acid, uric acid, dopamine pesticides, metals ions and hydrogen peroxide.

  19. Electrochemical lectin based biosensors as a label-free tool in glycomics

    PubMed Central

    Bertók, Tomáš; Katrlík, Jaroslav; Gemeiner, Peter; Tkac, Jan

    2016-01-01

    Glycans and other saccharide moieties attached to proteins and lipids, or present on the surface of a cell, are actively involved in numerous physiological or pathological processes. Their structural flexibility (that is based on the formation of various kinds of linkages between saccharides) is making glycans superb “identity cards”. In fact, glycans can form more “words” or “codes” (i.e., unique sequences) from the same number of “letters” (building blocks) than DNA or proteins. Glycans are physicochemically similar and it is not a trivial task to identify their sequence, or - even more challenging - to link a given glycan to a particular physiological or pathological process. Lectins can recognise differences in glycan compositions even in their bound state and therefore are most useful tools in the task to decipher the “glycocode”. Thus, lectin-based biosensors working in a label-free mode can effectively complement the current weaponry of analytical tools in glycomics. This review gives an introduction into the area of glycomics and then focuses on the design, analytical performance, and practical utility of lectin-based electrochemical label-free biosensors for the detection of isolated glycoproteins or intact cells. PMID:27239071

  20. Immobilization Techniques in the Fabrication of Nanomaterial-Based Electrochemical Biosensors: A Review

    PubMed Central

    Putzbach, William; Ronkainen, Niina J.

    2013-01-01

    The evolution of 1st to 3rd generation electrochemical biosensors reflects a simplification and enhancement of the transduction pathway. However, in recent years, modification of the transducer with nanomaterials has become increasingly studied and imparts many advantages. The sensitivity and overall performance of enzymatic biosensors has improved tremendously as a result of incorporating nanomaterials in their fabrication. Given the unique and favorable qualities of gold nanoparticles, graphene and carbon nanotubes as applied to electrochemical biosensors, a consolidated survey of the different methods of nanomaterial immobilization on transducer surfaces and enzyme immobilization on these species is beneficial and timely. This review encompasses modification of enzymatic biosensors with gold nanoparticles, carbon nanotubes, and graphene. PMID:23580051

  1. Electrochemical biosensor with pH regulation of CNTs/HRP multilayer for phenols.

    PubMed

    Yang, Shaoming; Huang, Aihua; Jiang, Dan; Wei, Zhipeng; Zheng, Longzhen

    2011-01-01

    An amperometric horseradish peroxidase (HRP) biosensor based on multilayer films containing carbon nanotubes (CNTs) and HRP was developed. With the pH regulation of the dispersion solution of CNTs, the sensitivity of the HRP multilayer film biosensor is tunable by the control of the dissociation of CNTs. The successful formation of multilayers was confirmed by UV-visible spectroscopy. The features of multilayers were characterized by SEM and electrochemical impedance spectrum (EIS). The performance of the HRP biosensor is reported for the amperometric detection of phenols. The biosensor presented a linear response for catechol from 9.1 × 10(-8) - 6.45 × 10(-5) mol/L, with a sensitivity of 0.00554 A · L/mol and a detection limit of 8.5 × 10(-8) mol/L. The study can provide a feasible simple approach for developing a new sensitivity tunable method for CNTs-based biosensors.

  2. Electrochemical and optical biosensors based on nanomaterials and nanostructures: a review.

    PubMed

    Li, Ming; Li, Rui; Li, Chang Ming; Wu, Nianqiang

    2011-06-01

    Nanomaterials and nanostructures exhibit unique size-tunable and shape-dependent physicochemical properties that are different from those of bulk materials. Advances of nanomaterials and nanostructures open a new door to develop various novel biosensors. The present work has reviewed the recent progress in electrochemical, surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS) and fluorescent biosensors based on nanomaterials and nanostructures. An emphasis is put on the research that demonstrates how the performance of biosensors such as the limit of detection, sensitivity and selectivity is improved by the use of nanomaterials and nanostructures.

  3. Passive micromixers and organic electrochemical transistors for biosensor applications

    NASA Astrophysics Data System (ADS)

    Kanakamedala, Senaka Krishna

    Fluid handling at the microscale has greatly affected different fields such as biomedical, pharmaceutical, biochemical engineering and environmental monitoring due to its reduced reagent consumption, portability, high throughput, lower hardware cost and shorter analysis time compared to large devices. The challenges associated with mixing of fluids in microscale enabled us in designing, simulating, fabricating and characterizing various micromixers on silicon and flexible polyester substrates. The mixing efficiency was evaluated by injecting the fluids through the two inlets and collecting the sample at outlet. The images collected from the microscope were analyzed, and the absorbance of the color product at the outlet was measured to quantify the mixing efficacy. A mixing efficiency of 96% was achieved using a flexible disposable micromixer. The potential for low-cost processing and the device response tuning using chemical doping or synthesis opened doorways to use organic semiconductor devices as transducers in chemical and biological sensor applications. A simple, inexpensive organic electrochemical transistor (OECT) based on conducting polymer poly(3,4- ethyelenedioxythiphene) poly(styrene sulfonate) (PEDOT:PSS) was fabricated using a novel one step fabrication method. The developed transistor was used as a biosensor to detect glucose and glutamate. The developed glucose sensor showed a linear response for the glucose levels ranging from 1 muM-10 mM and showed a decent response for the glucose levels similar to those found in human saliva and to detect glutamate released from brain tumor cells. The developed glutamate sensor was used to detect the glutamate released from astrocytes and glioma cells after stimulation, and the results are compared with fluorescent spectrophotometer. The developed sensors employ simple fabrication, operate at low potentials, utilize lower enzyme concentrations, do not employ enzyme immobilization techniques, require only 5 muL of

  4. Microfabricated Electrochemical Cell-Based Biosensors for Analysis of Living Cells In Vitro

    PubMed Central

    Wang, Jun; Wu, Chengxiong; Hu, Ning; Zhou, Jie; Du, Liping; Wang, Ping

    2012-01-01

    Cellular biochemical parameters can be used to reveal the physiological and functional information of various cells. Due to demonstrated high accuracy and non-invasiveness, electrochemical detection methods have been used for cell-based investigation. When combined with improved biosensor design and advanced measurement systems, the on-line biochemical analysis of living cells in vitro has been applied for biological mechanism study, drug screening and even environmental monitoring. In recent decades, new types of miniaturized electrochemical biosensor are emerging with the development of microfabrication technology. This review aims to give an overview of the microfabricated electrochemical cell-based biosensors, such as microelectrode arrays (MEA), the electric cell-substrate impedance sensing (ECIS) technique, and the light addressable potentiometric sensor (LAPS). The details in their working principles, measurement systems, and applications in cell monitoring are covered. Driven by the need for high throughput and multi-parameter detection proposed by biomedicine, the development trends of electrochemical cell-based biosensors are also introduced, including newly developed integrated biosensors, and the application of nanotechnology and microfluidic technology. PMID:25585708

  5. A sensitive DNA capacitive biosensor using interdigitated electrodes.

    PubMed

    Wang, Lei; Veselinovic, Milena; Yang, Lang; Geiss, Brian J; Dandy, David S; Chen, Tom

    2017-01-15

    This paper presents a label-free affinity-based capacitive biosensor using interdigitated electrodes. Using an optimized process of DNA probe preparation to minimize the effect of contaminants in commercial thiolated DNA probe, the electrode surface was functionalized with the 24-nucleotide DNA probes based on the West Nile virus sequence (Kunjin strain). The biosensor has the ability to detect complementary DNA fragments with a detection limit down to 20 DNA target molecules (1.5aM range), making it suitable for a practical point-of-care (POC) platform for low target count clinical applications without the need for amplification. The reproducibility of the biosensor detection was improved with efficient covalent immobilization of purified single-stranded DNA probe oligomers on cleaned gold microelectrodes. In addition to the low detection limit, the biosensor showed a dynamic range of detection from 1µL(-1) to 10(5)µL(-1) target molecules (20 to 2 million targets), making it suitable for sample analysis in a typical clinical application environment. The binding results presented in this paper were validated using fluorescent oligomers.

  6. Fabrication of Electrochemical Model Influenza A Virus Biosensor Based on the Measurements of Neuroaminidase Enzyme Activity.

    PubMed

    Anik, Ülkü; Tepeli, Yudum; Diouani, Mohamed F

    2016-06-21

    Neuroaminidase (NA) enzyme is a kind of glycoprotein that is found on the influenza A virus. During infection, NA is important for the release of influenza virions from the host cell surface together with viral aggregates. It may also be involved in targeting the virus to respiratory epithelial cells. In this study, a model electrochemical influenza A viral biosensor in which receptor-binding properties have been based on NA was developed for the first time. The biosensor's working principle is based on monitoring the interactions between fetuin A and NA enzyme. The assay was monitored step by step by using electrochemical impedance spectroscopy.

  7. Mimicking enzymatic effects of cytochrome P450 by an efficient biosensor for in vitro detection of DNA damage.

    PubMed

    Jalalvand, Ali R; Gholivand, Mohammad-Bagher; Goicoechea, Hector C; Skov, Thomas; Mansouri, Kamran

    2015-08-01

    A novel biosensor for detecting DNA damage induced by benzo(a)pyrene (BP) and its metabolite was presented in this work. The nafion-solubilized single wall carbon nanotubes-ionic liquid (SWCNTs-NA-IL) composite film was prepared and then horseradish peroxidase (HRP) and double-stranded DNA were alternately assembled on the composite film by the layer-by-layer method. The biosensor was characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), scanning electron microscopy (SEM) and computational methods. UV-vis spectrophotometry was also used to investigate DNA damage induced by BP and its metabolites in solution. The DNA biosensor was treated separately in BP, hydrogen peroxide (H2O2) and in their mixture, respectively. The EIS analysis showed a decrease in the charge transfer resistance at the DNA/HRP/SWCNTs-NA-IL/GCE incubated in a mixture of HRP and H2O2, because HRP in the presence of H2O2 could mimic enzymatic effects of cytochrome P450 (CYP450) to metabolize BP which could cause significant DNA damage and the exposed DNA bases reduced the electrostatic repulsion of the negatively charged redox probe and leads to Faradaic impedance changes. Finally, a novel biosensor for BP determination was developed and this method provided an indirect, and quantitative estimation of DNA damage in vitro.

  8. A liquid-crystal-based DNA biosensor for pathogen detection

    NASA Astrophysics Data System (ADS)

    Khan, Mashooq; Khan, Abdur Rahim; Shin, Jae-Ho; Park, Soo-Young

    2016-03-01

    A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection.

  9. A liquid-crystal-based DNA biosensor for pathogen detection

    PubMed Central

    Khan, Mashooq; Khan, Abdur Rahim; Shin, Jae-Ho; Park, Soo-Young

    2016-01-01

    A liquid-crystal (LC)-filled transmission electron microscopy (TEM) grid cell coated with the cationic surfactant dodecyltrimethylammonium bromide (DTAB), to which a single-stranded deoxyribonucleic acid probe (ssDNAprobe) was adsorbed at the LC/aqueous interface (TEMDTAB/DNA), was applied for the highly specific detection of target DNA molecules. The DTAB-coated E7 (used LC mixture) in the TEM grid (TEMDTAB) exhibited a homeotropic orientation, and changed to a planar orientation upon adsorption of the ssDNAprobe. The TEMDTAB/DNA was then exposed to complementary (target) ssDNA, which resulted in a planar-to-homeotropic configurational change of E7 that could be observed through a polarized optical microscope under crossed polarizers. The optimum adsorption density (2 μM) of ssDNAprobe enabled the detection of ≥0.05 nM complementary ssDNA. This TEMDTAB/DNA biosensor could differentiate complementary ssDNA from mismatched ssDNA as well as double-stranded DNA. It also successfully detected the genomic DNAs of the bacterium Erwinia carotovora and the fungi Rhazictonia solani. Owe to the high specificity, sensitivity, and label-free detection, this biosensor may broaden the applications of LC-based biosensors to pathogen detection. PMID:26940532

  10. Improving the Stability and Sensing of Electrochemical Biosensors by Employing Trithiol-Anchoring Groups in a Six-carbon Self-assembled Monolayer

    PubMed Central

    Phares, Noelle; White, Ryan J.; Plaxco, Kevin W.

    2009-01-01

    Alkane thiol self-assembled monolayers (SAMs) have seen widespread utility in the fabrication of electrochemical biosensors. Their utility, however, reflects a potentially significant compromise. While shorter SAMs support efficient electron transfer, they pack poorly and are thus relatively unstable. Longer SAMs are more stable, but suffer from less efficient electron transfer, thus degrading sensor performance. Here we use the electrochemical DNA (E-DNA) sensor platform to compare the signaling and stability of biosensors fabricated using a short, six-carbon monothiol with those employing either of two commercially available, trihexylthiol anchors (a flexible Letsinger-type and a rigid adamantane type). We find that all three anchors support efficient electron transfer and E-DNA signaling, with the gain, specificity and selectivity of all three being effectively indistinguishable. The stabilities of the three anchors, however, vary significantly. Sensors anchored with the flexible trithiol exhibit enhanced stability, retaining 75% of their original signal and maintaining excellent signaling properties after 50 days storage in buffer. Likewise these sensors exhibit excellent temperature stability and robustness to electrochemical interrogation. The stability of sensors fabricated using the rigid trithiol anchor, by comparison, are similar to those of the monothiol. Both exhibit significant (>60%) loss of signal upon wet storage or thermocycling. Employing a flexible trithiol anchor in the fabrication of SAM-based electrochemical biosensors may provide a means of improving sensor robustness without sacrificing electron transfer efficiency or otherwise impeding sensor performance. PMID:19133790

  11. Fabrication strategies, sensing modes and analytical applications of ratiometric electrochemical biosensors.

    PubMed

    Jin, Hui; Gui, Rijun; Yu, Jianbo; Lv, Wei; Wang, Zonghua

    2017-05-15

    Previously developed electrochemical biosensors with single-electric signal output are probably affected by intrinsic and extrinsic factors. In contrast, the ratiometric electrochemical biosensors (RECBSs) with dual-electric signal outputs have an intrinsic built-in correction to the effects from system or background electric signals, and therefore exhibit a significant potential to improve the accuracy and sensitivity in electrochemical sensing applications. In this review, we systematically summarize the fabrication strategies, sensing modes and analytical applications of RECBSs. First, the different fabrication strategies of RECBSs were introduced, referring to the analytes-induced single- and dual-dependent electrochemical signal strategies for RECBSs. Second, the different sensing modes of RECBSs were illustrated, such as differential pulse voltammetry, square wave voltammetry, cyclic voltammetry, alternating current voltammetry, electrochemiluminescence, and so forth. Third, the analytical applications of RECBSs were discussed based on the types of target analytes. Finally, the forthcoming development and future prospects in the research field of RECBSs were also highlighted.

  12. Electrochemical DNA Hybridization Sensors Based on Conducting Polymers

    PubMed Central

    Rahman, Md. Mahbubur; Li, Xiao-Bo; Lopa, Nasrin Siraj; Ahn, Sang Jung; Lee, Jae-Joon

    2015-01-01

    Conducting polymers (CPs) are a group of polymeric materials that have attracted considerable attention because of their unique electronic, chemical, and biochemical properties. This is reflected in their use in a wide range of potential applications, including light-emitting diodes, anti-static coating, electrochromic materials, solar cells, chemical sensors, biosensors, and drug-release systems. Electrochemical DNA sensors based on CPs can be used in numerous areas related to human health. This review summarizes the recent progress made in the development and use of CP-based electrochemical DNA hybridization sensors. We discuss the distinct properties of CPs with respect to their use in the immobilization of probe DNA on electrode surfaces, and we describe the immobilization techniques used for developing DNA hybridization sensors together with the various transduction methods employed. In the concluding part of this review, we present some of the challenges faced in the use of CP-based DNA hybridization sensors, as well as a future perspective. PMID:25664436

  13. DETECTION OF DNA DAMAGE USING A FIBEROPTIC BIOSENSOR

    EPA Science Inventory

    A rapid and sensitive fiber optic biosensor assay for radiation-induced DNA damage is reported. For this assay, a biotin-labeled capture oligonucleotide (38 mer) was immobilized to an avidin-coated quartz fiber. Hybridization of a dye-labeled complementary sequence was observed...

  14. Enzyme-based electrochemical biosensors for determination of organophosphorus and carbamate pesticides

    SciTech Connect

    Everett, W.R.; Rechnitz, G.A.

    1999-01-01

    A mini review of enzyme-based electrochemical biosensors for inhibition analysis of organophosphorus and carbamate pesticides is presented. Discussion includes the most recent literature to present advances in detection limits, selectivity and real sample analysis. Recent reviews on the monitoring of pesticides and their residues suggest that the classical analytical techniques of gas and liquid chromatography are the most widely used methods of detection. These techniques, although very accurate in their determinations, can be quite time consuming and expensive and usually require extensive sample clean up and pro-concentration. For these and many other reasons, the classical techniques are very difficult to adapt for field use. Numerous researchers, in the past decade, have developed and made improvements on biosensors for use in pesticide analysis. This mini review will focus on recent advances made in enzyme-based electrochemical biosensors for the determinations of organophosphorus and carbamate pesticides.

  15. A silicon nanowire-based electrochemical glucose biosensor with high electrocatalytic activity and sensitivity

    NASA Astrophysics Data System (ADS)

    Su, Shao; He, Yao; Song, Shiping; Li, Di; Wang, Lihua; Fan, Chunhai; Lee, Shuit-Tong

    2010-09-01

    An electrochemical glucose biosensor was developed by immobilizing glucose oxidase (GOx) on an electrode decorated with a novel nanostructure, silicon nanowires (SiNWs) with in situ grown gold nanoparticles (AuNPs). The immobilized GOx displayed a pair of well-defined and quasi-reversible redox peaks with a formal potential (E°') of -0.376 V in a phosphate buffer solution. The fabricated glucose biosensor has good electrocatalytic activity toward oxidation of glucose. In addition, such resultant SiNWs-based glucose biosensor possesses high biological affinity. Particularly, the apparent Michaelis-Mentan constant was estimated to be 0.902 mM, which is much smaller than the reported values for GOx at a range of nanomaterials-incorporated electrodes. Consequently, this novel SiNWs-based biosensor is expected to be a promising tool for biological assays (e.g., monitoring blood glucose).

  16. Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms.

    PubMed

    Pilehvar, Sanaz; De Wael, Karolien

    2015-11-23

    Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing.

  17. Recent Advances in Electrochemical Biosensors Based on Fullerene-C60 Nano-Structured Platforms

    PubMed Central

    Pilehvar, Sanaz; De Wael, Karolien

    2015-01-01

    Nanotechnology is becoming increasingly important in the field of (bio)sensors. The performance and sensitivity of biosensors is greatly improved with the integration of nanomaterials into their construction. Since its first discovery, fullerene-C60 has been the object of extensive research. Its unique and favorable characteristics of easy chemical modification, conductivity, and electrochemical properties has led to its tremendous use in (bio)sensor applications. This paper provides a concise review of advances in fullerene-C60 research and its use as a nanomaterial for the development of biosensors. We examine the research work reported in the literature on the synthesis, functionalization, approaches to nanostructuring electrodes with fullerene, and outline some of the exciting applications in the field of (bio)sensing. PMID:26610583

  18. Electrochemical biosensing strategies for DNA methylation analysis.

    PubMed

    Hossain, Tanvir; Mahmudunnabi, Golam; Masud, Mostafa Kamal; Islam, Md Nazmul; Ooi, Lezanne; Konstantinov, Konstantin; Hossain, Md Shahriar Al; Martinac, Boris; Alici, Gursel; Nguyen, Nam-Trung; Shiddiky, Muhammad J A

    2017-02-17

    DNA methylation is one of the key epigenetic modifications of DNA that results from the enzymatic addition of a methyl group at the fifth carbon of the cytosine base. It plays a crucial role in cellular development, genomic stability and gene expression. Aberrant DNA methylation is responsible for the pathogenesis of many diseases including cancers. Over the past several decades, many methodologies have been developed to detect DNA methylation. These methodologies range from classical molecular biology and optical approaches, such as bisulfite sequencing, microarrays, quantitative real-time PCR, colorimetry, Raman spectroscopy to the more recent electrochemical approaches. Among these, electrochemical approaches offer sensitive, simple, specific, rapid, and cost-effective analysis of DNA methylation. Additionally, electrochemical methods are highly amenable to miniaturization and possess the potential to be multiplexed. In recent years, several reviews have provided information on the detection strategies of DNA methylation. However, to date, there is no comprehensive evaluation of electrochemical DNA methylation detection strategies. Herein, we address the recent developments of electrochemical DNA methylation detection approaches. Furthermore, we highlight the major technical and biological challenges involved in these strategies and provide suggestions for the future direction of this important field.

  19. Developing a high performance superoxide dismutase based electrochemical biosensor for radiation dosimetry of thallium 201

    NASA Astrophysics Data System (ADS)

    Salem, Fatemeh; Tavakoli, Hassan; Sadeghi, Mahdi; Riazi, Abbas

    2014-09-01

    To develop a new biosensor for measurement of superoxide free radical generated in radiolysis reaction, three combinations of SOD-based biosensors including Au/Cys/SOD, Au/GNP/Cys/SOD and Au/GNP/Cys/SOD/Chit were fabricated. In these biosensors Au, GNP, Cys, SOD and Chit represent gold electrode, gold nano-particles, cysteine, superoxide dismutase and chitosan, respectively. For biosensors fabrication, SOD, GNP, Cys and Chit were immobilized at the surface of gold electrode. Cyclic voltametry and chronoamperometry were utilized for evaluation of biosensors performances. The results showed that Au/GNP/Cys/SOD/Chit has significantly better responses compared to Au/Cys/SOD and Au/GNP/Cys/SOD. As a result, this biosensor was selected for dosimetry of ionizing radiation. For this purpose, thallium 201 at different volumes was added to buffer phosphate solution in electrochemical cell. To obtain analytical parameters of Au/GNP/Cys/SOD/Chit, calibration curve was sketched. The results showed that this biosensor has a linear response in the range from 0.5 to 4 Gy, detection limit 0.03 μM. It also has a proper sensitivity (0.6038 nA/Gy), suitable long term stability and cost effective as well as high function for radiation dosimetry.

  20. Detection of Aeromonas hydrophila DNA oligonucleotide sequence using a biosensor design based on Ceria nanoparticles decorated reduced graphene oxide and Fast Fourier transform square wave voltammetry.

    PubMed

    Jafari, Safiye; Faridbod, Farnoush; Norouzi, Parviz; Dezfuli, Amin Shiralizadeh; Ajloo, Davood; Mohammadipanah, Fatemeh; Ganjali, Mohammad Reza

    2015-10-01

    A new strategy was introduced for ssDNA immobilization on a modified glassy carbon electrode. The electrode surface was modified using polyaniline and chemically reduced graphene oxide decorated cerium oxide nanoparticles (CeO2NPs-RGO). A single-stranded DNA (ssDNA) probe was immobilized on the modified electrode surface. Fast Fourier transform square wave voltammetry (FFT-SWV) was applied as detection technique and [Ru(bpy)3](2+/3+) redox signal was used as electrochemical marker. The hybridization of ssDNA with its complementary target caused a dramatic decrease in [Ru(bpy)3](2+/3+) FFT-SW signal. The proposed electrochemical biosensor was able to detect Aeromonas hydrophila DNA oligonucleotide sequence encoding aerolysin protein. Under optimal conditions, the biosensor showed excellent selectivity toward complementary sequence in comparison with noncomplementary and two-base mismatch sequences. The dynamic linear range of this electrochemical DNA biosensor for detecting 20-mer oligonucleotide sequence of A. hydrophila was from 1 × 10(-15) to 1 × 10(-8) mol L(-1). The proposed biosensor was successfully applied for the detection of DNA extracted from A. hydrophila in fish pond water up to 0.01 μg mL(-1) with RSD of 5%. Besides, molecular docking was applied to consider the [Ru(bpy)3](2+/3+) interaction with ssDNA before and after hybridization.

  1. Electrochemical current rectification-a novel signal amplification strategy for highly sensitive and selective aptamer-based biosensor.

    PubMed

    Feng, Lingyan; Sivanesan, Arumugam; Lyu, Zhaozi; Offenhäusser, Andreas; Mayer, Dirk

    2015-04-15

    Electrochemical aptamer-based (E-AB) sensors represent an emerging class of recently developed sensors. However, numerous of these sensors are limited by a low surface density of electrode-bound redox-oligonucleotides which are used as probe. Here we propose to use the concept of electrochemical current rectification (ECR) for the enhancement of the redox signal of E-AB sensors. Commonly, the probe-DNA performs a change in conformation during target binding and enables a nonrecurring charge transfer between redox-tag and electrode. In our system, the redox-tag of the probe-DNA is continuously replenished by solution-phase redox molecules. A unidirectional electron transfer from electrode via surface-linked redox-tag to the solution-phase redox molecules arises that efficiently amplifies the current response. Using this robust and straight-forward strategy, the developed sensor showed a substantial signal amplification and consequently improved sensitivity with a calculated detection limit of 114nM for ATP, which was improved by one order of magnitude compared with the amplification-free detection and superior to other previous detection results using enzymes or nanomaterials-based signal amplification. To the best of our knowledge, this is the first demonstration of an aptamer-based electrochemical biosensor involving electrochemical rectification, which can be presumably transferred to other biomedical sensor systems.

  2. Characterization of immobilization methods of antiviral antibodies in serum for electrochemical biosensors

    NASA Astrophysics Data System (ADS)

    Huy, Tran Quang; Hanh, Nguyen Thi Hong; Van Chung, Pham; Anh, Dang Duc; Nga, Phan Thi; Tuan, Mai Anh

    2011-06-01

    In this paper, we describes different methods to immobilize Japanese encephalitis virus (JEV) antibodies in human serum onto the interdigitated surface of a microelectrode sensor for optimizing electrochemical detection: (1) direct covalent binding to the silanized surface, (2) binding to the silanized surface via a cross-linker of glutaraldehyde (GA), (3) binding to glutaraldehyde/silanized surface via goat anti-human IgG polyclonal antibody and (4) binding to glutaraldehyde/silanized surface via protein A (PrA). Field emission scanning electron microscopy, Fourier transform infrared spectrometry, and fluorescence microscopy are used to verify the characteristics of antibodies on the interdigitated surface after the serum antibodies immobilization. The analyzed results indicate that the use of protein A is an effective choice for immobilization and orientation of antibodies in serum for electrochemical biosensors. This study provides an advantageous immobilization method of serum containing antiviral antibodies to develop electrochemical biosensors for preliminary screening of viruses in clinical samples from outbreaks.

  3. A Review on the Electrochemical Sensors and Biosensors Composed of Nanowires as Sensing Material

    PubMed Central

    Yogeswaran, Umasankar; Chen, Shen-Ming

    2008-01-01

    The development and application of nanowires for electrochemical sensors and biosensors are reviewed in this article. Next generation sensor platforms will require significant improvements in sensitivity, specificity and parallelism in order to meet the future needs in variety of fields. Sensors made of nanowires exploit some fundamental nanoscopic effect in order to meet these requirements. Nanowires are new materials, which have the characteristic of low weight with extraordinary mechanical, electrical, thermal and multifunctional properties. The advantages such as size scale, aspect ratio and other properties of nanowires are especially apparent in the use of electrical sensors such as electrochemical sensors and in the use of field-effect transistors. The preparation methods of nanowires and their properties are discussed along with their advantages towards electrochemical sensors and biosensors. Some key results from each article are summarized, relating the concept and mechanism behind each sensor, with experimental conditions as well as their behavior at different conditions. PMID:27879709

  4. Carbon Nanotubes (CNTs) for the Development of Electrochemical Biosensors

    SciTech Connect

    Lin, Yuehe; Yantasee, Wassana; Wang, Joseph

    2005-01-01

    Carbon nanotube (CNT) is a very attractive material for the development of biosensors because of its capability to provide strong electrocatalytic activity and minimize surface fouling of the sensors. This article reviews our recent developments of oxidase- and dehydrogenase-amperometric biosensors based on the immobilization of CNTs, the co-immobilization of enzymes on the CNTs/Nafion or the CNT/Teflon composite materials, or the attachment of enzymes on the controlled-density aligned CNT-nanoelectrode arrays. The excellent electrocatalytic activities of the CNTs on the redox reactions of hydrogen peroxide, nicotinamide adenine dinucleotide (NADH), and homocysteine have been demonstrated. Successful applications of the CNT-based biosensors reviewed herein include the low-potential detections of glucose, organophosphorus compounds, and alcohol.

  5. Detection of parathyroid hormone using an electrochemical impedance biosensor based on PAMAM dendrimers.

    PubMed

    Özcan, Hakkı Mevlüt; Sezgintürk, Mustafa Kemal

    2015-01-01

    This paper presents a novel hormone-based impedimetric biosensor to determine parathyroid hormone (PTH) level in serum for diagnosis and monitoring treatment of hyperparathyroidism, hypoparathyroidism and thyroid cancer. The interaction between PTH and the biosensor was investigated by an electrochemical method. The biosensor was based on the gold electrode modified by 12-mercapto dodecanoic (12MDDA). Antiparathyroid hormone (anti-PTH) was covalently immobilized on to poly amidoamine dendrimer (PAMAM) which was bound to a 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide (EDC/NHS) couple, self-assembled monolayer structure from one of the other NH2 sites. The immobilization of anti-PTH was monitored by electrochemical impedance spectroscopy, cyclic voltammetry and scanning electron microscope techniques. After the optimization studies of immobilization materials such as 12MDDA, EDC-NHS, PAMAM, and glutaraldehyde, the performance of the biosensor was investigated in terms of linearity, sensitivity, repeatability, and reproducibility. PTH was detected within a linear range of 10-60 fg/mL. Finally the described biosensor was used to monitor PTH levels in artificial serum samples.

  6. A fully integrated electrochemical biosensor platform fabrication process for cytokines detection.

    PubMed

    Baraket, Abdoullatif; Lee, Michael; Zine, Nadia; Sigaud, Monique; Bausells, Joan; Errachid, Abdelhamid

    2017-07-15

    Interleukin-1b (IL-1b) and interleukin-10 (IL-10) biomarkers are one of many antigens that are secreted in acute stages of inflammation after left ventricle assisted device (LVAD) implantation for patients suffering from heart failure (HF). In the present study, we have developed a fully integrated electrochemical biosensor platform for cytokine detection at minute concentrations. Using eight gold working microelectrodes (WEs) the design will increase the sensitivity of detection, decrease the time of measurements, and allow a simultaneous detection of varying cytokine biomarkers. The biosensor platform was fabricated onto silicon substrates using silicon technology. Monoclonal antibodies (mAb) of anti-human IL-1b and anti-human IL-10 were electroaddressed onto the gold WEs through functionalization with 4-carboxymethyl aryl diazonium (CMA). Cyclic voltammetry (CV) was applied during the WE functionalization process to characterize the gold WE surface properties. Finally, electrochemical impedance spectroscopy (EIS) characterized the modified gold WE. The biosensor platform was highly sensitive to the corresponding cytokines and no interference with other cytokines was observed. Both cytokines: IL-10 and IL-1b were detected within the range of 1pgmL(-1) to 15pgmL(-1). The present electrochemical biosensor platform is very promising for multi-detection of biomolecules which can dramatically decrease the time of analysis. This can provide data to clinicians and doctors concerning cytokines secretion at minute concentrations and the prediction of the first signs of inflammation after LVAD implantation.

  7. Conducting polymer based DNA biosensor for the detection of the Bacillus cereus group species

    NASA Astrophysics Data System (ADS)

    Velusamy, Vijayalakshmi; Arshak, Khalil; Korostynska, Olga; Oliwa, Kamila; Adley, Catherine

    2009-05-01

    Biosensor designs are emerging at a significant rate and play an increasingly important role in foodborne pathogen detection. Conducting polymers are excellent tools for the fabrication of biosensors and polypyrrole has been used in the detection of biomolecules due to its unique properties. The prime intention of this paper was to pioneer the design and fabrication of a single-strand (ss) DNA biosensor for the detection of the Bacillus cereus (B.cereus) group species. Growth of B. cereus, results in production of several highly active toxins. Therefore, consumption of food containing >106 bacteria/gm may results in emetic and diarrhoeal syndromes. The most common source of this bacterium is found in liquid food products, milk powder, mixed food products and is of particular concern in the baby formula industry. The electrochemical deposition technique, such as cyclic voltammetry, was used to develop and test a model DNA-based biosensor on a gold electrode electropolymerized with polypyrrole. The electrically conducting polymer, polypyrrole is used as a platform for immobilizing DNA (1μg) on the gold electrode surface, since it can be more easily deposited from neutral pH aqueous solutions of pyrrolemonomers. The average current peak during the electrodeposition event is 288μA. There is a clear change in the current after hybridization of the complementary oligonucleotide (6.35μA) and for the noncomplementary oligonucleotide (5.77μA). The drop in current after each event was clearly noticeable and it proved to be effective.

  8. A Graphene and Aptamer Based Liquid Gated FET-Like Electrochemical Biosensor to Detect Adenosine Triphosphate.

    PubMed

    Mukherjee, Souvik; Meshik, Xenia; Choi, Min; Farid, Sidra; Datta, Debopam; Lan, Yi; Poduri, Shripriya; Sarkar, Ketaki; Baterdene, Undarmaa; Huang, Ching-En; Wang, Yung Yu; Burke, Peter; Dutta, Mitra; Stroscio, Michael A

    2015-12-01

    Here we report successful demonstration of a FET-like electrochemical nano-biosensor to accurately detect ultralow concentrations of adenosine triphosphate. As a 2D material, graphene is a promising candidate due to its large surface area, biocompatibility, and demonstrated surface binding chemistries and has been employed as the conducting channel. A short 20-base DNA aptamer is used as the sensing element to ensure that the interaction between the analyte and the aptamer occurs within the Debye length of the electrolyte (PBS). Significant increase in the drain current with progressive addition of ATP is observed whereas for control experiments, no distinct change in the drain current occurs. The sensor is found to be highly sensitive in the nanomolar (nM) to micromolar ( μM) range with a high sensitivity of 2.55 μA (mM) (-1), a detection limit as low as 10 pM, and it has potential application in medical and biological settings to detect low traces of ATP. This simplistic design strategy can be further extended to efficiently detect a broad range of other target analytes.

  9. Comparison of impedimetric detection of DNA hybridization on the various biosensors based on modified glassy carbon electrodes with PANHS and nanomaterials of RGO and MWCNTs.

    PubMed

    Benvidi, Ali; Tezerjani, Marzieh Dehghan; Jahanbani, Shahriar; Mazloum Ardakani, Mohammad; Moshtaghioun, Seyed Mohammad

    2016-01-15

    In this research, we have developed lable free DNA biosensors based on modified glassy carbon electrodes (GCE) with reduced graphene oxide (RGO) and carbon nanotubes (MWCNTs) for detection of DNA sequences. This paper compares the detection of BRCA1 5382insC mutation using independent glassy carbon electrodes (GCE) modified with RGO and MWCNTs. A probe (BRCA1 5382insC mutation detection (ssDNA)) was then immobilized on the modified electrodes for a specific time. The immobilization of the probe and its hybridization with the target DNA (Complementary DNA) were performed under optimum conditions using different electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The proposed biosensors were used for determination of complementary DNA sequences. The non-modified DNA biosensor (1-pyrenebutyric acid-N- hydroxysuccinimide ester (PANHS)/GCE), revealed a linear relationship between ∆Rct and logarithm of the complementary target DNA concentration ranging from 1.0×10(-16)molL(-1) to 1.0×10(-10)mol L(-1) with a correlation coefficient of 0.992, for DNA biosensors modified with multi-wall carbon nanotubes (MWCNTs) and reduced graphene oxide (RGO) wider linear range and lower detection limit were obtained. For ssDNA/PANHS/MWCNTs/GCE a linear range 1.0×10(-17)mol L(-1)-1.0×10(-10)mol L(-1) with a correlation coefficient of 0.993 and for ssDNA/PANHS/RGO/GCE a linear range from 1.0×10(-18)mol L(-1) to 1.0×10(-10)mol L(-1) with a correlation coefficient of 0.985 were obtained. In addition, the mentioned biosensors were satisfactorily applied for discriminating of complementary sequences from noncomplementary sequences, so the mentioned biosensors can be used for the detection of BRCA1-associated breast cancer.

  10. Universal Dynamic DNA Assembly-Programmed Surface Hybridization Effect for Single-Step, Reusable, and Amplified Electrochemical Nucleic Acid Biosensing.

    PubMed

    Liu, Shufeng; Fang, Li; Wang, Yanqun; Wang, Li

    2017-03-07

    The traditional sensitive electrochemical biosensors are commonly confronted with the cumbersome interface operation and washing procedures and the inclusion of extra exogenous reagents, which impose the challenge on the detection simplicity, reliability, and reusability. Herein, we present the proof-of-principle of a unique biosensor architecture based on dynamic DNA assembly programmed surface hybridization, which confers the single-step, reusable, and enzyme-free amplified electrochemical nucleic acid analysis. To demonstrate the fabrication universality three dynamic DNA assembly strategies including DNA-fueled target recycling, catalytic hairpin DNA assembly, and hybridization chain reaction were flexibly harnessed to convey the homogeneous target recognition and amplification events into various DNA scaffolds for the autonomous proximity-based surface hybridization. The current biosensor architecture features generalizability, simplicity, low cost, high sensitivity, and specificity over the traditional nucleic acid-related amplified biosensors. The lowest detection limit of 50 aM toward target DNA could be achieved by hybridization chain reaction-programmed surface hybridization. The reliable working ability for both homogeneous solution and heterogeneous inteface facilitates the target analysis with a robust reliability and reproducibility, also making it to be readily extended for the integration with the kinds of detecting platforms. Thus, it may hold great potential for the biosensor fabrication served for the point-of-care applications in resource constrained regions.

  11. An electrochemical biosensor for double-stranded Wnt7B gene detection based on enzymatic isothermal amplification.

    PubMed

    Li, Junlong; Chen, Zhongping; Xiang, Yu; Zhou, Lili; Wang, Ting; Zhang, Zhang; Sun, Kexin; Yin, Dan; Li, Yi; Xie, Guoming

    2016-12-15

    Wnt7B gene plays an important role in the development and progression of breast cancer, gastric cancer, esophageal cancer and pancreatic cancer. While, the natural state of DNA is double stranded, which makes it difficult to be directly detected. Here, we develop an electrochemical biosensor method for Wnt7B gene detection without the need to denature the target. This method firstly used nicking enzyme for exploiting in the double-stranded DNA (dsDNA). Then, long single-stranded DNA (ssDNA) was generated from the cutting site through polymerase extension reaction. Whereafter, the long ssDNA triggered a hairpin self-assembly recycling reaction, which gave rise to another isothermal amplification reaction. Last, short ssDNA was formed after the this amplification process, which could hybridize with the capture probe immobilized on Au electrode and result in signal variation. This method showed excellent analytical performance for dsDNA, of which the linear range was 2fM to 500pM and the detection limit was 1.6fM (S/N=3). It also showed an good results when applied to the real sample of Wnt7B gene detection.

  12. A novel GMO biosensor for rapid ultrasensitive and simultaneous detection of multiple DNA components in GMO products.

    PubMed

    Huang, Lin; Zheng, Lei; Chen, Yinji; Xue, Feng; Cheng, Lin; Adeloju, Samuel B; Chen, Wei

    2015-04-15

    Since the introduction of genetically modified organisms (GMOs), there has been on-going and continuous concern and debates on the commercialization of products derived from GMOs. There is an urgent need for development of highly efficient analytical methods for rapid and high throughput screening of GMOs components, as required for appropriate labeling of GMO-derived foods, as well as for on-site inspection and import/export quarantine. In this study, we describe, for the first time, a multi-labeling based electrochemical biosensor for simultaneous detection of multiple DNA components of GMO products on the same sensing interface. Two-round signal amplification was applied by using both an exonuclease enzyme catalytic reaction and gold nanoparticle-based bio-barcode related strategies, respectively. Simultaneous multiple detections of different DNA components of GMOs were successfully achieved with satisfied sensitivity using this electrochemical biosensor. Furthermore, the robustness and effectiveness of the proposed approach was successfully demonstrated by application to various GMO products, including locally obtained and confirmed commercial GMO seeds and transgenetic plants. The proposed electrochemical biosensor demonstrated unique merits that promise to gain more interest in its use for rapid and on-site simultaneous multiple screening of different components of GMO products.

  13. Electrochemical H2O2 biosensor composed of myoglobin on MoS2 nanoparticle-graphene oxide hybrid structure.

    PubMed

    Yoon, Jinho; Lee, Taek; Bapurao G, Bharate; Jo, Jinhee; Oh, Byung-Keun; Choi, Jeong-Woo

    2017-07-15

    In this research, the electrochemical biosensor composed of myoglobin (Mb) on molybdenum disulfide nanoparticles (MoS2 NP) encapsulated with graphene oxide (GO) was fabricated for the detection of hydrogen peroxide (H2O2). Hybrid structure composed of MoS2 NP and GO (GO@MoS2) was fabricated for the first time to enhance the electrochemical signal of the biosensor. As a sensing material, Mb was introduced to fabricate the biosensor for H2O2 detection. Formation and immobilization of GO@MoS2 was confirmed by transmission electron microscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and scanning tunneling microscopy. Immobilization of Mb, and electrochemical property of biosensor were investigated by cyclic voltammetry and amperometric i-t measurements. Fabricated biosensor showed the electrochemical signal enhanced redox current as -1.86μA at an oxidation potential and 1.95μA at a reduction potential that were enhanced relative to those of electrode prepared without GO@MoS2. Also, this biosensor showed the reproducibility of electrochemical signal, and retained the property until 9 days from fabrication. Upon addition of H2O2, the biosensor showed enhanced amperometric response current with selectivity relative to that of the biosensor prepared without GO@MoS2. This novel hybrid material-based biosensor can suggest a milestone in the development of a highly sensitive detecting platform for biosensor fabrication with highly sensitive detection of target molecules other than H2O2.

  14. Development and Electrochemical Investigations of an EIS- (Electrolyte-Insulator-Semiconductor) based Biosensor for Cyanide Detection

    PubMed Central

    Turek, Monika; Ketterer, Lothar; Claβen, Melanie; Berndt, Heinz K.; Elbers, Gereon; Krüger, Peter; Keusgen, Michael; Schöning, Michael J.

    2007-01-01

    A cyanide biosensor based on a pH-sensitive p-doped electrolyte-insulator-semiconductor (EIS) structure with an immobilised enzyme (cyanidase) is realised at the laboratory scale. The immobilisation of the cyanidase is performed in two distinct steps: first, the covalent coupling of cyanidase to an N-hydroxysuccinimide- (NHS) activated Sepharose™ gel and then, the physical entrapment of NHS-activated Sepharose™ with the immobilised cyanidase in a dialysis membrane onto the EIS structure. The immobilisation of the cyanidase to the NHS-activated Sepharose™ is studied by means of gel electrophoresis measurements and investigations using an ammonia- (NH3) selective electrode. For the electrochemical characterisation of the cyanide biosensor, capacitance/voltage and constant capacitance measurements, respectively, have been carried out. A differential measurement procedure is presented to evaluate the cyanide concentration-dependent biosensor signals.

  15. Acetylcholinesterase Biosensors for Electrochemical Detection of Organophosphorus Compounds: A Review

    PubMed Central

    Dhull, Vikas; Gahlaut, Anjum; Dilbaghi, Neeraj

    2013-01-01

    The exponentially growing population, with limited resources, has exerted an intense pressure on the agriculture sector. In order to achieve high productivity the use of pesticide has increased up to many folds. These pesticides contain organophosphorus (OP) toxic compounds which interfere with the proper functioning of enzyme acetylcholinesterase (AChE) and finally affect the central nervous system (CNS). So, there is a need for routine, continuous, on spot detection of OP compounds which are the main limitations associated with conventional analytical methods. AChE based enzymatic biosensors have been reported by researchers as the most promising tool for analysis of pesticide level to control toxicity and for environment conservation. The present review summarises AChE based biosensors by discussing their characteristic features in terms of fabrication, detection limit, linearity range, time of incubation, and storage stability. Use of nanoparticles in recently reported fabrication strategies has improved the efficiency of biosensors to a great extent making them more reliable and robust. PMID:24383001

  16. Increased electrocatalyzed performance through hairpin oligonucleotide aptamer-functionalized gold nanorods labels and graphene-streptavidin nanomatrix: Highly selective and sensitive electrochemical biosensor of carcinoembryonic antigen.

    PubMed

    Wen, Wei; Huang, Jing-Yi; Bao, Ting; Zhou, Jun; Xia, Hong-Xing; Zhang, Xiu-Hua; Wang, Sheng-Fu; Zhao, Yuan-Di

    2016-09-15

    We report a triplex signal amplification strategy for sensitive biosensing of cancer biomarker by taking advantage of hairpin-shaped oligonucleotide-functionalized gold nanorods (HO-GNRs), graphene and the avidin-biotin reation. The strategy expands electrochemical detection of carcinoembryonic antigen (CEA) by using an aptamer as biosensor's recognition element and HO-GNRs as signal enhancer. To construct this biosensor, the GNR was used as a carrier of horseradish peroxidase (HRP) and HO aptamer with a biotin at the 3'-end and a thiol at the 5'-end, which amplified the electrochemical response because of a large molar ratio of HRP to HO. In the presence of target CEA, the binding reactions of CEA with the loop portions of the HOs caused HOs' loop-stem structure opened and exposed the biotins, and then HRP-GNRs-HO conjugates were captured on graphene and streptavidin modified electrodes via the reaction between the exposed biotins and preimmobilized streptavidins. The accumulation of HRP effectively catalyzed the hydrogen peroxide-mediated oxidation of o-phenylenediamine to generate an electrochemical reduction current for CEA detection. Under optimal conditions, the electrochemical biosensor exhibited a wide dynamic range of 5pgmL(-1) and 50ngmL(-1) toward CEA standards with a low detection limit of 1.5pgmL(-1) (signal-to-noise ratio of 3). The proposed biosensor accurately detected CEA concentration in 8 human serum samples from patients with lung diseases, showing excellent correlations with standard chemiluminescence immunoassay. Furthermore, these results of target DNA detection made it abundantly clear that the proposed strategy can also be extended for detection of other relative biomarkers using different functional DNA structures, which shows great prospects in single-nucleotide polymorphisms analysis, biomedical sensing and application for accurate clinical diseases diagnostic.

  17. Label-Free Electrochemical Biosensor for Monitoring of Chloride Ion in an Animal Model of Alzhemier's Disease.

    PubMed

    Dong, Hui; Zhang, Limin; Liu, Wei; Tian, Yang

    2017-02-15

    The potential damage of Alzheimer's disease (AD) in brain function has attracted extensive attention. As the most common anion, Cl(-) has been indicated to play significant roles in brain diseases, particularly in the pathological process of AD. In this work, a label-free selective and accurate electrochemical biosensor was first developed for real-time monitoring of Cl(-) levels in a mouse brain model of AD and rat brain upon global cerebral ischemia. Silver nanoparticles (AgNPs) were designed and synthesized as selective recognition element for Cl(-), while 5'-MB-GGCGCGATTTT-SH-3' (SH-DNA-MB, MB = methylene blue) was selected as an inner reference molecule for a built-in correction to avoid the effects from the complicated brain. The electrochemical biosensor showed high accuracy and remarkable selectivity for determination of Cl(-) over other anions, metal ions, amino acids, and other biomolecules. Furthermore, three-dimensional nanostructures composed of single-walled carbon nanotubes (SWNTs) and Au nanoleaves were assembled on the carbon fiber microelectrode (CFME) surface to enhance the response signal. Finally, the developed biosensor with high analytical performance, as well as the unique characteristic of CFME itself including inertness in live brain and good biocompatibility, was successfully applied to in vivo determination of Cl(-) levels in three brain regions: striatum, hippocampus, and cortex of live mouse and rat brains. The comparison of average levels of Cl(-) in normal striatum, hippocampus, and cortex of normal mouse brains and those in the mouse model brains of AD was reported. In addition, the results in rat brains followed by cerebral ischemia demonstrated that the concentrations of Cl(-) decreased by 19.8 ± 0.5% (n = 5) in the striatum and 27.2 ± 0.3% (n = 5) in hippocampus after cerebral ischemia for 30 min, but that negligible change in Cl(-) concentration was observed in cortex.

  18. A lactate electrochemical biosensor with a titanate nanotube as direct electron transfer promoter

    NASA Astrophysics Data System (ADS)

    Yang, Mingli; Wang, Jin; Li, Huaqing; Zheng, Jian-Guo; Wu, Nianqiang Nick

    2008-02-01

    Hydrogen titanate (H2Ti3O7) nanotubes (TNTs) have been synthesized by a one-step hydrothermal processing. Lactate oxidase (LOx) enzyme has been immobilized on the three-dimensional porous TNT network to make an electrochemical biosensor for lactate detection. Cyclic voltammetry and amperometry tests reveal that the LOx enzyme, which is supported on TNTs, maintains their substrate-specific catalytic activity. The nanotubes offer the pathway for direct electron transfer between the electrode surface and the active redox centers of LOx, which enables the biosensor to operate at a low working potential and to avoid the influence of the presence of O2 on the amperometric current response. The biosensor exhibits a sensitivity of 0.24 µA cm-2 mM-1, a 90% response time of 5 s, and a linear response in the range from 0.5 to 14 mM and the redox center of enzyme obviates the need of redox mediators for electrochemical enzymatic sensors, which is attractive for the development of reagentless biosensors.

  19. DNA-based biosensors for Hg(2+) determination by polythymine-methylene blue modified electrodes.

    PubMed

    Tortolini, Cristina; Bollella, Paolo; Antonelli, Marta Letizia; Antiochia, Riccarda; Mazzei, Franco; Favero, Gabriele

    2015-05-15

    In this work we have developed a new electrochemical DNA-based biosensor for the selective determination of the Hg(2+) ion by the use of different electrodes modified with polythymine, bearing methylene blue, as redox probe, in 3' position. The determination of Hg(2+) can be employed with an excellent degree of selectivity by the use of DNA biosensors through the formation of the complex Thymine-Hg-Thymine (T-Hg-T): in fact, Hg(2+) tends to bind two thymines, generating a T-Hg-T complex with a formation constant higher than that one of the coupling Adenine-Thymine, which can be employed for a selective, fast and cost-effective Hg(2+) detection. The presence of the Hg(2+) in solution leads to the formation of T-Hg-T complex thus causing the "hairpin-like" folding of oligonucleotide, leading to an improved electronic exchange of methylene blue with the electrode surface due to the reduced distance and thus to an increase of the faradic current which is detected by means of square wave voltammetry (SWV). To test the feasibility of this kind of biosensor to be applied to the analysis of Hg(2+) we have developed several biosensors configuration by modifying the electrochemical sensor transducer: (a) Au electrode; (b) Au screen-printed electrode (SPE). The proposed system, allows the determination of Hg(2+) in the range 0.2-100 nM (0.05-20 ppb), with a sensitivity 0.327 µA/nM, LOD 0.1 nM (0.02 ppb), LOQ 0.2 nM (0.05 ppb) and RSD ≤4.3% when Au electrode is used as electrochemical transducer; on the other hand, in the case of Au SPE the linear range is 0.2-50 nM (0.05-10 ppb), with a sensitivity 0.285 µA/nM, while LOD and LOQ are the same as previously and RSD is ≤3.8%. This enabled the detection of mercury in real samples (waters and fishes) with good accuracy (recoveries 92-101% on waters and 92-107% on fishes, respectively) and reproducibility (RSD ≤9.6% for measurements on waters and ≤8.8% on fishes, respectively).

  20. Facile Fabrication of 3D Layer-by-layer Graphene-gold Nanorod Hybrid Architecture for Hydrogen Peroxide Based Electrochemical Biosensor

    DTIC Science & Technology

    2015-01-01

    Facile fabrication of 3D layer-by-layer graphene-gold nanorod hybrid architecture for hydrogen peroxide based electrochemical biosensor Chenming Xue...the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). 1. Introduction Electrochemical biosensors are highly effective in...measurement techniques such as radioisotope tracing, NMR spectroscopy, and microfluorometry assay [12,25,18]. In recent years, electrochemical biosensors

  1. Zwitterionic peptide anchored to conducting polymer PEDOT for the development of antifouling and ultrasensitive electrochemical DNA sensor.

    PubMed

    Wang, Guixiang; Han, Rui; Su, Xiaoli; Li, Yinan; Xu, Guiyun; Luo, Xiliang

    2017-06-15

    Zwitterionic peptides were anchored to a conducting polymer of citrate doped poly(3,4-ethylenedioxythiophene) (PEDOT) via the nickel cation coordination, and the obtained peptide modified PEDOT, with excellent antifouling ability and good conductivity, was further used for the immobilization of a DNA probe to construct an electrochemical biosensor for the breast cancer marker BRCA1. The DNA biosensor was highly sensitive (with detection limit of 0.03fM) and selective, and it was able to detect BRCA1 in 5% (v/v) human plasma with satisfying accuracy and low fouling. The marriage of antifouling and biocompatible peptides with conducting polymers opened a new avenue to construct electrochemical biosensors capable of assaying targets in complex biological media with high sensitivity and without biofouling.

  2. Flexible organic electrochemical transistors for highly selective enzyme biosensors and used for saliva testing.

    PubMed

    Liao, Caizhi; Mak, Chunhin; Zhang, Meng; Chan, Helen L W; Yan, Feng

    2015-01-27

    Flexible organic electrochemical transistors (OECTs) are successfully used as high-performance enzyme biosensors, such as uric acid (UA) and cholesterol sensors. The sensitivity and selectivity of the sensors can be simultaneously enhanced by co-modifying the gate electrodes with positively/negatively charged bilayer polymer films and enzymes. These OECT-based UA sensors are successfully utilized for non-invasive UA detection in human saliva.

  3. Development of electrochemical biosensor for detection of pathogenic microorganism in Asian dust events.

    PubMed

    Yoo, Min-Sang; Shin, Minguk; Kim, Younghun; Jang, Min; Choi, Yoon-E; Park, Si Jae; Choi, Jonghoon; Lee, Jinyoung; Park, Chulhwan

    2017-05-01

    We developed a single-walled carbon nanotubes (SWCNTs)-based electrochemical biosensor for the detection of Bacillus subtilis, one of the microorganisms observed in Asian dust events, which causes respiratory diseases such as asthma and pneumonia. SWCNTs plays the role of a transducer in biological antigen/antibody reaction for the electrical signal while 1-pyrenebutanoic acid succinimidyl ester (1-PBSE) and ant-B. subtilis were performed as a chemical linker and an acceptor, respectively, for the adhesion of target microorganism in the developed biosensor. The detection range (10(2)-10(10) CFU/mL) and the detection limit (10(2) CFU/mL) of the developed biosensor were identified while the response time was 10 min. The amount of target B. subtilis was the highest in the specificity test of the developed biosensor, compared with the other tested microorganisms (Staphylococcus aureus, Flavobacterium psychrolimnae, and Aquabacterium commune). In addition, target B. subtilis detected by the developed biosensor was observed by scanning electron microscope (SEM) analysis.

  4. Zinc oxide nanowires-based electrochemical biosensor for L-lactic acid amperometric detection

    NASA Astrophysics Data System (ADS)

    Zhao, Yanguang; Yan, Xiaoqin; Kang, Zhuo; Fang, Xiaofei; Zheng, Xin; Zhao, Lanqing; Du, Hongwu; Zhang, Yue

    2014-05-01

    In this work, zinc oxide (ZnO) nanowires-based electrochemical biosensor is designed and fabricated for the detection of L-lactic acid. ZnO nanowires were successfully synthesized via the chemical vapor deposition method. The morphology and structure of the prepared products were characterized, and the average diameter of synthesized ZnO samples was 500 nm. The fluorescence characterization was performed to verify the immobilization of lactate oxidase onto the ZnO surface. Biosensors based on large-area ZnO nanowires were then constructed, and a series of electrochemical experiments showed that ZnO could provide the efficient electron transfer channel between the enzymic active sites and the electrode surface. The proposed electrochemical biosensor exhibited a sensitivity of 15.6 µA cm-2 mM-1, a wide linear range of 12 µM-1.2 mM with a low-detection limit of 12 µM for L-lactic acid detection. This study has indicated the potential applications for ZnO nanowires to construct the simple and economic nano-bio devices for the detection of biological species.

  5. Biosensors.

    ERIC Educational Resources Information Center

    Rechnitz, Garry A.

    1988-01-01

    Describes theory and principles behind biosensors that incorporate biological components as part of a sensor or probe. Projects major applications in medicine and veterinary medicine, biotechnology, food and agriculture, environmental studies, and the military. Surveys current use of biosensors. (ML)

  6. Influence of different nanoparticles on electrochemical behavior of glucose biosensor

    NASA Astrophysics Data System (ADS)

    Nenkova, R. D.; Ivanov, Y. L.; Godjevargova, T. I.

    2017-02-01

    The influence of nanosized particles on the glucose oxidase loading and the performance of amperometric glucose bionsensors were studied. Four enzyme electrodes (Pt/PAN/GOD, Pt/PAN/NZ/GOD, Pt/PAN/NZ/MNP/GOD, Pt/PAN/NZ/MWNT/GOD) were prepared by cross-linking of glucose oxidase (GOD) on nanocomposite material. Nanocomposites were prepared by entrapping nanozeolite (NZ), multiwalled carbon nanotubes (MWNT) and magnetic nanoparticles (MNP) in polyacrylonitrile (PAN) film. Cyclic voltammetric kinetic studies have been carried out with the four biosensors and the surface concentration of the adsorbed electroactive species on the electrodes was estimated. The highest enzyme concentration on the electrode surface corresponded to the electrodes prepared by nanozeolite separate (Pt/PAN/NZ/GOD) and combined with multi-walled carbon nanotubes (Pt/PAN/NZ/MWNT/GOD). The sensitivity of these two biosensors was the highest and that is in accordance with the greater amount of the adsorbed electroactive species on the electrodes (0.373 mol.cm-2). This was indication that a good synergistic effect happened when MWNTs and NZ were combined and these greatly improve the electron transfer ability of the sensor interface. Amperometric measurement of the two glucose oxidase electrodes (Pt/PAN/NZ/GOD and Pt/PAN/NZ/MWNT/GOD) with best results was carried out. The linear concentration interval of the Pt/PAN/NZ/MWNT/GOD biosensor was up to 3 mM, the detection limit - 0.02 mM glucose and the storage stability - 81% of its initial current response after 30 days.

  7. Gallium nitride electrodes for membrane-based electrochemical biosensors

    NASA Astrophysics Data System (ADS)

    Schubert, T.; Steinhoff, G.; von Ribbeck, H.-G.; Stutzmannn, M.; Eickhoff, M.; Tanaka, M.

    2009-10-01

    We report on the deposition of planar lipid bilayers (supported membranes) on gallium nitride (GaN) electrodes for potential applications as membrane-based biosensors. The kinetics of the lipid membrane formation upon vesicle fusion were monitored by simultaneous measurements of resistance and capacitance of the membrane using AC impedance spectroscopy in the frequency range between 50mHz and 50kHz. We could identify a two-step process of membrane spreading and self-healing. Despite its relatively low resistance, the membrane can be modeled by a parallel combination of an ideal resistor and capacitor, indicating that the membrane efficiently blocks the diffusion of ions.

  8. Gallium nitride electrodes for membrane-based electrochemical biosensors.

    PubMed

    Schubert, T; Steinhoff, G; von Ribbeck, H-G; Stutzmannn, M; Eickhoff, M; Tanaka, M

    2009-10-01

    We report on the deposition of planar lipid bilayers (supported membranes) on gallium nitride (GaN) electrodes for potential applications as membrane-based biosensors. The kinetics of the lipid membrane formation upon vesicle fusion were monitored by simultaneous measurements of resistance and capacitance of the membrane using AC impedance spectroscopy in the frequency range between 50 mHz and 50 kHz. We could identify a two-step process of membrane spreading and self-healing. Despite its relatively low resistance, the membrane can be modeled by a parallel combination of an ideal resistor and capacitor, indicating that the membrane efficiently blocks the diffusion of ions.

  9. Nanoporous-Gold-Based Electrode Morphology Libraries for Investigating Structure-Property Relationships in Nucleic Acid Based Electrochemical Biosensors.

    PubMed

    Matharu, Zimple; Daggumati, Pallavi; Wang, Ling; Dorofeeva, Tatiana S; Li, Zidong; Seker, Erkin

    2017-01-31

    Nanoporous gold (np-Au) electrode coatings significantly enhance the performance of electrochemical nucleic acid biosensors because of their three-dimensional nanoscale network, high electrical conductivity, facile surface functionalization, and biocompatibility. Contrary to planar electrodes, the np-Au electrodes also exhibit sensitive detection in the presence of common biofouling media due to their porous structure. However, the pore size of the nanomatrix plays a critical role in dictating the extent of biomolecular capture and transport. Small pores perform better in the case of target detection in complex samples by filtering out the large nonspecific proteins. On the other hand, larger pores increase the accessibility of target nucleic acids in the nanoporous structure, enhancing the detection limits of the sensor at the expense of more interference from biofouling molecules. Here, we report a microfabricated np-Au multiple electrode array that displays a range of electrode morphologies on the same chip for identifying feature sizes that reduce the nonspecific adsorption of proteins but facilitate the permeation of target DNA molecules into the pores. We demonstrate the utility of the electrode morphology library in studying DNA functionalization and target detection in complex biological media with a special emphasis on revealing ranges of electrode morphologies that mutually enhance the limit of detection and biofouling resilience. We expect this technique to assist in the development of high-performance biosensors for point-of-care diagnostics and facilitate studies on the electrode structure-property relationships in potential applications ranging from neural electrodes to catalysts.

  10. Multi-channel PMMA microfluidic biosensor with integrated IDUAs for electrochemical detection

    PubMed Central

    Wongkaew, Nongnoot; He, Peng; Kurth, Vanessa; Surareungchai, Werasak; Baeumner, Antje J.

    2013-01-01

    A novel multi-channel poly(methyl methacrylate) (PMMA) microfluidic biosensor with interdigitated ultramicroelectrode arrays (IDUAs) for electrochemical detection was developed. The focus of the development was a simple fabrication procedure and the realization of a reliable large IDUA that can provide detection simultaneously to several microchannels. As proof of concept, five microchannels are positioned over a large single IDUA where the channels are parallel with the length of electrode finger. The IDUAs were fabricated on the PMMA cover piece and bonded to a PMMA substrate containing the microfluidic channels using UV/ozone-assisted thermal bonding. Conditions of device fabrication were optimized realizing a rugged large IDUA within a bonded PMMA device. Gold adhesion to the PMMA, protective coatings and pressure during bonding were optimized. Its electrochemical performance was studied using amperometric detection of potassium ferri and ferro hexacyanide. Cumulative signals within the same chip showed very good linearity over a range of 0 - 38 μM (R2 = 0.98) and a limit of detection of 3.48 μM. The bonding of the device was optimized so that no cross-talk between the channels was observed which otherwise would have resulted in unreliable electrochemical responses. The highly reproducible signals achieved were comparable to those obtained with separate single-channel devices. Subsequently, the multi-channel microfluidic chip was applied to a model bioanalytical detection strategy, i.e. the quantification of specific nucleic acid sequences using a sandwich approach. Here probe-coated paramagnetic beads and probe-tagged liposomes entrapping ferri/ferro hexacyanide as the redox marker were used to bind to a single stranded DNA sequence. Flow rates of the non-ionic detergent n-octyl-β-D-glucopyranoside (OG) for liposome lysis were optimized and the detection of the target sequences was carried out coulometrically within 250 s and with a limit of detection of 12

  11. Chemically modified diamondoids as biosensors for DNA

    NASA Astrophysics Data System (ADS)

    Sivaraman, Ganesh; Fyta, Maria

    2014-03-01

    Understanding the interaction of biological molecules with materials is essential in view of the novel potential applications arising when these two are combined. To this end, we investigate the interaction of DNA with diamondoids, a broad family of tiny hydrogen-terminated diamond clusters with high technological potential. We model this interaction through quantum-mechanical computer simulations and focus on the hydrogen bonding possibilities of the different DNA nucleobases to the lower amine-modified diamondoids with respect to their relative distance and orientation. Our aim is to promote the binding between these two units, and probe this through the association energy, the electronic structure of the nucleobase-diamondoid system, and the specific role of their frontier orbitals. We discuss the relevance of our results in view of biosensing applications and specifically nanopore sequencing of DNA.

  12. Microfabricated EIS biosensor for detection of DNA

    NASA Astrophysics Data System (ADS)

    Taing, M.; Sweatman, D.

    2006-01-01

    This paper focuses on the design of an EIS (electrolyte on insulator on Silicon) structure as a detection method for pathogenic DNA. Current rapid detection methods rely on fluorescent labeling to determine binding affinity. Fluorescent quenching is seen by a change in activity as opposed to non-quenched states. Sensitive optical equipment is required to detect and distinguish these colour changes because they cannot be seen by the naked eye. The disadvantages of this is (1) a portable, independent device cannot be made since samples have to be brought back to the benchtop and (2) the obvious cost of acquiring and maintaining these optical detection systems. A low cost, portable electrical detection method has been investigated. The EIS structure (Electrolyte on Insulator on Silicon) provides a novel, label-free and simple to fabricate way to make a small field effect DNA detection sensor. The sensor responds to fluctuating capacitances caused by a depletion layer thickness change at the surface of the silicon substrate as a result of DNA adsorption onto the dielectric oxide/APTES (Aminopropylthioxysilane) surface. As DNA molecules diffuse to the sensor surface, they are bound to their complimentary capture probes. The negative charge exhibited by the DNA forces negative charge carriers in the silicon substrate to move away from the surface. This causes a depletion layer in n-type substrate to thicken and for a p-type to thin and can be observed as a change in capacitance. A low ionic solution strength will ensure that counter-ions do not affect the sensor measurements. The EIS sensor is designed to be later integrated into a complete lab on chip solution. A full lab on chip can incorporate the sensor to perform DNA quantity based measurements. Nucleic acids can be amplified by the on chip PCR system and then fed into the sensor to work out the DNA concentration. The sensor surface contains capture probes that will bind to the pathogen. They are held onto the

  13. Simple and rapid fabrication of disposable carbon-based electrochemical cells using an electronic craft cutter for sensor and biosensor applications.

    PubMed

    Afonso, André S; Uliana, Carolina V; Martucci, Diego H; Faria, Ronaldo C

    2016-01-01

    This work describes the construction of an all-plastic disposable carbon-based electrochemical cell (DCell) using a simple procedure based on the use of a home cutter printer for prototyping and laminating. The cutter printer and adhesive vinyl films were used to produce three electrodes in an electrochemical cell layout, and a laminating process was then used to define the geometric area and insulate the electrodes. The DCell showed excellent performance in several applications including the determination of toxic metals in water samples, the immobilization of DNA and the detection of Salmonella. An unmodified DCell was applied for Pb and Cd detection in the range of 100-300 ng mL(-1) with a limit of detection of 50 and 39 ng mL(-1) for Cd and Pb, respectively. DNA was successfully immobilized on a DCell and used for studies of interaction between bisphenol A and DNA. The square wave voltammetry of a DNA modified DCell presented a guanine oxidation current 2.5 times greater after exposure of the electrode to bisphenol A and no current variation for the adenine moiety indicating that bisphenol A showed a preference for DNA interaction sites. A magneto-immunoassay was developed using a DCell for Salmonella detection in milk samples. The system presented a linear range from 100 to 700 cells mL(-1) with a limit of detection of 100 cells mL(-1) and good recovery values between 93% and 101% in milk samples, with no interference from Escherichia coli. Using the proposed method, hundreds of DCells can be assembled in less than two hours, at a material cost of less than US $0.02 per cell. The all-plastic disposable electrochemical cell developed was successfully applied as an electrochemical sensor and biosensor. The feasibility of the developed all-plastic disposable electrochemical cell was demonstrated in applications as both sensor and biosensor.

  14. A Label-Free Electrochemical Biosensor Based on a Reduced Graphene Oxide and Indole-5-Carboxylic Acid Nanocomposite for the Detection of Klebsiella pneumoniae.

    PubMed

    Zhang, Ze; Yu, Hong-Wei; Wan, Guang-Cai; Jiang, Jing-Hui; Wang, Na; Liu, Zhi-Yong; Chang, Dong; Pan, Hong-Zhi

    2017-03-01

    A label-free DNA hybridization electrochemical sensor for the detection of Klebsiella pneumoniae was developed, which could be helpful in the diagnosis of bacterial infections. Indole-5-carboxylic acid (ICA) and graphene oxide (GO) were electrodeposited on a glassy carbon electrode, and the resulting reduced GO (rGO)-ICA hybrid film served as a platform for immobilizing oligonucleotides on a single-stranded DNA (ssDNA) sequence. The conditions were optimized, with excellent electrochemical performance. A significant change was observed after hybridization of ssDNA with the target probe under optimum conditions. Hybridization with complementary, noncomplementary, one-base mismatched, and three-base mismatched DNA targets was studied effectively by differential pulse voltammetry. The proposed strategy could detect target DNA down to 3 × 10-11 M, with a linear range from 1 × 10-6 M to 1 × 10-10 M, showing high sensitivity. This electrochemical method is simple, free from indicator, and shows good selectivity. Hence, electrochemical biosensors are successfully demonstrated for the detection of K. pneumoniae.

  15. Electrochemical sensors and biosensors based on redox polymer/carbon nanotube modified electrodes: a review.

    PubMed

    Barsan, Madalina M; Ghica, M Emilia; Brett, Christopher M A

    2015-06-30

    The aim of this review is to present the contributions to the development of electrochemical sensors and biosensors based on polyphenazine or polytriphenylmethane redox polymers together with carbon nanotubes (CNT) during recent years. Phenazine polymers have been widely used in analytical applications due to their inherent charge transport properties and electrocatalytic effects. At the same time, since the first report on a CNT-based sensor, their application in the electroanalytical chemistry field has demonstrated that the unique structure and properties of CNT are ideal for the design of electrochemical (bio)sensors. We describe here that the specific combination of phenazine/triphenylmethane polymers with CNT leads to an improved performance of the resulting sensing devices, because of their complementary electrical, electrochemical and mechanical properties, and also due to synergistic effects. The preparation of polymer/CNT modified electrodes will be presented together with their electrochemical and surface characterization, with emphasis on the contribution of each component on the overall properties of the modified electrodes. Their importance in analytical chemistry is demonstrated by the numerous applications based on polymer/CNT-driven electrocatalytic effects, and their analytical performance as (bio) sensors is discussed.

  16. Effect of DNA type on response of DNA biosensor for carcinogens

    NASA Astrophysics Data System (ADS)

    Sani, Nor Diyana bt. Md.; Heng, Lee Yook; Surif, Salmijah; Lazim, Azwani Mat

    2013-11-01

    Carcinogens are cancer causing chemicals that can bind to DNA and cause damage to the DNA. These chemicals are available everywhere including in water, air, soil and food. Therefore, a sensor that can detect the presence of these chemicals will be a very useful tool. Since carcinogens bind to DNA, DNA can be used as the biological element in a biosensor. This study has utilized different types of DNA in a biosensor for carcinogen detection. The DNAs include double stranded calf thymus DNA, single stranded calf thymus DNA and guanine rich single stranded DNA. The modified SPE was exposed to a carcinogen followed by interaction with methylene blue which acts as the electroactive indicator. The SPE was then analysed using differential pulse voltammetry (DPV). Optimization studies were conducted for MB concentration and accumulation time, DNA concentration, as well as effect of buffer concentration, buffer pH and ionic strength. The performance of the biosensor was tested on a group 1 carcinogen, formaldehyde. The results indicated that the usage of guanine rich single stranded DNA also gives higher response as carcinogens prefer to bind with guanine compared to other bases.

  17. Graphene-metallic nanocomposites as modifiers in electrochemical glucose biosensor transducers

    NASA Astrophysics Data System (ADS)

    Altuntas, Derya Bal; Tepeli, Yudum; Anik, Ulku

    2016-09-01

    Graphene sheets and three different graphene-metallic nanocomposites including graphene-copper (graphene-Cu), graphene-nickel (graphene-Ni) and graphene-platinum (graphene-Pt) were prepared and characterized in the first place. Then the electrochemical performances of these nanocomposites were tested in glucose biosensor transducers, which were formed by combining these metallic nanocomposites with glucose oxidase enzyme and glassy carbon paste electrode (GCPE). This is the first work that includes the usage of these graphene-Me nanocomposites as a part of glucose biosensor transducer. Fabricated amperometric biosensors linear ranges were obtained as follow: For the plain graphene, the linear range was found in the concentration range between 50 μM and 800 μM with the RSD (n = 3 for 50 μM glucose) value of 12.86% and LOD value of 7.2 μM. For graphene-Pt modified glucose biosensor, the linear range was between 10 μM and 600 μM with the RSD (n = 3 for 50 μM glucose) value of 3.45% and LOD value of 3.06 μM. In the case of graphene-Ni modified glucose biosensor, the values were 25 μM to 600 μM with the RSD (n = 3 for 50 μM glucose) value of 8.76% and LOD value of 24.71 μM and for graphene-Cu modified glucose biosensor linear range was 25 μM to 400 μM with the RSD (n = 3 for 50 μM glucose) value of 3.93% and LOD value of 2.87 μM.

  18. Single strand DNA functionalized single wall carbon nanotubes as sensitive electrochemical labels for arsenite detection.

    PubMed

    Wang, Yonghong; Wang, Ping; Wang, Yiqiang; He, Xiaoxiao; Wang, Kemin

    2015-08-15

    In this work, a simple and sensitive electrochemical strategy for arsenite detection based on the ability of arsenite bound to single-strand DNA (ssDNA) and the signal transduction of single wall carbon nanotubes (SWCNTs) is developed. To realize this purpose, the ssDNA/SWCNTs complexes were formed at first by making ssDNA wrapped around SWCNTs via π-stacking. In the presence of arsenite, the arsenite could strongly bind with the G/T bases of ssDNA and decrease the π-π interaction between ssDNA and SWCNTs, resulting in a certain amount of ssDNA dissociating from the complexes. The separated SWCNTs were selectively assembled on the self-assembled monolayer (SAM) modified Au electrode. Then the SWCNTs onto the SAM-modified Au electrode substantially restored heterogeneous electron transfer that was almost totally blocked by the SAM. The assembled SWCNTs could generate a considerably sensitive and specific tactic for signal transduction, which was related to the concentration of the arsenite. Through detecting the currents mediated by SWCNTs, a linear response to concentration of arsenite ranging from 0.5 to 10ppb and a detection limit of 0.5ppb was readily achieved with desirable specificity and sensitivity. Such a SWCNTs-based biosensor creates a simple, sensitive, nonradioactive route for detection of arsenite. In addition, this demonstration provides a new approach to fabrication of stable biosensors with favorable electrochemical properties believed to be appealing to electroanalytical applications.

  19. 2D nanomaterials based electrochemical biosensors for cancer diagnosis.

    PubMed

    Wang, Lu; Xiong, Qirong; Xiao, Fei; Duan, Hongwei

    2017-03-15

    Cancer is a leading cause of death in the world. Increasing evidence has demonstrated that early diagnosis holds the key towards effective treatment outcome. Cancer biomarkers are extensively used in oncology for cancer diagnosis and prognosis. Electrochemical sensors play key roles in current laboratory and clinical analysis of diverse chemical and biological targets. Recent development of functional nanomaterials offers new possibilities of improving the performance of electrochemical sensors. In particular, 2D nanomaterials have stimulated intense research due to their unique array of structural and chemical properties. The 2D materials of interest cover broadly across graphene, graphene derivatives (i.e., graphene oxide and reduced graphene oxide), and graphene-like nanomaterials (i.e., 2D layered transition metal dichalcogenides, graphite carbon nitride and boron nitride nanomaterials). In this review, we summarize recent advances in the synthesis of 2D nanomaterials and their applications in electrochemical biosensing of cancer biomarkers (nucleic acids, proteins and some small molecules), and present a personal perspective on the future direction of this area.

  20. Electrochemical Affinity Biosensors Based on Disposable Screen-Printed Electrodes for Detection of Food Allergens

    PubMed Central

    Vasilescu, Alina; Nunes, Gilvanda; Hayat, Akhtar; Latif, Usman; Marty, Jean-Louis

    2016-01-01

    Food allergens are proteins from nuts and tree nuts, fish, shellfish, wheat, soy, eggs or milk which trigger severe adverse reactions in the human body, involving IgE-type antibodies. Sensitive detection of allergens in a large variety of food matrices has become increasingly important considering the emergence of functional foods and new food manufacturing technologies. For example, proteins such as casein from milk or lysozyme and ovalbumin from eggs are sometimes used as fining agents in the wine industry. Nonetheless, allergen detection in processed foods is a challenging endeavor, as allergen proteins are degraded during food processing steps involving heating or fermentation. Detection of food allergens was primarily achieved via Enzyme-Linked Immuno Assay (ELISA) or by chromatographic methods. With the advent of biosensors, electrochemical affinity-based biosensors such as those incorporating antibodies and aptamers as biorecognition elements were also reported in the literature. In this review paper, we highlight the success achieved in the design of electrochemical affinity biosensors based on disposable screen-printed electrodes towards detection of protein allergens. We will discuss the analytical figures of merit for various disposable screen-printed affinity sensors in relation to methodologies employed for immobilization of bioreceptors on transducer surface. PMID:27827963

  1. A double-mediator based whole cell electrochemical biosensor for acute biotoxicity assessment of wastewater.

    PubMed

    Gao, Guanyue; Fang, Deyu; Yu, Yuan; Wu, Liangzhuan; Wang, Yu; Zhi, Jinfang

    2017-05-15

    This work investigates the feasibility and sensitivity of a double-mediator based whole cell electrochemical biosensor to detect the acute biotoxicity of wastewater. The lipophilic mediator menadione was used to mediate the intracellular metabolic activities whereas hydrophilic potassium ferricyanide was employed as extracellular electron acceptor to transport the electron from the menadiol to anode. A chitosan hydrogel polymer film with boron-doped nanocrystalline diamond (BND) particles was electrodeposited onto a glassy carbon (GC) electrode to immobilize Saccharomyces cerevisiae cells and the mediators. The feasibility of the as-prepared biosensor was verified by determine the acute biotoxicity of four heavy metal ions(Cu(2+), Cd(2+), Ni(2+), Pb(2+)), three phenol pollutants (3,5-dichlorophenol, 4-chlorophenol, phenol) and three real wastewater samples. The IC50 values for Cu(2+), Cd(2+), Ni(2+), Pb(2+) are 10.12mg/L,13.88mg/L, 17.06mg/L and 34.56mg/L. And the IC50 value is 16.48mg/L, 34.40mg/L and 44.55mg/L for 3,5-dichlorophenol, 4-chlorophenol and phenol, respectively. The results of this work indicate that the double-mediator based whole cell electrochemical biosensor could be applied into the acute toxicity assessment of real wastewater samples with excellent performance and highlight their merit as portable and sensitive, which may providing a reasonable and reliable way for wastewater toxicity online detection.

  2. Zirconia-poly(propylene imine) dendrimer nanocomposite based electrochemical urea biosensor.

    PubMed

    Shukla, Sudheesh K; Mishra, Ajay K; Mamba, Bhekie B; Arotiba, Omotayo A

    2014-11-01

    In this article we report a selective urea electrochemical biosensor based on electro-co-deposited zirconia-polypropylene imine dendrimer (ZrO2-PPI) nanocomposite modified screen printed carbon electrode (SPCE). ZrO2 nanoparticles, prepared by modified sol-gel method were dispersed in PPI solution, and electro-co-deposited by cyclic voltammetry onto a SPCE surface. The material and the modified electrodes were characterised using FTIR, electron microscopy and electrochemistry. The synergistic effect of the high active surface area of both materials, i.e. PPI and ZrO2 nanoparticles, gave rise to a remarkable improvement in the electrocatalytic properties of the biosensor and aided the immobilisation of the urease enzyme. The biosensor has an ampereometric response time of ∼4 s in urea concentration ranging from 0.01 mM to 2.99 mM with a correlation coefficient of 0.9985 and sensitivity of 3.89 μA mM(-1) cm(-2). The biosensor was selective in the presence of interferences. Photochemical study of the immobilised enzyme revealed high stability and reactivity.

  3. Reagentless Measurement of Aminoglycoside Antibiotics in Blood Serum via an Electrochemical, Ribonucleic Acid Aptamer-Based Biosensor

    PubMed Central

    Rowe, Aaron A.; Miller, Erin A.; Plaxco, Kevin W.

    2011-01-01

    Biosensors built using ribonucleic acid (RNA) aptamers show promise as tools for point-of-care medical diagnostics, but they remain vulnerable to nuclease degradation when deployed in clinical samples. To explore methods for protecting RNA-based biosensors from such degradation we have constructed and characterized an electrochemical, aptamer-based sensor for the detection of aminoglycosidic antibiotics. We find that while this sensor achieves low micromolar detection limits and subminute equilibration times when challenged in buffer, it deteriorates rapidly when immersed directly in blood serum. In order to circumvent this problem, we have developed and tested sensors employing modified versions of the same aptamer. Our first effort to this end entailed the methylation of all of the 2′-hydroxyl groups outside of the aptamer’s antibiotic binding pocket. However, while devices employing this modified aptamer are as sensitive as those employing an unmodified parent, the modification fails to confer greater stability when the sensor is challenged directly in blood serum. As a second potentially naive alternative, we replaced the RNA bases in the aptamer with their more degradation-resistant deoxyribonucleic acid (DNA) equivalents. Surprisingly and unlike control DNA-stem loops employing other sequences, this DNA aptamer retains the ability to bind aminoglycosides, albeit with poorer affinity than the parent RNA aptamer. Unfortunately, however, while sensors fabricated using this DNA aptamer are stable in blood serum, its lower affinity pushes their detection limits above the therapeutically relevant range. Finally, we find that ultrafiltration through a low-molecular-weight-cutoff spin column rapidly and efficiently removes the relevant nucleases from serum samples spiked with gentamicin, allowing the convenient detection of this aminoglycoside at clinically relevant concentrations using the original RNA-based sensor. PMID:20687587

  4. Carbon Nanomaterials Based Electrochemical Sensors/Biosensors for the Sensitive Detection of Pharmaceutical and Biological Compounds

    PubMed Central

    Adhikari, Bal-Ram; Govindhan, Maduraiveeran; Chen, Aicheng

    2015-01-01

    Electrochemical sensors and biosensors have attracted considerable attention for the sensitive detection of a variety of biological and pharmaceutical compounds. Since the discovery of carbon-based nanomaterials, including carbon nanotubes, C60 and graphene, they have garnered tremendous interest for their potential in the design of high-performance electrochemical sensor platforms due to their exceptional thermal, mechanical, electronic, and catalytic properties. Carbon nanomaterial-based electrochemical sensors have been employed for the detection of various analytes with rapid electron transfer kinetics. This feature article focuses on the recent design and use of carbon nanomaterials, primarily single-walled carbon nanotubes (SWCNTs), reduced graphene oxide (rGO), SWCNTs-rGO, Au nanoparticle-rGO nanocomposites, and buckypaper as sensing materials for the electrochemical detection of some representative biological and pharmaceutical compounds such as methylglyoxal, acetaminophen, valacyclovir, β-nicotinamide adenine dinucleotide hydrate (NADH), and glucose. Furthermore, the electrochemical performance of SWCNTs, rGO, and SWCNT-rGO for the detection of acetaminophen and valacyclovir was comparatively studied, revealing that SWCNT-rGO nanocomposites possess excellent electrocatalytic activity in comparison to individual SWCNT and rGO platforms. The sensitive, reliable and rapid analysis of critical disease biomarkers and globally emerging pharmaceutical compounds at carbon nanomaterials based electrochemical sensor platforms may enable an extensive range of applications in preemptive medical diagnostics. PMID:26404304

  5. Carbon Nanomaterials Based Electrochemical Sensors/Biosensors for the Sensitive Detection of Pharmaceutical and Biological Compounds.

    PubMed

    Adhikari, Bal-Ram; Govindhan, Maduraiveeran; Chen, Aicheng

    2015-09-04

    Electrochemical sensors and biosensors have attracted considerable attention for the sensitive detection of a variety of biological and pharmaceutical compounds. Since the discovery of carbon-based nanomaterials, including carbon nanotubes, C60 and graphene, they have garnered tremendous interest for their potential in the design of high-performance electrochemical sensor platforms due to their exceptional thermal, mechanical, electronic, and catalytic properties. Carbon nanomaterial-based electrochemical sensors have been employed for the detection of various analytes with rapid electron transfer kinetics. This feature article focuses on the recent design and use of carbon nanomaterials, primarily single-walled carbon nanotubes (SWCNTs), reduced graphene oxide (rGO), SWCNTs-rGO, Au nanoparticle-rGO nanocomposites, and buckypaper as sensing materials for the electrochemical detection of some representative biological and pharmaceutical compounds such as methylglyoxal, acetaminophen, valacyclovir, β-nicotinamide adenine dinucleotide hydrate (NADH), and glucose. Furthermore, the electrochemical performance of SWCNTs, rGO, and SWCNT-rGO for the detection of acetaminophen and valacyclovir was comparatively studied, revealing that SWCNT-rGO nanocomposites possess excellent electrocatalytic activity in comparison to individual SWCNT and rGO platforms. The sensitive, reliable and rapid analysis of critical disease biomarkers and globally emerging pharmaceutical compounds at carbon nanomaterials based electrochemical sensor platforms may enable an extensive range of applications in preemptive medical diagnostics.

  6. Photonic Crystal Biosensor with In-Situ Synthesized DNA Probes for Enhanced Sensitivity

    SciTech Connect

    Hu, Shuren; Zhao, Y.; Retterer, Scott T; Kravchenko, Ivan I; Weiss, Sharon

    2013-01-01

    We report on a nearly 8-fold increase in multi-hole defect photonic crystal biosensor response by incorporating in-situ synthesis of DNA probes, as compared to the conventional functionalization method employing pre-synthesized DNA probe immobilization.

  7. Improved electrochemical biosensor response via metal oxide pre-oxidation of chemical interferents

    NASA Astrophysics Data System (ADS)

    Houseknecht, Jamie G.; Tapsak, Mark A.

    2007-09-01

    Typical biological samples are inherently complicated. They may contain a myriad of compounds that are electroactive at the same potential as that used in many electrochemical biosensors. Therefore, a biosensor design feature must be included that either eliminates or blocks the interferents from generating false positive signals. The ability to use an insoluble compound, that of MnO II, in order to oxidize interferents such as ascorbic acid, acetaminophen and uric acid, was investigated in a prototype sensor system at a bias potential of 0.6 V versus Ag/AgCl. Unlike previous work with these materials, a difference between the ability for the metal oxide to oxidize the interferents was observed. Most effective was the capability of MnO II to oxidize uric acid. Alternatively, the MnO II had little effect on acetaminophen. The study is both introduced and results are discussed within the context of an implantable glucose sensor.

  8. Fabrication of magneto-controlled moveable architecture to develop reusable electrochemical biosensors

    PubMed Central

    Zhu, Xiaoli; Feng, Chang; Ye, Zonghuang; Chen, Yangyang; Li, Genxi

    2014-01-01

    Electrochemical biosensors have been studied intensively for several decades. Numerous sensing concepts and related interface architectures have been developed. However, all such architectures suffer a trade-off: simple architectures favour usability, whereas complex architectures favour better performance. To overcome this problem, we propose a novel concept by introducing a magneto-controlled moveable architecture (MCMA) instead of the conventional surface-fixed architecture. As a model, human breast cancer cells were used in this study. The results showed that a detection range from 100 to 1 × 106 cells could be achieved. Moreover, the whole detection cycle, including the measurement and the regeneration, could be completed in only 2 min. Thus, usability and excellent performance can be achieved in a single biosensor. PMID:24566810

  9. Fabrication of magneto-controlled moveable architecture to develop reusable electrochemical biosensors.

    PubMed

    Zhu, Xiaoli; Feng, Chang; Ye, Zonghuang; Chen, Yangyang; Li, Genxi

    2014-02-25

    Electrochemical biosensors have been studied intensively for several decades. Numerous sensing concepts and related interface architectures have been developed. However, all such architectures suffer a trade-off: simple architectures favour usability, whereas complex architectures favour better performance. To overcome this problem, we propose a novel concept by introducing a magneto-controlled moveable architecture (MCMA) instead of the conventional surface-fixed architecture. As a model, human breast cancer cells were used in this study. The results showed that a detection range from 100 to 1 × 10(6) cells could be achieved. Moreover, the whole detection cycle, including the measurement and the regeneration, could be completed in only 2 min. Thus, usability and excellent performance can be achieved in a single biosensor.

  10. High-Sensitivity and High-Efficiency Detection of DNA Hydroxymethylation in Genomic DNA by Multiplexing Electrochemical Biosensing.

    PubMed

    Chen, Shixing; Dou, Yanzhi; Zhao, Zhihan; Li, Fuwu; Su, Jing; Fan, Chunhai; Song, Shiping

    2016-04-05

    DNA hydroxymethylation (5-hmC) is a kind of new epigenetic modification, which plays key roles in DNA demethylation, genomic reprogramming, and the gene expression in mammals. For further exploring the functions of 5-hmC, it is necessary to develop sensitive and selective methods for detecting 5-hmC. Herein, we developed a novel multiplexing electrochemical (MEC) biosensor for 5-hmC detection based on the glycosylation modification of 5-hmC and enzymatic signal amplification. The 5-hmC was first glycosylated by T4 β-glucosyltransferase and then oxidated by sodium periodate. The resulting glucosyl-modified 5-hmC (5-ghmC) was incubated with ARP-biotin and was bound to avidin-HRP. The 5-hmC can be detected at the subnanogram level. Finally, we performed 5-hmC detection for mouse tissue samples and cancer cell lines. The limit of detection of the MEC biosensor is 20 times lower than that of commercial kits based on optical meaurement. Also, the biosensor presented high detection specificity because the chemical reaction for 5-hmC modification can not happen at any other unhydroxymethylated nucleic acid bases. Importantly, benefited by its multiplexing capacity, the developed MEC biosensor showed excellent high efficiency, which was time-saving and cost less.

  11. Novel and simple electrochemical biosensor monitoring attomolar levels of miRNA-155 in breast cancer.

    PubMed

    Cardoso, Ana R; Moreira, Felismina T C; Fernandes, Rúben; Sales, M Goreti F

    2016-06-15

    This work, describes for the first time, a simple biosensing design to yield an ultrasensitive electrochemical biosensor for a cancer biomarker detection, miRNA-155, with linear response down to the attomolar range. MiRNA-155 was selected for being overexpressed in breast cancer. The biosensor was assembled in two stages: (1) the immobilization of the anti-miRNA-155 that was thiol modified on an Au-screen printed electrode (Au-SPE), followed by (2) blocking the areas of non-specific binding with mercaptosuccinic acid. Atomic force microscopy (AFM) and electrochemical techniques including cyclic voltammetry (CV), impedance spectroscopy (EIS) and square wave voltammetry (SWV) confirmed the surface modification of these devices and their ability to hybridize successfully and stably with miRNA-155. The final biosensor provided a sensitive detection of miRNA-155 from 10 aM to 1.0 nM with a low detection limit (LOD) of 5.7 aM in real human serum samples. Good results were obtained in terms of selectivity towards breast cancer antigen CA-15.3 and bovine serum albumin (BSA). Raw fluid extracts from cell-lines of melanoma did not affect the biosensor response (no significant change of the blank), while raw extracts from breast cancer yielded a positive signal against miRNA-155. This simple and sensitive strategy is a promising alternative for simultaneous quantitative analysis of multiple miRNA in physiological fluids for biomedical research and point-of-care (POC) diagnosis.

  12. A paper-based nanomodified electrochemical biosensor for ethanol detection in beers.

    PubMed

    Cinti, Stefano; Basso, Mattia; Moscone, Danila; Arduini, Fabiana

    2017-04-01

    Herein, we report the first example of a paper-based screen-printed biosensor for the detection of ethanol in beer samples. Common office paper was adopted to fabricate the analytical device. The properties of this paper-based screen-printed electrode (SPE) were investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy, and they were compared with the well-established polyester-based SPEs as well. Paper demonstrated similar properties when compared with polyester, highlighting suitability towards its utilization in sensor development, with the advantages of low cost and simple disposal by incineration. A nanocomposite formed by Carbon Black (CB) and Prussian Blue nanoparticles (PBNPs), namely CB/PBNPs, was utilized as an electrocatalyst to detect the hydrogen peroxide generated by the enzymatic reaction between alcohol oxidase (AOx) and ethanol. After optimizing the analytical parameters, such as pH, enzyme, concentration, and working potential, the developed biosensor allowed a facile quantification of ethanol up to 10 mM (0.058 %vol), with a sensitivity of 9.13 μA/mM cm(2) (1574 μA/%vol cm(2)) and a detection limit equal to 0.52 mM (0.003%vol). These satisfactory performances rendered the realized paper-based biosensor reliable over the analysis of ethanol contained in four different types of beers, including Pilsner, Weiss, Lager, and alcohol-free. The proposed manufacturing approach offers an affordable and sustainable tool for food quality control and for the realization of different electrochemical sensors and biosensors as well.

  13. Electrochemical biosensor based on self-assembled monolayers modified with gold nanoparticles for detection of HER-3.

    PubMed

    Canbaz, Mehmet Çetin; Simşek, Ciğdem Sayıklı; Sezgintürk, Mustafa Kemal

    2014-03-03

    We have developed a new immunological biosensor for ultrasensitive quantification of human epidermal growth factor receptor-3(HER-3). In order to construct the biosensor, the gold electrode surface was layered with, hexanedithiol, gold nanoparticles, and cysteamine, respectively. Anti-HER-3 antibody was covalently attached to cysteamine by glutaraldehyde and used as a bioreceptor in a biosensor system for the first time by this study. Surface characterization was obtained by means of electrochemical impedance spectroscopy and voltammetry. The proposed biosensor showed a good analytical performance for the detection of HER-3 ranging from 0.2 to 1.4 pg mL(-1). Kramers-Kronig transform was performed on the experimental impedance data. Moreover, in an immunosensor system, the single frequency impedance technique was firstly used for characterization of interaction between HER-3 and anti-HER-3. Finally the presented biosensor was applied to artificial serum samples spiked with HER-3.

  14. Hydrodynamics studies of cyclic voltammetry for electrochemical micro biosensors

    NASA Astrophysics Data System (ADS)

    Adesokan, B. J.; Quan, X.; Evgrafov, A.; Sørensen, M. P.; Heiskanen, A.; Boisen, A.

    2015-01-01

    We investigate the effect of flow rate on the electrical current response to the applied voltage in a micro electrochemical system. To accomplish this, we considered an ion-transport model that is governed by the Nernst-Planck equation coupled to the Navier-Stokes equations for hydrodynamics. The Butler-Volmer relation provides the boundary conditions, which represent reaction kinetics at the electrode-electrolyte interface. The result shows that convection drastically affects the rate of surface kinetics. At a physically sufficient high flow rates and lower scan rates, the current response is limited by the convection due to fresh ions being brought to the electrode surface and immediately taken away before any surface reaction. However, at high flow and scan rates, the Faradaic current overrides current due to convection. The model also allows predicting the effect of varying electrolyte concentration and scan rates respectively.

  15. Electro-microchip DNA-biosensor for bacteria detection.

    PubMed

    Yeh, Chia Hsien; Chang, Yu Huai; Chang, Tsung Chain; Lin, Hong Ping; Lin, Yu Cheng

    2010-10-01

    This paper presents a bacteria biosensor based on DNA hybridization detection with an electro-microchip transducer. Acinetobacter baumannii was chosen as DNA sample source, because the occurrence of bacteremia caused by Acinetobacter baumannii is high in hospitals worldwide. Our strategy is based on DNA hybridization of PCR amplified bacteria DNA with biotin labelled primers and detection enhancement using gold-streptavidin nanoparticles and Ag(+)-hydroquinone solution. Gold nanoparticles catalyze silver ions reduction by hydroquinone. The gradually precipitated silver metal between the two electrodes of the electro-microchip allows electrons to pass. The detection limit for Acinetobacter baumannii genomic DNA sample is 0.825 ng mL(-1) (1.2 fM). Probe specificity was investigated by screening various species of bacteria, various strains of a single species and various species of a single genus. The proposed DNA hybridization method is easy, convenient, and rapid. Moreover, it has potential applications in detection of bacteria causing infections and clinical diagnosis.

  16. Electrochemical Quartz Crystal Nanobalance (EQCN) Based Biosensor for Sensitive Detection of Antibiotic Residues in Milk.

    PubMed

    Bhand, Sunil; Mishra, Geetesh K

    2017-01-01

    An electrochemical quartz crystal nanobalance (EQCN), which provides real-time analysis of dynamic surface events, is a valuable tool for analyzing biomolecular interactions. EQCN biosensors are based on mass-sensitive measurements that can detect small mass changes caused by chemical binding to small piezoelectric crystals. Among the various biosensors, the piezoelectric biosensor is considered one of the most sensitive analytical techniques, capable of detecting antigens at picogram levels. EQCN is an effective monitoring technique for regulation of the antibiotics below the maximum residual limit (MRL). The analysis of antibiotic residues requires high sensitivity, rapidity, reliability and cost effectiveness. For analytical purposes the general approach is to take advantage of the piezoelectric effect by immobilizing a biosensing layer on top of the piezoelectric crystal. The sensing layer usually comprises a biological material such as an antibody, enzymes, or aptamers having high specificity and selectivity for the target molecule to be detected. The biosensing layer is usually functionalized using surface chemistry modifications. When these bio-functionalized quartz crystals are exposed to a particular substance of interest (e.g., a substrate, inhibitor, antigen or protein), binding interaction occurs. This causes a frequency or mass change that can be used to determine the amount of material interacted or bound. EQCN biosensors can easily be automated by using a flow injection analysis (FIA) setup coupled through automated pumps and injection valves. Such FIA-EQCN biosensors have great potential for the detection of different analytes such as antibiotic residues in various matrices such as water, waste water, and milk.

  17. Graphene oxide directed in-situ deposition of electroactive silver nanoparticles and its electrochemical sensing application for DNA analysis.

    PubMed

    Gao, Ningning; Gao, Feng; He, Suyu; Zhu, Qionghua; Huang, Jiafu; Tanaka, Hidekazu; Wang, Qingxiang

    2017-01-25

    The development of high-performance biosensing platform is heavily dependent on the recognition property of the sensing layer and the output intensity of the signal probe. Herein, we present a simple and highly sensitive biosensing interface for DNA detection on the basis of graphene oxide nanosheets (GONs) directed in-situ deposition of silver nanoparticles (AgNPs). The fabrication process and electrochemical properties of the biosensing interface were probed by electrochemical techniques and scanning electron microscopy. The results indicate that GONs can specifically adsorb at the single-stranded DNA probe surface, and induces the deposition of highly electroactive AgNPs. Upon hybridization with complementary oligonucleotides to generate the duplex DNA on the electrode surface, the GONs with the deposited AgNPs will be liberated from the sensing interface due to the inferior affinity of GONs and duplex DNA, resulting in the reduction of the electrochemical signal. Such a strategy combines the superior recognition of GONs toward single-stranded DNA and double-stranded DNA, and the strong electrochemical response of in-situ deposited AgNPs. Under optimal conditions, the biosensor can detect target DNA over a wide range from 10 fM to 10 nM with a detection limit of 7.6 fM. Also, the developed biosensor shows outstanding discriminating ability toward oligonucleotides with different mismatching degrees.

  18. Electrochemical biosensors for biocontaminant detection consisting of carbon nanotubes, platinum nanoparticles, dendrimers, and enzymes.

    PubMed

    Siriviriyanun, Ampornphan; Imae, Toyoko; Nagatani, Naoki

    2013-12-15

    The presented approach provides the advanced development of effective, rapid, and versatile electrochemical sensors for a small amount of analytes on potential, cheap, and disposable printed chips. The electrocatalytic activity of this biosensor revealed the feasible detection of hydrogen peroxide at low potential (~0.09 V) and the detection of a biocontaminant inhibitor (organophosphorus pesticide) in a wide range of concentrations. This efficiency comes from the chemical immobilization of catalysts (Pt nanoparticles) and electron transfer-enlarging materials (carbon nanotubes) on an electrode. Especially, dendrimers raise the stable conjugation of enzymes (acetylcholinesterase/choline oxidase/peroxidase) as well as nanoparticles and carbon nanotubes on an electrode.

  19. Textile Organic Electrochemical Transistors as a Platform for Wearable Biosensors

    NASA Astrophysics Data System (ADS)

    Gualandi, I.; Marzocchi, M.; Achilli, A.; Cavedale, D.; Bonfiglio, A.; Fraboni, B.

    2016-09-01

    The development of wearable chemical sensors is receiving a great deal of attention in view of non-invasive and continuous monitoring of physiological parameters in healthcare applications. This paper describes the development of a fully textile, wearable chemical sensor based on an organic electrochemical transistor (OECT) entirely made of conductive polymer (PEDOT:PSS). The active polymer patterns are deposited into the fabric by screen printing processes, thus allowing the device to actually “disappear” into it. We demonstrate the reliability of the proposed textile OECTs as a platform for developing chemical sensors capable to detect in real-time various redox active molecules (adrenaline, dopamine and ascorbic acid), by assessing their performance in two different experimental contexts: i) ideal operation conditions (i.e. totally dipped in an electrolyte solution); ii) real-life operation conditions (i.e. by sequentially adding few drops of electrolyte solution onto only one side of the textile sensor). The OECTs response has also been measured in artificial sweat, assessing how these sensors can be reliably used for the detection of biomarkers in body fluids. Finally, the very low operating potentials (<1 V) and absorbed power (~10‑4 W) make the here described textile OECTs very appealing for portable and wearable applications.

  20. Textile Organic Electrochemical Transistors as a Platform for Wearable Biosensors.

    PubMed

    Gualandi, I; Marzocchi, M; Achilli, A; Cavedale, D; Bonfiglio, A; Fraboni, B

    2016-09-26

    The development of wearable chemical sensors is receiving a great deal of attention in view of non-invasive and continuous monitoring of physiological parameters in healthcare applications. This paper describes the development of a fully textile, wearable chemical sensor based on an organic electrochemical transistor (OECT) entirely made of conductive polymer (PEDOT:PSS). The active polymer patterns are deposited into the fabric by screen printing processes, thus allowing the device to actually "disappear" into it. We demonstrate the reliability of the proposed textile OECTs as a platform for developing chemical sensors capable to detect in real-time various redox active molecules (adrenaline, dopamine and ascorbic acid), by assessing their performance in two different experimental contexts: i) ideal operation conditions (i.e. totally dipped in an electrolyte solution); ii) real-life operation conditions (i.e. by sequentially adding few drops of electrolyte solution onto only one side of the textile sensor). The OECTs response has also been measured in artificial sweat, assessing how these sensors can be reliably used for the detection of biomarkers in body fluids. Finally, the very low operating potentials (<1 V) and absorbed power (~10(-4 )W) make the here described textile OECTs very appealing for portable and wearable applications.

  1. Textile Organic Electrochemical Transistors as a Platform for Wearable Biosensors

    PubMed Central

    Gualandi, I.; Marzocchi, M.; Achilli, A.; Cavedale, D.; Bonfiglio, A.; Fraboni, B.

    2016-01-01

    The development of wearable chemical sensors is receiving a great deal of attention in view of non-invasive and continuous monitoring of physiological parameters in healthcare applications. This paper describes the development of a fully textile, wearable chemical sensor based on an organic electrochemical transistor (OECT) entirely made of conductive polymer (PEDOT:PSS). The active polymer patterns are deposited into the fabric by screen printing processes, thus allowing the device to actually “disappear” into it. We demonstrate the reliability of the proposed textile OECTs as a platform for developing chemical sensors capable to detect in real-time various redox active molecules (adrenaline, dopamine and ascorbic acid), by assessing their performance in two different experimental contexts: i) ideal operation conditions (i.e. totally dipped in an electrolyte solution); ii) real-life operation conditions (i.e. by sequentially adding few drops of electrolyte solution onto only one side of the textile sensor). The OECTs response has also been measured in artificial sweat, assessing how these sensors can be reliably used for the detection of biomarkers in body fluids. Finally, the very low operating potentials (<1 V) and absorbed power (~10−4 W) make the here described textile OECTs very appealing for portable and wearable applications. PMID:27667396

  2. E-DNA sensor of Mycobacterium tuberculosis based on electrochemical assembly of nanomaterials (MWCNTs/PPy/PAMAM).

    PubMed

    Miodek, Anna; Mejri, Nawel; Gomgnimbou, Michel; Sola, Christophe; Korri-Youssoufi, Hafsa

    2015-09-15

    Two-step electrochemical patterning methods have been employed to elaborate composite nanomaterials formed with multiwalled carbon nanotubes (MWCNTs) coated with polypyrrole (PPy) and redox PAMAM dendrimers. The nanomaterial has been demonstrated as a molecular transducer for electrochemical DNA detection. The nanocomposite MWCNTs-PPy has been formed by wrapping the PPy film on MWCNTs during electrochemical polymerization of pyrrole on the gold electrode. The MWCNTs-PPy layer was modified with PAMAM dendrimers of fourth generation (PAMAM G4) with covalent bonding by electro-oxidation method. Ferrocenyl groups were then attached to the surface as a redox marker. The electrochemical properties of the nanomaterial (MWCNTs-PPy-PAMAM-Fc) were studied using both square wave voltammetry and cyclic voltammetry to demonstrate efficient electron transfer. The nanomaterial shows high performance in the electrochemical detection of DNA hybridization leading to a variation in the electrochemical signal of ferrocene with a detection limit of 0.3 fM. Furthermore, the biosensor demonstrates ability for sensing DNA of rpoB gene of Mycobacterium tuberculosis in real PCR samples. Developed biosensor was suitable for detection of sequences with a single nucleotide polymorphism (SNP) T (TCG/TTG), responsible for resistance of M. tuberculosis to rifampicin drug, and discriminating them from wild-type samples without such mutation. This shows potential of such systems for further application in pathogens diagnostic and therapeutic purpose.

  3. Nanomaterial-Assisted Signal Enhancement of Hybridization for DNA Biosensors: A Review

    PubMed Central

    Liu, Jinhuai; Liu, Jinyun; Yang, Liangbao; Chen, Xing; Zhang, Meiyun; Meng, Fanli; Luo, Tao; Li, Minqiang

    2009-01-01

    Detection of DNA sequences has received broad attention due to its potential applications in a variety of fields. As sensitivity of DNA biosensors is determined by signal variation of hybridization events, the signal enhancement is of great significance for improving the sensitivity in DNA detection, which still remains a great challenge. Nanomaterials, which possess some unique chemical and physical properties caused by nanoscale effects, provide a new opportunity for developing novel nanomaterial-based signal-enhancers for DNA biosensors. In this review, recent progress concerning this field, including some newly-developed signal enhancement approaches using quantum-dots, carbon nanotubes and their composites reported by our group and other researchers are comprehensively summarized. Reports on signal enhancement of DNA biosensors by non-nanomaterials, such as enzymes and polymer reagents, are also reviewed for comparison. Furthermore, the prospects for developing DNA biosensors using nanomaterials as signal-enhancers in future are also indicated. PMID:22399999

  4. Disposable DNA biosensor with the carbon nanotubes-polyethyleneimine interface at a screen-printed carbon electrode for tests of DNA layer damage by quinazolines.

    PubMed

    Galandová, Júlia; Ovádeková, Renáta; Ferancová, Adriana; Labuda, Ján

    2009-06-01

    A screen-printed carbon working electrode within a commercially available screen-printed three-electrode assembly was modified by using a composite of multiwalled carbon nanotubes (MWCNT) dispersed in polyethylenimine (PEI) followed by covering with the calf thymus dsDNA layer. Several electrochemical methods were used to characterize the biosensor and to evaluate damage to the surface-attached DNA: square wave voltammetry of the [Ru(bpy)(3)](2+) redox indicator and mediator of the guanine moiety oxidation, cyclic voltammetry and electrochemical impedance spectroscopy in the presence of the [Fe(CN)(6)](3-/4-) indicator in solution. Due to high electroconductivity and large surface area of MWCNT and positive charge of PEI, the MWCNT-PEI composite is an advantageous platform for the DNA immobilization by the polyelectrolyte complexation and its voltammetric and impedimetric detection. In this respect, the MWCNT-PEI interface exhibited better properties than the MWCNT-chitosan one reported from our laboratory previously. A deep DNA layer damage at incubation of the biosensor in quinazoline solution was found, which depends on the quinazoline concentration and incubation time.

  5. RNA aptamer based electrochemical biosensor for sensitive and selective detection of cAMP.

    PubMed

    Zhao, Fulin; Xie, Qingyun; Xu, Mingfei; Wang, Shouyu; Zhou, Jiyong; Liu, Fei

    2015-04-15

    Cyclic adenosine monophosphate (cAMP) is an important small biological molecule associated with the healthy state of living organism. In order to realize highly sensitive and specific detection of cAMP, here an RNA aptamer and electrochemical impedance spectroscopy (EIS) based biosensor enhanced by gold nanoparticles electrodeposited on the surface of gold electrode is designed. The designed aptasensor has a wide effective measuring range from 50pM to 250pM with a detection limit of 50pM in PBS buffer, and an effective measuring range from 50nM to 1μM with a detection limit of 50nM in serum. The designed biosensor is also able to detect cAMP with high sensitivity, specificity, and stability. Since the biosensor can be easily fabricated with low cost and repeatedly used for at least two times, it owns great potential in wide application fields such as clinical test and food inspection, etc.

  6. Carbon nanostructured materials for applications in nano-medicine, cultural heritage, and electrochemical biosensors.

    PubMed

    Valentini, F; Carbone, M; Palleschi, G

    2013-01-01

    This review covers applications of pristine and functionalized single-wall carbon nanotubes (SWCNTs) in nano-medicine, cultural heritage, and biosensors. The physicochemical properties of these engineered nanoparticles are similar to those of ultrafine components of airborne pollution (UF) and might have similar adverse effects. UF may impair cardiovascular autonomic control (inducing a high-risk condition for adverse cardiovascular effects), cause mammalian embryo toxicity, and increase geno-cytotoxic risk. SWCNTs coated with a biopolymer, for example polyethylenimine (PEI), become extremely biocompatible, hence are useful for in-vivo and in-vitro drug delivery and gene transfection. It is also possible to successfully immobilize a human enteric virus on PEI/SWCNT composites, suggesting application as a carrier in non-permissive media. The effectiveness of carbon nanostructured materials in the cleaning, restoration, and consolidation of deteriorated historical surfaces has been widely shown by the use of carbon nanomicelles to remove black dendritic crust from stone surfaces. The nanomicelles, here, have the twofold role of delivery and controlled release of the cleaning agents. The high biocompatibility of functionalized SWCNTs with enzymes and proteins is a fundamental feature used in the assembly of electrochemical biosensors. In particular, a third-generation protoporphyrin IX-based biosensor has been assembled for amperometric detection of nitrite, an environmental pollutant involved in the biodeterioration and black encrustation of historical surfaces.

  7. Sensitivity improvement of a miniaturized label-free electrochemical impedance biosensor by electrode edge effect

    NASA Astrophysics Data System (ADS)

    Kuo, Yi-Ching; Chen, Ching-Sung; Chang, Ku-Ning; Lin, Chih-Ting; Lee, Chih-Kung

    2014-07-01

    Point-of-care (PoC) biosensors continue to gain popularity because of the desire to improve cost performance in today's health care industry. As cardiovascular disease (CVD) remains one of the top three leading causes of death in Asia, a tool that can help to detect CVDs is highly sought after. We present a high-sensitivity PoC biosensor that can be used to detect CVD biomarkers. To meet the requirements of a PoC biosensor, we adopted electrochemical methods as the basis of the detection. A more stable three-electrode configuration was miniaturized and put onto a biochip. To improve the detection sensitivity associated with the reduced size in the biochip, computer simulation was used to investigate several potential effective possibilities. We found that the electrolyte current density on the edge near the working electrode (WE) and counter electrode (CE) was higher. This was verified using an atomic force microscope to measure the surface potential. We then experimented with the configuration by lengthening the edge of the WE and CE without changing the area of the WE and CE and maintained the gap between the two electrodes. We found improved measurement efficiency with our newly developed biochip.

  8. New Catalytic DNA Biosensors for Radionuclides and Metal ions

    SciTech Connect

    Lu, Yi

    2003-06-01

    The goals of the project are to develop new catalytic DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides and metal ions, and apply the sensors for on-site, real-time assessment of concentration, speciation and stability of the individual contaminants during and after bioremediation. A negative selection strategy was tested and validated. In vitro selection was shown to yield highly active and specific transition metal ion-dependent catalytic DNA/RNA. A fluorescence resonance energy transfer (FRET) study of in vitro selected DNA demonstrated that the trifluorophore labeled system is a simple and powerful tool in studying complex biomolecules structure and dynamics, and is capable of revealing new sophisticated structural changes. New fluorophore/quenchers in a single fluorosensor yielded improved signal to noise ratio in detection, identification and quantification of metal contaminants. Catalytic DNA fluorescent and colorimetric sensors were shown useful in sensing lead in lake water and in leaded paint. Project results were described in two papers and two patents, and won an international prize.

  9. New Catalytic DNA Biosensors for Radionuclides and Metal ions

    SciTech Connect

    Lu, Yi

    2002-06-01

    The goals of the project are to develop new catalytic DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides and metal ions, and apply the sensors for on-site, real-time assessment of concentration, speciation and stability of the individual contaminants during and after bioremediation. A negative selection strategy was tested and validated. In vitro selection was shown to yield highly active and specific transition metal ion-dependent catalytic DNA/RNA. A fluorescence resonance energy transfer (FRET) study of in vitro selected DNA demonstrated that the trifluorophore labeled system is a simple and powerful tool in studying complex biomolecules structure and dynamics, and is capable of revealing new sophisticated structural changes. New fluorophore/quenchers in a single fluorosensor yielded improved signal to noise ratio in detection, identification and quantification of metal contaminants. Catalytic DNA fluorescent and colorimetric sensors were shown useful in sensing lead in lake water and in leaded paint. Project results were described in two papers and two patents, and won an international prize.

  10. A novel label-free electrochemical miRNA biosensor using methylene blue as redox indicator: application to breast cancer biomarker miRNA-21.

    PubMed

    Rafiee-Pour, Hossain-Ali; Behpour, Mohsen; Keshavarz, Mahin

    2016-03-15

    Small noncoding microRNAs (miRNAs) have emerged as ideal noninvasive biomarkers for early-phase cancer detection. In this report, a label-free and simple electrochemical miRNA biosensor is developed based on employing methylene blue (MB) as a redox indicator. The successfully immobilization of the single strand DNA (ss-DNA) probe and hybridization with the target miRNA sequence were confirmed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) methods. Differential pulse voltammetry (DPV) technique was used to record the oxidation peak current of MB under optimal condition and an increase in the peak current was observed after hybridization. By employing this strategy, miRNA can detect in a range from 0.1 to 500.0 pM with a relatively low detection limit of 84.3 fM. The electrochemical response of MB on ss-DNA and duplex of miRNA/DNA was characterized by CV and chronocoulometry method. The linear relation between the redox peak currents (Ip) and scan rate (ν) indicates that the electron transfer (ET) between MB and the electrode surface was mediated by the miRNA/DNA π-stacked duplex. The value of surface coverage (Γ) was calculated that indicated increase amount of MB on the surface of modified electrode after hybridization event and revealed the adsorption of MB at modified electrode is monolayer. Also, the electron transfer rate constants (ks) of MB were estimated. The results of kinetic analysis were confirmed by chronocoulometry method. The discrimination ability of miRNA biosensor even against a noncomplementary target was also studied. Consequently, this strategy will be valuable for sensitive, selective and label-free detection of miRNA.

  11. Graphene-Assisted Label-Free Homogeneous Electrochemical Biosensing Strategy based on Aptamer-Switched Bidirectional DNA Polymerization.

    PubMed

    Wang, Wenxiao; Ge, Lei; Sun, Ximei; Hou, Ting; Li, Feng

    2015-12-30

    In this contribution, taking the discrimination ability of graphene over single-stranded (ss) DNA/double-stranded (ds) DNA in combination with the electrochemical impedance transducer, we developed a novel label-free homogeneous electrochemical biosensor using graphene-modified glassy carbon electrode (GCE) as the sensing platform. To convert the specific aptamer-target recognition into ultrasensitive electrochemical signal output, a novel aptamer-switched bidirectional DNA polymerization (BDP) strategy, capable of both target recycling and exponential signal amplification, was compatibly developed in this study. In this strategy, all the designed DNA structures could be adsorbed on the graphene/GCE and, thus, serve as the electrochemical impedance signal reporter, while the target acts as a trigger of this BDP reaction, in which these designed DNA structures are bound together and, then, converted to long dsDNA duplex. The distinct difference in electrochemical impedance spectroscopy between the designed structures and generated long dsDNA duplex on the graphene/GCE allows label-free and homogeneous detection of target down to femto-gram level. The target can be displaced from aptamer through the polymerization to initiate the next recognition-polymerization cycle. Herein, the design and signaling principle of aptamer-switched BDP amplification system were elucidated, and the working conditions were optimized. This method not only provides a universal platform for electrochemical biosensing but also shows great potential in biological process researches and clinic diagnostics.

  12. Detection of the tau protein in human serum by a sensitive four-electrode electrochemical biosensor.

    PubMed

    Wang, Scarlet Xiaoyan; Acha, Desiree; Shah, Ajit J; Hills, Frank; Roitt, Ivan; Demosthenous, Andreas; Bayford, Richard H

    2017-06-15

    This study presents a novel approach based on a four-electrode electrochemical biosensor for the detection of tau protein - one of the possible markers for the prediction of Alzheimer's disease (AD). The biosensor is based on the formation of stable antibody-antigen complexes on gold microband electrodes covered with a layer of a self-assembled monolayer and protein G. Antibodies were immobilized on the gold electrode surface in an optimal orientation by protein G interaction. Electrochemical impedance spectroscopy was used to analyze impedance change, which revealed a linear response with increasing tau concentrations. The assay is fast (<1h for incubation and measurement) and very sensitive. The limit of quantification for the full-length 2N4R tau protein is 0.03pM, a value unaltered when the assay was processed in bovine serum albumin or human serum. This technology could be adapted for the detection of other biomarkers to provide a multiple assay to identify AD progression in a point of care setting.

  13. Aptamer-Based Microfluidic Electrochemical Biosensor for Monitoring Cell-Secreted Trace Cardiac Biomarkers.

    PubMed

    Shin, Su Ryon; Zhang, Yu Shrike; Kim, Duck-Jin; Manbohi, Ahmad; Avci, Huseyin; Silvestri, Antonia; Aleman, Julio; Hu, Ning; Kilic, Tugba; Keung, Wendy; Righi, Martina; Assawes, Pribpandao; Alhadrami, Hani A; Li, Ronald A; Dokmeci, Mehmet R; Khademhosseini, Ali

    2016-10-04

    Continual monitoring of secreted biomarkers from organ-on-a-chip models is desired to understand their responses to drug exposure in a noninvasive manner. To achieve this goal, analytical methods capable of monitoring trace amounts of secreted biomarkers are of particular interest. However, a majority of existing biosensing techniques suffer from limited sensitivity, selectivity, stability, and require large working volumes, especially when cell culture medium is involved, which usually contains a plethora of nonspecific binding proteins and interfering compounds. Hence, novel analytical platforms are needed to provide noninvasive, accurate information on the status of organoids at low working volumes. Here, we report a novel microfluidic aptamer-based electrochemical biosensing platform for monitoring damage to cardiac organoids. The system is scalable, low-cost, and compatible with microfluidic platforms easing its integration with microfluidic bioreactors. To create the creatine kinase (CK)-MB biosensor, the microelectrode was functionalized with aptamers that are specific to CK-MB biomarker secreted from a damaged cardiac tissue. Compared to antibody-based sensors, the proposed aptamer-based system was highly sensitive, selective, and stable. The performance of the sensors was assessed using a heart-on-a-chip system constructed from human embryonic stem cell-derived cardiomyocytes following exposure to a cardiotoxic drug, doxorubicin. The aptamer-based biosensor was capable of measuring trace amounts of CK-MB secreted by the cardiac organoids upon drug treatments in a dose-dependent manner, which was in agreement with the beating behavior and cell viability analyses. We believe that, our microfluidic electrochemical biosensor using aptamer-based capture mechanism will find widespread applications in integration with organ-on-a-chip platforms for in situ detection of biomarkers at low abundance and high sensitivity.

  14. A fully microfabricated carbon nanotube three-electrode system on glass substrate for miniaturized electrochemical biosensors.

    PubMed

    Kim, Joon Hyub; Lee, Jun-Yong; Jin, Joon-Hyung; Park, Chan Won; Lee, Cheol Jin; Min, Nam Ki

    2012-06-01

    We present an integration process to fabricate single-walled carbon nanotube (SWCNT) three-electrode systems on glass substrate for electrochemical biosensors. Key issues involve optimization of the SWCNT working electrode to achieve high sensitivity, developing an optimal Ag/AgCl reference electrode with good stability, and process development to integrate these electrodes. Multiple spray coatings of the SWCNT film on glass substrate enabled easier integration of the SWCNT film into an electrochemical three-electrode system. O₂ plasma etching and subsequent activation of spray-coated SWCNT films were needed to pattern and functionalize the SWCNT working electrode films without serious damage to the SWCNTs, and to remove organic residues. The microfabricated three-electrode systems were characterized by microscopic and spectroscopic techniques, and the electrochemical properties were investigated using cyclic voltammetry and chrono-amperometry. The fully-integrated CNT three-electrode system showed an effective working electrode area about three times larger than its geometric surface area and an improved electrochemical activity for hydrogen peroxide decomposition. Finally, the effectiveness of miniaturized pf-SWCNT electrodes as biointerfaces was examined by applying them to immunosensors to detect Legionella(L) pneumophila, based on a direct sandwich enzyme-linked immunosorbent assay (ELISA) format with 3,3',5,5'-tetramethylbenzidine dihydrochloride/hydrogen peroxide(TMB/H₂O₂) as the substrate/mediator system. The lower detection limit of the pf-SWCNT-based immunosensors to L. pneumophila is about 1500 times lower than that of the standard ELISA assay.

  15. Facile synthesis of tetragonal columnar-shaped TiO2 nanorods for the construction of sensitive electrochemical glucose biosensor.

    PubMed

    Yang, Zhanjun; Tang, Yan; Li, Juan; Zhang, Yongcai; Hu, Xiaoya

    2014-04-15

    A tetragonal columnar-shaped TiO2 (TCS-TiO2) nanorods are synthesized via a facile route for the immobilization of glucose oxidase (GOx). A novel electrochemical glucose biosensor is constructed based on the direct electrochemistry of GOx at TCS-TiO2 modified glassy carbon electrode. The fabricated biosensor is characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, electrochemical impedance spectra and cyclic voltammetry. The immobilized enzyme molecules on TCS-TiO2 nanorods retain its native structure and bioactivity and show a surface controlled, quasi-reversible and fast electron transfer process. The TCS-TiO2 nanorods have large surface area and provide a favorable microenvironment for enhancing the electron transfer between enzyme and electrode surface. The constructed glucose biosensor shows wide linear range from 5.0×10(-6) to 1.32×10(-3) M with a high sensitivity of 23.2 mA M(-1) cm(-2). The detection limit is calculated to be 2.0×10(-6) M at signal-to-noise of 3. The proposed glucose biosensor also exhibits excellent selectivity, good reproducibility, and acceptable operational stability. Furthermore, the biosensor can be successfully applied in the detection of glucose in serum sample at the applied potential of -0.50 V. The TCS-TiO2 nanorods provide an efficient and promising platform for the immobilization of proteins and development of excellent biosensors.

  16. Antibody functionalized graphene biosensor for label-free electrochemical immunosensing of fibrinogen, an indicator of trauma induced coagulopathy.

    PubMed

    Saleem, Waqas; Salinas, Carlos; Watkins, Brian; Garvey, Gavin; Sharma, Anjal C; Ghosh, Ritwik

    2016-12-15

    An antibody, specific to fibrinogen, has been covalently attached to graphene and deposited onto screen printed electrodes using a chitosan hydrogel binder to prepare an inexpensive electrochemical fibrinogen biosensor. Fourier Transform Infrared (FT-IR) spectroscopy has been utilized to confirm the presence of the antibody on the graphene scaffold. Electrochemical Impedance Spectroscopy (EIS) has been utilized to demonstrate that the biosensor responds in a selective manner to fibrinogen in aqueous media even in the presence of plasminogen, a potentially interfering molecule in the coagulopathy cascade. Furthermore, the biosensor was shown to reliably sense fibrinogen in the presence of high background serum albumin levels. Finally, we demonstrated detection of clinically relevant fibrinogen concentrations (938-44,542μg/dL) from human serum and human whole blood samples using this biosensor. This biosensor can potentially be used in a point-of-care device to detect the onset of coagulopathy and monitor response following therapeutic intervention in trauma patients. Thus this biosensor may improve the clinical management of patients with trauma-induced coagulopathy.

  17. Electrochemical investigation of the interaction between topotecan and DNA at disposable graphite electrodes.

    PubMed

    Congur, Gulsah; Erdem, Arzum; Mese, Fehmi

    2015-04-01

    Topotecan (TPT) is a semisynthetic, water soluble analog of the plant alkaloid camptothecin which has been widely used for the treatment of ovarian and cervical cancers. To obtain better understanding on how it can affect DNA structure, electrochemical biosensor platforms for the investigation of TPT-double stranded DNA (dsDNA) interaction were developed for the first time in this study. The electrochemical detection of TPT, and TPT-dsDNA interaction were investigated at the surface of pencil graphite electrodes (PGEs) and single-walled carbon nanotube (SWCNT) modified PGEs by using differential pulse voltammetry (DPV). The changes at the oxidation signals of TPT and guanine were evaluated before/after each modification/immobilization step. An enhanced sensor response was obtained by using SWCNT-PGEs compared to unmodified PGEs with resulting limits of detection (LODs) for TPT as 0.51 μg/mL, 0.45 μg/mL, 0.37 μg/mL (130 pmol, 117 pmol, 96.5 pmol in a 110 μL sample, respectively) by using electrochemically pretreated PGE, unmodified PGE and SWCNT modified PGE. In addition, electrochemical impedance spectroscopy (EIS) measurements were performed for the purpose of modification of PGEs by using SWCNTs and the interaction process at the surface of SWCNT-PGEs by evaluating the changes at the charge transfer resistance (Rct).

  18. DNA interaction of [Cu(dmp)(phen-dion)] (dmp=4,7 and 2,9 dimethyl phenanthroline, phen-dion=1,10-phenanthroline-5,6-dion) complexes and DNA-based electrochemical biosensor using chitosan-carbon nanotubes composite film.

    PubMed

    Kashanian, Soheila; Khodaei, Mohammad Mehdi; Roshanfekr, Hamideh; Peyman, Hossein

    2013-10-01

    The interaction of two new water-soluble [Cu(4,7-dmp)(phen-dione)Cl]Cl (1) and [Cu(2,9-dmp)(phen-dione)Cl]Cl (2) which dmp is dimethyl-1,10-phenanthroline and phen-dion represents 1,10-phenanthroline-5,6-dion, with DNA in solution and immobilized DNA on a chitosan-carbon nanotubes composite modified glassy carbon electrode were investigated by cyclic voltammetry and UV-Vis spectroscopy techniques. In solution interactions, spectroscopic and electrochemical evidences indicate outside binding of these complexes. To clarify the binding mode of complexes, it was done competition studies with Hoechst and Neutral red as groove binder and intercalative probes, respectively. All these results indicating that, these two complexes (1) and (2) interact with DNA via groove binding and partially intercalative modes, respectively. The electrochemical characterization experiments showed that the nanocomposite film of chitosan-carbon nanotubes could effectively immobilize DNA and greatly improve the electron-transfer reactions of the electroactive molecules that latter finding is the result of strong interactions between captured DNA and Cu complexes. This result indicates that these complexes could be noble candidates as hybridization indicators in further studies. At the end, these new complexes showed excellent antitumor activity against K562 (human chronic myeloid leukemia) cell lines.

  19. DNA interaction of [Cu(dmp)(phen-dion)] (dmp = 4,7 and 2,9 dimethyl phenanthroline, phen-dion = 1,10-phenanthroline-5,6-dion) complexes and DNA-based electrochemical biosensor using chitosan-carbon nanotubes composite film

    NASA Astrophysics Data System (ADS)

    Kashanian, Soheila; Khodaei, Mohammad Mehdi; Roshanfekr, Hamideh; Peyman, Hossein

    2013-10-01

    The interaction of two new water-soluble [Cu(4,7-dmp)(phen-dione)Cl]Cl (1) and [Cu(2,9-dmp)(phen-dione)Cl]Cl (2) which dmp is dimethyl-1,10-phenanthroline and phen-dion represents 1,10-phenanthroline-5,6-dion, with DNA in solution and immobilized DNA on a chitosan-carbon nanotubes composite modified glassy carbon electrode were investigated by cyclic voltammetry and UV-Vis spectroscopy techniques. In solution interactions, spectroscopic and electrochemical evidences indicate outside binding of these complexes. To clarify the binding mode of complexes, it was done competition studies with Hoechst and Neutral red as groove binder and intercalative probes, respectively. All these results indicating that, these two complexes (1) and (2) interact with DNA via groove binding and partially intercalative modes, respectively. The electrochemical characterization experiments showed that the nanocomposite film of chitosan-carbon nanotubes could effectively immobilize DNA and greatly improve the electron-transfer reactions of the electroactive molecules that latter finding is the result of strong interactions between captured DNA and Cu complexes. This result indicates that these complexes could be noble candidates as hybridization indicators in further studies. At the end, these new complexes showed excellent antitumor activity against K562 (human chronic myeloid leukemia) cell lines.

  20. A nanoparticle label/immunochromatographic electrochemical biosensor for rapid and sensitive detection of prostate-specific antigen

    SciTech Connect

    Lin, Ying-Ying; Wang, Jun; Liu, Guodong; Wu, Hong; Wai, Chien M.; Lin, Yuehe

    2008-06-15

    We present a nanoparticle (NP) label/immunochromatographic electrochemical biosensor (IEB) for rapid and sensitive detection of prostate-specific antigen (PSA) in human serum. This IEB integrates the immunochromatographic strip with the electrochemical detector for transducing quantitative signals. The NP label, made of CdSe@ZnS, serves as a signal-amplifier vehicle. A sandwich immunoreaction was performed on the immunochromatographic strip. The captured NP labels in the test zone were determined by highly sensitive stripping voltammetric measurement of the dissolved metallic component (cadmium) with a disposable-screen-printed electrode, which is embedded underneath the membrane of the test zone. Experimental parameters (e.g., immunoreaction time, the amount of anti-PSA-NP conjugations applied) and electrochemical detection conditions (e.g., preconcentration potential and time) were optimized using this biosensor for PSA detection. The analytical performance of this biosensor was evaluated with serum PSA samples according to the “figure-of-merits” (e.g., dynamic range, reproducibility, and detection limit). The results were validated with enzyme-linked immunosorbent assay (ELISA) and show high consistency. It is found that this biosensor is very sensitive with the detection limit of 0.02 ng/mL PSA and is quite reproducible. This method is rapid, clinically accurate, and less expensive than other diagnosis tools for PSA; therefore, this IEB coupled with a portable electrochemical analyzer shows great promise for simple, sensitive, quantitative point-of-care testing of disease-related protein biomarkers.

  1. Electrochemical detection of malathion pesticide using acetylcholinesterase biosensor based on glassy carbon electrode modified with conducting polymer film.

    PubMed

    Guler, Muhammet; Turkoglu, Vedat; Kivrak, Arif

    2016-06-01

    Acetylcholinesterase (AChE) biosensor based on conducting poly([2,2̍';5̍' 2″]-terthiophene-3̍-carbaldehyde) (PTT) modified glassy carbon electrode (GCE) was constructed. AChE was immobilized on PTT film surface through the covalent bond between aldehyde and amino groups. The properties of PTT modified GCE were studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The biosensor showed an oxidation peak at +0.83 V related to the oxidation of thiocholine, hydrolysis product of acetylthiocholine iodide (ATCI), catalyzed by AChE. The optimum current response of the biosensor was observed at pH 7.5-8.0, 40 °C and 120 U/cm(2) of AChE concentration. The biosensor showed a high sensitivity (183.19 μA/mM), a linear range from 0.015 to 1.644 mM, and a good reproducibility with 1.7 % of relative standard deviation (RSD). The biosensor showed a good stability. The interference of glycin, ascorbic acid, histidine, uric acid, dopamine, and arginine on the biosensor response was studied. An important analytical response from these inteferents that overlaps the biosensor response was not observed. The inhibition rate of malathion as a model pesticide was proportional to its concentrations from 9.99 to 99.01 nM. The detection limit was 4.08 nM.

  2. Monitoring of malolactic fermentation in wine using an electrochemical bienzymatic biosensor for L-lactate with long term stability.

    PubMed

    Giménez-Gómez, Pablo; Gutiérrez-Capitán, Manuel; Capdevila, Fina; Puig-Pujol, Anna; Fernández-Sánchez, César; Jiménez-Jorquera, Cecilia

    2016-01-28

    L-lactic acid is monitored during malolactic fermentation process of wine and its evolution is strongly related with the quality of the final product. The analysis of L-lactic acid is carried out off-line in a laboratory. Therefore, there is a clear demand for analytical tools that enabled real-time monitoring of this process in field and biosensors have positioned as a feasible alternative in this regard. The development of an amperometric biosensor for L-lactate determination showing long-term stability is reported in this work. The biosensor architecture includes a thin-film gold electrochemical transducer selectively modified with an enzymatic membrane, based on a three-dimensional matrix of polypyrrole (PPy) entrapping lactate oxidase (LOX) and horseradish peroxidase (HRP) enzymes. The experimental conditions of the biosensor fabrication regarding the pyrrole polymerization and the enzymes entrapment are optimized. The biosensor response to L-lactate is linear in a concentration range of 1 × 10(-6)-1 × 10(-4) M, with a detection limit of 5.2 × 10(-7) M and a sensitivity of - (13500 ± 600) μA M(-1) cm(-2). The biosensor shows an excellent working stability, retaining more than 90% of its original sensitivity after 40 days. This is the determining factor that allowed for the application of this biosensor to monitor the malolactic fermentation of three red wines, showing a good agreement with the standard colorimetric method.

  3. Ultrasensitive detection of streptomycin using flow injection analysis-electrochemical quartz crystal nanobalance (FIA-EQCN) biosensor.

    PubMed

    Mishra, Geetesh K; Sharma, Atul; Bhand, Sunil

    2015-05-15

    This work presents the development of an ultrasensitive biosensor for detection of streptomycin residues in milk samples using flow injection analysis-electrochemical quartz crystal nanobalance (FIA-EQCN) technique. Monoclonal antibody specific to streptomycin was immobilized on to the thiol modified gold quartz crystal surface. A broad dynamic range (0.3-300 ng/mL) was obtained for streptomycin with a good linearity in the range 0.3-10 ng/mL for PBS and 0.3-50 ng/mL for milk. The correlation coefficient (R(2)) of the biosensor was found to be 0.994 and 0.997 for PBS and milk respectively. Excellent recoveries were obtained from the streptomycin spiked milk samples in the range 98-99.33%, which shows the applicability of the developed biosensor in milk. The reproducibility of the developed biosensor was found satisfactory with % RSD (n=5) 0.351. A good co-relation was observed between the streptomycin recoveries measured through the developed biosensor and the commercial ELISA kit. The analytical figures of merit of the developed biosensor confirm that the developed FIA-EQCN biosensor could be very effective for low-level detection of streptomycin in milk samples.

  4. An isothermal electrochemical biosensor for the sensitive detection of microRNA based on a catalytic hairpin assembly and supersandwich amplification.

    PubMed

    Zhang, Hua; Wang, Qing; Yang, Xiaohai; Wang, Kemin; Li, Qing; Li, Zhiping; Gao, Lei; Nie, Wenyan; Zheng, Yan

    2017-01-16

    A novel isothermal electrochemical biosensor was proposed for the sensitive detection of microRNA (miRNA) based on the ingenious combination of the target-catalyzed hairpin assembly (CHA) and supersandwich amplification strategies. Since miRNA-221 has been reported to be overexpressed in cancers and has been a potentially useful biomarker for the diagnosis of the related diseases, miRNA-221 was chosen as a model target miRNA. The target miRNA-221 triggered a toehold strand displacement assembly of the two hairpin substrates, which led to the cyclicality of the target miRNA and the CHA products. Subsequently, the CHA products hybridized with a capture probe on the electrode and the exposed stem of the CHA products was further used to propagate the supersandwich. After this, the signal probe was modified with horseradish peroxidase (HRP) to form a supersandwich multiplex HRP-DNA label, which could achieve an amplified electrochemical signal. Using the isothermal dual signal amplification strategies, miRNA-221 as low as 0.6 pM (3σ) could be detected. In addition, this biosensor showed high selectivity and could discriminate miRNA-221 from the homologous miRNAs. Note that human miRNA from cancer cells could also be detected and the results were in excellent agreement with those obtained using qRT-PCR. Given that the biosensor avoided the introduction of nanoparticles, the limitation of using the nanoparticles was overcome. The proposed biosensor has great potential for broad applications in the field of clinical analysis.

  5. Luminescent Iridium(III) Complex Labeled DNA for Graphene Oxide-Based Biosensors.

    PubMed

    Zhao, Qingcheng; Zhou, Yuyang; Li, Yingying; Gu, Wei; Zhang, Qi; Liu, Jian

    2016-02-02

    There has been growing interest in utilizing highly photostable iridium(III) complexes as new luminescent probes for biotechnology and life science. Herein, iridium(III) complex with carboxyl group was synthesized and activated with N-hydroxysuccinimide, followed by tagging to the amino terminate of single-stranded DNA (ssDNA). The Ir-ssDNA probe was further combined with graphene oxide (GO) nanosheets to develop a GO-based biosensor for target ssDNA detection. The quenching efficiency of GO, and the photostability of iridium(III) complex and GO-Ir-ssDNA biosensor, were also investigated. On the basis of the high luminescence quenching efficiency of GO toward iridium(III) complex, the GO-Ir-ssDNA biosensor exhibited minimal background signals, while strong emission was observed when Ir-ssDNA desorbed from GO nanosheets and formed a double helix with the specific target, leading to a high signal-to-background ratio. Moreover, it was found that luminescent intensities of iridium(III) complex and GO-Ir-ssDNA biosensor were around 15 and 3 times higher than those of the traditional carboxyl fluorescein (FAM) dye and the GO-FAM-ssDNA biosensor after UV irradiation, respectively. Our study suggested the sensitive and selective Ir-ssDNA probe was suitable for the development of highly photostable GO-based detection platforms, showing promise for application beyond the OLED (organic light emitting diode) area.

  6. Multi-wall carbon nanotubes (MWCNTs)-doped polypyrrole DNA biosensor for label-free detection of genetically modified organisms by QCM and EIS.

    PubMed

    Truong, Thi Ngoc Lien; Tran, Dai Lam; Vu, Thi Hong An; Tran, Vinh Hoang; Duong, Tuan Quang; Dinh, Quang Khieu; Tsukahara, Toshifumi; Lee, Young Hoon; Kim, Jong Seung

    2010-01-15

    In this paper, we describe DNA electrochemical detection for genetically modified organism (GMO) based on multi-wall carbon nanotubes (MWCNTs)-doped polypyrrole (PPy). DNA hybridization is studied by quartz crystal microbalance (QCM) and electrochemical impedance spectroscopy (EIS). An increase in DNA complementary target concentration results in a decrease in the faradic charge transfer resistance (R(ct)) and signifying "signal-on" behavior of MWCNTs-PPy-DNA system. QCM and EIS data indicated that the electroanalytical MWCNTs-PPy films were highly sensitive (as low as 4pM of target can be detected with QCM technique). In principle, this system can be suitable not only for DNA but also for protein biosensor construction.

  7. A miniaturized electrochemical toxicity biosensor based on graphene oxide quantum dots/carboxylated carbon nanotubes for assessment of priority pollutants.

    PubMed

    Zhu, Xiaolin; Wu, Guanlan; Lu, Nan; Yuan, Xing; Li, Baikun

    2017-02-15

    The study presented a sensitive and miniaturized cell-based electrochemical biosensor to assess the toxicity of priority pollutants in the aquatic environment. Human hepatoma (HepG2) cells were used as the biological recognition agent to measure the changes of electrochemical signals and reflect the cell viability. The graphene oxide quantum dots/carboxylated carbon nanotubes hybrid was developed in a facile and green way. Based on the hybrid composite modified pencil graphite electrode, the cell culture and detection vessel was miniaturized to a 96-well plate instead of the traditional culture dish. In addition, three sensitive electrochemical signals attributed to guanine/xanthine, adenine, and hypoxanthine were detected simultaneously. The biosensor was used to evaluate the toxicity of six priority pollutants, including Cd, Hg, Pb, 2,4-dinitrophenol, 2,4,6-trichlorophenol, and pentachlorophenol. The 24h IC50 values obtained by the electrochemical biosensor were lower than those of conventional MTT assay, suggesting the enhanced sensitivity of the electrochemical assay towards heavy metals and phenols. This platform enables the label-free and sensitive detection of cell physiological status with multi-parameters and constitutes a promising approach for toxicity detection of pollutants. It makes possible for automatical and high-throughput analysis on nucleotide catabolism, which may be critical for life science and toxicology.

  8. QCM DNA biosensor for the diagnosis of a fish pathogenic virus VHSV.

    PubMed

    Hong, Sung-Rok; Jeong, Hyun-Do; Hong, Suhee

    2010-08-15

    Viral haemorrhagic septicaemia (VHS) is one of the most serious viral diseases damaging both fresh and marine fish species. VHS caused by VHSV and diagnosis of VHSV has been dependent on the conventional methods, such as cell culture and RT-PCR, which takes a few days or several hours. This study demonstrates a rapid and sensitive QCM biosensor for diagnosis of VHSV infection in fish. The QCM biosensor was developed to detect a main viral RNA encoding G protein in VHSV using the specific DNA probe. To maximize the sensitivity of the biosensor, we prepared three different DNA probes which modified 3' end of DNA by thiol, amine, or biotin and compared three different immobilisation methods on quartz surface coated with gold: immobilisation of thiol labelled probe DNA on naked gold surface, immobilisation of amino labelled probe DNA on gold surface prepared as carboxyl chip using MPA followed by EDC/NHS activation, and immobilisation of biotin labelled probe DNA on gold surface after immobilising avidin on carboxyl chip prior to biotin. As a result, immobilisation method using avidin-biotin interaction was most efficient to immobilise probe DNA and to detect target DNA. The QCM biosensor system using biotinylated probe DNA was stable enough to withstand 32 times of repeated regenerations and the detection limit was 0.0016muM. Diagnosis using the QCM biosensor system was more sensitive and much faster than a conventional RT-PCR analysis in detecting the viral RNA.

  9. Fully integrated ready-to-use paper-based electrochemical biosensor to detect nerve agents.

    PubMed

    Cinti, Stefano; Minotti, Clarissa; Moscone, Danila; Palleschi, Giuseppe; Arduini, Fabiana

    2017-07-15

    Paper-based microfluidic devices are gaining large popularity because of their uncontested advantages of simplicity, cost-effectiveness, limited necessity of laboratory infrastructure and skilled personnel. Moreover, these devices require only small volumes of reagents and samples, provide rapid analysis, and are portable and disposable. Their combination with electrochemical detection offers additional benefits of high sensitivity, selectivity, simplicity of instrumentation, portability, and low cost of the total system. Herein, we present the first example of an integrated paper-based screen-printed electrochemical biosensor device able to quantify nerve agents. The principle of this approach is based on dual electrochemical measurements, in parallel, of butyrylcholinesterase (BChE) enzyme activity towards butyrylthiocholine with and without exposure to contaminated samples. The sensitivity of this device is largely improved using a carbon black/Prussian Blue nanocomposite as a working electrode modifier. The proposed device allows an entirely reagent-free analysis. A strip of a nitrocellulose membrane, that contains the substrate, is integrated with a paper-based test area that holds a screen-printed electrode and BChE. Paraoxon, chosen as nerve agent simulant, is linearly detected down to 3µg/L. The use of extremely affordable manufacturing techniques provides a rapid, sensitive, reproducible, and inexpensive tool for in situ assessment of nerve agent contamination. This represents a powerful approach for use by non-specialists, that can be easily broadened to other (bio)systems.

  10. Electrochemical performance and biosensor application of TiO2 nanotube arrays with mesoporous structures constructed by chemical etching.

    PubMed

    Wang, Jinwen; Xu, Guangqing; Zhang, Xu; Lv, Jun; Zhang, Xinyi; Zheng, Zhixiang; Wu, Yucheng

    2015-04-28

    Novel mesoporous TiO2 nanotube arrays (TiO2 NTAs) were synthesized by an anodization method combined with chemical etching in HF solution, and the electrochemical performance was studied. Glucose oxidase (GOx) was immobilized on the mesoporous TiO2 NTAs to achieve an efficient biosensor for amperometric detection of glucose. The morphology, structure, component and electrochemical performance of mesoporous TiO2 NTAs were characterized by scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffractometry, X-ray photoelectron spectrometry and an electrochemical workstation, respectively. The influence of the mesoporous structure on the electrochemical performance is discussed in detail by comparing the cyclic voltammograms and electrochemical impedance spectrum of TiO2 and mesoporous TiO2 NTAs in different conditions. High electrochemical active surface area and electron transfer rate play key roles in enhancing the electrochemical performance of mesoporous TiO2 NTAs. When used as the basis of a biosensor, the amperometric response of glucose on a GOx/TiO2-0.5 NTAs electrode is linearly proportion to the glucose concentration in the range from 0.1 to 6 mM with a sensitivity of 0.954 μA mM(-1) cm(-2), which is 14.3 times that of un-etched GOx/TiO2 NTAs.

  11. Highly sensitive amperometric biosensor based on electrochemically-reduced graphene oxide-chitosan/hemoglobin nanocomposite for nitromethane determination.

    PubMed

    Wen, Yunping; Wen, Wei; Zhang, Xiuhua; Wang, Shengfu

    2016-05-15

    Nitromethane (CH3NO2) is an important organic chemical raw material with a wide variety of applications as well as one of the most common pollutants. Therefore it is pretty important to establish a simple and sensitive detection method for CH3NO2. In our study, a novel amperometric biosensor for nitromethane (CH3NO2) based on immobilization of electrochemically-reduced graphene oxide (rGO), chitosan (CS) and hemoglobin (Hb) on a glassy carbon electrode (GCE) was constructed. Scanning electron microscopy, infrared spectroscopy and electrochemical methods were used to characterize the Hb-CS/rGO-CS composite film. The effects of scan rate and pH of phosphate buffer on the biosensor have been studied in detail and optimized. Due to the graphene and chitosan nanocomposite, the developed biosensor demonstrating direct electrochemistry with faster electron-transfer rate (6.48s(-1)) and excellent catalytic activity towards CH3NO2. Under optimal conditions, the proposed biosensor exhibited fast amperometric response (<5s) to CH3NO2 with a wide linear range of 5 μM~1.46 mM (R=0.999) and a low detection limit of 1.5 μM (S/N=3). In addition, the biosensor had high selectivity, reproducibility and stability, providing the possibility for monitoring CH3NO2 in complex real samples.

  12. Label-free DNA biosensor based on resistance change of platinum nanoparticles assemblies.

    PubMed

    Skotadis, Evangelos; Voutyras, Konstantinos; Chatzipetrou, Marianneza; Tsekenis, Georgios; Patsiouras, Lampros; Madianos, Leonidas; Chatzandroulis, Stavros; Zergioti, Ioanna; Tsoukalas, Dimitris

    2016-07-15

    A novel nanoparticle based biosensor for the fast and simple detection of DNA hybridization events is presented. The sensor utilizes hybridized DNA's charge transport properties, combining them with metallic nanoparticle networks that act as nano-gapped electrodes. The DNA hybridization events can be detected by a significant reduction in the sensor's resistance due to the conductive bridging offered by hybridized DNA. By modifying the nanoparticle surface coverage, which can be controlled experimentally being a function of deposition time, and the structural properties of the electrodes, an optimized biosensor for the in situ detection of DNA hybridization events is ultimately fabricated. The fabricated biosensor exhibits a wide response range, covering four orders of magnitude, a limit of detection of 1nM and can detect a single base pair mismatch between probe and complementary DNA.

  13. On the sensitivity improvement of a miniaturized label-free electrochemical impedance biosensor

    NASA Astrophysics Data System (ADS)

    Kuo, Yi-Ching; Chou, Shin-Ting; Tsai, Pei-I.; Li, Guan-Wei; Lin, Chih-Ting; Lee, Chih-Kung

    2014-03-01

    Development of point-of-care biosensors continues to gain popularity due to the demand of improving the cost performance in today's health care. As cardiovascular disease induced death remains on the top 3 death causes for most Asian countries, this paper is to present a high-sensitivity point-of-care biosensor for the detection of cardiovascular disease biomarkers. To meet the point-of-care biosensors requirements, which include characteristics such as small size, low cost, and ease of operation, we adopted electrochemical methods as the basis of detection. The 4-aminothiophenol was adopted as the bio-linkers to facilitate the antibody-antigen interaction. A more stable three-electrode configuration was miniaturized and laid out onto a biochip. A microfluidics subsystem based on opto-piezoelectronic technology was also integrated to create the microfluidic biochip system. To improve the detection sensitivity associated with the reduction in biochip size, electrochemistry simulation was used to investigate several potentially effective means. We found that the electric field on the edge near working electrode and counter electrode was higher, which was verified by using atomic force microscopy to measure the surface potential. With the successful verification, we explored the configuration, i.e., lengthened the edge of working electrode and counter electrode without changing the areas of working electrode and counter electrode and the gap between these two electrodes, so as to evaluate the possibility of improving the measurement efficiency in our newly developed biochips. Detailed design, simulation and experimental results, improved design identified, etc. were all presented in detail.

  14. LDHs as electrode materials for electrochemical detection and energy storage: supercapacitor, battery and (bio)-sensor.

    PubMed

    Mousty, Christine; Leroux, Fabrice

    2012-11-01

    From an exhaustive overview based on applicative academic literature and patent domain, the relevance of Layered Double Hydroxide (LDHs) as electrode materials for electrochemical detection of organic molecules having environmental or health impact and energy storage is evaluated. Specifically the focus is driven on their application as supercapacitor, alkaline or lithium battery and (bio)-sensor. Inherent to the high versatility of their chemical composition, charge density, anion exchange capability, LDH-based materials are extensively studied and their performances for such applications are reported. Indeed the analytical characteristics (sensitivity and detection limit) of LDH-based electrodes are scrutinized, and their specific capacity or capacitance as electrode battery or supercapacitor materials, are detailed.

  15. Electrochemical biosensor array for liver diagnosis using silanization technique on nanoporous silicon electrode.

    PubMed

    Song, Min-Jung; Yun, Dong-Hwa; Min, Nam-Ki; Hong, Suk-In

    2007-01-01

    An electrochemical biosensor array system was fabricated for the diagnosis and monitoring of liver diseases. Analysis on this array system with multiple samples was performed for point-of-care testing or home-use applications. Cholesterol, bilirubin and aminotransferases present in the serum are well-known biomarkers for liver diseases. For this study, we describe our biosensor array system consisting of cholesterol, bilirubin and glutamate sensors. To immobilize sensing enzymes on the array system, we employed a silanization technique. We observed that porous silicon layers formed on each working electrode notably increase the effective surface area. Sensing electrodes were placed in sampling wells to minimize the cross-interference effect so that multiple sampling would be possible with a low noise current. Compared with traditional analyte measurement procedures, our novel analytical device demonstrated acceptable sensitivities for the analyses of multiple samples and analytes without a marked cross-interference effect. The device sensitivities observed were 0.2656 microA/mM for cholesterol, 0.15354 mA/mM for bilirubin, 0.13698 microA/(U/l) for alanine aminotransferase (ALT) and 0.45439 microA/(U/l) for aspartate aminotransferase (AST).

  16. A novel bi-enzyme electrochemical biosensor for selective and sensitive determination of methyl salicylate.

    PubMed

    Fang, Yi; Umasankar, Yogeswaran; Ramasamy, Ramaraja P

    2016-07-15

    An amperometric sensor based on a bi-enzyme modified electrode was fabricated to detect methyl salicylate, a volatile organic compound released by pathogen-infected plants via systemic response. The detection is based on cascadic conversion reactions that result in an amperometric electrochemical signal. The bi-enzyme electrode is made of alcohol oxidase and horseradish peroxidase enzymes immobilized on to a carbon nanotube matrix through a molecular tethering method. Methyl salicylate undergoes hydrolysis to form methanol, which is consumed by alcohol oxidase to form formaldehyde while simultaneously reducing oxygen to hydrogen peroxide. The hydrogen peroxide will be further reduced to water by horseradish peroxidase, which results in an amperometric signal via direct electron transfer. The bi-enzyme biosensor was evaluated by cyclic voltammetry and constant potential amperometry using hydrolyzed methyl salicylate as the analyte. The sensitivity of the bi-enzyme biosensor as determined by cyclic voltammetry and constant potential amperometry were 112.37 and 282.82μAcm(-2)mM(-1) respectively, and the corresponding limits of detection were 22.95 and 0.98μM respectively. Constant potential amperometry was also used to evaluate durability, repeatability and interference from other compounds. Wintergreen oil was used for real sample study to establish the application of the bi-enzyme sensor for selective determination of plant pathogen infections.

  17. Dynamics of an electrochemical biosensor for the detection of toxic substances in water

    NASA Astrophysics Data System (ADS)

    Simon, Laurent; Ospina, Juan

    2016-05-01

    A proposed analytical method focuses on electrolyte transport to the electrode of an electrochemical cell. The recombinant Escherichia coli whole-cell biosensor detects toxicity in water based on a set of biochemical reactors. Previous contributions elucidated the kinetics of product formation and validated a mathematical model for its diffusion in the chamber. This work introduces an approach to investigate the dynamics of the probe using Laplace transforms and an effective time constant. The transfer function between the electrolyte production and the total current revealed a faster response for larger electrode radii. Both the first-order and effective time constants increased with the chamber height and radius. Separation of variables yields closed-form solutions and helps estimate the kinetics of p-aminophenol generation. When the bacteria were exposed to phenol concentrations of 1.6, 8.3 and 16 ppm, the corresponding overall rate constants were 5.11x10-7, 1.13x10-6 and 1.99x10-6 (product concentration unit/s2), respectively. In addition to parameter estimation, the method can be applied to perform sensitivity analysis and aid manufacturers in meeting design specifications of biosensors.

  18. A Multi-Technique Reconfigurable Electrochemical Biosensor: Enabling Personal Health Monitoring in Mobile Devices.

    PubMed

    Sun, Alexander; Venkatesh, A G; Hall, Drew A

    2016-09-26

    This paper describes the design and characterization of a reconfigurable, multi-technique electrochemical biosensor designed for direct integration into smartphone and wearable technologies to enable remote and accurate personal health monitoring. By repurposing components from one mode to the next, the biosensor's potentiostat is able reconfigure itself into three different measurements modes to perform amperometric, potentiometric, and impedance spectroscopic tests all with minimal redundant devices. A [Formula: see text] PCB prototype of the module was developed with discrete components and tested using Google's Project Ara modular smartphone. The amperometric mode has a ±1 nA to [Formula: see text] measurement range. When used to detect pH, the potentiometric mode achieves a resolution of < 0.08 pH units. In impedance measurement mode, the device can measure 50 Ω-10 [Formula: see text] and has been shown to have of phase error. This prototype was used to perform several point-of-care health tracking assays suitable for use with mobile devices: 1) Blood glucose tests were conducted and shown to cover the diagnostic range for Diabetic patients (  ∼ 200 mg/dL). 2) Lactoferrin, a biomarker for urinary tract infections, was detected with a limit of detection of approximately 1 ng/mL. 3) pH tests of sweat were conducted to track dehydration during exercise. 4) EIS was used to determine the concentration of NeutrAvidin via a label-free assay.

  19. A Multi-Technique Reconfigurable Electrochemical Biosensor: Enabling Personal Health Monitoring in Mobile Devices.

    PubMed

    Sun, Alexander; Venkatesh, A G; Hall, Drew A

    2016-10-01

    This paper describes the design and characterization of a reconfigurable, multi-technique electrochemical biosensor designed for direct integration into smartphone and wearable technologies to enable remote and accurate personal health monitoring. By repurposing components from one mode to the next, the biosensor's potentiostat is able reconfigure itself into three different measurements modes to perform amperometric, potentiometric, and impedance spectroscopic tests all with minimal redundant devices. A [Formula: see text] PCB prototype of the module was developed with discrete components and tested using Google's Project Ara modular smartphone. The amperometric mode has a ±1 nA to [Formula: see text] measurement range. When used to detect pH, the potentiometric mode achieves a resolution of < 0.08 pH units. In impedance measurement mode, the device can measure 50 Ω-10 [Formula: see text] and has been shown to have of phase error. This prototype was used to perform several point-of-care health tracking assays suitable for use with mobile devices: 1) Blood glucose tests were conducted and shown to cover the diagnostic range for Diabetic patients (  ∼  200 mg/dL). 2) Lactoferrin, a biomarker for urinary tract infections, was detected with a limit of detection of approximately 1 ng/mL. 3) pH tests of sweat were conducted to track dehydration during exercise. 4) EIS was used to determine the concentration of NeutrAvidin via a label-free assay.

  20. Glycoprofiling of cancer biomarkers: Label-free electrochemical lectin-based biosensors

    PubMed Central

    Pihíková, Dominika; Kasák, Peter

    2016-01-01

    Glycosylation of biomolecules is one of the most prevalent post- and co-translational modification in a human body, with more than half of all human proteins being glycosylated. Malignant transformation of cells influences glycosylation machinery resulting in subtle changes of the glycosylation pattern within the cell populations as a result of cancer. Thus, an altered terminal glycan motif on glycoproteins could provide a warning signal about disease development and progression and could be applied as a reliable biomarker in cancer diagnostics. Among all highly effective glycoprofiling tools, label-free electrochemical impedance spectroscopy (EIS)-based biosensors have emerged as especially suitable tool for point-of-care early-stage cancer detection. Herein, we highlight the current challenges in glycoprofiling of various cancer biomarkers by ultrasensitive impedimetric-based biosensors with low sample consumption, low cost fabrication and simple miniaturization. Additionally, this review provides a short introduction to the field of glycomics and lectinomics and gives a brief overview of glycan alterations in different types of cancer. PMID:27275016

  1. A superstructure-based electrochemical assay for signal-amplified detection of DNA methyltransferase activity.

    PubMed

    Zhang, Hui; Yang, Yin; Dong, Huilei; Cai, Chenxin

    2016-12-15

    DNA methyltransferase (MTase) activity is highly correlated with the occurrence and development of cancer. This work reports a superstructure-based electrochemical assay for signal-amplified detection of DNA MTase activity using M.SssI as an example. First, low-density coverage of DNA duplexes on the surface of the gold electrode was achieved by immobilized mercaptohexanol, followed by immobilization of DNA duplexes. The duplex can be cleaved by BstUI endonuclease in the absence of DNA superstructures. However, the cleavage is blocked after the DNA is methylated by M.SssI. The DNA superstructures are formed with the addition of helper DNA. By using an electroactive complex, RuHex, which can bind to DNA double strands, the activity of M.SssI can be quantitatively detected by differential pulse voltammetry. Due to the high site-specific cleavage by BstUI and signal amplification by the DNA superstructure, the biosensor can achieve ultrasensitive detection of DNA MTase activity down to 0.025U/mL. The method can be used for evaluation and screening of the inhibitors of MTase, and thus has potential in the discovery of methylation-related anticancer drugs.

  2. Direct ultrasensitive electrochemical biosensing of pathogenic DNA using homogeneous target-initiated transcription amplification

    NASA Astrophysics Data System (ADS)

    Yan, Yurong; Ding, Shijia; Zhao, Dan; Yuan, Rui; Zhang, Yuhong; Cheng, Wei

    2016-01-01

    Sensitive and specific methodologies for detection of pathogenic gene at the point-of-care are still urgent demands in rapid diagnosis of infectious diseases. This work develops a simple and pragmatic electrochemical biosensing strategy for ultrasensitive and specific detection of pathogenic nucleic acids directly by integrating homogeneous target-initiated transcription amplification (HTITA) with interfacial sensing process in single analysis system. The homogeneous recognition and specific binding of target DNA with the designed hairpin probe triggered circular primer extension reaction to form DNA double-strands which contained T7 RNA polymerase promoter and served as templates for in vitro transcription amplification. The HTITA protocol resulted in numerous single-stranded RNA products which could synchronously hybridized with the detection probes and immobilized capture probes for enzyme-amplified electrochemical detection on the biosensor surface. The proposed electrochemical biosensing strategy showed very high sensitivity and selectivity for target DNA with a dynamic response range from 1 fM to 100 pM. Using salmonella as a model, the established strategy was successfully applied to directly detect invA gene from genomic DNA extract. This proposed strategy presented a simple, pragmatic platform toward ultrasensitive nucleic acids detection and would become a versatile and powerful tool for point-of-care pathogen identification.

  3. Direct ultrasensitive electrochemical biosensing of pathogenic DNA using homogeneous target-initiated transcription amplification

    PubMed Central

    Yan, Yurong; Ding, Shijia; Zhao, Dan; Yuan, Rui; Zhang, Yuhong; Cheng, Wei

    2016-01-01

    Sensitive and specific methodologies for detection of pathogenic gene at the point-of-care are still urgent demands in rapid diagnosis of infectious diseases. This work develops a simple and pragmatic electrochemical biosensing strategy for ultrasensitive and specific detection of pathogenic nucleic acids directly by integrating homogeneous target-initiated transcription amplification (HTITA) with interfacial sensing process in single analysis system. The homogeneous recognition and specific binding of target DNA with the designed hairpin probe triggered circular primer extension reaction to form DNA double-strands which contained T7 RNA polymerase promoter and served as templates for in vitro transcription amplification. The HTITA protocol resulted in numerous single-stranded RNA products which could synchronously hybridized with the detection probes and immobilized capture probes for enzyme-amplified electrochemical detection on the biosensor surface. The proposed electrochemical biosensing strategy showed very high sensitivity and selectivity for target DNA with a dynamic response range from 1 fM to 100 pM. Using salmonella as a model, the established strategy was successfully applied to directly detect invA gene from genomic DNA extract. This proposed strategy presented a simple, pragmatic platform toward ultrasensitive nucleic acids detection and would become a versatile and powerful tool for point-of-care pathogen identification. PMID:26729209

  4. Ultrasensitive and selective electrochemical biosensor for detection of mercury (II) ions by nicking endonuclease-assisted target recycling and hybridization chain reaction signal amplification.

    PubMed

    Hong, Minqiang; Wang, Mengyan; Wang, Jing; Xu, Xueqin; Lin, Zhenyu

    2017-02-22

    In this paper, a novel and signal-on electrochemical biosensor based on Hg(2+)- triggered nicking endonuclease-assisted target recycling and hybridization chain reaction (HCR) amplification tactics was developed for sensitive and selective detection of Hg(2+). The hairpin-shaped capture probe A (PA) contained a specific sequence which was recognized by nicking endonuclease (NEase). In the presence of Hg(2+), probe B (PB) hybridized with PA to form stand-up duplex DNA strands via the Hg(2+) mediated thymine-Hg(2+)-thymine (T-Hg(2+)-T) structure, which automatically triggered NEase to selectively digest duplex region from the recognition sites, spontaneously dissociating PB and Hg(2+) and leaving the remnant initiators. The released PB and Hg(2+) could be reused to initiate the next cycle and more initiators were generated. The long nicked double helices were formed through HCR event, which was triggered by the initiators and two hairpin-shaped signal probes labeled with methylene blue, resulting in a significant signal increase. Under optimum conditions, the resultant biosensor showed the high sensitivity and selectivity for the detection of Hg(2+) in a linear range from 10 pM to 50nM (R(2)=0.9990), and a detection limit as low as 1.6 pM (S/N=3). Moreover, the proposed biosensor was successfully applied in the detection of Hg(2+) in environment water samples with satisfactory results.

  5. Highly selective and sensitive electrochemical biosensor for ATP based on the dual strategy integrating the cofactor-dependent enzymatic ligation reaction with self-cleaving DNAzyme-amplified electrochemical detection.

    PubMed

    Lu, Lu; Si, Jing Cao; Gao, Zhong Feng; Zhang, Yu; Lei, Jing Lei; Luo, Hong Qun; Li, Nian Bing

    2015-01-15

    A dual strategy that combines the adenosine triphosphate (ATP)-dependent enzymatic ligation reaction with self-cleaving DNAzyme-amplified electrochemical detection is employed to construct the biosensor. In this design, the methylene blue-labeled hairpin-structured DNA was self-assembled onto a gold electrode surface to prepare the modified electrode through the interaction of Au-S bond. In the procedure of ATP-dependent ligation reaction, when the specific cofactor ATP was added, the two split oligonucleotide fragments of 8-17 DNAzyme were linked by T4 DNA ligase and then released to hybridize with the labeled hairpin-structured DNA substrate. The linked 8-17 DNAzyme catalyzes the cleavage of the hairpin-structured substrate by the addition of Zn(2+), causing the methylene blue which contains high electrochemical activity to leave the surface of the gold electrode, therefore generating a dramatic decrease of electrochemical signal. The decrease of peak current was readily measured by square wave voltammetry and a relatively low detection limit (0.05 nM) was obtained with a linear response range from 0.1 to 1000 nM. By taking advantage of the highly specific cofactor dependence of the DNA ligation reaction, the proposed ligation-induced DNAzyme cascades demonstrate ultrahigh selectivity toward the target cofactor ATP. A catalytic and molecular beacons strategy is further adopted to amplify the electrochemical signal detection achieved by cycling and regenerating the 8-17 DNAzyme to realize enzymatic multiple turnover, thus one DNAzyme can catalyze the cleavage of several hairpin-structured substrates, which improves the sensitivity of the newly designed electrochemical sensing system.

  6. Biosensors in clinical chemistry.

    PubMed

    D'Orazio, Paul

    2003-08-01

    Biosensors are analytical devices composed of a recognition element of biological origin and a physico-chemical transducer. The biological element is capable of sensing the presence, activity or concentration of a chemical analyte in solution. The sensing takes place either as a binding event or a biocatalytical event. These interactions produce a measurable change in a solution property, which the transducer converts into a quantifiable electrical signal. Present-day applications of biosensors to clinical chemistry are reviewed, including basic and applied research, commercial applications and fabrication techniques. Recognition elements include enzymes as biocatalytic recognition elements and immunoagents and DNA segments as affinity ligand recognition elements, coupled to electrochemical and optical modes of transduction. The future will include biosensors based on synthetic recognition elements to allow broad applicability to different classes of analytes and modes of transduction extending lower limits of sensitivity. Microfabrication will permit biosensors to be constructed as arrays and incorporated into lab-on-a-chip devices.

  7. Combination of cascade chemical reactions with graphene-DNA interaction to develop new strategy for biosensor fabrication.

    PubMed

    Zhu, Xiaoli; Sun, Liya; Chen, Yangyang; Ye, Zonghuang; Shen, Zhongming; Li, Genxi

    2013-09-15

    Graphene, a single atom thick and two dimensional carbon nano-material, has been proven to possess many unique properties, one of which is the recent discovery that it can interact with single-stranded DNA through noncovalent π-π stacking. In this work, we demonstrate that a new strategy to fabricate many kinds of biosensors can be developed by combining this property with cascade chemical reactions. Taking the fabrication of glucose sensor as an example, while the detection target, glucose, may regulate the graphene-DNA interaction through three cascade chemical reactions, electrochemical techniques are employed to detect the target-regulated graphene-DNA interaction. Experimental results show that in a range from 5μM to 20mM, the glucose concentration is in a natural logarithm with the logarithm of the amperometric response, suggesting a best detection limit and detection range. The proposed biosensor also shows favorable selectivity, and it has the advantage of no need for labeling. What is more, by controlling the cascade chemical reactions, detection of a variety of other targets may be achieved, thus the strategy proposed in this work may have a wide application potential in the future.

  8. Parallel Optical and Electrochemical DNA Detection

    NASA Astrophysics Data System (ADS)

    Knoll, Wolfgang; Liu, Jianyun; Niu, Lifang; Nielsen, Peter Eigil; Tiefenauer, Louis

    This contribution introduces strategies for the sensitive detection of oligonucleotides as bio-analytes binding from solution to a variety of probe architectures assembled at the (Au-) sensor surface. Detection principles based on surface plasmon optics and electrochemical techniques are compared. In particular, cyclic- and square wave voltammetry (SWV) are applied for the read-out of ferrocene redox labels conjugated to streptavidin that binds to the (biotinylated) DNA targets after hybridizing to the interfacial probe matrix of either DNA or peptide nucleic acid (PNA) strands. By employing streptavidin modified with fluorophores the identical sensor architecture can be used for the recording of hybridization reactions by surface plasmon fluorescence spectroscopy (SPFS). The Langmuir isotherms determined by both techniques, i.e., by SWV and SPFS, give virtually identical affinity constants KA, confirming that the mode of detection has no influence on the hybridization reaction. By using semiconducting nanoparticles as luminescence labels that can be tuned in their bandgap energies over a wide range of emission wavelengths surface plasmon fluorescence microscopy allows for the parallel read-out of multiple analyte binding events simultaneously.

  9. A microfluidic-based electrochemical biochip for label-free DNA hybridization analysis.

    PubMed

    Ben-Yoav, Hadar; Dykstra, Peter H; Gordonov, Tanya; Bentley, William E; Ghodssi, Reza

    2014-09-10

    Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration of pre-processing steps. Utilizing these devices towards the analysis of DNA hybridization events is important because it offers a technology for real time assessment of biomarkers at the point-of-care for various diseases. However, when the device footprint decreases the dominance of various physical phenomena increases. These phenomena influence the fabrication precision and operation reliability of the device. Therefore, there is a great need to accurately fabricate and operate these devices in a reproducible manner in order to improve the overall performance. Here, we describe the protocols and the methods used for the fabrication and the operation of a microfluidic-based electrochemical biochip for accurate analysis of DNA hybridization events. The biochip is composed of two parts: a microfluidic chip with three parallel micro-channels made of polydimethylsiloxane (PDMS), and a 3 x 3 arrayed electrochemical micro-chip. The DNA hybridization events are detected using electrochemical impedance spectroscopy (EIS) analysis. The EIS analysis enables monitoring variations of the properties of the electrochemical system that are dominant at these length scales. With the ability to monitor changes of both charge transfer and diffusional resistance with the biosensor, we demonstrate the selectivity to complementary ssDNA targets, a calculated detection limit of 3.8 nM, and a 13% cross-reactivity with other non-complementary ssDNA following 20 min of incubation. This methodology can improve the performance of miniaturized devices by elucidating on the behavior of diffusion at the micro-scale regime and by enabling the study of DNA hybridization events.

  10. A Microfluidic-based Electrochemical Biochip for Label-free DNA Hybridization Analysis

    PubMed Central

    Ben-Yoav, Hadar; Dykstra, Peter H.; Gordonov, Tanya; Bentley, William E.; Ghodssi, Reza

    2014-01-01

    Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration of pre-processing steps. Utilizing these devices towards the analysis of DNA hybridization events is important because it offers a technology for real time assessment of biomarkers at the point-of-care for various diseases. However, when the device footprint decreases the dominance of various physical phenomena increases. These phenomena influence the fabrication precision and operation reliability of the device. Therefore, there is a great need to accurately fabricate and operate these devices in a reproducible manner in order to improve the overall performance. Here, we describe the protocols and the methods used for the fabrication and the operation of a microfluidic-based electrochemical biochip for accurate analysis of DNA hybridization events. The biochip is composed of two parts: a microfluidic chip with three parallel micro-channels made of polydimethylsiloxane (PDMS), and a 3 x 3 arrayed electrochemical micro-chip. The DNA hybridization events are detected using electrochemical impedance spectroscopy (EIS) analysis. The EIS analysis enables monitoring variations of the properties of the electrochemical system that are dominant at these length scales. With the ability to monitor changes of both charge transfer and diffusional resistance with the biosensor, we demonstrate the selectivity to complementary ssDNA targets, a calculated detection limit of 3.8 nM, and a 13% cross-reactivity with other non-complementary ssDNA following 20 min of incubation. This methodology can improve the performance of miniaturized devices by elucidating on the behavior of diffusion at the micro-scale regime and by enabling the study of DNA hybridization events. PMID:25285529

  11. Aptamer-based electrochemical biosensor for detection of adenosine triphosphate using a nanoporous gold platform.

    PubMed

    Kashefi-Kheyrabadi, Leila; Mehrgardi, Masoud A

    2013-12-01

    In spite of the promising applications of aptamers in the bioassays, the development of aptamer-based electrochemical biosensors with the improved limit of detection has remained a great challenge. A strategy for the amplification of signal, based on application of nanostructures as platforms for the construction of an electrochemical adenosine triphosphate (ATP) aptasensor, is introduced in the present manuscript. A sandwich assay is designed by immobilizing a fragment of aptamer on a nanoporous gold electrode (NPGE) and its association to second fragment in the presence of ATP. Consequently, 3, 4-diaminobenzoic acid (DABA), as a molecular reporter, is covalently attached to the amine-label of the second fragment, and the direct oxidation signal of DABA is followed as the analytical signal. The sensor can detect the concentrations of ATP as low as submicromolar scales. Furthermore, 3.2% decrease in signal is observed by keeping the aptasensor at 4 °C for a week in buffer solution, implying a desirable stability. Moreover, analog nucleotides, including GTP, UTP and CTP, do not show serious interferences and this sensor easily detects its target in deproteinized human blood plasma.

  12. Biocompatible enzymatic roller pens for direct writing of biocatalytic materials: "do-it-yourself" electrochemical biosensors.

    PubMed

    Bandodkar, Amay J; Jia, Wenzhao; Ramírez, Julian; Wang, Joseph

    2015-06-03

    The development of enzymatic-ink-based roller pens for direct drawing of biocatalytic sensors, in general, and for realizing renewable glucose sensor strips, in particular, is described. The resulting enzymatic-ink pen allows facile fabrication of high-quality inexpensive electrochemical biosensors of any design by the user on a wide variety of surfaces having complex textures with minimal user training. Unlike prefabricated sensors, this approach empowers the end user with the ability of "on-demand" and "on-site" designing and fabricating of biocatalytic sensors to suit their specific requirement. The resulting devices are thus referred to as "do-it-yourself" sensors. The bio-active pens produce highly reproducible biocatalytic traces with minimal edge roughness. The composition of the new enzymatic inks has been optimized for ensuring good biocatalytic activity, electrical conductivity, biocompati-bility, reproducible writing, and surface adherence. The resulting inks are characterized using spectroscopic, viscometric, electrochemical, thermal and microscopic techniques. Applicability to renewable blood glucose testing, epidermal glucose monitoring, and on-leaf phenol detection are demonstrated in connection to glucose oxidase and tyrosinase-based carbon inks. The "do-it-yourself" renewable glucose sensor strips offer a "fresh," reproducible, low-cost biocatalytic sensor surface for each blood test. The ability to directly draw biocatalytic conducting traces even on unconventional surfaces opens up new avenues in various sensing applications in low-resource settings and holds great promise for diverse healthcare, environmental, and defense domains.

  13. Fabrication and Electrochemical Characterization of Nanoporous Silicon Electrode for Amperometric Urea Biosensor

    NASA Astrophysics Data System (ADS)

    Yun, Donghwa; Song, Min-Jung; Hwang, Sungwoo; Hong, Suk-In

    2012-06-01

    We describe a new type of biosensor that employs a modified gold electrode based on nanoporous silicon (NPSi) for the electrochemical detection of urea. Urease (Urs) was covalently immobilized onto an Au/NPSi electrode functionalized with 3-mercaptopropionic acid (3-MPA). Amperometric calibration curves for both NPSi and planar silicon (PLSi)-based urea sensitive electrodes were compared in the range of 0.3 to 4.5 mM urea concentrations. The Michaelis-Menten constant (Km) was determined using the amperometric method. The electrochemical active area (Aea) of the 3-MPA/Au/NPSi electrode was evaluated using cyclic voltammetry (CV) and the result was compared with the 3-MPA/Au/PLSi electrode. Measured sensitivity of the Urs/SAMs/Au/NPSi electrode is ca. 2.05 µA mM-1 cm-2 and that of the Urs/SAMs/Au/PLSi electrode is ca. 1.10 µA mM-1 cm-2. About 1.8 times of sensitivity increase is obtained in the Au/NPSi electrode.

  14. Integrated electrochemical biosensor based on algal metabolism for water toxicity analysis.

    PubMed

    Tsopela, A; Lale, A; Vanhove, E; Reynes, O; Séguy, I; Temple-Boyer, P; Juneau, P; Izquierdo, R; Launay, J

    2014-11-15

    An autonomous electrochemical biosensor with three electrodes integrated on the same silicon chip dedicated to the detection of herbicides in water was fabricated by means of silicon-based microfabrication technology. Platinum (Pt), platinum black (Pt Bl), tungsten/tungsten oxide (W/WO3) and iridium oxide (Pt/IrO2) working ultramicroelectrodes were developed. Ag/AgCl and Pt electrodes were used as reference and counter-integrated electrodes respectively. Physical vapor deposition (PVD) and electrodeposition were used for thin film deposition. The ultramicroelectrodes were employed for the detection of O2, H2O2 and pH related ions H3O(+)/OH(-), species taking part in photosynthetic and metabolic activities of algae. By measuring the variations in consumption-production rates of these electroactive species by algae, the quantity of herbicides present at trace level in the solution can be estimated. Fabricated ultramicroelectrodes were electrochemically characterized and calibrated. Pt Black ultramicroelectrodes exhibited the greatest sensitivity regarding O2 and H2O2 detection while Pt/IrO2 ultramicroelectrodes were more sensitive for pH measurement compared to W/WO3 ultramicroelectrodes for pH measurement. Bioassays were then conducted to detect traces of Diuron herbicide in water samples by evaluating disturbances in photosynthetic and metabolic activities of algae caused by this herbicide.

  15. A wide range and high sensitivity four-channel compact electrochemical biosensor for neurotransmitter detection on a microfluidic platform.

    PubMed

    Ghodsevali, Elnaz; Landari, Hamza; Boukadoum, Mounir; Gosselin, Benoit; Miled, Amine

    2016-08-01

    We present a four-channel, high-sensitivity and linearity electrochemical biosensor for neurotransmitter (NT) detection and measurement. Using a multi-channel microfluidic platform makes this biosensor capable of detecting NT-related currents going from nanoamperes to milliamperes, with a sensitivity of the order of picoamperes. Moreover, by using a fully differential potentiostat architecture, the biosensor offers a high common-mode rejection ratio (90 dB), making it appropriate for low-noise and high-sensitive applications. The system was implemented on a 15 mm × 15 mm PCB with direct interface to the microfluidic chambers. It was calibrated with a 5 mM ferrocyanide solution and successfully tested with dopamine at three concentrations. The system shows a minimum sensistivity of 100 pA and consumes 60 mW.

  16. A Graphene-Based Biosensing Platform Based on Regulated Release of an Aptameric DNA Biosensor.

    PubMed

    Mao, Yu; Chen, Yongli; Li, Song; Lin, Shuo; Jiang, Yuyang

    2015-11-09

    A novel biosensing platform was developed by integrating an aptamer-based DNA biosensor with graphene oxide (GO) for rapid and facile detection of adenosine triphosphate (ATP, as a model target). The DNA biosensor, which is locked by GO, is designed to contain two sensing modules that include recognition site for ATP and self-replication track that yields the nicking domain for Nt.BbvCI. By taking advantage of the different binding affinity of single-stranded DNA, double-stranded DNA and aptamer-target complex toward GO, the DNA biosensor could be efficiently released from GO in the presence of target with the help of a complementary DNA strand (CPDNA) that partially hybridizes to the DNA biosensor. Then, the polymerization/nicking enzyme synergetic isothermal amplification could be triggered, leading to the synthesis of massive DNA amplicons, thus achieving an enhanced sensitivity with a wide linear dynamic response range of four orders of magnitude and good selectivity. This biosensing strategy expands the applications of GO-DNA nanobiointerfaces in biological sensing, showing great potential in fundamental research and biomedical diagnosis.

  17. Use of 3,3',5,5' tetramethylbenzidine as new electrochemical indicator of DNA hybridization and its application in genossensor.

    PubMed

    Alves-Balvedi, R P; Caetano, L P; Madurro, J M; Brito-Madurro, A G

    2016-11-15

    Electrochemical tools are important biosensor platforms for disease diagnosis, due to their speediness, easiness, low cost and portability. However, for DNA detection, the use of indicators and/or intercalators is necessary to improve electrochemical sensitivity. Currently, ethidium bromide (EthBr) is the cheapest and most used DNA intercalators, but presents carcinogenic and teratogenic properties. Other indicators may be important for DNA photonic detection, and besides being more expensive, they behave similarly to EthBr. This investigation shows for the first time the use of tetramethylbenzidine(TMB) as a new remarkable non-carcinogenic DNA indicator for genosensing purposes, which may be used for nucleic acid detection of microorganisms, based on complementarity of base-pairing between probe and target molecules. The results indicate that TMB can be used as a new electrochemical indicator readily applicable in genosensors, which is able to detect the hybridization of single stranded DNA probe with its complementary target strand. An additional advantage of TMB, beside its non-genotoxicity, is the electrochemical reduction property, which prevents interference of serum components and other oxidative samples in the electrochemical analysis.

  18. Construction of titanium dioxide nanorod/graphite microfiber hybrid electrodes for a high performance electrochemical glucose biosensor

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Yu, Xin; Guo, Weibo; Qiu, Jichuan; Mou, Xiaoning; Li, Aixue; Liu, Hong

    2016-04-01

    The demand for a highly sensitive and selective glucose biosensor which can be used for implantable or on-time monitoring is constantly increasing. In this work, TiO2 nanorods were synthesized in situ on the surface of graphite microfibers to yield TiO2 nanorod/graphite microfiber hybrid electrodes. The TiO2 nanorods not only retain the high activity of the immobilized glucose molecule, but also promote the direct electron transfer process on the electrode surface. As a working electrode in an electrochemical glucose biosensor in a flowing system, the microfiber hybrid electrodes exhibit high sensitivity, selectivity and stability. Due to its simplicity, low cost, high stability, and unique morphology, the TiO2 nanorod/graphite microfiber hybrid electrode is expected to be an excellent candidate for an implantable biosensor or for in situ flow monitoring.The demand for a highly sensitive and selective glucose biosensor which can be used for implantable or on-time monitoring is constantly increasing. In this work, TiO2 nanorods were synthesized in situ on the surface of graphite microfibers to yield TiO2 nanorod/graphite microfiber hybrid electrodes. The TiO2 nanorods not only retain the high activity of the immobilized glucose molecule, but also promote the direct electron transfer process on the electrode surface. As a working electrode in an electrochemical glucose biosensor in a flowing system, the microfiber hybrid electrodes exhibit high sensitivity, selectivity and stability. Due to its simplicity, low cost, high stability, and unique morphology, the TiO2 nanorod/graphite microfiber hybrid electrode is expected to be an excellent candidate for an implantable biosensor or for in situ flow monitoring. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01360k

  19. Electrochemical Detection of Hybridized DNA Using Reduction of Methylene Blue

    DTIC Science & Technology

    2007-11-02

    Amplified microgravimetric quartz crystal-microbalance analyses of oligonucleotide complexes: a route to a Tay - Sachs biosensor device,” Chemical...Abstract - One of the important roles of a DNA sensor is the capability of detecting genetic diseases or mutations by analyzing DNA sequence. The...intercalator I. INTRODUCTION With the progress of biotechnology, the efforts of detecting genetic diseases and mutations for improving functions of

  20. Ultrasensitive electrochemical biosensing for DNA using quantum dots combined with restriction endonuclease.

    PubMed

    Zhang, Can; Lou, Jing; Tu, Wenwen; Bao, Jianchun; Dai, Zhihui

    2015-01-21

    A universal and sensitive electrochemical biosensing platform for the detection and identification of DNA using CdSe quantum dots (CdSe QDs) as signal markers was designed. The detection mechanism was based on the specific recognition of MspI endonuclease combined with the signal amplification of gold nanoparticles (AuNPs). MspI endonuclease could recognize its specific sequence in the double-strand DNA (dsDNA) and cleave the dsDNA fragments linked with CdSe QDs from the electrode. The remaining attached CdSe QDs can be easily read out by square-wave voltammetry using an electrodeposited bismuth (Bi) film-modified glass carbon electrode. The concentrations of target DNA could be simultaneously detected by the signal of metal markers. Using mycobacterium tuberculosis (Mtb) DNA as a model, under the optimal conditions, the proposed biosensor could detect Mtb DNA down to 8.7 × 10(-15) M with a linear range of 5 orders of magnitude (from 1.0 × 10(-14) to 1.0 × 10(-9) M) and discriminate mismatched DNA with high selectivity. This strategy presented a universal and convenient biosensing platform for DNA assay, and its satisfactory performances make it a potential candidate for the early diagnosis of gene-related diseases.

  1. Development of a multilayered polymeric DNA biosensor using radio frequency technology with gold and magnetic nanoparticles.

    PubMed

    Yang, Cheng-Hao; Kuo, Long-Sheng; Chen, Ping-Hei; Yang, Chii-Rong; Tsai, Zuo-Min

    2012-01-15

    This study utilized the radio frequency (RF) technology to develop a multilayered polymeric DNA sensor with the help of gold and magnetic nanoparticles. The flexible polymeric materials, poly (p-xylylene) (Parylene) and polyethylene naphtholate (PEN), were used as substrates to replace the conventional rigid substrates such as glass and silicon wafers. The multilayered polymeric RF biosensor, including the two polymer layers and two copper transmission structure layers, was developed to reduce the total sensor size and further enhance the sensitivity of the biochip in the RF DNA detection. Thioglycolic acid (TGA) was used on the surface of the proposed biochip to form a thiolate-modified sensing surface for DNA hybridization. Gold nanoparticles (AuNPs) and magnetic nanoparticles (MNPs) were used to immobilize on the surface of the biosensor to enhance overall detection sensitivity. In addition to gold nanoparticles, the magnetic nanoparticles has been demonstrated the applicability for RF DNA detection. The performance of the proposed biosensor was evaluated by the shift of the center frequency of the RF biosensor because the electromagnetic characteristic of the biosensors can be altered by the immobilized multilayer nanoparticles on the biosensor. The experimental results show that the detection limit of the DNA concentration can reach as low as 10 pM, and the largest shift of the center frequency with triple-layer AuNPs and MNPs can approach 0.9 and 0.7 GHz, respectively. Such the achievement implies that the developed biosensor can offer an alternative inexpensive, disposable, and highly sensitive option for application in biomedicine diagnostic systems because the price and size of each biochip can be effectively reduced by using fully polymeric materials and multilayer-detecting structures.

  2. Sensitivity Enhancement of Bead-based Electrochemical Impedance Spectroscopy (BEIS) biosensor by electric field-focusing in microwells.

    PubMed

    Shin, Kyeong-Sik; Ji, Jae Hoon; Hwang, Kyo Seon; Jun, Seong Chan; Kang, Ji Yoon

    2016-11-15

    This paper reports a novel electrochemical impedance spectroscopy (EIS) biosensors that uses magnetic beads trapped in a microwell array to improve the sensitivity of conventional bead-based EIS (BEIS) biosensors. Unloading the previously measured beads by removing the magnetic bar enables the BEIS sensor to be used repeatedly by reloading it with new beads. Despite its recyclability, the sensitivity of conventional BEIS biosensors is so low that it has not attracted much attentions from the biosensor industry. We significantly improved the sensitivity of the BEIS system by introducing of a microwell array that contains two electrodes (a working electrode and a counter electrode) to concentrate the electric field on the surfaces of the beads. We confirmed that the performance of the BEIS sensor in a microwell array using an immunoassay of prostate specific antigen (PSA) in PBS buffer and human plasma. The experimental results showed that a low concentration of PSA (a few tens or hundreds of fg/mL) were detectable as a ratio of the changes in the impedance of the PBS buffer or in human plasma. Therefore, our BEIS sensor with a microwell array could be a promising platform for low cost, high-performance biosensors for applications that require high sensitivity and recyclability.

  3. Clinical Validation of Integrated Nucleic Acid and Protein Detection on an Electrochemical Biosensor Array for Urinary Tract Infection Diagnosis

    PubMed Central

    Mohan, Ruchika; Mach, Kathleen E.; Bercovici, Moran; Pan, Ying; Dhulipala, Lakshmi; Wong, Pak Kin; Liao, Joseph C.

    2011-01-01

    Background Urinary tract infection (UTI) is a common infection that poses a substantial healthcare burden, yet its definitive diagnosis can be challenging. There is a need for a rapid, sensitive and reliable analytical method that could allow early detection of UTI and reduce unnecessary antibiotics. Pathogen identification along with quantitative detection of lactoferrin, a measure of pyuria, may provide useful information towards the overall diagnosis of UTI. Here, we report an integrated biosensor platform capable of simultaneous pathogen identification and detection of urinary biomarker that could aid the effectiveness of the treatment and clinical management. Methodology/Principal Findings The integrated pathogen 16S rRNA and host lactoferrin detection using the biosensor array was performed on 113 clinical urine samples collected from patients at risk for complicated UTI. For pathogen detection, the biosensor used sandwich hybridization of capture and detector oligonucleotides to the target analyte, bacterial 16S rRNA. For detection of the protein biomarker, the biosensor used an analogous electrochemical sandwich assay based on capture and detector antibodies. For this assay, a set of oligonucleotide probes optimized for hybridization at 37°C to facilitate integration with the immunoassay was developed. This probe set targeted common uropathogens including E. coli, P. mirabilis, P. aeruginosa and Enterococcus spp. as well as less common uropathogens including Serratia, Providencia, Morganella and Staphylococcus spp. The biosensor assay for pathogen detection had a specificity of 97% and a sensitivity of 89%. A significant correlation was found between LTF concentration measured by the biosensor and WBC and leukocyte esterase (p<0.001 for both). Conclusion/Significance We successfully demonstrate simultaneous detection of nucleic acid and host immune marker on a single biosensor array in clinical samples. This platform can be used for multiplexed detection

  4. Electrochemical DNA hybridization sensors applied to real and complex biological samples.

    PubMed

    Tosar, J P; Brañas, G; Laíz, J

    2010-12-15

    DNA hybridization biosensors, also known as genosensors, are analytical devices for the detection of specific DNA "target" sequences in solution, upon hybridization of the targets with complementary "probes" immobilized on a solid substrate. Electrochemical genosensors hold great promise to serve as devices suitable for point-of-care diagnostics and multiplexed platforms for fast, simple and inexpensive nucleic acids analysis. Although a lot of progress has been made in the past few years, the performance of genosensors in complex biological samples has been assayed in only a small fraction of published research articles. This review covers such a group of reports, from the year 2000 onwards. Special attention is played in the nature and complexity of the samples and in the way matrix effects were treated and specificity controls were performed.

  5. Fabrication and functionalization of PCB gold electrodes suitable for DNA-based electrochemical sensing.

    PubMed

    Salvo, P; Henry, O Y F; Dhaenens, K; Acero Sanchez, J L; Gielen, A; Werne Solnestam, B; Lundeberg, J; O'Sullivan, C K; Vanfleteren, J

    2014-01-01

    The request of high specificity and selectivity sensors suitable for mass production is a constant demand in medical research. For applications in point-of-care diagnostics and therapy, there is a high demand for low cost and rapid sensing platforms. This paper describes the fabrication and functionalization of gold electrodes arrays for the detection of deoxyribonucleic acid (DNA) in printed circuit board (PCB) technology. The process can be implemented to produce efficiently a large number of biosensors. We report an electrolytic plating procedure to fabricate low-density gold microarrays on PCB suitable for electrochemical DNA detection in research fields such as cancer diagnostics or pharmacogenetics, where biosensors are usually targeted to detect a small number of genes. PCB technology allows producing high precision, fast and low cost microelectrodes. The surface of the microarray is functionalized with self-assembled monolayers of mercaptoundodecanoic acid or thiolated DNA. The PCB microarray is tested by cyclic voltammetry in presence of 5 mM of the redox probe K3Fe(CN6) in 0.1 M KCl. The voltammograms prove the correct immobilization of both the alkanethiol systems. The sensor is tested for detecting relevant markers for breast cancer. Results for 5 nM of the target TACSTD1 against the complementary TACSTD1 and non-complementary GRP, MYC, SCGB2A1, SCGB2A2, TOP2A probes show a remarkable detection limit of 0.05 nM and a high specificity.

  6. Determination of atropine sulfate using a novel sensitive DNA-biosensor based on its interaction on a modified pencil graphite electrode.

    PubMed

    Ensafi, Ali A; Nasr-Esfahani, Parisa; Heydari-Bafrooei, Esmaeil; Rezaei, B

    2015-01-01

    A novel, selective, rapid and simple electrochemical method is developed for the determination of atropine sulfate. UV-Vis and differential pulse voltammetry are used to study the interaction of atropine sulfate with salmon sperm ds-DNA on the surface of salmon sperm ds-DNA modified-pencil graphite electrode (PGE). For this purpose, a pencil graphite electrode (PGE) modified with multiwall carbon nanotubes (MWCNTs), titanium dioxide nanoparticles (TiO2NPs), and poly-dialyldimethylammonium chloride (PDDA) decorated with ds-DNA is tested for the determination of atropine sulfate. The electrochemical oxidation peak current of adenine and guanine bonded on the surface of ds-DNA/PDDA-TiO2NPs-MWCNTs/PGE is used to obtain the analytical signal. Decreases in the intensities of guanine and adenine oxidation signals after their interaction with atropine sulfate are used as indicator signals for the sensitive determination of atropine sulfate. Using ds-DNA/PDDA-TiO2NPs-MWCNTs/PGE and based on the guanine signal, linear calibration curves were obtained in the range of 0.6 to 30.0 μmol L(-1) and 30.0 to 600.0 μmol L(-1) atropine sulfate with low detection limits of 30.0 nmol L(-1). The biosensor shows a good selectivity for the determination of atropine sulfate. Finally, the applicability of the biosensor is evaluated by measuring atropine sulfate in real samples with good accuracy.

  7. A novel electrochemical biosensor based on Fe3O4 nanoparticles-polyvinyl alcohol composite for sensitive detection of glucose.

    PubMed

    Sanaeifar, Niuosha; Rabiee, Mohammad; Abdolrahim, Mojgan; Tahriri, Mohammadreza; Vashaee, Daryoosh; Tayebi, Lobat

    2017-02-15

    In this research, a new electrochemical biosensor was constructed for the glucose detection. Iron oxide nanoparticles (Fe3O4) were synthesized through co-precipitation method. Polyvinyl alcohol-Fe3O4 nanocomposite was prepared by dispersing synthesized nanoparticles in the polyvinyl alcohol (PVA) solution. Glucose oxidase (GOx) was immobilized on the PVA-Fe3O4 nanocomposite via physical adsorption. The mixture of PVA, Fe3O4 nanoparticles and GOx was drop cast on a tin (Sn) electrode surface (GOx/PVA-Fe3O4/Sn). The Fe3O4 nanoparticles were characterized by X-ray diffraction (XRD). Also, Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FE-SEM) techniques were utilized to evaluate the PVA-Fe3O4 and GOx/PVA-Fe3O4 nanocomposites. The electrochemical performance of the modified biosensor was investigated using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Presence of Fe3O4 nanoparticles in the PVA matrix enhanced the electron transfer between enzyme and electrode surface and the immobilized GOx showed excellent catalytic characteristic toward glucose. The GOx/PVA-Fe3O4/Sn bioelectrode could measure glucose in the range from 5 × 10(-3) to 30 mM with a sensitivity of 9.36 μA mM(-1) and exhibited a lower detection limit of 8 μM at a signal-to-noise ratio of 3. The value of Michaelis-Menten constant (KM) was calculated as 1.42 mM. The modified biosensor also has good anti-interfering ability during the glucose detection, fast response (10 s), good reproducibility and satisfactory stability. Finally, the results demonstrated that the GOx/PVA-Fe3O4/Sn bioelectrode is promising in biosensor construction.

  8. Electrochemical Synthesis of Polypyrrole, Reduced Graphene Oxide, and Gold Nanoparticles Composite and Its Application to Hydrogen Peroxide Biosensor

    PubMed Central

    Wu, Baoyan; Zhao, Na; Hou, Shihua; Zhang, Cong

    2016-01-01

    Here we report a facile eco-friendly one-step electrochemical approach for the fabrication of a polypyrrole (PPy), reduced graphene oxide (RGO), and gold nanoparticles (nanoAu) biocomposite on a glassy carbon electrode (GCE). The electrochemical behaviors of PPy–RGO–nanoAu and its application to electrochemical detection of hydrogen peroxide were investigated by cyclic voltammetry. Graphene oxide and pyrrole monomer were first mixed and casted on the surface of a cleaned GCE. After an electrochemical processing consisting of the electrooxidation of pyrrole monomer and simultaneous electroreduction of graphene oxide and auric ions (Au3+) in aqueous solution, a PPy–RGO–nanoAu biocomposite was synthesized on GCE. Each component of PPy–RGO–nanoAu is electroactive without non-electroactive substance. The obtained PPy–RGO–nanoAu/GCE exhibited high electrocatalytic activity toward hydrogen peroxide, which allows the detection of hydrogen peroxide at a negative potential of about −0.62 V vs. SCE. The amperometric responses of the biosensor displayed a sensitivity of 40 µA/mM, a linear range of 32 µM–2 mM, and a detection limit of 2.7 µM (signal-to-noise ratio = 3) with good stability and acceptable reproducibility and selectivity. The results clearly demonstrate the potential of the as-prepared PPy–RGO–nanoAu biocomposite for use as a highly electroactive matrix for an amperometric biosensor. PMID:28335348

  9. Electrochemical Synthesis of Polypyrrole, Reduced Graphene Oxide, and Gold Nanoparticles Composite and Its Application to Hydrogen Peroxide Biosensor.

    PubMed

    Wu, Baoyan; Zhao, Na; Hou, Shihua; Zhang, Cong

    2016-11-21

    Here we report a facile eco-friendly one-step electrochemical approach for the fabrication of a polypyrrole (PPy), reduced graphene oxide (RGO), and gold nanoparticles (nanoAu) biocomposite on a glassy carbon electrode (GCE). The electrochemical behaviors of PPy-RGO-nanoAu and its application to electrochemical detection of hydrogen peroxide were investigated by cyclic voltammetry. Graphene oxide and pyrrole monomer were first mixed and casted on the surface of a cleaned GCE. After an electrochemical processing consisting of the electrooxidation of pyrrole monomer and simultaneous electroreduction of graphene oxide and auric ions (Au(3+)) in aqueous solution, a PPy-RGO-nanoAu biocomposite was synthesized on GCE. Each component of PPy-RGO-nanoAu is electroactive without non-electroactive substance. The obtained PPy-RGO-nanoAu/GCE exhibited high electrocatalytic activity toward hydrogen peroxide, which allows the detection of hydrogen peroxide at a negative potential of about -0.62 V vs. SCE. The amperometric responses of the biosensor displayed a sensitivity of 40 µA/mM, a linear range of 32 µM-2 mM, and a detection limit of 2.7 µM (signal-to-noise ratio = 3) with good stability and acceptable reproducibility and selectivity. The results clearly demonstrate the potential of the as-prepared PPy-RGO-nanoAu biocomposite for use as a highly electroactive matrix for an amperometric biosensor.

  10. Graphene-based screen-printed electrochemical (bio)sensors and their applications: Efforts and criticisms.

    PubMed

    Cinti, Stefano; Arduini, Fabiana

    2017-03-15

    K.S. Novoselov in his Nobel lecture (December 8, 2010), described graphene as "more than just a flat crystal" and summarized the best possible impression of graphene with (i) it is the first example of 2D atomic crystals, (ii) it demonstrated unique electronic properties, thanks to charge carriers which mimic massless relativistic particles, and (iii) it has promise for a number of applications. The fascinating and unusual properties of this 2D material were indeed recently investigated and exploited in several disciplines including physics, medicine, and chemistry, indicating the extremely versatile and polyedric aspect of this nanomaterial. The utilization of nanomaterials, printed technology, and microfluidics in electroanalysis has resulted in a period that can be called the "Electroanalysis Renaissance" (Escarpa, 2012) in which graphene is without any doubt a forefront nanomaterial. The rise in affordable fabrication processes, along with the great dispersing attitude in a plenty of matrices, have made graphene powerful in large-scale production of electrochemical platforms. Herein, we overview the employment of graphene to customize and/or fabricate printable based (bio)sensors over the past 5 years, including several modification approaches such as drop casting, screen- and inkjet-printing, different strategies of graphene-based sensing, and applications as well. The objective of this review is to provide a critical perspective related to advantages and disadvantages of using graphene in biosensing tools, based on screen-printed sensors.

  11. Investigation of Hemoglobin/Gold Nanoparticle Heterolayer on Micro-Gap for Electrochemical Biosensor Application

    PubMed Central

    Lee, Taek; Kim, Tae-Hyung; Yoon, Jinho; Chung, Yong-Ho; Lee, Ji Young; Choi, Jeong-Woo

    2016-01-01

    In the present study, we fabricated a hemoglobin/gold nanoparticle (Hb/GNP) heterolayer immobilized on the Au micro-gap to confirm H2O2 detection with a signal-enhancement effect. The hemoglobin which contained the heme group catalyzed the reduction of H2O2. To facilitate the electron transfer between hemoglobin and Au micro-gap electrode, a gold nanoparticle was introduced. The Au micro-gap electrode that has gap size of 5 µm was fabricated by conventional photolithographic technique to locate working and counter electrodes oppositely in a single chip for the signal sensitivity and reliability. The hemoglobin was self-assembled onto the Au surface via chemical linker 6-mercaptohexanoic acid (6-MHA). Then, the gold nanoparticles were adsorbed onto hemoglobin/6-MHA heterolayers by the layer-by-layer (LbL) method. The fabrication of the Hb/GNP heterolayer was confirmed by atomic force microscopy (AFM) and surface-enhanced Raman spectroscopy (SERS). The redox property and H2O2 detection of Hb/GNP on the micro-gap electrode was investigated by a cyclic voltammetry (CV) experiment. Taken together, the present results show that the electrochemical signal-enhancement effect of a hemoglobin/nanoparticle heterolayer was well confirmed on the micro-scale electrode for biosensor applications. PMID:27171089

  12. A Low-Cost Smartphone-Based Electrochemical Biosensor for Point-of-Care Diagnostics

    PubMed Central

    Sun, Alexander; Wambach, Travis; Venkatesh, A. G.; Hall, Drew A.

    2015-01-01

    This paper describes the development of a smartphone-based electrochemical biosensor module. The module contains a low power potentiostat that interfaces and harvests power from a smartphone through the phone’s audio jack. A prototype with two different potentiostat designs was constructed and used to conduct proof of concept cyclic voltammetry experiments with potassium ferro-/ferricyanide (K4[Fe(CN)6] / K3[Fe(CN)6]) in a side-by-side comparison with a laboratory grade instrument. Results show that the module functions within the available power budget and that the recovered voltammogram data matches well with the data from an expensive bench top tool. Excluding the loses from supply rectification and regulation, the module consumes either 5.7 mW or 4.3 mW peak power, depending on which of the two discussed potentiostat designs is used. At single quantity pricing, the hardware for the prototype device costs less than $30. PMID:26097899

  13. Electrochemical impedance spectroscopy biosensor with interdigitated electrode for detection of human immunoglobulin A.

    PubMed

    Ohno, Ryuzo; Ohnuki, Hitoshi; Wang, Huihui; Yokoyama, Takuya; Endo, Hideaki; Tsuya, Daiju; Izumi, Mitsuru

    2013-02-15

    Interdigitated electrodes (IDEs) that have a series of parallel microband electrodes with alternating microbands connected together were utilized in electrochemical impedance spectroscopy (EIS) to build a label-free human immunoglobulin A (IgA) immunosensor. Anti-human IgA (anti-IgA) was employed as an IgA receptor and was covalently immobilized on the IDE surface through a self-assembled monolayer, as confirmed by atomic force microscopy. EIS measurements revealed that the specific adsorption of IgA onto the immobilized anti-IgA gave rise to a clear increase in the value of interfacial charge transfer resistance (R(ct)). A linear relationship between ΔR(ct) and the logarithm of IgA concentration was found for the concentration range of 0.01-100 ng/mL. No modulation of R(ct) was detected by immersing the sensor in solutions of other proteins such as human immunoglobulin G or bovine serum albumin, which confirmed a high selectivity of this immunosensor for IgA. These results demonstrated that the anti-IgA receptor simply immobilized on the IDE surface can provide a sensitive biosensor.

  14. A silk derived carbon fiber mat modified with Au@Pt urchilike nanoparticles: A new platform as electrochemical microbial biosensor.

    PubMed

    Deng, Liu; Guo, Shaojun; Zhou, Ming; Liu, Ling; Liu, Chang; Dong, Shaojun

    2010-06-15

    We present here a facile and efficient route to prepare silk derived carbon mat modified with Au@Pt urchilike nanoparticles (Au@Pt NPs) and develop an Escherichia coli (E. coli)-based electrochemical sensor using this material. Silk is a natural protein fiber, and it is abundant with kinds of functionalities which are important in the development of the derived material. The S-derived carbon fiber mat have amino, pyridine and carbonyl functional groups, these natural existent functionalities allow the Au@Pt NPs to self-assemble on the carbon fiber surface and provide a biocompatible microenvironment for bacteria. The Au@Pt NPs modified S-derived carbon fiber is sensitive to detect the E. coli activities with a low detection limit, where glucose is used as a prelimiltary substrate to evaluate them. The performance of Au@Pt/carbon fiber mat based biosensor is much better than that of commercial carbon paper based biosensor. The high sensitivity of this biosensor stems from the unique electrocatalytic properties of Au@Pt urchilike NPs and quinone groups presented in S-derived carbon fiber. This biosensor is also tested for detection of organophosphate pesticides, fenamiphos. The relative inhibition of E. coli activity is linear with -log[fenamiphos] at the concentration range from 0.5mg/L to 36.6 mg/L with lowest observable effect concentration (LOEC) of 0.09 mg/L. The Au@Pt NPs modified S-derived carbon fiber mat possesses high conductivity, biocompatibility and high electrocatalytic activity and be can used as advanced electrode materials for microbial biosensor improvement. The microbial biosensor based on this material shows potential applications in environmental monitoring.

  15. A label-free ultrasensitive electrochemical DNA sensor based on thin-layer MoS2 nanosheets with high electrochemical activity.

    PubMed

    Wang, Xinxing; Nan, Fuxin; Zhao, Jinlong; Yang, Tao; Ge, Tong; Jiao, Kui

    2015-02-15

    A label-free and ultrasensitive electrochemical DNA biosensor, based on thin-layer molybdenum disulfide (MoS2) nanosheets sensing platform and differential pulse voltammetry detection, is constructed in this paper. The thin-layer MoS2 nanosheets were prepared via a simple ultrasound exfoliation method from bulk MoS2, which is simpler and no distortion compared with mechanical cleavage and lithium intercalation. Most importantly, this procedure allows the formation of MoS2 with enhanced electrochemical activity. Based on the high electrochemical activity and different affinity toward ssDNA versus dsDNA of the thin-layer MoS2 nanosheets sensing platform, the tlh gene sequence assay can be performed label-freely from 1.0 × 10(-16)M to 1.0 × 10(-10)M with a detection limit of 1.9 × 10(-17)M. Without labeling and the use of amplifiers, the detection method described here not only expands the application of MoS2, but also offers a viable alternative for DNA analysis, which has the priority in sensitivity, simplicity, and costs. Moreover, the proposed sensing platform has good electrocatalytic activity, and can be extended to detect more targets, such as guanine and adenine, which further expands the application of MoS2.

  16. A novel self-powered and sensitive label-free DNA biosensor in microbial fuel cell.

    PubMed

    Asghary, Maryam; Raoof, Jahan Bakhsh; Rahimnejad, Mostafa; Ojani, Reza

    2016-08-15

    In this work, a novel self-powered, sensitive, low-cost, and label-free DNA biosensor is reported by applying a two-chambered microbial fuel cell (MFC) as a power supply. A graphite electrode and an Au nanoparticles modified graphite electrode (AuNP/graphite electrode) were used as anode and cathode in the MFC system, respectively. The active biocatalyst in the anodic chamber was a mixed culture of microorganisms. The sensing element of the biosensor was fabricated by the well-known Au-thiol binding the ssDNA probe on the surface of an AuNP/graphite cathode. Electrons produced by microorganisms were transported from the anode to the cathode through an external circuit, which could be detected by the terminal multi-meter detector. The difference between power densities of the ssDNA probe modified cathode in the absence and presence of complementary sequence served as the detection signal of the DNA hybridization with detection limit of 3.1nM. Thereafter, this biosensor was employed for diagnosis and determination of complementary sequence in a human serum sample. The hybridization specificity studies further revealed that the developed DNA biosensor could distinguish fully complementary sequences from one-base mismatched and non-complementary sequences.

  17. Graphene coated fiber optic surface plasmon resonance biosensor for the DNA hybridization detection: Simulation analysis

    NASA Astrophysics Data System (ADS)

    Shushama, Kamrun Nahar; Rana, Md. Masud; Inum, Reefat; Hossain, Md. Biplob

    2017-01-01

    In this paper, a graphene coated optical fiber surface plasmon resonance (SPR) biosensor is presented for the detection of DNA Hybridization. For the proposed sensor, a four layer model (fiber core /metal /sensing layer /sample) where a sheet of graphene (biomolecular recognition elements (BRE)) acting as a sensing layer is coated around the gold film because graphene enhances the sensitivity of fiber optic SPR biosensor. Numerical analysis shows the variation of resonance wavelength and spectrum of transmitted power for mismatched DNA strands and for complementary DNA strands. For mismatched DNA strands variation is negligible whereas for complementary DNA strands is considerably countable. Proposed sensor successfully distinguishes hybridization and single nucleotide polymorphisms (SNP) by observing the variation level of resonance wavelength and spectrum of transmitted power.

  18. A high sensitivity wireless mass-loading surface acoustic wave DNA biosensor

    NASA Astrophysics Data System (ADS)

    Cai, Hua-Lin; Yang, Yi; Zhang, Yi-Han; Zhou, Chang-Jian; Guo, Cang-Ran; Liu, Jing; Ren, Tian-Ling

    2014-03-01

    In this paper, a surface acoustic wave (SAW) biosensor with gold delay area on LiNbO3 substrate detecting DNA sequences is proposed. By well-designed device parameters of the SAW sensor, it achieves a high performance for highly sensitive detection of target DNA. In addition, an effective biological treatment method for DNA immobilization and abundant experimental verification of the sensing effect have made it a reliable device in DNA detection. The loading mass of the probe and target DNA sequences is obtained from the frequency shifts, which are big enough in this work due to an effective biological treatment. The experimental results show that the biosensor has a high sensitivity of 1.2 pg/ml/Hz and high selectivity characteristic is also verified by the few responses of other substances. In combination with wireless transceiver, we develop a wireless receiving and processing system that can directly display the detection results.

  19. Electrochemical sandwich-type biosensors for α-1 antitrypsin with carbon nanotubes and alkaline phosphatase labeled antibody-silver nanoparticles.

    PubMed

    Zhu, Gangbing; Lee, Hye Jin

    2017-03-15

    A novel sandwich-type biosensor was developed for the electrochemical detection of α-1 antitrypsin (AAT, a recognized biomarker for Alzheimer's disease). The biosensor was composed of 3, 4, 9, 10-perylene tetracarboxylic acid/carbon nanotubes (PTCA-CNTs) as a sensing platform and alkaline phosphatase-labeled AAT antibody functionalized silver nanoparticles (ALP-AAT Ab-Ag NPs) as a signal enhancer. CNTs offer high surface area and good electrical conductivity. Importantly, Ag NPs could increase the amount of ALP on the sensing surface and the ALP could dephosphorylate 4-amino phenyl phosphate (APP) enzymatically to produce electroactive species 4-aminophenol (AP). For detecting AAT based on the sandwich-type biosensor, the results show that the peak current value of AP using ALP-AAT Ab-Ag NPs as signal enhancer is much higher than that by using ALP-AAT Ab bioconjugate (without Ag NPs), the biosensor exhibited desirable performance for AAT determination with a wide linearity in the range from 0.05 to 20.0pM and a low detection limit of 0.01pM. Finally, the developed sensor was successfully applied to the analysis of AAT concentration in serum samples.

  20. Co-immobilization of glucoamylase and glucose oxidase for electrochemical sequential enzyme electrode for starch biosensor and biofuel cell.

    PubMed

    Lang, Qiaolin; Yin, Long; Shi, Jianguo; Li, Liang; Xia, Lin; Liu, Aihua

    2014-01-15

    A novel electrochemical sequential biosensor was constructed by co-immobilizing glucoamylase (GA) and glucose oxidase (GOD) on the multi-walled carbon nanotubes (MWNTs)-modified glassy carbon electrode (GCE) by chemical crosslinking method, where glutaraldehyde and bovine serum albumin was used as crosslinking and blocking agent, respectively. The proposed biosensor (GA/GOD/MWNTs/GCE) is capable of determining starch without using extra sensors such as Clark-type oxygen sensor or H2O2 sensor. The current linearly decreased with the increasing concentration of starch ranging from 0.005% to 0.7% (w/w) with the limit of detection of 0.003% (w/w) starch. The as-fabricated sequential biosensor can be applicable to the detection of the content of starch in real samples, which are in good accordance with traditional Fehling's titration. Finally, a stable starch/O2 biofuel cell was assembled using the GA/GOD/MWNTs/GCE as bioanode and laccase/MWNTs/GCE as biocathode, which exhibited open circuit voltage of ca. 0.53 V and the maximum power density of 8.15 μW cm(-2) at 0.31 V, comparable with the other glucose/O2 based biofuel cells reported recently. Therefore, the proposed biosensor exhibited attractive features such as good stability in weak acidic buffer, good operational stability, wide linear range and capable of determination of starch in real samples as well as optimal bioanode for the biofuel cell.

  1. Effect of platinum nanoparticle deposition parameters on hydrogen peroxide transduction for applications in wearable electrochemical glucose biosensors

    NASA Astrophysics Data System (ADS)

    Cargill, Allison A.; Neil, Kathrine M.; Hondred, John A.; McLamore, Eric S.; Claussen, Jonathan C.

    2016-05-01

    Enhanced interest in wearable biosensor technology over the past decade is directly related to the increasing prevalence of diabetes and the associated requirement of daily blood glucose monitoring. In this work we investigate the platinum-carbon transduction element used in traditional first-generation glucose biosensors which rely on the concentration of hydrogen peroxide produced by the glucose-glucose oxidase binding scheme. We electrodeposit platinum nanoparticles on a commercially-available screen printed carbon electrode by stepping an applied current between 0 and 7.12 mA/cm2 for a varying number of cycles. Next, we examine the trends in deposition and the effect that the number of deposition cycles has on the sensitivity of electrochemical glucose sensing. Results from this work indicate that applying platinum nanoparticles to screen printed carbon via electrodeposition from a metal salt solution improves overall biosensor sensitivity. This work also pinpoints the amount of platinum (i.e., number of deposition cycles) that maximizes biosensor sensitivity in an effort to minimize the use of the precious metals, viz., platinum, in electrode fabrication. In summary, this work quantifies the relationship between platinum electrodeposition and sensor performance, which is crucial in designing and producing cost-effective sensors.

  2. RCA-Based Biosensor for Electrical and Colorimetric Detection of Pathogen DNA

    NASA Astrophysics Data System (ADS)

    Jeong, Jaepil; Kim, Hyejin; Lee, Dong Jun; Jung, Byung Jun; Lee, Jong Bum

    2016-05-01

    For the diagnosis and prevention of diseases, a range of strategies for the detection of pathogens have been developed. In this study, we synthesized the rolling circle amplification (RCA)-based biosensor that enables detection of pathogen DNA in two analytical modes. Only in the presence of the target DNA, the template DNA can be continuously polymerized by simply carrying out RCA, which gives rise to a change of surface structure of Au electrodes and the gap between the electrodes. Electrical signal was generated after introducing hydrogen tetrachloroaurate (HAuCl4) to the DNA-coated biosensor for the improvement of the conductivity of DNA, which indicates that the presence of the pathogen DNA can be detected in an electrical approach. Furthermore, the existence of the target DNA was readily detected by the naked eyes through change in colors of the electrodes from bright yellow to orange-red after RCA reaction. The RCA-based biosensor offers a new platform for monitoring of pathogenic DNA with two different detection modes in one system.

  3. The utilization of SiNWs/AuNPs-modified indium tin oxide (ITO) in fabrication of electrochemical DNA sensor.

    PubMed

    Rashid, Jahwarhar Izuan Abdul; Yusof, Nor Azah; Abdullah, Jaafar; Hashim, Uda; Hajian, Reza

    2014-12-01

    This work describes the incorporation of SiNWs/AuNPs composite as a sensing material for DNA detection on indium tin-oxide (ITO) coated glass slide. The morphology of SiNWs/AuNPs composite as the modifier layer on ITO was studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The morphological studies clearly showed that SiNWs were successfully decorated with 20 nm-AuNPs using self-assembly monolayer (SAM) technique. The effective surface area for SiNWs/AuNPs-modified ITO enhanced about 10 times compared with bare ITO electrode. SiNWs/AuNPs nanocomposite was further explored as a matrix for DNA probe immobilization in detection of dengue virus as a bio-sensing model to evaluate its performance in electrochemical sensors. The hybridization of complementary DNA was monitored by differential pulse voltammetry (DPV) using methylene blue (MB) as the redox indicator. The fabricated biosensor was able to discriminate significantly complementary, non-complementary and single-base mismatch oligonucleotides. The electrochemical biosensor was sensitive to target DNA related to dengue virus in the range of 9.0-178.0 ng/ml with detection limit of 3.5 ng/ml. In addition, SiNWs/AuNPs-modified ITO, regenerated up to 8 times and its stability was up to 10 weeks at 4°C in silica gel.

  4. Macrocyclic Metal Complex-DNA Conjugates for Electrochemical Sensing of Single Nucleobase Changes in DNA.

    PubMed

    Duprey, Jean-Louis H A; Carr-Smith, James; Horswell, Sarah L; Kowalski, Jarosław; Tucker, James H R

    2016-01-27

    The direct incorporation of macrocyclic cyclidene complexes into DNA via automated synthesis results in a new family of metal-functionalized DNA derivatives that readily demonstrate their utility through the ability of one redox-active copper(II)-containing strand to distinguish electrochemically between all four canonical DNA nucleobases at a single site within a target sequence of DNA.

  5. Electrospun manganese (III) oxide nanofiber based electrochemical DNA-nanobiosensor for zeptomolar detection of dengue consensus primer.

    PubMed

    Tripathy, Suryasnata; Krishna Vanjari, Siva Rama; Singh, Vikrant; Swaminathan, S; Singh, Shiv Govind

    2017-04-15

    Nanoscale biosensors, owing to their high-sensitivity and extremely low limits-of-detection, have enabled the realization of highly complex and sophisticated miniaturized platforms for several important healthcare applications, the most predominant one being disease diagnosis. In particular, nanomaterial facilitated electrochemical detection of DNA hybridization has had an exceptional impact on fields such as genetics and cancerous mutation detection Here we report an ultrasensitive electrochemical platform using electrospun semi-conducting Manganese (III) Oxide (Mn2O3) nanofibers for DNA Hybridization detection. The proposed platform coalesces the inherent advantages of metal-oxide nanofibers and electrochemical transduction techniques, resulting in label-free zeptomolar detection of DNA hybridization. As proof of concept, we demonstrate zeptomolar detection of Dengue consensus primer (limit of detection: 120×10(-21)M) both in control as well as spiked serum samples. Our reported detection limit is superior in comparison with previously reported electrochemical DNA hybridization sensors for Dengue virus detection, spanning both labeled and label-free transductions. This ultra-sensitivity, we believe, is a result of synthesizing a low bandgap electrospun metal-oxide nanomaterial corresponding to a specific oxidation state of Manganese. This methodology can be extended for detection of any hybridization of interest by simply adapting an appropriate functionalization protocol and thus is very generic in nature.

  6. Electrochemical studies on polysorbate-20 (Tween 20)-entrapped haemoglobin and its application in a hydrogen peroxide biosensor.

    PubMed

    Ma, Xiang; Chen, Ting; Liu, Lifang; Li, Genxi

    2005-06-01

    Haemoglobin (Hb) was entrapped in polysorbate 20 and then modified on a pyrolytic graphite electrode. Electrochemical studies revealed that a pair of stable and well-defined redox peaks attributed to the direct redox reaction of Hb could be observed in a phosphate buffer solution (pH 6.0). The anodic and cathodic peaks were located at -236 and -316 mV (versus a saturated calomel reference electrode) separately. The formal potential, E0', was linearly varied with pH in the range from 3.0 to 10.0 with a slope of -48.0 mV.pH-1. Moreover, the protein was capable of catalysing the reduction of H2O2. Accordingly, an unmediated biosensor for H2O2 was prepared with a linear range from 8.0x10(-7) to 1.0x10(-3) M. This biosensor exhibited good stability, sensitivity and reproducibility.

  7. Determination of Parathion and Carbaryl Pesticides in Water and Food Samples Using a Self Assembled Monolayer/Acetylcholinesterase Electrochemical Biosensor

    PubMed Central

    Pedrosa, Valber A.; Caetano, Josiane; Machado, Sergio A. S.; Bertotti, Mauro

    2008-01-01

    An acetylcholinesterase (AchE) based amperometric biosensor was developed by immobilisation of the enzyme onto a self assembled modified gold electrode. Cyclic voltammetric experiments performed with the SAM-AchE biosensor in phosphate buffer solutions (pH = 7.2) containing acetylthiocholine confirmed the formation of thiocholine and its electrochemical oxidation at Ep = 0.28 V vs Ag/AgCl. An indirect methodology involving the inhibition effect of parathion and carbaryl on the enzymatic reaction was developed and employed to measure both pesticides in spiked natural water and food samples without pre-treatment or pre-concentration steps. Values higher than 91-98.0% in recovery experiments indicated the feasibility of the proposed electroanalytical methodology to quantify both pesticides in water or food samples. HPLC measurements were also performed for comparison and confirmed the values measured amperometrically. PMID:27873775

  8. Recent Advances in the Fabrication and Application of Screen-Printed Electrochemical (Bio)Sensors Based on Carbon Materials for Biomedical, Agri-Food and Environmental Analyses.

    PubMed

    Hughes, Gareth; Westmacott, Kelly; Honeychurch, Kevin C; Crew, Adrian; Pemberton, Roy M; Hart, John P

    2016-09-28

    This review describes recent advances in the fabrication of electrochemical (bio)sensors based on screen-printing technology involving carbon materials and their application in biomedical, agri-food and environmental analyses. It will focus on the various strategies employed in the fabrication of screen-printed (bio)sensors, together with their performance characteristics; the application of these devices for the measurement of selected naturally occurring biomolecules, environmental pollutants and toxins will be discussed.

  9. Recent Advances in the Fabrication and Application of Screen-Printed Electrochemical (Bio)Sensors Based on Carbon Materials for Biomedical, Agri-Food and Environmental Analyses

    PubMed Central

    Hughes, Gareth; Westmacott, Kelly; Honeychurch, Kevin C.; Crew, Adrian; Pemberton, Roy M.; Hart, John P.

    2016-01-01

    This review describes recent advances in the fabrication of electrochemical (bio)sensors based on screen-printing technology involving carbon materials and their application in biomedical, agri-food and environmental analyses. It will focus on the various strategies employed in the fabrication of screen-printed (bio)sensors, together with their performance characteristics; the application of these devices for the measurement of selected naturally occurring biomolecules, environmental pollutants and toxins will be discussed. PMID:27690118

  10. Electrochemical Characterization of Graphene and MWCNT Screen-Printed Electrodes Modified with AuNPs for Laccase Biosensor Development

    PubMed Central

    Favero, Gabriele; Fusco, Giovanni; Mazzei, Franco; Tasca, Federico; Antiochia, Riccarda

    2015-01-01

    The aim of this work is to show how the integration of gold nanoparticles (AuNPs) into multi-wall-carbon-nanotubes (MWCNTs) based screen-printed electrodes and into graphene-based screen-printed electrodes (GPHs) could represent a potential way to further enhance the electrochemical properties of those electrodes based on nanoparticles. Laccase from Trametes versicolor (TvL) was immobilized over MWCNTs and GPH previously modified with AuNPs (of 5 and 10 nm). The characterization of the modified electrode surface has been carried out by cyclic voltammetry. The results showed that the use of AuNPs for modification of both graphene and MWCNTs screen-printed electrode surfaces would increase the electrochemical performances of the electrodes. MWCNTs showed better results than GPH in terms of higher electroactive area formation after modification with AuNPs. The two modified nanostructured electrodes were successively proven to efficiently immobilize the TvL; the electrochemical sensing properties of the GPH- and MWCNT-based AuNPs-TvL biosensors were investigated by choosing 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic-acid diammonium salt (ABTS), catechol and caffeic acid as laccase mediators; and the kinetic parameters of the laccase biosensor were carefully evaluated. PMID:28347108

  11. Enzyme-catalyzed O2 removal system for electrochemical analysis under ambient air: application in an amperometric nitrate biosensor.

    PubMed

    Plumeré, Nicolas; Henig, Jörg; Campbell, Wilbur H

    2012-03-06

    Electroanalytical procedures are often subjected to oxygen interferences. However, achieving anaerobic conditions in field analytical chemistry is difficult. In this work, novel enzymatic systems were designed to maintain oxygen-free solutions in open, small volume electrochemical cells and implemented under field conditions. The oxygen removal system consists of an oxidase enzyme, an oxidase-specific substrate, and catalase for dismutation of hydrogen peroxide generated in the enzyme catalyzed oxygen removal reaction. Using cyclic voltammetry, three oxidase enzyme/substrate combinations with catalase were analyzed: glucose oxidase with glucose, galactose oxidase with galactose, and pyranose 2-oxidase with glucose. Each system completely removed oxygen for 1 h or more in unstirred open vessels. Reagents, catalysts, reaction intermediates, and products involved in the oxygen reduction reaction were not detected electrochemically. To evaluate the oxygen removal systems in a field sensing device, a model nitrate biosensor based on recombinant eukaryotic nitrate reductase was implemented in commercial screen-printed electrochemical cells with 200 μL volumes. The products of the aldohexose oxidation catalyzed by glucose oxidase and galactose oxidase deactivate nitrate reductase and must be quenched for biosensor applications. For general application, the optimum catalyst is pyranose 2-oxidase since the oxidation product does not interfere with the biorecognition element.

  12. Paper-based enzyme immobilization for flow injection electrochemical biosensor integrated with reagent-loaded cartridge toward portable modular device.

    PubMed

    Tan, Swee Ngin; Ge, Liya; Tan, Hsih Yin; Loke, Weng Keong; Gao, Jinrong; Wang, Wei

    2012-11-20

    Paper-based enzyme immobilization for a flow injection electrochemical biosensor integrated with a reagent-loaded cartridge toward a portable device was developed. A paper disk was immobilized with enzyme, then it was integrated in a flow cell as an electrochemical biosensor. A silicon tube reagent-loaded cartridge was integrated into the system, a complicated procedure was simplified as a one-click operation toward development for point-of-care applications. In this research, glucose oxidase (GOx) was employed as a model enzyme, silver ion as an inhibition reagent for GOx, and EDTA as a regeneration reagent. When GOx was inhibited by silver ions, glucose was introduced for electrochemical measurements before and after inhibited enzyme regeneration and the difference was caused by silver inhibition. The modular device has great potential for other applications, e.g., detection of enzyme activity and substrate. The platform based on double-test mode provided accurate results due to elimination of an average or control value in comparison with classical routine approaches.

  13. Sensitive detection of maltose and glucose based on dual enzyme-displayed bacteria electrochemical biosensor.

    PubMed

    Liu, Aihua; Lang, Qiaolin; Liang, Bo; Shi, Jianguo

    2017-01-15

    Glucoamylase-displayed bacteria (GA-bacteria) and glucose dehydrogenase-displayed bacteria (GDH-bacteria) were co-immobilized on multi-walled carbon nanotubes (MWNTs) modified glassy carbon electrode (GCE) to construct GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor. The biosensor was developed by optimizing the loading amount and the ratio of GA-bacteria to GDH-bacteria. The as-prepared biosensor exhibited a wide dynamic range of 0.2-10mM and a low detection limit of 0.1mM maltose (S/N=3). The biosensor also had a linear response to glucose in the range of 0.1-2.0mM and a low detection limit of 0.04mM glucose (S/N=3). Interestingly, at the same concentration, glucose was 3.75-fold sensitive than that of maltose at the proposed biosensor. No interferences were observed for other possible mono- and disaccharides. The biosensor also demonstrated good long-term storage stability and repeatability. Further, using both GDH-bacteria/MWNTs/GCE biosensor and GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor, glucose and maltose in real samples can be detected. Therefore, the proposed biosensor is capable of monitoring the food manufacturing and fermentation process.

  14. Identification and quantitation of Bacillus globigii using metal enhanced electrochemical detection and capillary biosensor.

    PubMed

    Mwilu, Samuel K; Aluoch, Austin O; Miller, Seth; Wong, Paula; Sadik, Omowunmi A; Fatah, Alim A; Arcilesi, Richard D

    2009-09-15

    Presented herein are two detection strategies for the identification and quantification of Bacillus globigii, a spore forming nonpathogenic simulant of Bacillus anthracis. The first strategy involves a label-free, metal-enhanced electrochemical immunosensor for the quantitative detection of Bacillus globigii (atrophaeus). The immunosensor comprises of antibacillus globigii (BG) antibody self-assembled onto a gold quartz crystal electrode via cystamine bond. A solid-phase monolayer of silver underpotentially deposited onto the cystamine modified-Au-electrode surface is used as the redox probe. The monolayer was also generated by adsorbing silver nanoparticles on the gold electrode. When the antibody-modified electrode is exposed to BG spores, the antibody-antigen (Ab-Ag) complex formed insulated the electrode surface toward the silver redox probe. The variation of redox current was found to be proportional to the concentration of the BG spores between 1 x 10(2)-3.5 x 10(4) spores/mL. A detection limit of 602 spores/mL was obtained, which is well-below the infectious dose of anthrax spores at 2.5 x 10(5) spores/mL. The second approach involves the use of ultrasensitive portable capillary biosensor (UPAC) to detect the spores. The capillary is an enclosed system that acts as the flow cell, the waveguide, and the solid support for immobilized bimolecular probes. An evanescent excitation generates a signal from an antigen-antibody-fluorophore complex, which propagates along the capillary and is guided to the detector. A limit of detection of 112 spores/mL was reported using the UPAC sensor. Both methods showed lower detection limits compared to the conventional ELISA. The effect of potential interferants tested using Bacillus pumilus confirmed the selectivity for the analyte. This work should allow the first responders to rapidly detect and quantify Bacillus globigii spores at concentrations that are well-below the infectious dose.

  15. Electrochemical magnetic microbeads-based biosensor for point-of-care serodiagnosis of infectious diseases.

    PubMed

    Cortina, María E; Melli, Luciano J; Roberti, Mariano; Mass, Mijal; Longinotti, Gloria; Tropea, Salvador; Lloret, Paulina; Serantes, Diego A Rey; Salomón, Francisco; Lloret, Matías; Caillava, Ana J; Restuccia, Sabrina; Altcheh, Jaime; Buscaglia, Carlos A; Malatto, Laura; Ugalde, Juan E; Fraigi, Liliana; Moina, Carlos; Ybarra, Gabriel; Ciocchini, Andrés E; Comerci, Diego J

    2016-06-15

    Access to appropriate diagnostic tools is an essential component in the evaluation and improvement of global health. Additionally, timely detection of infectious agents is critical in early diagnosis and treatment of infectious diseases. Conventional pathogen detection methods such as culturing, enzyme linked immunosorbent assay (ELISA) or polymerase chain reaction (PCR) require long assay times, and complex and expensive instruments making them not adaptable to point-of-care (PoC) needs at resource-constrained places and primary care settings. Therefore, there is an unmet need to develop portable, simple, rapid, and accurate methods for PoC detection of infections. Here, we present the development and validation of a portable, robust and inexpensive electrochemical magnetic microbeads-based biosensor (EMBIA) platform for PoC serodiagnosis of infectious diseases caused by different types of microorganisms (parasitic protozoa, bacteria and viruses). We demonstrate the potential use of the EMBIA platform for in situ diagnosis of human (Chagas disease and human brucellosis) and animal (bovine brucellosis and foot-and-mouth disease) infections clearly differentiating infected from non-infected individuals or animals. For Chagas disease, a more extensive validation of the test was performed showing that the EMBIA platform displayed an excellent diagnostic performance almost indistinguishable, in terms of specificity and sensitivity, from a fluorescent immunomagnetic assay and the conventional ELISA using the same combination of antigens. This platform technology could potentially be applicable to diagnose other infectious and non-infectious diseases as well as detection and/or quantification of biomarkers at the POC and primary care settings.

  16. Electrochemical study of DNA damaged by oxidation stress.

    PubMed

    Zitka, Ondrej; Krizkova, Sona; Skalickova, Sylvie; Kopel, Pavel; Babula, Petr; Adam, Vojtech; Kizek, Rene

    2013-02-01

    Many compounds can interact with DNA leading to changes of DNA structure as point mutation and bases excision, which could trigger some metabolic failures, which leads to the changes in DNA structure resulting in cancer. Oxidation of nucleic acid bases belongs to the one of the mostly occurred type of DNA damaging leading to the above mentioned phenomena. The investigation of processes of DNA oxidation damage is topical and electrochemical methods include a versatile and sensitive tool for these purposes. 8-hydroxydeoxyguanosine (8-OHdG) is the most widely accepted marker of DNA damage. Oxidative damage to DNA by free radicals and exposure to ionizing radiation generate several other products within the double helix besides mentioned oxidation products of nucleic acid bases. The basic electrochemical behaviour of nucleic acids bases on various types of carbon electrodes is reviewed. Further, we address our attention on description of oxidation mechanisms and on detection of the most important products of nucleic bases oxidation. The miniaturization of detector coupled with some microfluidic devices is suggested and discussed. The main aim of this review is to report the advantages and features of the electrochemical detection of guanine oxidation product as 8-OHdG and other similarly produced molecules as markers for DNA damage.

  17. A Multiwell Electrochemical Biosensor for Real-Time Monitoring of the Behavioural Changes of Cells in Vitro

    PubMed Central

    Adlam, Daman J.; Woolley, David E.

    2010-01-01

    We report the development of a multiwell biosensor for detecting changes in the electrochemical open circuit potential (OCP) generated by viable human cells in vitro. The instrument features eight culture wells; each containing three gold sensors around a common silver/silver chloride reference electrode, prepared using screen-printed conductive inks. The potential applications of the device were demonstrated by monitoring rheumatoid synovial fibroblasts (RSF) and HepG2 hepatocarcinoma cells in response to chemical and biological treatments. This technology could provide an alternative to conventional end-point assays used in the fields of chemotherapy, toxicology and drug discovery. PMID:22319322

  18. Dendritic structure DNA for specific metal ion biosensor based on catalytic hairpin assembly and a sensitive synergistic amplification strategy.

    PubMed

    Zhao, Jianmin; Jing, Pei; Xue, Shuyan; Xu, Wenju

    2017-01-15

    In this work, a sensitive electrochemical biosensing to Pb(2+) was proposed based on the high specificity of DNAzymes to Pb(2+). The response signal was efficiently amplified by the catalytic hairpin assembly induced by strand replacement reaction and the formation of dendritic structure DNA (DSDNA) by layer-by-layer assembly. Firstly, in the presence of Pb(2+), the substrate strand (S1) of the Pb(2+)-specific DNAzymes was specifically cleaved by Pb(2+). Secondly, one of the two fragments (rS1) introduced into the electrode surface was hybridized with a hairpin DNA (H1) and further replaced by another hairpin DNA (H2) by the hybridization reaction of H1 with H2. The released rS1 then induced the next hybridization with H1. After repeated cycles, the catalytic recycling assembly of H2 with H1 was completed. Thirdly, two bioconjugates of Pt@Pd nanocages (Pt@PdNCs) labeled with DNA S3/S4 and electroactive toluidine blue (Tb) (Tb-S3-Pt@PdNCs and Tb-S4-Pt@PdNCs) were captured onto the resultant electrode surface through the hybridization of S3 and H2, S3 and S4, resulting in the formation of DSDNA triggered by layer-by-layer assembly. This formed DSDNA greatly facilitated the immobilization of manganese(III) meso-tetrakis (4-N-methylpyridiniumyl)-porphyrin (MnTMPyP) as mimicking enzyme. Under the synergistic catalysis of Pt@PdNCs and MnTMPyP to H2O2 reduction, the effective signal amplification of the developed Pb(2+) biosensor was achieved. As a result, the sensitive detection of the proposed electrochemical strategy for Pb(2+) was greatly improved in the range of 0.1pM-200nM with a detection limit of 0.033pM.

  19. Label-free slot-waveguide biosensor for the detection of DNA hybridization.

    PubMed

    Dar, Tuffail; Homola, Jiri; Rahman, B M Azizur; Rajarajan, Muttukrishnan

    2012-12-01

    A finite element method based on the full-vectorial H-field formulation has been employed to achieve the maximum field penetration in the sensing medium of the slot-waveguide-based ring resonator biosensor. The use of nanometer scale guiding structure where optical mode is confined in a low-index region permits a very compact sensor with high optical intensity in the region, which makes it possible to detect minimum refractive index change, and offers higher sensitivities. We analyze the change in effective refractive index of mode, sensitivity, and power confinement of the proposed slot-waveguide-based ring resonator biosensor for the detection of DNA hybridization. The biosensor exhibited theoretical sensitivity of 856 nm per refractive index unit (RIU) and a detection limit of 1.43×10(-6)  RIU.

  20. Facile construction of a highly sensitive DNA biosensor by in-situ assembly of electro-active tags on hairpin-structured probe fragment

    PubMed Central

    Wang, Qingxiang; Gao, Feng; Ni, Jiancong; Liao, Xiaolei; Zhang, Xuan; Lin, Zhenyu

    2016-01-01

    An ultrasensitive DNA biosensor has been developed through in-situ labeling of electroactive melamine-Cu2+ complex (Mel-Cu2+) on the end of hairpin-like probe using gold nanoparticles (AuNPs) as the signal amplification platform. The 3′-thiolated hairpin-like probe was first immobilized to the gold electrode surface by the Au-S bond. The AuNPs were then tethered on the free 5′-end of the immobilized probe via the special affinity between Au and the modified -NH2. Followed by, the Mel and Cu2+ were assembled on the AuNPs surface through Au-N bond and Cu2+-N bond, respectively. Due to the surface area and electrocatalytic effects of the AuNPs, the loading amount and electron transfer kinetic of the Mel-Cu2+ were enhanced greatly, resulting in significantly enhanced electrochemical response of the developed biosensor. Compared with the synthesis process of conventional electroactive probe DNA accomplished by homogeneous method, the method presented in this work is more reagent- and time-saving. The proposed biosensor showed high selectivity, wide linear range and low detection limit. This novel strategy could also be extended to the other bioanalysis platforms such as immunosensors and aptasensors. PMID:26931160

  1. An integrated lab-on-a-chip-based electrochemical biosensor for rapid and sensitive detection of cancer biomarkers.

    PubMed

    Uludag, Yildiz; Narter, Fehmi; Sağlam, Erkin; Köktürk, Güzin; Gök, M Yağmur; Akgün, Mete; Barut, Serkan; Budak, Sinan

    2016-11-01

    Recent advances in the area of biosensor technology and microfluidic applications have enabled the miniaturisation of the sensing platforms. Here we describe a new integrated and fully automated lab-on-a-chip-based biosensor device prototype (MiSens) that has potential to be used for point-of-care cancer biomarker testing. The key features of the device include a new biochip, a device integrated microfluidic system and real-time amperometric measurements during the flow of enzyme substrate. For ease of use, a new plug and play type sensor chip docking station has been designed. This system allows the formation of an ∼7 μL capacity flow cell on the electrode array with the necessary microfluidic and electronic connections with one move of a handle. As a case study, the developed prototype has been utilised for the detection of prostate-specific antigen (PSA) level in serum that is routinely used as a biomarker for the diagnosis of prostate cancer. The patient samples from a nearby hospital have been collected and tested using the MiSens device, and the results have been compared to the hospital results. The obtained results indicate the potential of the MiSens device as a useful tool for point-of-care testing. Graphical abstract Microfluidics integrated and automated electrochemical biosensor device "MiSens" has been designed and fabricated by a multidisciplinary team and utilised to detect PSA from clinical samples.

  2. A novel mesoporous silica nanosphere matrix for the immobilization of proteins and their applications as electrochemical biosensor.

    PubMed

    Li, Juan; Qin, Xingzhang; Yang, Zhanjun; Qi, Huamei; Xu, Qin; Diao, Guowang

    2013-01-30

    A mesoporous silica nanoshpere (MSN) was proposed to modify glassy carbon electrode (GCE) for the immobilization of protein. Using glucose oxidase (GOD) as a model, direct electrochemistry of protein and biosensing at the MSN modified GCE was studied for the first time. The MNS had large surface area and offered a favorable microenvironment for facilitating the direct electron transfer between enzyme and electrode surface. Scanning electron microscopy, transmission electron microscopy, UV-vis spectroscopy and cyclic voltammetry were used to examine the interaction between GOD and the MSN matrix. The results demonstrated that the immobilized enzyme on the MSN retained its native structure and bioactivity. In addition, the electrochemical reaction showed a surface controlled, reversible two-proton and two-electron transfer process with the apparent electron transfer rate constant of 3.96 s(-1). The MNS-based glucose biosensor exhibited the two linear ranges of 0.04-2.0 mM and 2.0-4.8 mM, a high sensitivity of 14.5 mA M(-1) cm(-2) and a low detection limit of 0.02 mM at signal-to-noise of 3. The proposed biosensor showed excellent selectivity, good reproducibility, acceptable stability and could be successfully applied in the reagentless detection of glucose in real samples at -0.45 V. The work displayed that mesoporous silica nanosphere provided a promising approach for immobilizing proteins and fabrication of excellent biosensors.

  3. Aptamer-based biosensor for label-free detection of ethanolamine by electrochemical impedance spectroscopy.

    PubMed

    Liang, Gang; Man, Yan; Jin, Xinxin; Pan, Ligang; Liu, Xinhui

    2016-09-14

    A label-free sensing assay for ethanolamine (EA) detection based on G-quadruplex-EA binding interaction is presented by using G-rich aptamer DNA (Ap-DNA) and electrochemical impedance spectroscopy (EIS). The presence of K(+) induces the Ap-DNA to form a K(+)-stabilized G-quadruplex structure which provides binding sites for EA. The sensing mechanism was further confirmed by circular dichroism (CD) spectroscopy and EIS measurement. As a result, the charge transfer resistance (RCT) is strongly increased as demonstrated by using the ferro/ferricyanide ([Fe(CN)6](3-/4-)) as a redox probe. Under the optimized conditions, a linear relationship between ΔRCT and EA concentration was obtained over the range of 0.16 nM and 16 nM EA, with a detection limit of 0.08 nM. Interference by other selected chemicals with similar structure was negligible. Analytical results of EA spiked into tap water and serum by the sensor suggested the assay could be successfully applied to real sample analysis. With the advantages of high sensitivity, selectivity and simple sensor construction, this method is potentially suitable for the on-site monitoring of EA contamination.

  4. A simple, portable, electrochemical biosensor to screen shellfish for Vibrio parahaemolyticus.

    PubMed

    Nordin, Noordiana; Yusof, Nor Azah; Abdullah, Jaafar; Radu, Son; Hushiarian, Roozbeh

    2017-12-01

    An earlier electrochemical mechanism of DNA detection was adapted and specified for the detection of Vibrio parahaemolyticus in real samples. The reader, based on a screen printed carbon electrode, was modified with polylactide-stabilized gold nanoparticles and methylene blue was employed as the redox indicator. Detection was assessed using a microprocessor to measure current response under controlled potential. The fabricated sensor was able to specifically distinguish complementary, non-complementary and mismatched oligonucleotides. DNA was measured in the range of 2.0 × 10(-8)-2.0 × 10(-13) M with a detection limit of 2.16 pM. The relative standard deviation for 6 replications of differential pulse voltammetry (DPV) measurement of 0.2 µM complementary DNA was 4.33%. Additionally, cross-reactivity studies against various other food-borne pathogens showed a reliably sensitive detection of the target pathogen. Successful identification of Vibrio parahaemolyticus (spiked and unspiked) in fresh cockles, combined with its simplicity and portability demonstrate the potential of the device as a practical screening tool.

  5. Biointerfacial Property of Plasma-Treated Single-Walled Carbon Nanotube Film Electrodes for Electrochemical Biosensors

    NASA Astrophysics Data System (ADS)

    Hyub Kim, Joon; Lee, Jun-Yong; Jin, Joon-Hyung; Park, Eun Jin; Min, Nam Ki

    2013-01-01

    The single-walled carbon nanotube (SWCNT)-based thin film was spray-coated on the Pt support and functionalized using O2 plasma. The effects of plasma treatment on the biointerfacial properties of the SWCNT films were analyzed by cyclic voltammogram (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). The plasma-functionalized (pf) SWCNT electrodes modified with Legionella pneumophila-specific probe DNA strands showed a much higher peak current and a smaller peak separation in differential pulse voltammetry and a lower charge transfer resistance, compared to the untreated samples. These results suggest that the pf-SWCNT films have a better electrocatalytic character and an electron transfer capability faster than the untreated SWCNTs, due to the fact that the oxygen-containing functional groups promote direct electron transfer in the biointerfacial region of the electrocatalytic activity of redox-active biomolecules.

  6. Nanomaterials-based enzyme electrochemical biosensors operating through inhibition for biosensing applications.

    PubMed

    Kurbanoglu, Sevinc; Ozkan, Sibel A; Merkoçi, Arben

    2017-03-15

    In recent years great progress has been made in applying nanomaterials to design novel biosensors. Use of nanomaterials offers to biosensing platforms exceptional optical, electronic and magnetic properties. Nanomaterials can increase the surface of the transducing area of the sensors that in turn bring an increase in catalytic behaviors. They have large surface-to-volume ratio, controlled morphology and structure that also favor miniaturization, an interesting advantage when the sample volume is a critical issue. Biosensors have great potential for achieving detect-to-protect devices: devices that can be used in detections of pollutants and other treating compounds/analytes (drugs) protecting citizens' life. After a long term focused scientific and financial efforts/supports biosensors are expected now to fulfill their promise such as being able to perform sampling and analysis of complex samples with interest for clinical or environment fields. Among all types of biosensors, enzymatic biosensors, the most explored biosensing devices, have an interesting property, the inherent inhibition phenomena given the enzyme-substrate complex formation. The exploration of such phenomena is making remarkably important their application as research and applied tools in diagnostics. Different inhibition biosensor systems based on nanomaterials modification has been proposed and applied. The role of nanomaterials in inhibition-based biosensors for the analyses of different groups of drugs as well as contaminants such as pesticides, phenolic compounds and others, are discussed in this review. This deep analysis of inhibition-based biosensors that employ nanomaterials will serve researchers as a guideline for further improvements and approaching of these devices to real sample applications so as to reach society needs and such biosensor market demands.

  7. Precise and selective sensing of DNA-DNA hybridization by graphene/Si-nanowires diode-type biosensors

    PubMed Central

    Kim, Jungkil; Park, Shin-Young; Kim, Sung; Lee, Dae Hun; Kim, Ju Hwan; Kim, Jong Min; Kang, Hee; Han, Joong-Soo; Park, Jun Woo; Lee, Hosun; Choi, Suk-Ho

    2016-01-01

    Single-Si-nanowire (NW)-based DNA sensors have been recently developed, but their sensitivity is very limited because of high noise signals, originating from small source-drain current of the single Si NW. Here, we demonstrate that chemical-vapor-deposition-grown large-scale graphene/surface-modified vertical-Si-NW-arrays junctions can be utilized as diode-type biosensors for highly-sensitive and -selective detection of specific oligonucleotides. For this, a twenty-seven-base-long synthetic oligonucleotide, which is a fragment of human DENND2D promoter sequence, is first decorated as a probe on the surface of vertical Si-NW arrays, and then the complementary oligonucleotide is hybridized to the probe. This hybridization gives rise to a doping effect on the surface of Si NWs, resulting in the increase of the current in the biosensor. The current of the biosensor increases from 19 to 120% as the concentration of the target DNA varies from 0.1 to 500 nM. In contrast, such biosensing does not come into play by the use of the oligonucleotide with incompatible or mismatched sequences. Similar results are observed from photoluminescence microscopic images and spectra. The biosensors show very-uniform current changes with standard deviations ranging ~1 to ~10% by ten-times endurance tests. These results are very promising for their applications in accurate, selective, and stable biosensing. PMID:27534818

  8. Precise and selective sensing of DNA-DNA hybridization by graphene/Si-nanowires diode-type biosensors.

    PubMed

    Kim, Jungkil; Park, Shin-Young; Kim, Sung; Lee, Dae Hun; Kim, Ju Hwan; Kim, Jong Min; Kang, Hee; Han, Joong-Soo; Park, Jun Woo; Lee, Hosun; Choi, Suk-Ho

    2016-08-18

    Single-Si-nanowire (NW)-based DNA sensors have been recently developed, but their sensitivity is very limited because of high noise signals, originating from small source-drain current of the single Si NW. Here, we demonstrate that chemical-vapor-deposition-grown large-scale graphene/surface-modified vertical-Si-NW-arrays junctions can be utilized as diode-type biosensors for highly-sensitive and -selective detection of specific oligonucleotides. For this, a twenty-seven-base-long synthetic oligonucleotide, which is a fragment of human DENND2D promoter sequence, is first decorated as a probe on the surface of vertical Si-NW arrays, and then the complementary oligonucleotide is hybridized to the probe. This hybridization gives rise to a doping effect on the surface of Si NWs, resulting in the increase of the current in the biosensor. The current of the biosensor increases from 19 to 120% as the concentration of the target DNA varies from 0.1 to 500 nM. In contrast, such biosensing does not come into play by the use of the oligonucleotide with incompatible or mismatched sequences. Similar results are observed from photoluminescence microscopic images and spectra. The biosensors show very-uniform current changes with standard deviations ranging ~1 to ~10% by ten-times endurance tests. These results are very promising for their applications in accurate, selective, and stable biosensing.

  9. Precise and selective sensing of DNA-DNA hybridization by graphene/Si-nanowires diode-type biosensors

    NASA Astrophysics Data System (ADS)

    Kim, Jungkil; Park, Shin-Young; Kim, Sung; Lee, Dae Hun; Kim, Ju Hwan; Kim, Jong Min; Kang, Hee; Han, Joong-Soo; Park, Jun Woo; Lee, Hosun; Choi, Suk-Ho

    2016-08-01

    Single-Si-nanowire (NW)-based DNA sensors have been recently developed, but their sensitivity is very limited because of high noise signals, originating from small source-drain current of the single Si NW. Here, we demonstrate that chemical-vapor-deposition-grown large-scale graphene/surface-modified vertical-Si-NW-arrays junctions can be utilized as diode-type biosensors for highly-sensitive and -selective detection of specific oligonucleotides. For this, a twenty-seven-base-long synthetic oligonucleotide, which is a fragment of human DENND2D promoter sequence, is first decorated as a probe on the surface of vertical Si-NW arrays, and then the complementary oligonucleotide is hybridized to the probe. This hybridization gives rise to a doping effect on the surface of Si NWs, resulting in the increase of the current in the biosensor. The current of the biosensor increases from 19 to 120% as the concentration of the target DNA varies from 0.1 to 500 nM. In contrast, such biosensing does not come into play by the use of the oligonucleotide with incompatible or mismatched sequences. Similar results are observed from photoluminescence microscopic images and spectra. The biosensors show very-uniform current changes with standard deviations ranging ~1 to ~10% by ten-times endurance tests. These results are very promising for their applications in accurate, selective, and stable biosensing.

  10. A novel bio-sensor based on DNA strand displacement.

    PubMed

    Shi, Xiaolong; Wang, Zhiyu; Deng, Chenyan; Song, Tao; Pan, Linqiang; Chen, Zhihua

    2014-01-01

    DNA strand displacement technology performs well in sensing and programming DNA segments. In this work, we construct DNA molecular systems based on DNA strand displacement performing computation of logic gates. Specifically, a class of so-called "DNA neurons" are achieved, in which a "smart" way inspired by biological neurons encoding information is developed to encode and deliver information using DNA molecules. The "DNA neuron" is bistable, that is, it can sense DNA molecules as input signals, and release "negative" or "positive" signals DNA molecules. We design intelligent DNA molecular systems that are constructed by cascading some particularly organized "DNA neurons", which could perform logic computation, including AND, OR, XOR logic gates, automatically. Both simulation results using visual DSD (DNA strand displacement) software and experimental results are obtained, which shows that the proposed systems can detect DNA signals with high sensitivity and accretion; moreover, the systems can process input signals automatically with complex nonlinear logic. The method proposed in this work may provide a new way to construct a sensitive molecular signal detection system with neurons spiking behavior in vitro, and can be used to develop intelligent molecular processing systems in vivo.

  11. A Nanoporous Alumina Membrane Based Electrochemical Biosensor for Histamine Determination with Biofunctionalized Magnetic Nanoparticles Concentration and Signal Amplification.

    PubMed

    Ye, Weiwei; Xu, Yifan; Zheng, Lihao; Zhang, Yu; Yang, Mo; Sun, Peilong

    2016-10-22

    Histamine is an indicator of food quality and indispensable in the efficient functioning of various physiological systems. Rapid and sensitive determination of histamine is urgently needed in food analysis and clinical diagnostics. Traditional histamine detection methods require qualified personnel, need complex operation processes, and are time-consuming. In this study, a biofunctionalized nanoporous alumina membrane based electrochemical biosensor with magnetic nanoparticles (MNPs) concentration and signal amplification was developed for histamine determination. Nanoporous alumina membranes were modified by anti-histamine antibody and integrated into polydimethylsiloxane (PDMS) chambers. The specific antibody modified MNPs were used to concentrate histamine from samples and transferred to the antibody modified nanoporous membrane. The MNPs conjugated to histamine were captured in the nanopores via specific reaction between histamine and anti-histamine antibody, resulting in a blocking effect that was amplified by MNPs in the nanopores. The blockage signals could be measured by electrochemical impedance spectroscopy across the nanoporous alumina membrane. The sensing platform had great sensitivity and the limit of detection (LOD) reached as low as 3 nM. This biosensor could be successfully applied for histamine determination in saury that was stored in frozen conditions for different hours, presenting a potentially novel, sensitive, and specific sensing system for food quality assessment and safety support.

  12. A Nanoporous Alumina Membrane Based Electrochemical Biosensor for Histamine Determination with Biofunctionalized Magnetic Nanoparticles Concentration and Signal Amplification

    PubMed Central

    Ye, Weiwei; Xu, Yifan; Zheng, Lihao; Zhang, Yu; Yang, Mo; Sun, Peilong

    2016-01-01

    Histamine is an indicator of food quality and indispensable in the efficient functioning of various physiological systems. Rapid and sensitive determination of histamine is urgently needed in food analysis and clinical diagnostics. Traditional histamine detection methods require qualified personnel, need complex operation processes, and are time-consuming. In this study, a biofunctionalized nanoporous alumina membrane based electrochemical biosensor with magnetic nanoparticles (MNPs) concentration and signal amplification was developed for histamine determination. Nanoporous alumina membranes were modified by anti-histamine antibody and integrated into polydimethylsiloxane (PDMS) chambers. The specific antibody modified MNPs were used to concentrate histamine from samples and transferred to the antibody modified nanoporous membrane. The MNPs conjugated to histamine were captured in the nanopores via specific reaction between histamine and anti-histamine antibody, resulting in a blocking effect that was amplified by MNPs in the nanopores. The blockage signals could be measured by electrochemical impedance spectroscopy across the nanoporous alumina membrane. The sensing platform had great sensitivity and the limit of detection (LOD) reached as low as 3 nM. This biosensor could be successfully applied for histamine determination in saury that was stored in frozen conditions for different hours, presenting a potentially novel, sensitive, and specific sensing system for food quality assessment and safety support. PMID:27782087

  13. Nanotubes, Nanowires, and Nanocantilevers in Biosensor Development

    SciTech Connect

    Wang, Jun; Liu, Guodong; Lin, Yuehe

    2007-03-08

    In this chapter, the reviews on biosensor development based on 1-D nanomaterials, CNTs, semiconducting nanowires, and some cantilevers will be introduced. The emphasis of this review will be placed on CNTs and electrochemical/electronic biosensor developments. Section 2 of this chapter gives a detailed description of carbon nanotubes-based biosensor development, from fabrication of carbon nanotubes, the strategies for construction of carbon nanotube based biosensors to their bioapplications. In the section of the applications of CNTs based biosensors, various detection principles, e. g. electrochemical, electronic, and optical method, and their applications are reviewed in detail. Section 3 introduces the method for synthesis of semiconducting nanowires, e.g. silicon nanowires, conducting polymer nanowires and metal oxide nanowires and their applications in DNA and proteins sensing. Section 4 simply describes the development for nanocantilevers based biosensors and their application in DNA and protein diagnosis. Each section starts from a brief introduction and then goes into details. Finally in the Conclusion section, the development of 1-D nanomaterials based biosensor development is summarized.

  14. Fabrication of Ultrasensitive Field-Effect Transistor DNA Biosensors by a Directional Transfer Technique Based on CVD-Grown Graphene.

    PubMed

    Zheng, Chao; Huang, Le; Zhang, Hong; Sun, Zhongyue; Zhang, Zhiyong; Zhang, Guo-Jun

    2015-08-12

    Most graphene field-effect transistor (G-FET) biosensors are fabricated through a routine process, in which graphene is transferred onto a Si/SiO2 substrate and then devices are subsequently produced by micromanufacture processes. However, such a fabrication approach can introduce contamination onto the graphene surface during the lithographic process, resulting in interference for the subsequent biosensing. In this work, we have developed a novel directional transfer technique to fabricate G-FET biosensors based on chemical-vapor-deposition- (CVD-) grown single-layer graphene (SLG) and applied this biosensor for the sensitive detection of DNA. A FET device with six individual array sensors was first fabricated, and SLG obtained by the CVD-growth method was transferred onto the sensor surface in a directional manner. Afterward, peptide nucleic acid (PNA) was covalently immobilized on the graphene surface, and DNA detection was realized by applying specific target DNA to the PNA-functionalized G-FET biosensor. The developed G-FET biosensor was able to detect target DNA at concentrations as low as 10 fM, which is 1 order of magnitude lower than those reported in a previous work. In addition, the biosensor was capable of distinguishing the complementary DNA from one-base-mismatched DNA and noncomplementary DNA. The directional transfer technique for the fabrication of G-FET biosensors is simple, and the as-constructed G-FET DNA biosensor shows ultrasensitivity and high specificity, indicating its potential application in disease diagnostics as a point-of-care tool.

  15. A highly sensitive electrochemical biosensor for catechol using conducting polymer reduced graphene oxide-metal oxide enzyme modified electrode.

    PubMed

    Sethuraman, V; Muthuraja, P; Anandha Raj, J; Manisankar, P

    2016-10-15

    The fabrication, characterization and analytical performances were investigated for a catechol biosensor, based on the PEDOT-rGO-Fe2O3-PPO composite modified glassy carbon (GC) electrode. The graphene oxide (GO) doped conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) was prepared through electrochemical polymerization by potential cycling. Reduction of PEDOT-GO was carried out by amperometric method. Fe2O3 nanoparticles were synthesized in ethanol by hydrothermal method. The mixture of Fe2O3, PPO and glutaraldehyde was casted on the PEDOT-rGO electrode. The surface morphology of the modified electrodes was studied by FE-SEM and AFM. Cyclic voltammetric studies of catechol on the enzyme modified electrode revealed higher reduction peak current. Determination of catechol was carried out successfully by Differential Pulse Voltammetry (DPV) technique. The fabricated biosensor investigated shows a maximum current response at pH 6.5. The catechol biosensor exhibited wide sensing linear range from 4×10(-8) to 6.20×10(-5)M, lower detection limit of 7×10(-9)M, current maxima (Imax) of 92.55µA and Michaelis-Menten (Km) constant of 30.48µM. The activation energy (Ea) of enzyme electrode is 35.93KJmol(-1) at 50°C. There is no interference from d-glucose and l-glutamic acid, ascorbic acid and o-nitrophenol. The PEDOT-rGO-Fe2O3-PPO biosensor was stable for at least 75 days when stored in a buffer at about 4°C.

  16. On-Electrode Synthesis of Shape-Controlled Hierarchical Flower-Like Gold Nanostructures for Efficient Interfacial DNA Assembly and Sensitive Electrochemical Sensing of MicroRNA.

    PubMed

    Su, Shao; Wu, Yan; Zhu, Dan; Chao, Jie; Liu, Xingfen; Wan, Ying; Su, Yan; Zuo, Xiaolei; Fan, Chunhai; Wang, Lianhui

    2016-07-01

    The performance for biomolecular detection is closely associated with the interfacial structure of a biosensor, which profoundly affects both thermodynamics and kinetics of the assembly, binding and signal transduction of biomolecules. Herein, it is reported on a one-step and template-free on-electrode synthesis method for making shape-controlled gold nanostructures on indium tin oxide substrates, which provide an electrochemical sensing platform for ultrasensitive detection of nucleic acids. Thus-prepared hierarchical flower-like gold nanostructures (HFGNs) possess large surface area that can readily accommodate the assembly of DNA probes for subsequent hybridization detection. It is found that the sensitivity for electrochemical DNA sensing is critically dependent on the morphology of HFGNs. By using this new strategy, a highly sensitive electrochemical biosensor is developed for label-free detection of microRNA-21 (miRNA-21), a biomarker for lung cancers. Importantly, it is demonstrated that this biosensor can be employed to measure the miRNA-21 expression level from human lung cancer cell (A549) lysates and worked well in 100% serum, suggesting its potential for applications in clinical diagnosis and a wide range of bioanalysis.

  17. A highly oriented hybrid microarray modified electrode fabricated by a template-free method for ultrasensitive electrochemical DNA recognition

    NASA Astrophysics Data System (ADS)

    Shi, Lei; Chu, Zhenyu; Dong, Xueliang; Jin, Wanqin; Dempsey, Eithne

    2013-10-01

    Highly oriented growth of a hybrid microarray was realized by a facile template-free method on gold substrates for the first time. The proposed formation mechanism involves an interfacial structure-directing force arising from self-assembled monolayers (SAMs) between gold substrates and hybrid crystals. Different SAMs and variable surface coverage of the assembled molecules play a critical role in the interfacial directing forces and influence the morphologies of hybrid films. A highly oriented hybrid microarray was formed on the highly aligned and vertical SAMs of 1,4-benzenedithiol molecules with rigid backbones, which afforded an intense structure-directing power for the oriented growth of hybrid crystals. Additionally, the density of the microarray could be adjusted by controlling the surface coverage of assembled molecules. Based on the hybrid microarray modified electrode with a large specific area (ca. 10 times its geometrical area), a label-free electrochemical DNA biosensor was constructed for the detection of an oligonucleotide fragment of the avian flu virus H5N1. The DNA biosensor displayed a significantly low detection limit of 5 pM (S/N = 3), a wide linear response from 10 pM to 10 nM, as well as excellent selectivity, good regeneration and high stability. We expect that the proposed template-free method can provide a new reference for the fabrication of a highly oriented hybrid array and the as-prepared microarray modified electrode will be a promising paradigm in constructing highly sensitive and selective biosensors.Highly oriented growth of a hybrid microarray was realized by a facile template-free method on gold substrates for the first time. The proposed formation mechanism involves an interfacial structure-directing force arising from self-assembled monolayers (SAMs) between gold substrates and hybrid crystals. Different SAMs and variable surface coverage of the assembled molecules play a critical role in the interfacial directing forces and

  18. Electrochemical Sensors Based on Carbon Nanotubes

    PubMed Central

    Saleh Ahammad, A. J.; Lee, Jae-Joon; Rahman, Md. Aminur

    2009-01-01

    This review focuses on recent contributions in the development of the electrochemical sensors based on carbon nanotubes (CNTs). CNTs have unique mechanical and electronic properties, combined with chemical stability, and behave electrically as a metal or semiconductor, depending on their structure. For sensing applications, CNTs have many advantages such as small size with larger surface area, excellent electron transfer promoting ability when used as electrodes modifier in electrochemical reactions, and easy protein immobilization with retention of its activity for potential biosensors. CNTs play an important role in the performance of electrochemical biosensors, immunosensors, and DNA biosensors. Various methods have been developed for the design of sensors using CNTs in recent years. Herein we summarize the applications of CNTs in the construction of electrochemical sensors and biosensors along with other nanomaterials and conducting polymers. PMID:22574013

  19. The development of a silica nanoparticle-based label-free DNA biosensor

    NASA Astrophysics Data System (ADS)

    Kell, Arnold J.; Pagé, Lilianne; Tan, Sophie; Charlebois, Isabelle; Boissinot, Maurice; Leclerc, Mario; Simard, Benoit

    2011-09-01

    A silica nanoparticle-based DNA biosensor capable of detecting Bacillus anthracis bacteria through the use of unlabelled ss-oligonucleotides has been developed. The biosensor makes use of the optical changes that accompany a nanoparticle-immobilized cationic conjugated polymer (polythiophene) interacting with single-stranded vs. hybridized oligonucleotides, where a fluorescence signal appears only when hybridized DNA is present (i.e. only when the ss-oligonucleotide interacting with the polymer has hybridized with its complement). In order to enhance the sensitivity of the biosensor, two different nanoparticle architectures were developed and used to elucidate how the presence of neighboring fluorophores on the nanoparticle surface affects Förster-resonant energy transfer (FRET) between the polythiophene/oligonucleotide complex (FRET donor) and the fluorophores (FRET acceptors). We demonstrate that the silica nanoparticle-based FRET platform lowers the limit of detection at least 10-fold in comparison to the polythiophene itself, and allows the detection of ~2 × 10-12 moles of ss-oligonucleotide in a 100 μL sample with a standard fluorimeter (i.e. has a limit of detection of ~2 nM ssDNA). Such nanoparticle-based biosensor platforms are beneficial because of the robustness and stability inherent to their covalent assembly and they provide a valuable new tool that may allow for the sensitive, label-free detection (the target DNA that produces the fluorescence signal is unlabelled) without the use of polymerase chain reaction.A silica nanoparticle-based DNA biosensor capable of detecting Bacillus anthracis bacteria through the use of unlabelled ss-oligonucleotides has been developed. The biosensor makes use of the optical changes that accompany a nanoparticle-immobilized cationic conjugated polymer (polythiophene) interacting with single-stranded vs. hybridized oligonucleotides, where a fluorescence signal appears only when hybridized DNA is present (i.e. only when

  20. An InN/InGaN Quantum Dot Electrochemical Biosensor for Clinical Diagnosis

    PubMed Central

    Alvi, Naveed ul Hassan; Gómez, Victor J.; Rodriguez, Paul E.D. Soto; Kumar, Praveen; Zaman, Saima; Willander, Magnus; Nötzel, Richard

    2013-01-01

    Low-dimensional InN/InGaN quantum dots (QDs) are demonstrated for realizing highly sensitive and efficient potentiometric biosensors owing to their unique electronic properties. The InN QDs are biochemically functionalized. The fabricated biosensor exhibits high sensitivity of 97 mV/decade with fast output response within two seconds for the detection of cholesterol in the logarithmic concentration range of 1 × 10−6 M to 1 × 10−3 M. The selectivity and reusability of the biosensor are excellent and it shows negligible response to common interferents such as uric acid and ascorbic acid. We also compare the biosensing properties of the InN QDs with those of an InN thin film having the same surface properties, i.e., high density of surface donor states, but different morphology and electronic properties. The sensitivity of the InN QDs-based biosensor is twice that of the InN thin film-based biosensor, the EMF is three times larger, and the response time is five times shorter. A bare InGaN layer does not produce a stable response. Hence, the superior biosensing properties of the InN QDs are governed by their unique surface properties together with the zero-dimensional electronic properties. Altogether, the InN QDs-based biosensor reveals great potential for clinical diagnosis applications. PMID:24132228

  1. Folding- and Dynamics-Based Electrochemical DNA Sensors.

    PubMed

    Lai, Rebecca Y

    2017-01-01

    A number of electrochemical DNA sensors based on the target-induced change in the conformation and/or flexibility of surface-bound oligonucleotides have been developed in recent years. These sensors, which are often termed E-DNA sensors, are comprised of an oligonucleotide probe modified with a redox label (e.g., methylene blue) at one terminus and attached to a gold electrode via a thiol-gold bond at the other. Binding of the target to the DNA probe changes its structure and dynamics, which, in turn, influences the efficiency of electron transfer to the interrogating electrode. Since electrochemically active contaminants are less common, these sensors are resistant to false-positive signals arising from the nonspecific adsorption of contaminants and perform well even when employed directly in serum, whole blood, and other realistically complex sample matrices. Moreover, because all of the sensor components are chemisorbed to the electrode, the E-DNA sensors are essentially label-free and readily reusable. To date, these sensors have achieved state-of-the-art sensitivity, while offering the unprecedented selectivity, reusability, and the operational convenience of direct electrochemical detection. This chapter reviews the recent advances in the development of both "signal-off" and "signal-on" E-DNA sensors. Critical aspects that dictate the stability and performance of these sensors are also addressed so as to provide a realistic overview of this oligonucleotide detection platform.

  2. Electrochemical detection of Piscirickettsia salmonis genomic DNA from salmon samples using solid-phase recombinase polymerase amplification.

    PubMed

    Del Río, Jonathan Sabaté; Svobodova, Marketa; Bustos, Paulina; Conejeros, Pablo; O'Sullivan, Ciara K

    2016-12-01

    Electrochemical detection of solid-phase isothermal recombinase polymerase amplification (RPA) of Piscirickettsia salmonis in salmon genomic DNA is reported. The electrochemical biosensor was constructed by surface functionalization of gold electrodes with a thiolated forward primer specific to the genomic region of interest. Solid-phase RPA and primer elongation were achieved in the presence of the specific target sequence and biotinylated reverse primers. The formation of the subsequent surface-tethered duplex amplicons was electrochemically monitored via addition of streptavidin-linked HRP upon completion of solid-phase RPA. Successful quantitative amplification and detection were achieved in less than 1 h at 37 °C, calibrating with PCR-amplified genomic DNA standards and achieving a limit of detection of 5 · 10(-8) μg ml(-1) (3 · 10(3) copies in 10 μl). The presented system was applied to the analysis of eight real salmon samples, and the method was also compared to qPCR analysis, observing an excellent degree of correlation. Graphical abstract Schematic of use of electrochemical RPA for detection of Psiricketessia salmonis in salmon liver.

  3. Scanning Electrochemical Microscopy of DNA Monolayers Modified with Nile Blue

    PubMed Central

    Gorodetsky, Alon A.; Hammond, William J.; Hill, Michael G.; Slowinski, Krzysztof; Barton, Jacqueline K.

    2009-01-01

    Scanning electrochemical microscopy (SECM) is used to probe long-range charge transport (CT) through DNA monolayers containing the redox-active Nile Blue (NB) intercalator covalently affixed at a specific location in the DNA film. At substrate potentials negative of the formal potential of covalently attached NB, the electrocatalytic reduction of Fe(CN)63− generated at the SECM tip is observed only when NB is located at the DNA/solution interface; for DNA films containing NB in close proximity to the DNA/electrode interface, the electrocatalytic effect is absent. This behavior is consistent with both rapid DNA-mediated CT between the NB intercalator and the gold electrode as well as a rate-limiting electron transfer between NB and the solution phase Fe(CN)63−. The DNA-mediated nature of the catalytic cycle is confirmed through sequence-specific and localized detection of attomoles of TATA-binding protein, a transcription factor that severely distorts DNA upon binding. Importantly, the strategy outlined here is general and allows for the local investigation of the surface characteristics of DNA monolayers both in the absence and in the presence of DNA binding proteins. These experiments highlight the utility of DNA-modified electrodes as versatile platforms for SECM detection schemes that take advantage of CT mediated by the DNA base pair stack. PMID:19053641

  4. Trends in tactile biosensors, smell-sensitive biosensors

    NASA Astrophysics Data System (ADS)

    Higuchi, K.; Kawana, Y.; Kimura, J.

    1986-03-01

    Biosensors, whch combine substances from living organisms such as enzymes with electrochemical transducers, are considered taste-sensitive biosensors. Touch sensors were analyzed using various pressure-sensitive elements, but no attempts were made to use substances from organisms. The sense of smell is a gase sensor for the body; there are numerous uncertainties about the meaning of smell-sensitive biosensors. Tactile biosensors and olfactor biosensors were examined. Biosensors include sensors directly apply materials extracted from organisms and sensors which copy sensors.

  5. Label-free detection of DNA hybridization and single point mutations in a nano-gap biosensor.

    PubMed

    Zaffino, R L; Mir, M; Samitier, J

    2014-03-14

    We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transport for the label-free and direct electrical detection of DNA hybridization. This biosensor platform comprises an array of vertical nano-gap biosensors made of gold and fabricated through standard photolithography combined with focused ion beam lithography. The nano-gap walls are covalently modified with short, anti-symmetric thiolated DNA probes, which are terminated by 19 bases complementary to both the ends of a target DNA strand. The nano-gaps are separated by a distance of 50 nm, which was adjusted to fit the length of the DNA target plus the DNA probes. The hybridization of the target DNA closes the gap circuit in a switch on/off fashion, in such a way that it is readily detected by an increase in the current after nano-gap closure. The nano-biosensor shows high specificity in the discrimination of base-pair mismatching and does not require signal indicators or enhancing molecules. The design of the biosensor platform is applicable for multiplexed detection in a straightforward manner. The platform is well-suited to mass production, point-of-care diagnostics, and wide-scale DNA analysis applications.

  6. Label-free detection of DNA hybridization and single point mutations in a nano-gap biosensor

    NASA Astrophysics Data System (ADS)

    Zaffino, R. L.; Mir, M.; Samitier, J.

    2014-03-01

    We describe a conductance-based biosensor that exploits DNA-mediated long-range electron transport for the label-free and direct electrical detection of DNA hybridization. This biosensor platform comprises an array of vertical nano-gap biosensors made of gold and fabricated through standard photolithography combined with focused ion beam lithography. The nano-gap walls are covalently modified with short, anti-symmetric thiolated DNA probes, which are terminated by 19 bases complementary to both the ends of a target DNA strand. The nano-gaps are separated by a distance of 50nm, which was adjusted to fit the length of the DNA target plus the DNA probes. The hybridization of the target DNA closes the gap circuit in a switch on/off fashion, in such a way that it is readily detected by an increase in the current after nano-gap closure. The nano-biosensor shows high specificity in the discrimination of base-pair mismatching and does not require signal indicators or enhancing molecules. The design of the biosensor platform is applicable for multiplexed detection in a straightforward manner. The platform is well-suited to mass production, point-of-care diagnostics, and wide-scale DNA analysis applications.

  7. A novel label-free and sensitive electrochemical biosensor for Hg(2+) based on ligase-mediated formation of DNAzyme.

    PubMed

    Li, Guangwen; Li, Zhijun; You, Xiuhua; Chen, Jinghua; Tang, Shurong

    2016-12-01

    A novel label-free electrochemical biosensor for the detection of Hg(2+) based on ligase mediated creation of G-quadruplex-hemin DNAzyme has been developed. Firstly, Cp probe was immobilized on the gold electrode surface through Au-SH bond. In the presence of Hg(2+), Cp and Ap probes were partly hybridized with the LJ probe respectively through the specific T-Hg(2+)-T interaction. Then, the adjacent 3'-OH terminal of Cp will link with the 5'-PO4 terminal of Ap to form a G-rich DNA at the function of T4-ligase. After interaction with hemin, the G-rich DNA can form a G-quadruplex-hemin HRP-mimicking DNAzyme. Through measuring the current change caused by DNAzyme-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine(TMB), sensitive detection of Hg(2+) can be achieved. The proposed sensor is simple, sensitive and selective, without the need of complicated labeling process, thus holds great potential for routine analysis of Hg(2+) in environmental and biological samples.

  8. Electrochemical biosensor for carbofuran pesticide based on esterases from Eupenicillium shearii FREI-39 endophytic fungus.

    PubMed

    Grawe, Gregory Ferreira; de Oliveira, Tássia Regina; de Andrade Narciso, Esther; Moccelini, Sally Katiuce; Terezo, Ailton José; Soares, Marcos Antonio; Castilho, Marilza

    2015-01-15

    In this work, a biosensor was constructed by physical adsorption of the isolated endophytic fungus Eupenicillium shearii FREI-39 esterase on halloysite, using graphite powder, multi-walled carbon nanotubes and mineral oil for the determination of carbofuran pesticide by inhibition of the esterase using square-wave voltammetry (SWV). Specific esterase activities were determined each 2 days over a period of 15 days of growth in four different inoculation media. The highest specific activity was found on 6th day, with 33.08 U on PDA broth. The best performance of the proposed biosensor was obtained using 0.5 U esterase activity. The carbofuran concentration response was linear in the range from 5.0 to 100.0 µg L(-1) (r=0.9986) with detection and quantification limits of 1.69 µg L(-1) and 5.13 µg L(-1), respectively. A recovery study of carbofuran in spiked water samples showed values ranging from 103.8±6.7% to 106.7±9.7%. The biosensor showed good repeatability and reproducibility and remained stable for a period of 20 weeks. The determination of carbofuran in spiked water samples using the proposed biosensor was satisfactory when compared to the chromatographic reference method. The results showed no significant difference at the 95% confidence level with t-test statistics. The application of enzymes from endophytic fungi in constructing biosensors broadens the biotechnological importance of these microorganisms.

  9. An electrochemical biosensor based on cobalt nanoparticles synthesized in iron storage protein molecules to determine ascorbic acid.

    PubMed

    Rafipour, Ronak; Kashanian, Soheila; Hashemi, Sadegh; Shahabadi, Nahid; Omidfar, Kobra

    2016-09-01

    The electrochemical detection of ascorbic acid (AA) was investigated using a cobalt(III)-ferritin immobilized on a self-assembled monolayer modified gold electrode in phosphate buffer solution (pH 7.5). The modified electrode showed excellent electrochemical activity for oxidation of AA. The response to AA on the modified electrode was examined using cyclic and differential pulse voltammetry techniques. The resulting biosensor showed a linear response to AA in a concentration range from 6.25×10(-6) to 2.31×10(-5) M with sensitivity of 86,437 μAM(-)(1) and detection limit of 4.65 × 10(-6) M based on a signal-to-noise ratio of 3. Electrochemical parameters including the charge transfer coefficient (α) and the apparent heterogeneous electron transfer rate constant (ks ) for AA were found to be 0.52 and 1.054 Sec(-1) , respectively. It has been shown that, using this modified electrode, AA can be determined with high sensitivity, low detection limit, and high selectivity.

  10. An electrochemical DNA sensor without electrode pre-modification.

    PubMed

    Hong, Nian; Cheng, Lin; Wei, BingGuo; Chen, ChaDan; He, Ling Ling; Kong, DeRong; Ceng, JinXiang; Cui, Han-Feng; Fan, Hao

    2017-05-15

    We present a non-modification electrochemical DNA sensing strategy, which used Potential-Assisted Au-S Deposition and a clamp-like DNA probe. The dual-hairpin probe DNA was tagged with a methylene blue (MB) at the 3' terminal and a thiol at the 5' terminal., Without being hybridized with target DNA, the loop of probe prevented the thiol from reaching the bare gold electrode surface with an applied potential., After hybridization with the target DNA, the probe' s loop-stem structure opened through two distinct and sequential events, which led to the formation of a triplex DNA structure. Then the thiol easily contacted with electrode and resulted in potential-assisted Au-S self-assembly. Electrochemical signals of MB were measured by differential pulse voltammetry (DPV) and used for target quantitative detection. This strategy offered a detection limit down to 2.3pM. and an inherently high specificity for detecting even single mismatch.

  11. The Detection of Alkaline Phosphatase Using an Electrochemical Biosensor in a Single-Step Approach

    PubMed Central

    Wang, Joanne H.; Wang, Kevin; Bartling, Brandon; Liu, Chung-Chiun

    2009-01-01

    A one-step, single use, disposable Alkaline Phosphatase (ALP) biosensor has been developed. It is based on the detection of phenol produced by an ALP enzymatic reaction. It can operate at 25 °C in a pH 10 medium. It measures ALP of 0–300 IU/L. The permissible concentrations of glucose, ascorbic acid and urea without interference are 10 mM/L, 5 mg/L and 400 mg/L, respectively. Experimental results are compared to those obtained by spectrophotometric measurements in bovine serum. Excellent linearity between the biosensor outputs and the ALP concentrations exists. The agreement between the measurements of this biosensor and the spectrophotometer is also outstanding. PMID:22291532

  12. Determination of Organophosphate Pesticides at a Carbon Nanotube/Organophosphorus Hydrolase Electrochemical Biosensor

    SciTech Connect

    Deo, R P.; Wang, Joseph; Block, I; Mulchandani, Ashok; Joshi, K; Trojanowicz, M; Scholz, F; Chen, Wilfred; Lin, Yuehe

    2005-02-08

    An amperometric biosensor for organophosphorus (OP) pesticides based on a carbon-nanotube (CNT) modified transducer and an organophosphorus hydrolase (OPH) biocatalyst is described. A bilayer approach with the OPH layer atop of the CNT film was used for preparing the CNT/OPH biosensor. The CNT layer leads to a greatly improved anodic detection of the enzymatically-generated p-nitrophenol product, including higher sensitivity and stability. The sensor performance was optimized with respect to the surface modification and operating conditions. Under the optimal conditions the biosensor was used to measure as low as 0.15 {micro}M paraoxon and 0.8 {micro}M methyl parathion with sensitivities of 25 and 6 nA/{micro}M, respectively.

  13. An Electrochemical Gas Biosensor Based on Enzymes Immobilized on Chromatography Paper for Ethanol Vapor Detection.

    PubMed

    Kuretake, Tatsumi; Kawahara, Shogo; Motooka, Masanobu; Uno, Shigeyasu

    2017-02-01

    This paper presents a novel method of fabricating an enzymatic biosensor for breath analysis using chromatography paper as enzyme supporting layer and a liquid phase layer on top of screen printed carbon electrodes. We evaluated the performance with ethanol vapor being one of the breathing ingredients. The experimental results show that our sensor is able to measure the concentration of ethanol vapor within the range of 50 to 500 ppm. These results suggest the ability of detecting breath ethanol, and it can possibly be applied as a generic vapor biosensor to a wide range of diseases.

  14. An Electrochemical Gas Biosensor Based on Enzymes Immobilized on Chromatography Paper for Ethanol Vapor Detection

    PubMed Central

    Kuretake, Tatsumi; Kawahara, Shogo; Motooka, Masanobu; Uno, Shigeyasu

    2017-01-01

    This paper presents a novel method of fabricating an enzymatic biosensor for breath analysis using chromatography paper as enzyme supporting layer and a liquid phase layer on top of screen printed carbon electrodes. We evaluated the performance with ethanol vapor being one of the breathing ingredients. The experimental results show that our sensor is able to measure the concentration of ethanol vapor within the range of 50 to 500 ppm. These results suggest the ability of detecting breath ethanol, and it can possibly be applied as a generic vapor biosensor to a wide range of diseases. PMID:28157154

  15. Fabrication of a facile electrochemical biosensor for hydrogen peroxide using efficient catalysis of hemoglobin on the porous Pd@Fe3O4-MWCNT nanocomposite.

    PubMed

    Baghayeri, Mehdi; Veisi, Hojat

    2015-12-15

    In this work, a sensitive amperometric biosensor for hydrogen peroxide based on synergetic catalysis of hemoglobin and porous Pd@Fe3O4-MWCNT nanocomposite has been constructed. With attention to the utilities of large surface area and outstanding catalytic performance, Pd@Fe3O4-MWCNT nanocomposite was employed as the nano-stabilizer for the immobilization of hemoglobin (Hb). The immobilized Hb on the surface of nanocomposite as an electrochemical biosensor efficiently catalyzed the reduction of hydrogen peroxide, amplified the electrochemical signal and enhanced the sensitivity. Results of voltammetry and electrochemical impedance examinations showed that the nanocomposite could enhance the electron conductivity and provide more sites for the immobilization of Hb. A linear response from 0.2-500 µM with detection limit of 0.063 µM for hydrogen peroxide was achieved. The apparent Michaelis-Menten constant Kapp(M) value was 21 µM. Thus, the nanocomposite could be applied for fabrication of a third generation biosensor for hydrogen peroxide with high sensitivity, selectivity and low detection limit. The excellent performance of the biosensor indicated its promising prospect as a valuable tool in simple and fast hydrogen peroxide detection in environmental and clinical applications.

  16. Stable and Reusable Electrochemical Biosensor for Poly(ADP-ribose) Polymerase and Its Inhibitor Based on Enzyme-Initiated Auto-PARylation.

    PubMed

    Xu, Yuanyuan; Liu, Li; Wang, Zhaoyin; Dai, Zhihui

    2016-07-27

    A stable and reusable electrochemical biosensor for the label-free detection of poly(ADP-ribose) polymerase (PARP) is designed in this work. C-kit-1, a thiol-modified G-quadruplex oligonucleotide, is first self-assembled on a gold electrode surface. The G-quadruplex structure of c-kit-1 can specifically tether and activate PARP, resulting in the generation of negatively charged poly(ADP-ribose) polymer (PAR). On the basis of electrostatic attraction, PAR facilitates the surface accumulation of positively charged electrochemical signal molecules. Through the characterization of electrochemical signal molecules, the label-free quantification of PARP is simply implemented. On the basis of the proposed method, selective quantification of PARP can be achieved over the linear range from 0.01 to 1 U with a calculated detection limit of 0.003U. Further studies also demonstrate the applicability of the proposed method to biosamples revealing the broad potential in practical applications. Furthermore, inhibitor of PARP has also been detected with this biosensor. Meanwhile, benefited from self-assembly on solid surface, this biosensor possesses two important features, i.e., reusability and stability, which are desirable in related biosensors.

  17. Hierarchical porous microspheres of the Co3O4@graphene with enhanced electrocatalytic performance for electrochemical biosensors.

    PubMed

    Yang, MinHo; Jeong, Jae-Min; Lee, Kyoung G; Kim, Do Hyun; Lee, Seok Jae; Choi, Bong Gill

    2017-03-15

    The integration of organic and inorganic building blocks into hierarchical porous architectures makes potentially desirable electrocatalytic materials in many electrochemical applications due to their combination of attractive qualities of dissimilar components and well-constructed charge transfer pathways. Herein, we demonstrate the preparation of the hierarchical porous Co3O4@graphene (Co3O4@G) microspheres by one-step hydrothermal method to achieve high electrocatalytic performance for enzyme-free biosensor applications. The obtained Co3O4@G microspheres are consisted of the interconnected networks of Co3O4 and graphene sheets, and thus provide large accessible active sites through porous structure, while graphene sheets offer continuous electron pathways for efficient electrocatalytic reaction of Co3O4. These structural merits with synergy effect of Co3O4 and graphene lead to a high performance of enzyme-free detection for glucose: high sensitivity, good selectivity, and remarkable stability.

  18. Development of a Novel Biosensor Using Cationic Antimicrobial Peptide and Nickel Phthalocyanine Ultrathin Films for Electrochemical Detection of Dopamine

    PubMed Central

    Zampa, Maysa F.; Araújo, Inês Maria de S.; dos Santos Júnior, José Ribeiro; Zucolotto, Valtencir; Leite, José Roberto de S. A.; Eiras, Carla

    2012-01-01

    The antimicrobial peptide dermaseptin 01 (DS 01), from the skin secretion of Phyllomedusa hypochondrialis frogs, was immobilized in nanostructured layered films in conjunction with nickel tetrasulfonated phthalocyanines (NiTsPc), widely used in electronic devices, using layer-by-layer technique. The films were used as a biosensor to detect the presence of dopamine (DA), a neurotransmitter associated with diseases such as Alzheimer's and Parkinson's, with detection limits in the order of 10−6 mol L−1. The use of DS 01 in LbL film generated selectivity in the detection of DA despite the presence of ascorbic acid found in biological fluids. This work is the first to report that the antimicrobial peptide and NiTsPc LbL film exhibits electroanalytical activity to DA oxidation. The selectivity in the detection of DA is a fundamental aspect for the development of electrochemical sensors with potential applications in the biomedical and pharmaceutical industries. PMID:22287966

  19. Development of a novel biosensor using cationic antimicrobial Peptide and nickel phthalocyanine ultrathin films for electrochemical detection of dopamine.

    PubMed

    Zampa, Maysa F; Araújo, Inês Maria de S; Dos Santos Júnior, José Ribeiro; Zucolotto, Valtencir; Leite, José Roberto de S A; Eiras, Carla

    2012-01-01

    The antimicrobial peptide dermaseptin 01 (DS 01), from the skin secretion of Phyllomedusa hypochondrialis frogs, was immobilized in nanostructured layered films in conjunction with nickel tetrasulfonated phthalocyanines (NiTsPc), widely used in electronic devices, using layer-by-layer technique. The films were used as a biosensor to detect the presence of dopamine (DA), a neurotransmitter associated with diseases such as Alzheimer's and Parkinson's, with detection limits in the order of 10(-6) mol L(-1). The use of DS 01 in LbL film generated selectivity in the detection of DA despite the presence of ascorbic acid found in biological fluids. This work is the first to report that the antimicrobial peptide and NiTsPc LbL film exhibits electroanalytical activity to DA oxidation. The selectivity in the detection of DA is a fundamental aspect for the development of electrochemical sensors with potential applications in the biomedical and pharmaceutical industries.

  20. High sensitive and selective electrochemical biosensor: Label-free detection of human norovirus using affinity peptide as molecular binder.

    PubMed

    Hwang, Hye Jin; Ryu, Myung Yi; Park, Chan Young; Ahn, Junki; Park, Hyun Gyu; Choi, Changsun; Ha, Sang-Do; Park, Tae Jung; Park, Jong Pil

    2017-01-15

    Norovirus is known as the major cause of highly infection for gastrointestinal tracts. In this study, robust and highly sensitive biosensors for detecting human norovirus by employing a recognition affinity peptide-based electrochemical platform were described. A series of amino acid-substituted and cysteine-incorporated recognition peptides isolated from evolutionary phage display technique was chemically synthesized and immobilized to a gold sensor layer, the detection performance of the gold-immobilized synthetic peptide-based sensor system was assessed using QCM, CV and EIS. Using EIS, the limit of detection with Noro-1 as a molecular binder was found to be 99.8nM for recombinant noroviral capsid proteins (rP2) and 7.8copies/mL for human norovirus, thereby demonstrating a high degree of sensitivity for their corresponding targets. These results suggest that a biosensor which consists of affinity peptides as a molecular binder and miniaturized microdevices as diagnostic tool could be served as a new type of biosensing platform for point-of-care testing.

  1. Electrochemical biosensor for microRNA detection based on poly(U) polymerase mediated isothermal signal amplification.

    PubMed

    Zhou, Yunlei; Yin, Huanshun; Li, Jie; Li, Bingchen; Li, Xue; Ai, Shiyun; Zhang, Xiansheng

    2016-05-15

    MicroRNAs play crucial role in post-transcriptional regulation for gene expression in animals, plants, and viruses. For the better understanding of microRNA and its functions, it is very important to develop effectively analytical method for microRNA detection. Herein, a novel electrochemical biosensor was fabricated for sensitive and selective detection of microRNA based on poly(U) polymerase mediated isothermal signal amplification, where poly(U) polymerase can catalyze the template independent addition of UMP from UTP to the 3' end of RNA. Using this activity, the target microRNA can be successfully labeled with biotin conjugated UMPs at its 3'-end using biotin conjugated UTP (biotin-UTP) as donor. Then, the avidin conjugated alkaline phosphatase can be further captured to the 3'-end of the target microRNA based on the specific interaction between biotin and avidin. Finally, under the catalytic activity of alkaline phosphatase, the substrate of p-nitrophenyl phosphate disodium salt hexahydrate can be hydrolyzed to produce 4-nitrophenol. According to the relationship between the electrochemical signal of p-nitrophenol and the concentration of microRNA-319a, the content of microRNA-319a can be detected. This signal amplification method is simple and sensitive. The developed method can detect as low as 1.7 fM microRNA and produce precise and accurate linear dynamic range from 10 to 1000 fM. The fabricated biosensor was further applied to detect the expression level change of microRNA-319a in rice seedlings after incubation with five kinds of different phytohormones.

  2. Graphene and tricobalt tetraoxide nanoparticles based biosensor for electrochemical glutamate sensing.

    PubMed

    Dalkıran, Berna; Erden, Pınar Esra; Kılıç, Esma

    2017-03-01

    An amperometric biosensor based on tricobalt tetraoxide nanoparticles (Co3O4), graphene (GR), and chitosan (CS) nanocomposite modified glassy carbon electrode (GCE) for sensitive determination of glutamate was fabricated. Scanning electron microscopy was implemented to characterize morphology of the nanocomposite. The biosensor showed optimum response within 25 s at pH 7.5 and 37 °C, at +0.70 V. The linear working range of biosensor for glutamate was from 4.0 × 10(-)(6) to 6.0 × 10(-)(4) M with a detection limit of 2.0 × 10(-)(6) M and sensitivity of 0.73 μA/mM or 7.37 μA/mMcm(2). The relatively low Michaelis-Menten constant (1.09 mM) suggested enhanced enzyme affinity to glutamate. The glutamate biosensor lost 45% of its initial activity after three weeks.

  3. Invertase inhibition based electrochemical sensor for the detection of heavy metal ions in aqueous system: Application of ultra-microelectrode to enhance sucrose biosensor's sensitivity.

    PubMed

    Bagal-Kestwal, Dipali; Karve, Meena S; Kakade, Bhalchandra; Pillai, Vijayamohanan K

    2008-12-01

    We are reporting fabrication and characterization of electrochemical sucrose biosensor using ultra-microelectrode (UME) for the detection of heavy metal ions (Hg(II), Ag(I), Pb(II) and Cd(II)). The working UME, with 25 microm diameter, was modified with invertase (INV, EC: 3.2.1.26) and glucose oxidase (GOD, EC: 1.1.3.4) entrapped in agarose-guar gum. The hydrophilic character of the agarose-guar gum composite matrix was checked by water contact angle measurement. The atomic force microscopy (AFM) images of the membranes showed proper confinement of both the enzymes during co-immobilization. The dynamic range for sucrose biosensor was achieved in the range of 1 x 10(-10) to 1 x 10(-7)M with lower detection limit 1 x 10(-10)M at pH 5.5 with 9 cycles of reuse. The spectrophotometric and electrochemical studies showed linear relationship between concentration of heavy metal ions and degree of inhibition of invertase. The toxicity sequence for invertase using both methods was observed as Hg(2+)>Pb(2+)>Ag(+)>Cd(2+). The dynamic linear range for mercury using electrochemical biosensor was observed in the range of 5 x 10(-10) to 12.5 x 10(-10)M for sucrose. The lower detection limit for the fabricated biosensor was found to be 5 x 10(-10)M. The reliability of the electrochemical biosensor was conformed by testing the spike samples and the results were comparable with the conventional photometric DNSA method.

  4. Alpha-Glucosidase Enzyme Biosensor for the Electrochemical Measurement of Antidiabetic Potential of Medicinal Plants.

    PubMed

    Mohiuddin, M; Arbain, D; Islam, A K M Shafiqul; Ahmad, M S; Ahmad, M N

    2016-12-01

    A biosensor for measuring the antidiabetic potential of medicinal plants was developed by covalent immobilization of α-glucosidase (AG) enzyme onto amine-functionalized multi-walled carbon nanotubes (MWCNTs-NH2). The immobilized enzyme was entrapped in freeze-thawed polyvinyl alcohol (PVA) together with p-nitrophenyl-α-D-glucopyranoside (PNPG) on the screen-printed carbon electrode at low pH to prevent the premature reaction between PNPG and AG enzyme. The enzymatic reaction within the biosensor is inhibited by bioactive compounds in the medicinal plant extracts. The capability of medicinal plants to inhibit the AG enzyme on the electrode correlates to the potential of the medicinal plants to inhibit the production of glucose from the carbohydrate in the human body. Thus, the inhibition indicates the antidiabetic potential of the medicinal plants. The performance of the biosensor was evaluated to measure the antidiabetic potential of three medicinal plants such as Tebengau (Ehretis laevis), Cemumar (Micromelum pubescens), and Kedondong (Spondias dulcis) and acarbose (commercial antidiabetic drug) via cyclic voltammetry, amperometry, and spectrophotometry. The cyclic voltammetry (CV) response for the inhibition of the AG enzyme activity by Tebengau plant extracts showed a linear relation in the range from 0.423-8.29 μA, and the inhibition detection limit was 0.253 μA. The biosensor exhibited good sensitivity (0.422 μA/mg Tebengau plant extracts) and rapid response (22 s). The biosensor retains approximately 82.16 % of its initial activity even after 30 days of storage at 4 °C.

  5. Alpha-Glucosidase Enzyme Biosensor for the Electrochemical Measurement of Antidiabetic Potential of Medicinal Plants

    NASA Astrophysics Data System (ADS)

    Mohiuddin, M.; Arbain, D.; Islam, A. K. M. Shafiqul; Ahmad, M. S.; Ahmad, M. N.

    2016-02-01

    A biosensor for measuring the antidiabetic potential of medicinal plants was developed by covalent immobilization of α-glucosidase (AG) enzyme onto amine-functionalized multi-walled carbon nanotubes (MWCNTs-NH2). The immobilized enzyme was entrapped in freeze-thawed polyvinyl alcohol (PVA) together with p-nitrophenyl-α- d-glucopyranoside (PNPG) on the screen-printed carbon electrode at low pH to prevent the premature reaction between PNPG and AG enzyme. The enzymatic reaction within the biosensor is inhibited by bioactive compounds in the medicinal plant extracts. The capability of medicinal plants to inhibit the AG enzyme on the electrode correlates to the potential of the medicinal plants to inhibit the production of glucose from the carbohydrate in the human body. Thus, the inhibition indicates the antidiabetic potential of the medicinal plants. The performance of the biosensor was evaluated to measure the antidiabetic potential of three medicinal plants such as Tebengau ( Ehretis laevis), Cemumar ( Micromelum pubescens), and Kedondong ( Spondias dulcis) and acarbose (commercial antidiabetic drug) via cyclic voltammetry, amperometry, and spectrophotometry. The cyclic voltammetry (CV) response for the inhibition of the AG enzyme activity by Tebengau plant extracts showed a linear relation in the range from 0.423-8.29 μA, and the inhibition detection limit was 0.253 μA. The biosensor exhibited good sensitivity (0.422 μA/mg Tebengau plant extracts) and rapid response (22 s). The biosensor retains approximately 82.16 % of its initial activity even after 30 days of storage at 4 °C.

  6. Detection of DNA hybridization by field-effect DNA-based biosensors: mechanisms of signal generation and open questions.

    PubMed

    Cherstvy, A G

    2013-08-15

    We model theoretically the electrostatic effects taking place upon DNA hybridization in dense DNA arrays immobilized on a layer of Au nano-particles deposited on the surface of a field-effect-based DNA capacitive biosensor. We consider the influence of separation of a charged analyte from the sensor surface and the salinity of electrolyte solution, in the framework of both linear and nonlinear Poisson-Boltzmann theories. The latter predicts a substantially weaker sensor signals due to electrostatic saturation effects that is the main conclusion of this paper. We analyze how different physical parameters of dense DNA brushes affect the magnitude of hybridization signals. The list includes the fraction of DNA charge neutralization, the length and spatial conformations of adsorbed DNA molecules, as well as the discreteness of DNA charges. We also examine the effect of Donnan ionic equilibrium in DNA lattices on the sensor response. The validity of theoretical models is contrasted against recent experimental observations on detection of DNA hybridization via its intrinsic electric charge. The sensitivity of such biochemical sensing devices, their detection limit, and DNA hybridization efficiency are briefly discussed in the end.

  7. In vitro selection of DNA aptamers targeting β-lactoglobulin and their integration in graphene-based biosensor for the detection of milk allergen.

    PubMed

    Eissa, Shimaa; Zourob, Mohammed

    2017-05-15

    Food allergy has increased rapidly in recent years affecting millions of people worldwide. With the increased consumption of packed food nowadays, a sensitive, accurate and rapid screening method for potential food allergens has become an urgent need in order to protect the sensitive consumers from life-threatening reactions. The current detection methods for food allergens are mostly based on immunoassays which are costly and times-consuming. In this work, we developed an aptamer/graphene-based electrochemical biosensor for on-step, sensitive and low cost detection of β-lactoglobulin (β-LG) milk protein, one of the most common food allergens specially in infants. The selection of DNA aptamers against the two β-LG variants A and B was successfully realised using systemic evolution of ligands by exponential enrichment (SELEX) method. Among the selected aptamers, BLG14 aptamer sequence has shown high affinity and specificity to both β-LG A and B with dissociation constants (Kds) of 82 and 80nM, respectively as calculated using fluorescence binding assays. The aptamer was then integrated in a voltammetric biosensor utilizing graphene-modified screen printed carbon electrodes. The binding is monitored by following the change in the square wave voltammetry (SWV) reduction peak signal of ferrocyanide/ferricyanide redox couple due to the removal of the negatively charged aptamers from the surface upon protein binding. This one-step "signal on" biosensor takes 20min for the sensitive and selective detection of β-LG without using any labelling or sophisticated designs. The method was also tested in spiked food sample extract achieving good recovery percentage. The integration of the novel aptamer in the graphene biosensor allows a promising way for cost-effective, rapid and sensitive on-site detection of milk allergen in food stuff.

  8. A sensitive impedimetric DNA biosensor for the determination of the HIV gene based on graphene-Nafion composite film.

    PubMed

    Gong, Qiaojuan; Wang, Yongdong; Yang, Haiying

    2017-03-15

    An impedimetric HIV-1 gene biosensor has been developed based on graphene-Nafion composite film. The biosensor was fabricated by adsorbing the single-stranded DNA (ssDNA) on graphene-Nafion modified on the surface of glassy carbon electrode via the π-π* stacking interactions. As the negative ssDNA and the steric hindrance, the electron transfer resistance of the electrodes toward the [Fe(CN)6](3-/4) redox couple was difficult, the electron transfer resistance value increased. In the measurement of HIV gene, ssDNA probe with the target DNA to form double-stranded DNA (dsDNA), the formation of helix induced dsDNA to release from the surface of the biosensor. The decrease in the electron transfer resistance was in logarithmically direct proportion to the concentration of HIV-1 gene over a range from 1.0×10(-13) to 1.0×10(-10)M. The detection limit of this sensor was 2.3×10(-14)M. It was found that Nafion could not only stabilize graphene but also increase the dispersion of graphene. The results demonstrate that this graphene-Nafion biosensor possesses good selectivity, acceptable stability and reproducibility for HIV-1 gene detection.

  9. A novel electrochemical biosensor based on polyadenine modified aptamer for label-free and ultrasensitive detection of human breast cancer cells.

    PubMed

    Wang, Kun; He, Meng-Qi; Zhai, Fu-Heng; He, Rong-Huan; Yu, Yong-Liang

    2017-05-01

    Simple, rapid, sensitive, and specific detection of cancer cells plays a pivotal role in the diagnosis and prognosis of cancer. A sandwich electrochemical biosensor was developed based on polyadenine (polydA)-aptamer modified gold electrode (GE) and polydA-aptamer functionalized gold nanoparticles/graphene oxide (AuNPs/GO) hybrid for the label-free and selective detection of breast cancer cells (MCF-7) via a differential pulse voltammetry (DPV) technique. Due to the intrinsic affinity between multiple consecutive adenines of polydA sequences and gold, polydA modified aptamer instead of thiol terminated aptamer was immobilized on the surface of GE and AuNPs/GO. The label-free MCF-7 cells could be recognized by polydA-aptamer and self-assembled onto the surface of GE. The polydA-aptamer functionalized AuNPs/GO hybrid could further bind to MCF-7 cells to form a sandwich sensing system. Characterization of the surface modified GE was carried out by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) using Fe(CN)6(3-/4-) as a redox probe. Under the optimized experimental conditions, a detection limit of 8 cellsmL(-1) (3σ/slope) was obtained for MCF-7 cells by the present electrochemical biosensor, along with a linear range of 10-10(5) cellsmL(-1). By virtue of excellent sensitivity, specificity and repeatability, the present electrochemical biosensor provides a potential application in point-of-care cancer diagnosis.

  10. Construction of DNA biosensor at glassy carbon surface modified with 4-aminoethylbenzenediazonium salt.

    PubMed

    Kowalczyk, Agata; Nowicka, Anna; Jurczakowski, Rafal; Fau, Michal; Krolikowska, Agata; Stojek, Zbigniew

    2011-01-15

    A simple, label-free electrochemical impedance-spectroscopy method for sequence-specific detection of DNA using a 4-aminoethylbenzenediazonium (AEBD) salt as a binder for amino-modified probe DNA is reported. This novel method simplifies the anchoring of DNA at the GC surface and opens new ways for the detection of hybridization. The hybridization of target DNA, without and with mismatches, with the probe DNA anchored at the GC surface modified with AEBD, greatly increases the interfacial electron transfer resistance at the double-stranded DNA modified electrodes for the redox couple Fe(CN)(6)(3-/4-). The resistance was measured using electrochemical impedance spectroscopy. The sensor response increased linearly with logarithm of concentration of target DNA in the range 2×10(-12)÷2×10(-6) M. The obtained quantification limit was circa 6.5×10(-17) mole in a 7 μL droplet and corresponded to a concentration of 9.2×10(-12) M of target DNA in the sample. This limit is equivalent to the detection of circa 4×10(7) copies of DNA in a 7 μL droplet or circa 5.7×10(12) DNA copies in one litre of sample.

  11. A review on impedimetric biosensors.

    PubMed

    Bahadır, Elif Burcu; Sezgintürk, Mustafa Kemal

    2016-01-01

    Electrochemical impedance spectroscopy (EIS) is a sensitive technique for the analysis of the interfacial properties related to biorecognition events such as reactions catalyzed by enzymes, biomolecular recognition events of specific binding proteins, lectins, receptors, nucleic acids, whole cells, antibodies or antibody-related substances, occurring at the modified surface. Many studies on impedimetric biosensors are focused on immunosensors and aptasensors. In impedimetric immunosensors, antibodies and antigens are bound each other and thus immunocomplex is formed and the electrode is coated with a blocking layer. As a result of that electron transfer resistance increases. In impedimetric aptasensors, impedance changes following the binding of target sequences, conformational changes, or DNA damages. Impedimetric biosensors allow direct detection of biomolecular recognition events without using enzyme labels. In this paper, impedimetric biosensors are reviewed and the most interesting ones are discussed.

  12. Surface functionalisation of carbon for low cost fabrication of highly stable electrochemical DNA sensors.

    PubMed

    Debela, Ahmed M; Ortiz, Mayreli; Beni, Valerio; O'Sullivan, Ciara K

    2015-09-15

    An alternative strategy for surface tethering of DNA probes, where highly reactive glassy carbon (GC) substrates are prepared via electrochemical hydrogenation and electrochemical/chemical chlorination is reported. Thiolated DNA probes and alkanethiols were stably immobilised on the halogenated carbon, with electrochemical chlorination being milder, thus producing less damage to the surface. Electrochemical DNA sensors prepared using this surface chemistry on carbon with electrochemical chlorination providing an improved performance, producing a highly ordered surface and the use of lateral spacers to improve steric accessibility to immobilised probes was not required.

  13. CdS quantum dots modified CuO inverse opal electrodes for ultrasensitive electrochemical and photoelectrochemical biosensor

    PubMed Central

    Xia, Lei; Xu, Lin; Song, Jian; Xu, Ru; Liu, Dali; Dong, Biao; Song, Hongwei

    2015-01-01

    The CuO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method and modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR). CdS QDs modified CuO IOPCs FTO electrodes of different SILAR cycles were fabricated and their electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (I–t). Structure and morphology of the samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution TEM (HRTEM), Energy-dispersive X-ray analysis (EDX) and X-ray diffraction pattern (XRD). The result indicated that the structure of IOPCs and loading of CdS QDs could greatly improve the electrochemical properties. Three SILAR cycles of CdS QDs sensitization was the optimum condition for preparing electrodes, it exhibited a sensitivity of 4345 μA mM-1 cm-2 to glucose with a 0.15 μM detection limit (S/N= 3) and a linear range from 0.15 μM to 0.5 mM under a working potential of +0.7 V. It also showed strong stability, good reproducibility, excellent selectivity and fast amperometric response. This work provides a promising approach for realizing excellent photoelectrochemical nonenzymatic glucose biosensor of similar composite structure. PMID:26042520

  14. Label-free electrochemical impedance biosensor to detect human interleukin-8 in serum with sub-pg/ml sensitivity.

    PubMed

    Sharma, R; Deacon, S E; Nowak, D; George, S E; Szymonik, M P; Tang, A A S; Tomlinson, D C; Davies, A G; McPherson, M J; Wälti, C

    2016-06-15

    Biosensors with high sensitivity and short time-to-result that are capable of detecting biomarkers in body fluids such as serum are an important prerequisite for early diagnostics in modern healthcare provision. Here, we report the development of an electrochemical impedance-based sensor for the detection in serum of human interleukin-8 (IL-8), a pro-angiogenic chemokine implicated in a wide range of inflammatory diseases. The sensor employs a small and robust synthetic non-antibody capture protein based on a cystatin scaffold that displays high affinity for human IL-8 with a KD of 35 ± 10 nM and excellent ligand specificity. The change in the phase of the electrochemical impedance from the serum baseline, ∆θ(ƒ), measured at 0.1 Hz, was used as the measure for quantifying IL-8 concentration in the fluid. Optimal sensor signal was observed after 15 min incubation, and the sensor exhibited a linear response versus logarithm of IL-8 concentration from 900 fg/ml to 900 ng/ml. A detection limit of around 90 fg/ml, which is significantly lower than the basal clinical levels of 5-10 pg/ml, was observed. Our results are significant for the development of point-of-care and early diagnostics where high sensitivity and short time-to-results are essential.

  15. Detection of ESAT-6 by a label free miniature immuno-electrochemical biosensor as a diagnostic tool for tuberculosis.

    PubMed

    Diouani, Mohamed Fethi; Ouerghi, Oussama; Refai, Amira; Belgacem, Kamel; Tlili, Chaker; Laouini, Dhafer; Essafi, Makram

    2017-05-01

    Tuberculosis is a worldwide disease considered as a major health problem with high morbidity and mortality rates. Poor detection of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis remains a major obstacle to the global control of this disease. Here we report the development of a new test based on the detection of the major virulent factor of Mtb, namely the early secreted antigenic target 6-kDa protein or ESAT-6. A label free electrochemical immunosensor using an anti-ESAT-6 monoclonal antibody as a bio-receptor is described herein. Anti-ESAT-6 antibodies were first covalently immobilized on the surface of a gold screen-printed electrode functionalized via a self-assembled thiol monolayer. Interaction between the bio-receptor and ESAT-6 antigen was evaluated by square wave voltammetry method using [Fe(CN)6](3-/4-) as redox probe. The detection limit of ESAT-6 antigen was 7ng/ml. The immunosensor has also been able to detect native ESAT-6 antigen secreted in cell culture filtrates of three pathogenic strains of Mtb (CDC1551, H37RV and H8N8). Overall, this work describes an immune-electrochemical biosensor, based on ESAT-6 antigen detection, as a useful diagnostic tool for tuberculosis.

  16. An Efficient Power Harvesting Mobile Phone-Based Electrochemical Biosensor for Point-of-Care Health Monitoring.

    PubMed

    Sun, Alexander C; Yao, Chengyang; Venkatesh, A G; Hall, Drew A

    2016-11-01

    Cellular phone penetration has grown continually over the past two decades with the number of connected devices rapidly approaching the total world population. Leveraging the worldwide ubiquity and connectivity of these devices, we developed a mobile phone-based electrochemical biosensor platform for point-of-care (POC) diagnostics and wellness tracking. The platform consists of an inexpensive electronic module (< $20) containing a low-power potentiostat that interfaces with and efficiently harvests power from a wide variety of phones through the audio jack. Active impedance matching improves the harvesting efficiency to 79%. Excluding loses from supply rectification and regulation, the module consumes 6.9 mW peak power and can measure < 1 nA bidirectional current. The prototype was shown to operate within the available power budget set by mobile devices and produce data that matches well with that of an expensive laboratory grade instrument. We demonstrate that the platform can be used to track the concentration of secretory leukocyte protease inhibitor (SLPI), a biomarker for monitoring lung infections in cystic fibrosis patients, in its physiological range via an electrochemical sandwich assay on disposable screen-printed electrodes with a 1 nM limit of detection.

  17. Label-free electrochemical impedance biosensor to detect human interleukin-8 in serum with sub-pg/ml sensitivity

    PubMed Central

    Sharma, R.; Deacon, S.E.; Nowak, D.; George, S.E.; Szymonik, M.P.; Tang, A.A.S.; Tomlinson, D.C.; Davies, A.G.; McPherson, M.J.; Wälti, C.

    2016-01-01

    Biosensors with high sensitivity and short time-to-result that are capable of detecting biomarkers in body fluids such as serum are an important prerequisite for early diagnostics in modern healthcare provision. Here, we report the development of an electrochemical impedance-based sensor for the detection in serum of human interleukin-8 (IL-8), a pro-angiogenic chemokine implicated in a wide range of inflammatory diseases. The sensor employs a small and robust synthetic non-antibody capture protein based on a cystatin scaffold that displays high affinity for human IL-8 with a KD of 35±10 nM and excellent ligand specificity. The change in the phase of the electrochemical impedance from the serum baseline, ∆θ(ƒ), measured at 0.1 Hz, was used as the measure for quantifying IL-8 concentration in the fluid. Optimal sensor signal was observed after 15 min incubation, and the sensor exhibited a linear response versus logarithm of IL-8 concentration from 900 fg/ml to 900 ng/ml. A detection limit of around 90 fg/ml, which is significantly lower than the basal clinical levels of 5–10 pg/ml, was observed. Our results are significant for the development of point-of-care and early diagnostics where high sensitivity and short time-to-results are essential. PMID:26897263

  18. Real-time investigation of antibiotics-induced oxidative stress and superoxide release in bacteria using an electrochemical biosensor.

    PubMed

    Liu, Xiaobo; Marrakchi, Mouna; Jahne, Michael; Rogers, Shane; Andreescu, Silvana

    2016-02-01

    The involvement of oxidative stress in the mechanism of antibiotics-meditated cell death is unclear and subject to debate. The kinetic profile and a quantitative relationship between the release of reactive oxygen species (ROS), bacteria and antibiotic type remain elusive. Here we report direct measurements and analytical quantification of the release of superoxide radicals (O2(·-)), a major contributor to ROS, in antibiotics-treated bacterial cultures using a cytochrome c electrochemical biosensor. The specificity of electrochemical measurements was established by the addition of superoxide dismutase (SOD) which decreased the O2(·-) signal. Measurements using a general ROS-specific fluorescence dye and colony forming units (CFU) assays were performed side-by-side to determine the total ROS and establish the relationship between ROS and the degree of lethality. Exposure of Escherichia coli and Listeria monocytogenes cultures to antibiotics increased the release of O2(·-) radicals in a dose-dependent manner, suggesting that the transmembrane generation of ROS may occur as part of the antibiotic action. The study provides a quantitative methodology and fundamental knowledge to further explore the role of oxidative stress in antibiotics-meditated bacterial death and to assess physiological changes associated with the complex metabolic events related to oxidative stress and bacterial resistance.

  19. Cobalt oxide magnetic nanoparticles-chitosan nanocomposite based electrochemical urea biosensor

    NASA Astrophysics Data System (ADS)

    Ali, A.; Israr-Qadir, M.; Wazir, Z.; Tufail, M.; Ibupoto, Z. H.; Jamil-Rana, S.; Atif, M.; Khan, S. A.; Willander, M.

    2015-04-01

    In this study, a potentiometric urea biosensor has been fabricated on glass filter paper through the immobilization of urease enzyme onto chitosan/cobalt oxide (CS/Co3O4) nanocomposite. A copper wire with diameter of 500 µm is attached with nanoparticles to extract the voltage output signal. The shape and dimensions of Co3O4 magnetic nanoparticles are investigated by scanning electron microscopy and the average diameter is approximately 80-100 nm. Structural quality of Co3O4 nanoparticles is confirmed from X-ray powder diffraction measurements, while the Raman spectroscopy has been used to understand the chemical bonding between different atoms. The magnetic measurement has confirmed that Co3O4 nanoparticles show ferromagnetic behavior, which could be attributed to the uncompensated surface spins and/or finite size effects. The ferromagnetic order of Co3O4 nanoparticles is raised with increasing the decomposition temperature. A physical adsorption method is adopted to immobilize the surface of CS/Co3O4 nanocomposite. Potentiometric sensitivity curve has been measured over the concentration range between 1 × 10-4 and 8 × 10-2 M of urea electrolyte solution revealing that the fabricated biosensor holds good sensing ability with a linear slope curve of 45 mV/decade. In addition, the presented biosensor shows good reusability, selectivity, reproducibility and resistance against interferers along with the stable output response of 12 s.

  20. A highly sensitive electrochemical biosensor based on zinc oxide nanotetrapods for l-lactic acid detection

    NASA Astrophysics Data System (ADS)

    Lei, Yang; Luo, Ning; Yan, Xiaoqin; Zhao, Yanguang; Zhang, Gong; Zhang, Yue

    2012-05-01

    An amperometric biosensor based on zinc oxide (ZnO) nanotetrapods was designed to detect l-lactic acid. The lactate oxidase was immobilized on the surface of ZnO nanotetrapods by electrostatic adsorption. Unlike traditional detectors, the special four-leg individual ZnO nanostructure, as an adsorption layer, provides multiterminal charge transfer channels. Furthermore, a large amount of ZnO tetrapods are randomly stacked to form a three-dimensional network naturally that facilitates the exchange of electrons and ions in the phosphate buffer solution. Utilizing amperometric response measurements, the prepared ZnO nanotetrapod l-lactic acid biosensor displayed a detection limit of 1.2 μM, a low apparent Michaelis-Menten constant of 0.58 mM, a high sensitivity of 28.0 μA cm-2 mM-1 and a good linear relationship in the range of 3.6 μM-0.6 mM for the l-lactic acid detection. This study shows that the biosensor based on ZnO tetrapod nanostructures is highly sensitive and able to respond rapidly in detecting lactic acid.

  1. Development of swine-specific DNA markers for biosensor-based halal authentication.

    PubMed

    Ali, M E; Hashim, U; Kashif, M; Mustafa, S; Che Man, Y B; Abd Hamid, S B

    2012-06-29

    The pig (Sus scrofa) mitochondrial genome was targeted to design short (15-30 nucleotides) DNA markers that would be suitable for biosensor-based hybridization detection of target DNA. Short DNA markers are reported to survive harsh conditions in which longer ones are degraded into smaller fragments. The whole swine mitochondrial-genome was in silico digested with AluI restriction enzyme. Among 66 AluI fragments, five were selected as potential markers because of their convenient lengths, high degree of interspecies polymorphism and intraspecies conservatism. These were confirmed by NCBI blast analysis and ClustalW alignment analysis with 11 different meat-providing animal and fish species. Finally, we integrated a tetramethyl rhodamine-labeled 18-nucleotide AluI fragment into a 3-nm diameter citrate-tannate coated gold nanoparticle to develop a swine-specific hybrid nanobioprobe for the determination of pork adulteration in 2.5-h autoclaved pork-beef binary mixtures. This hybrid probe detected as low as 1% pork in deliberately contaminated autoclaved pork-beef binary mixtures and no cross-species detection was recorded, demonstrating the feasibility of this type of probe for biosensor-based detection of pork adulteration of halal and kosher foods.

  2. Electrochemical detection of DNA damage induced by acrylamide and its metabolite at the graphene-ionic liquid-Nafion modified pyrolytic graphite electrode.

    PubMed

    Qiu, Yanyan; Qu, Xiangjin; Dong, Jing; Ai, Shiyun; Han, Ruixia

    2011-06-15

    A new electrochemical biosensor for directly detecting DNA damage induced by acrylamide (AA) and its metabolite was presented in this work. The graphene-ionic liquid-Nafion modified pyrolytic graphite electrode (PGE) was prepared, and then horseradish peroxidase (HRP) and natural double-stranded DNA were alternately assembled on the modified electrode by the layer-by-layer method. The PGE/graphene-ionic liquid-Nafion and the construction of the (HRP/DNA)(n) film were characterized by electrochemical impedance spectroscopy. With the guanine signal in DNA as an indicator, the damage of DNA was detected by differential pulse voltammetry after PGE/graphene-ionic liquid-Nafion/(HRP/DNA)(n) was incubated in AA solution or AA+H(2)O(2) solution at 37°C. This method provides a new model to mimic and directly detect DNA damage induced by chemical pollutants and their metabolites in vitro. The results indicated that, in the presence of H(2)O(2), HRP was activated and catalyzed the transformation of AA to glycidamide, which could form DNA adducts and induce more serious damage of DNA than AA. In order to further verify these results, UV-vis spectrophotometry was also used to investigate DNA damage induced by AA and its metabolites in solution and the similar results were obtained.

  3. Non-enzymatic electrochemical biosensor based on Pt NPs/RGO-CS-Fc nano-hybrids for the detection of hydrogen peroxide in living cells.

    PubMed

    Bai, Zhihao; Li, Guiyin; Liang, Jingtao; Su, Jing; Zhang, Yue; Chen, Huaizhou; Huang, Yong; Sui, Weiguo; Zhao, Yongxiang

    2016-08-15

    A highly sensitive non-enzymatic electrochemical sensor based on platinum nanoparticles/reduced graphene oxide-chitosan-ferrocene carboxylic acid nano-hybrids (Pt NPs/RGO-CS-Fc biosensor) was developed for the measurement of hydrogen peroxide (H2O2). The RGO-CS-Fc nano-hybrids was prepared and characterized by UV-vis spectrum, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectrometer and electrochemical impedance spectroscopy. Under optimal experimental conditions, the Pt NPs/RGO-CS-Fc biosensor showed outstanding catalytic activity toward H2O2 reduction. The current response of the biosensor presented a linear relationship with H2O2 concentration from 2.0×10(-8)M to 3.0×10(-6)M with a correlation coefficient of R(2)=0.9968 and with logarithm of H2O2 concentration from 6.0×10(-6)M to 1.0×10(-2)M with a correlation coefficient of R(2)=0.9887, the low detection limit of 20nM was obtained at the signal/noise (S/N) ratio of 3. Moreover, the Pt NPs/RGO-CS-Fc biosensor exhibited excellent anti-interference capability and reproducibility for the detection of H2O2. The biosensor was also successfully applied for the detection of H2O2 from living cells containing normal and cancer cells. All these results prove that the Pt NPs/RGO-CS-Fc biosensor has the potential application in clinical diagnostics to evaluate oxidative stress of different living cells.

  4. Electrochemical Sensors for Clinic Analysis

    PubMed Central

    Wang, You; Xu, Hui; Zhang, Jianming; Li, Guang

    2008-01-01

    Demanded by modern medical diagnosis, advances in microfabrication technology have led to the development of fast, sensitive and selective electrochemical sensors for clinic analysis. This review addresses the principles behind electrochemical sensor design and fabrication, and introduces recent progress in the application of electrochemical sensors to analysis of clinical chemicals such as blood gases, electrolytes, metabolites, DNA and antibodies, including basic and applied research. Miniaturized commercial electrochemical biosensors will form the basis of inexpensive and easy to use devices for acquiring chemical information to bring sophisticated analytical capabilities to the non-specialist and general public alike in the future. PMID:27879810

  5. Development of an Automated DNA Detection System Using an Electrochemical DNA Chip Technology

    NASA Astrophysics Data System (ADS)

    Hongo, Sadato; Okada, Jun; Hashimoto, Koji; Tsuji, Koichi; Nikaido, Masaru; Gemma, Nobuhiro

    A new compact automated DNA detection system Genelyzer™ has been developed. After injecting a sample solution into a cassette with a built-in electrochemical DNA chip, processes from hybridization reaction to detection and analysis are all operated fully automatically. In order to detect a sample DNA, electrical currents from electrodes due to an oxidization reaction of electrochemically active intercalator molecules bound to hybridized DNAs are detected. The intercalator is supplied as a reagent solution by a fluid supply unit of the system. The feasibility test proved that the simultaneous typing of six single nucleotide polymorphisms (SNPs) associated with a rheumatoid arthritis (RA) was carried out within two hours and that all the results were consistent with those by conventional typing methods. It is expected that this system opens a new way to a DNA testing such as a test for infectious diseases, a personalized medicine, a food inspection, a forensic application and any other applications.

  6. Dual Signal Amplification Electrochemical Biosensor for Monitoring the Activity and Inhibition of the Alzheimer's Related Protease β-Secretase.

    PubMed

    Qu, Fengli; Yang, Minghui; Rasooly, Avraham

    2016-11-01

    The protease BACE1 (the β-site amyloid precursor protein cleaving enzyme 1) catalyzes the first step in the synthesis of β-amyloids (Aβ), peptides that accumulate in the brain in Alzheimer's disease (AD). Measurement of BACE1 activity is important for the development of BACE1 inhibitors to slow or stop AD. To measure BACE1 cleavage of the electrode-immobilized substrate peptide, we developed a redox-generating hydroxyapatite (HAP) probe which generates electrochemical current by reaction of the nanoparticle with molybdate (MoO4(2-)). The probe combines alkaline phosphatase (ALP) for dual signal amplification and Aβ antibody to bind the probe to the immobilized peptide substrate on the surface of the electrode. We measured the activity of BACE1 at concentrations ranging from 0.25 to 100 U/mL. The use of the dual-signal HAP-ALP probe increased the signal by an order of magnitude compared to HAP-only probe, enabling detection limits as low as 0.1 U/mL. To measure the inhibition of BACE1 activity, the BACE1 inhibitor OM99-2 was added to 25 U/mL of BACE1 in concentrations ranging from 5 to 150 nM. The observed detection limit of inhibition is 10 nM of OM99-2. These results demonstrate the capabilities of this novel biosensor to measure BACE1 activity and inhibitors of BACE1 activity. To the best of our knowledge this is the first report that reaction of HAP nanoparticles with molybdate can generate electrochemical current. This dual signal amplification strategy can be extended to other electrochemical assays and adapted for wide applications.

  7. A Sensitive and simple macrophage-based electrochemical biosensor for evaluating lipopolysaccharide cytotoxicity of pathogenic bacteria.

    PubMed

    Wang, Xiumei; Zhu, Pei; Pi, Fuwei; Jiang, Hui; Shao, Jingdong; Zhang, Yinzhi; Sun, Xiulan

    2016-07-15

    In this study, a sensitive and simple electrochemical murine macrophage (Ana-1) cell sensor has been developed for early detection of lipopolysaccharides (LPS) to evaluate the toxicity of pathogenic bacteria. Magnetic glassy carbon electrode (MGCE), which possesses excellent reproducibility and regeneration qualities, was modified with a nanocomposite to improve electrochemical signals and enhance the sensitivity. The synthesized magnetic nanoparticles (MNPs) were internalized into murine macrophages, which completed the immobilization of macrophages onto the modified electrode for evaluating the cytotoxicity of LPS by electrochemical impedance spectroscopy (EIS). The MNPs facilitated reusability of the proposed sensor by allowing removal of the magnetic core from the electrode. Our results indicated that LPS caused a marked decrease in electrochemical impedance in a dose-dependent manner in range of 1-5μg/mL. By SEM, we found that microvilli on the plasma membrane became scarce and the membrane became smooth on cells incubated with LPS, which lessens the absorption of cells to reduce the impedance. And biological assay indicated that EIS patterns were correlated with the calcium concentration in cells, and suggested that [Ca(2+)]i production increased in cells incubated with LPS and its mobilization altered electrochemical signals. Compared with conventional methods, this electrochemical test is inexpensive, highly sensitive, and has a quick response, and thus provides a new avenue for evaluating the cytotoxicity of pathogens.

  8. Ultrasensitive electrochemical biosensor based on reduced graphene oxide-tetraethylene pentamine-BMIMPF6 hybrids for the detection of α2,6-sialylated glycans in human serum.

    PubMed

    Li, Yuliang; He, Junlin; Niu, Yazhen; Yu, Chao

    2015-12-15

    In this paper, a simple, ultrasensitive and label-free electrochemical α2,6-sialylated glycans biosensor based on reduced graphene oxide-tetraethylene pentamine-1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) hybrids was developed. Due to the abundance of amino groups from reduced graphene oxide-tetraethylene pentamine (rGO-TEPA) and the electrostatic interaction of BMIMPF6, bimetallic gold platinum alloy nanoparticles (AuPtNPs) were densely adsorbed onto the surface of the nanocomposite, providing a large surface area available for the immobilization of Sambucus nigra agglutinin (SNA). AuPtNPs have excellent conductivity and catalytic activity, which can promote electron transfer between the electrolyte solution and the surface of electrode and can enhance the sensitivity of biosensor. SNA, which specifically binds α2,6-sialylated glycans, was covalently immobilized on AuPtNPs for specific detection of α2,6-sialylated glycans in human serum. Under optimal experimental conditions, amperometric response changes were used to detect α2,6-sialylated glycans with a broad linear range of 10 fg mL(-1) -1 μg mL(-1) and a low detection limit of 3 fg mL(-1) (S/N=3). When applied to spiked serum samples, the recovery of the developed biosensor ranged from 100.8% to 101.4%, suggesting that the electrochemical biosensor would be suitable for the practical detection of α2,6-sialylated glycans.

  9. A single electrochemical biosensor for detecting the activity and inhibition of both protein kinase and alkaline phosphatase based on phosphate ions induced deposition of redox precipitates.

    PubMed

    Shen, Congcong; Li, Xiangzhi; Rasooly, Avraham; Guo, Linyan; Zhang, Kaina; Yang, Minghui

    2016-11-15

    Protein kinase (PKA) and alkaline phosphatase (ALP) are clinically relevant enzymes for a number of diseases. In this work, we developed a new simple electrochemical biosensor for the detection of the activity and inhibition of both PKA and ALP. One common feature of the PKA and ALP catalyzing process is that PKA can hydrolysis adenosine-5'-triphosphate (ATP) and ALP can hydrolysis pyrophosphate, both reactions produce phosphate ions, and the amount of phosphate ion produced is proportional to enzyme activity. Our assay is based on the principle that phosphate ions react with molybdate to form redox molybdophosphate precipitates on the electrode surface, thus generating electrochemical current. The detection limit for PKA and ALP were much lower than existing assays. The biosensor has good specificity and was used to measure drug-stimulated PKA from lysates of HeLa cells. We also evaluated the use of the biosensor as a screening tool for enzyme inhibitors. To the best of our knowledge, this is the first report of a biosensor capable of detecting the activity of both PKA and ALP. This tool has the potential to simplify PKA and ALP clinical measurement, thereby improving diagnostics of relevant diseases. It also may serve as the basis for a simple screening method for new enzyme inhibitors for disease treatment.

  10. REVIEW ARTICLE: Environmental applications of analytical biosensors

    NASA Astrophysics Data System (ADS)

    Marco, María-Pilar; Barceló, Damià

    1996-11-01

    A review of the fundamental aspects and environmental applications of biosensors is presented. The bases of different transducer principles such as electrochemical, optical and piezoelectric are discussed. Various examples are given of the applications of such principles to develop immunosensor devices to determine common environmental contaminants. Attention is also paid to catalytic biosensors, using enzymes as sensing elements. Biosensor devices based on the use of cholinesterase and various oxidase enzymes such as tyrosinase, laccase, peroxidase and aldehyde dehydrogenase are reported. Some examples are given of the applications of other biomolecules such as whole cells, DNA or proteins, to determine pollution. Validation studies are presented comparing biosensors with chromatographic techniques to determine organophosphorus pesticides and phenolic compounds in environmental samples.

  11. Porphyrinic metal-organic framework as electrochemical probe for DNA sensing via triple-helix molecular switch.

    PubMed

    Ling, Pinghua; Lei, Jianping; Ju, Huangxian

    2015-09-15

    An electrochemical DNA sensor was developed based on the electrocatalysis of porphyrinic metal-organic framework (MOF) and triple-helix molecular switch for signal transduction. The streptavidin functionalized zirconium-porphyrin MOF (PCN-222@SA) was prepared as signal nanoprobe via covalent method and demonstrated high electrocatalysis for O2 reduction. Due to the large steric effect, the designed nanoprobe was blocked for the interaction with the biotin labeled triple-helix immobilized on the surface of glassy carbon electrode. In the presence of target DNA, the assistant DNA in triple-helix will hybridize with target DNA, resulting in the disassembly of triple-helix molecular. Consequently, the end biotin away from the electrode was ''activated'' for easy access to the signal nanoprobe, PCN-222@SA, on the basis of biotin-streptavidin biorecognition. The introduction of signal nanoprobe to a sensor surface led to a significantly amplified electrocatalytic current towards oxygen reduction. Integrating with DNA recycling amplification of Exonuclease III, the sensitivity of the biosensor was improved significantly with detection limit of 0.29 fM. Moreover, the present method has been successfully applied to detect DNA in complex serum matrix. This porphyrinic MOF-based strategy has promising application in the determination of various analytes for signal transduction and has great potential in bioassays.

  12. Triple-helix DNA structural studies using a Love wave acoustic biosensor.

    PubMed

    Papadakis, George; Tsortos, Achilleas; Gizeli, Electra

    2009-12-15

    The development of sensors for detecting the conformation of surface-attached molecules is an emerging field with significance in the pharmaceutical industry and in drug design. In this work, triplex-forming oligos (TFOs), a separate class of non-natural DNA bending agents that can affect the mechanical properties of DNA through the formation of triple-helical structures of specific conformation and/or flexibility, are used as a model system in combination with an acoustic biosensor to determine molecular geometrical features. In practice, the degree of bending of a specific DNA target caused by a particular TFO was evaluated by measuring the ratio of acoustic energy change over phase change observed during the binding of pre-formed triplex DNA molecules to the device surface. The DNA bending angle derived via acoustic measurements is in excellent agreement with previously reported values using molecular biology techniques. The reported acoustic technique appears quite appealing for the biophysical study of DNA molecules providing rapid qualitative and quantitative information, at the same time holding promise to be developed as a high-throughput method for the evaluation of DNA conformational changes.

  13. A DNA biosensor based on graphene paste electrode modified with Prussian blue and chitosan.

    PubMed

    Bo, Yang; Wang, Weiqi; Qi, Junfei; Huang, Shasheng

    2011-05-07

    A chemically modified graphene paste electrode was prepared by incorporating appropriate amounts of graphene in a paste mixture, followed by electrodepositing Prussian blue (PB) and coating chitosan on the electrode surface. The electrode was able to bind ssDNA, and gave a better voltammetric response for complement DNA than did ordinary carbon paste electrodes. The response of the electrode was characterized with respect to the paste composition, immobilization time of probe DNA on the chitosan and PB modified graphene paste electrode, and the effect of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride (EDC). The electrochemical behavior of PB assembled on the graphene paste electrode was investigated. The combination of graphene and PB can enhance the current response of the graphene paste electrode. As a consequence of DNA hybridization, a significant change in the current due to daunomycin intercalated with double-stranded DNA (ds-DNA) on the surface of the graphene paste electrode was observed.

  14. Electrochemical detection of DNA hybridization by using a zirconia modified renewable carbon paste electrode.

    PubMed

    Zuo, Shao-Hua; Zhang, Ling-Fan; Yuan, Hui-Hui; Lan, Min-Bo; Lawrance, Geoffrey A; Wei, Gang

    2009-02-01

    A simple, polishable and renewable DNA biosensor was fabricated based on a zirconia modified carbon paste electrode. Zirconia was mixed with graphite powder and paraffin wax to produce the paste for the electrode, and response-optimized at 56% graphite powder, 19% ZrO(2) and 25% paraffin wax. An oligonucleotide probe with a terminal 5'-phosphate group was attached to the surface of the electrode via the strong affinity of zirconia for phosphate groups. DNA immobilization and hybridization were characterized by cyclic voltammetry and differential pulse voltammetry, using methylene blue as indicator. Examination of changes in response with complementary or non-complementary DNA sequences showed that the developed biosensor had a high selectivity and sensitivity towards hybridization detection (< or =2x10(-10) M complementary DNA detectable). The surface of the biosensor can be renewed quickly and reproducibly (signal RSD+/-4.6% for five successive renewals) by a simple polishing step.

  15. New Catalytic DNA Biosensors for Radionuclides and Metal ions

    SciTech Connect

    Lu, Yi

    2005-06-01

    In vitro selection for DNAzymes that are catalytically active with UO22+ ions as the metal cofactor has been completed. The 10th generation pool of DNA was cloned and sequenced. A total of 84 clones were sequenced and placed into families based on sequence alignments. Selected members of each family were 5-labeled with 32P and amplified using PCR. Activity assays were conducted using the isotopically labeled DNAzymes in order to determine which sequences were the most active. The secondary structures of the two most active sequences, called Clone 13 and Clone 39, were determined using the computer program Mfold. A cleavage rate of approximately 1 min-1 in the presence of 10 uM UO22+ was observed for both clones. Clone 39 was determined to be the best candidate for truncation to create a trans-cleaving DNAzyme, based on its secondary structure. An enzyme strand, called 39E, and a substrate strand, called 39DS, were designed by truncating the cis-cleaving DNAzyme. An alternative enzyme strand, called 39Ec, was also assayed with the 39DS substrate. This strand was designed so that the two binding arms were perfectly complimentary, unlike 39E, which formed three mismatched base pairs with 39DS. Both 39E and 39Ec were found to be active, with a rate of approximately 1 min-1 in the presence of 10 uM UO22+. A preliminary UO22+ binding curve was obtained for the 39Ec/39DS trans-cleaving system. The enzyme is active with UO22+ concentrations as low as 1 nM. Based on the preliminary binding curve data, the apparent UO22+ binding constant is approximately 330 nM, and kmax is approximately 1 min-1.

  16. Mechanism for invalid detection of microcantilever-DNA biosensors due to environmental changes

    NASA Astrophysics Data System (ADS)

    Tan, Z.-Q.; Zhang, N.-H.; Meng, W.-L.; Tang, H.-S.

    2016-06-01

    Microcantilever-DNA biosensors can lose recognition signals under specific hybridization conditions; this could be termed as a type of invalid detection. Using a multiscale energy method, this paper presents an alternative mechanism for this invalid detection induced by bio-interactions and environmental changes in temperature and ionic strength. First, a scaling law for the nanoscale thickness of the DNA film, and a mesoscopic empirical potential for bio-interactions in DNA liquid crystal solution, were combined to update a multiscale analytical model revealing the relation between cantilever motion, temperature, ionic strength, elastic properties of multilayered cantilevers, and nanoscopic properties of DNA molecules. Second, we carried out isothermal and non-isothermal experiments for the bending motion during the formation of a self-assembled monolayer of thiolated single-stranded DNA covalently immobilized on the gold-coated side of the cantilevers, and during the subsequent hybridization with the complementary nucleic acid, in order to obtain the relevant model parameters, and also to validate the proposed analytical model. Third, the effects of temperature and ionic strength on the microcantilever deflections were investigated. Numerical results show that the competing interplay among electrostatic force, hydration force, and configurational entropy generates an invalid point of detection at a grafting density of about 0.05 chain nm-2. In the grafting density interval of 0.02-0.05 chain nm-2, the thermal effect induces distortion of signals; in the grafting density interval of 0.05-0.097 chain nm-2, fluctuations in ionic strength make detection fail. These findings will help to design and improve microcantilever-based biosensors with high sensitivity and robustness.

  17. Nanoparticle-based DNA biosensor for visual detection of genetically modified organisms.

    PubMed

    Kalogianni, Despina P; Koraki, Theodora; Christopoulos, Theodore K; Ioannou, Penelope C

    2006-01-15

    Although screening of raw ingredients and food products for genetically modified organisms (GMO) may be accomplished by detecting either the exogenous DNA or the novel protein, DNA is the preferred analyte because of its superior stability during food processing. The development of DNA biosensors is of increasing importance due to the growing demand for rapid and reliable methods for GMO detection. We report the first DNA biosensor in a dry-reagent dipstick configuration for visual detection and confirmation of GMO-related sequences by hybridization within minutes. The sensor is disposable and does not require special instrumentation. It detects the 35S promoter and nopaline synthase (NOS) terminator sequences that are present in the majority of transgenic plants. The target sequences are amplified by the polymerase chain reaction (PCR) and hybridized (7min) with probes bearing oligo(dA) tail. The biotinylated product is applied to the sensor followed by immersion in the appropriate buffer. Migration of the buffer rehydrates gold nanoparticles conjugated to oligo(dT), which hybridize with the oligo(dA) tails. The hybrids are captured by immobilized streptavidin at the test zone of the sensor giving a characteristic red line due to the accumulation of the nanoparticles. The excess of nanoparticle conjugates are captured at the control zone by immobilized oligo(dA) strands. Amplified 35S or NOS DNA is detectable at 0.16nM. Soybean powder certified reference material with 0.1% GMO content is clearly detectable after 35 and 40 amplification cycles for 35S and NOS sequence, respectively. The sensor was also applied to real samples from various sources.

  18. Piezoelectric Cantilever Biosensors for Label-free, Real-time Detection of DNA and RNA.

    PubMed

    Haring, Alexander P; Cesewski, Ellen; Johnson, Blake N

    2017-01-01

    This chapter reviews the design, fabrication, characterization, and application of piezoelectric-excited millimeter-sized cantilever (PEMC) sensors. The sensor transduction mechanism, sensing principle, and mode of operation are discussed. Bio-recognition strategies and surface functionalization methods for detection of DNA and RNA are discussed with a focus on self-assembly-based approaches. Methods for the verification of biosensor response via secondary binding assays, reversible binding assays, and the integration of complementary transduction mechanisms are presented. Sensing applications for medical diagnostics, food safety, and environmental monitoring are provided. PEMC sensor technology provides a robust platform for the real-time, label-free detection of DNA and RNA in complex matrices over nanomolar (nM) to attomolar (aM) concentration ranges.

  19. Electrochemical Quantification of the Antioxidant Capacity of Medicinal Plants Using Biosensors

    PubMed Central

    Rodríguez-Sevilla, Erika; Ramírez-Silva, María-Teresa; Romero-Romo, Mario; Ibarra-Escutia, Pedro; Palomar-Pardavé, Manuel

    2014-01-01

    The working area of a screen-printed electrode, SPE, was modified with the enzyme tyrosinase (Tyr) using different immobilization methods, namely entrapment with water-soluble polyvinyl alcohol (PVA), cross-linking using glutaraldehyde (GA), and cross-linking using GA and human serum albumin (HSA); the resulting electrodes were termed SPE/Tyr/PVA, SPE/Tyr/GA and SPE/Tyr/HSA/GA, respectively. These biosensors were characterized by means of amperometry and EIS techniques. From amperometric evaluations, the apparent Michaelis-Menten constant, Km′, of each biosensor was evaluated while the respective charge transfer resistance, Rct, was assessed from impedance measurements. It was found that the SPE/Tyr/GA had the smallest Km′ (57 ± 7) μM and Rct values. This electrode also displayed both the lowest detection and quantification limits for catechol quantification. Using the SPE/Tyr/GA, the Trolox Equivalent Antioxidant Capacity (TEAC) was determined from infusions prepared with “mirto” (Salvia microphylla), “hHierba dulce” (Lippia dulcis) and “salve real” (Lippia alba), medicinal plants commonly used in Mexico. PMID:25111237

  20. Fabrication of mediator-free hybrid nano-interfaced electrochemical biosensor for monitoring cancer cell proliferation.

    PubMed

    Madhurantakam, Sasya; Jayanth Babu, K; Balaguru Rayappan, John Bosco; Krishnan, Uma Maheswari

    2017-01-15

    Glucose, a chief energy source in cellular metabolism, has a significant role in cell proliferation. Cancer cells utilize more glucose than normal cells to meet the energy demand arising due to their uncontrolled proliferation. The present work reports the development of a nano-interfaced amperometric biosensor for rapid and accurate monitoring of glucose utilization by cancer cells. A hybrid nano-interface comprising a blend of carbon nanotubes (CNTs) and graphene (GR) was employed to enhance the surface area of the working electrode and favour direct electron transfer. Glucose oxidase (GOx) immobilized on the interface serves as the sensing element due to its high selectivity and sensitivity towards glucose. Utilization of glucose was monitored at pre-determined time intervals in MiaPaCa-2 cancer cells. The results obtained from the amperometric technique were compared with the values obtained from a commercial glucometer. Alamar blue assay was performed to check the proliferation rate of the cells. A good correlation was obtained between the proliferation rate and glucose utilization. The designed biosensor was found to be unaffected by the presence of potential interferents and hence may serve as a novel in vitro tool to rapidly quantify the proliferation rates of cancer cells in response to different treatment strategies.

  1. Electrochemical quantification of the antioxidant capacity of medicinal plants using biosensors.

    PubMed

    Rodríguez-Sevilla, Erika; Ramírez-Silva, María-Teresa; Romero-Romo, Mario; Ibarra-Escutia, Pedro; Palomar-Pardavé, Manuel

    2014-08-08

    The working area of a screen-printed electrode, SPE, was modified with the enzyme tyrosinase (Tyr) using different immobilization methods, namely entrapment with water-soluble polyvinyl alcohol (PVA), cross-linking using glutaraldehyde (GA), and cross-linking using GA and human serum albumin (HSA); the resulting electrodes were termed SPE/Tyr/PVA, SPE/Tyr/GA and SPE/Tyr/HSA/GA, respectively. These biosensors were characterized by means of amperometry and EIS techniques. From amperometric evaluations, the apparent Michaelis-Menten constant, Km', of each biosensor was evaluated while the respective charge transfer resistance, Rct, was assessed from impedance measurements. It was found that the SPE/Tyr/GA had the smallest Km' (57 ± 7) µM and Rct values. This electrode also displayed both the lowest detection and quantification limits for catechol quantification. Using the SPE/Tyr/GA, the Trolox Equivalent Antioxidant Capacity (TEAC) was determined from infusions prepared with "mirto" (Salvia microphylla), "hHierba dulce" (Lippia dulcis) and "salve real" (Lippia alba), medicinal plants commonly used in Mexico.

  2. Electrochemical Interrogation of Interactions between Surface-Confined DNA and Methylene Blue

    PubMed Central

    Pan, Dun; Zuo, Xiaolei; Wan, Ying; Wang, Lihua; Zhang, Jiong; Song, Shiping; Fan, Chunhai

    2007-01-01

    In this work, we reported a systematic investigation on the interactions between methylene blue (MB) and surface-confined DNA by using electrochemical methods. We demonstrated that the redox potential of MB and binding and dissociation kinetics of MB to DNA differed significantly for single-stranded DNA (ss-DNA) and double-stranded DNA (ds-DNA) immobilized on gold electrodes. This was possibly due to the different binding mechanism between MB and ss- or ds-DNA. This work might provide useful information for developing MB-based sequence-specific electrochemical DNA sensors.

  3. Electrochemical and spectroscopic study of octadecyltrimethylammonium bromide/DNA surfoplexes.

    PubMed

    Rodríguez-Pulido, Alberto; Aicart, Emilio; Junquera, Elena

    2009-04-21

    The use of cationic micelles consisting of octadecyltrimethylammonium bromide (C18TAB) to compact calf thymus DNA has been investigated in aqueous buffered solution at 310.15 K by means of conductometry, electrophoretic mobility, and several fluorescence spectroscopy methods. The results indicate that C18TAB micelles, consisting of 44 monomers on average, may compact DNA molecule by an electrostatic interaction that takes place at the cationic spherical micelle surface. The surfoplexes thus formed show a surface density charge that goes from negative to positive values at a Lmic/D mass ratio of around 1.0 (where Lmic and D are the masses of micellized cationic surfactant and DNA), called the isoneutrality ratio (Lmic/D)phi. Values of this characteristic parameter, determined in this work not only from the electrochemical experimental data but also from spectroscopic measurements, are in very good agreement with those ones calculated from molecular parameters and some other properties also obtained in this work. The electrostatic character of the DNA-micelle interaction has been confirmed by analyzing the decrease in fluorescence emission of the fluorophore ethidium bromide, EtBr, initially intercalated between DNA base pairs, as long as the surfoplexes are formed. Fluorescence anisotropy experiments have revealed that micelle packing becomes more rigid in the presence of DNA, but once the surfoplex is formed, the fluidity increases with the Lmic/D mass ratio, attaining its maximum when the isoneutrality ratio is exceeded. This fact, together with the net positive charge of the surfoplexes with the Lmic/D mass ratio over the isoneutrality ratio, makes this regimen of lipid and DNA content the optimum for efficiency in the transfection process.

  4. Electrochemical sensors and biosensors for determination of catecholamine neurotransmitters: A review.

    PubMed

    Ribeiro, José A; Fernandes, Paula M V; Pereira, Carlos M; Silva, F

    2016-11-01

    This work describes the state of the art of electrochemical devices for the detection of an important class of neurotransmitters: the catecholamines. This class of biogenic amines includes dopamine, noradrenaline (also called norepinephrine) and adrenaline (also called epinephrine). Researchers have focused on the role of catecholamine molecules within the human body because they are involved in many important biological functions and are commonly associated with several diseases, such as Alzheimer's and Parkinson. Furthermore, the release of catecholamines as a consequence of induced stimulus is an important indicator of reward-related behaviors, such as food, drink, sex and drug addiction. Thus, the development of simple, fast and sensitive electroanalytical methodologies for the determination of catecholamines is currently needed in clinical and biomedical fields, as they have the potential to serve as clinically relevant biomarkers for specific disease states or to monitor treatment efficacy. Currently, three main strategies have used by researchers to detect catecholamine molecules, namely: the use electrochemical materials in combination with, for example, HPLC or FIA, the incorporation of new materials/layers on the sensor surfaces (Tables 1-7) and in vivo detection, manly by using FSCV at CFMEs (Section 10). The developed methodologies were able not only to accurately detect catecholamines at relevant concentration levels, but to do so in the presence of co-existing interferences in samples detected (ascorbate, for example). This review examines the progress made in electrochemical sensors for the selective detection of catecholamines in the last 15 years, with special focus on highly innovative features introduced by nanotechnology. As the literature in rather extensive, we try to simplify this work by summarizing and grouping electrochemical sensors according to the manner their substrates were chemically modified. We also discuss the current and future

  5. Revealing and Resolving the Restrained Enzymatic Cleavage of DNA Self-Assembled Monolayers on Gold: Electrochemical Quantitation and ESI-MS Confirmation.

    PubMed

    Gao, Xiaoyi; Geng, Mingxi; Li, Yunchao; Wang, Xinglin; Yu, Hua-Zhong

    2017-02-21

    Herein, we report a combined electrochemical and ESI-MS study of the enzymatic hydrolysis efficiency of DNA self-assembled monolayers (SAMs) on gold, platform systems for understanding nucleic acid surface chemistry, and for constructing DNA-based biosensors. Our electrochemical approach is based on the comparison of the amounts of surface-tethered DNA nucleotides before and after exonuclease I (Exo I) incubation using electrostatically bound [Ru(NH3)6](3+) as redox indicators. It is surprising to reveal that the hydrolysis efficiency of ssDNA SAMs does not depend on the packing density and base sequence, and that the cleavage ends with surface-bound shorter strands (9-13 mers). The ex-situ ESI-MS observations confirmed that the hydrolysis products for ssDNA SAMs (from 24 to 56 mers) are dominated with 10-15 mer fragments, in contrast to the complete digestion in solution. Such surface-restrained hydrolysis behavior is due to the steric hindrance of the underneath electrode to the Exo I/DNA binding, which is essential for the occurrence of Exo I-catalyzed processive cleavage. More importantly, we have shown that the hydrolysis efficiency of ssDNA SAMs can be remarkably improved by adopting long alkyl linkers (locating DNA strands further away from the substrates).

  6. Integrating SPR-ellipsometry and electrochemical measurements for performance evaluation of label-free thiophene-based biosensor

    NASA Astrophysics Data System (ADS)

    Tsai, Pei-I.; Lee, Shu-Sheng; Chou, Shin-Ting; Chang, Yu-Ting; Lee, Adam Shih-Yuan; Lee, C. K.

    2014-03-01

    The surface plasmon resonance reflectance changes measured with a circularly polarized ellipsometry and an electrochemical impedance spectroscopy were identified to be able to characterize the critical roles of biomolecules for vastly different biological functions and processes. Throughout the course of this study, interferon-gamma (IFN-γ) was chosen as the biomarker to test and to verify the performance of this newly developed system for Tuberculosis detection. The interactions of IFN-γ with immobilized anti-IFN-γ antibody at various concentrations were interrogated both optically and electrochemically. A semi-conductive linker bis-thiophene was thiolated to ensure the cross-linked monoclonal human IFN-γ antibody got self-assembled onto the gold thin film and form a label-free biosensor. The functional features of the bis-thiophene coated-gold film were characterized by cyclic voltammetry and impedance spectroscopy methods. The association of IFN-γ to the bis-thiophene bridging units via antibody-antigen interactions provided the basis for ultrasensitive detection of IFN-γ by tracking the conformation changes in surface-bound protein molecules. The phase shift can be attributed to the average thickness and the real-time index of refraction of the protein layer in different protein layer. Experimental results obtained by impedance spectroscopy and by phase-interrogation SPR showed linear dynamic range. Our experimental results verified that an increase in the concentration of the IFN-γ usually accompanied by phase increase in SPR and an impedance decrease in EIS. These results indicated that our newly developed integrated biosensing system can potentially provide new insight into various conjugate phenomena and interfacial processes for observing molecular conformation changes.

  7. Nano-silver-modified PQC/DNA biosensor for detecting E. coli in environmental water.

    PubMed

    Sun, H; Choy, T S; Zhu, D R; Yam, W C; Fung, Y S

    2009-01-01

    To meet the requirement of World Health Organization for zero tolerance of E. coli cell in 100mL drinking water, a new procedure based on photodeposition of nano-Ag at TiO(2)-coated piezoelectric quartz crystal (PQC) electrode was developed to fabricate a highly sensitive PQC/DNA biosensor. Enhancement of 3.3 times for binding of complementary DNA has been shown and attributed to the following effects arising from the nano-Ag coating. First, a large increase in the active surface area and packing density of neutravidin enhances the maximum neutravidin load to 1.8 times of a normal electrode. Second, the functional activity of neutravidin is enhanced by chemical interaction with nano-Ag to give rise to an increase in the binding ratio between neutravidin and biotinylated DNA probe from 1.00:1.76 to 1.00:3.01. Third, the stronger binding leads to a higher stability of the biotinylated DNA probes bound and increase in hybridization with the complementary DNA. Under the optimized conditions for flow analysis with online PCR product denaturing and hybridization, a detection limit of eight E. coli cells are obtained which require sampling at least 800mL water to detect a single E. coli cell in 100mL water.

  8. Ultrasensitive Electrochemical Detection of mRNA Using Branched DNA Amplifiers

    SciTech Connect

    Mao, Xun; Liu, Guodong; Wang, Shengfu; Lin, Yuehe; Zhang, Aiguo; Zhang, Lurong; Ma, Yunqing

    2008-11-01

    We describe here an ultrasensitive electrochemical detection of m RNA protocol without RNA purification and PCR amplification. The new m RNA electrical detection capability is coupled to the amplification feature of branched DNA (bDNA) technology and with the nagnetic beads based electrochemical bioassay.

  9. A signal-on electrochemical aptasensor for ultrasensitive detection of endotoxin using three-way DNA junction-aided enzymatic recycling and graphene nanohybrid for amplification

    NASA Astrophysics Data System (ADS)

    Bai, Lijuan; Chai, Yaqin; Pu, Xiaoyun; Yuan, Ruo

    2014-02-01

    Endotoxin, also known as lipopolysaccharide (LPS), is able to induce a strong immune response on its internalization into mammalian cells. To date, aptamer-based biosensors for LPS detection have been rarely reported. This work describes a new signal-on electrochemical aptasensor for the ultrasensitive detection of LPS by combining the three-way DNA hybridization process and nanotechnology-based amplification. With the help of DNA1 (associated with the concentration of target LPS), the capture probe hybridizes with DNA1 and the assistant probe to open its hairpin structure and form a ternary ``Y'' junction structure. The DNA1 can be released from the structure in the presence of nicking endonuclease to initiate the next hybridization process. Then a great deal of cleaved capture probe produced in the cyclic process can bind with DNA2-nanocomposite, which contains the electroactive toluidine blue (Tb) with the amplification materials graphene (Gra) and gold nanoparticles (AuNPs). Thus, an enhanced electrochemical signal can be easily read out. With the cascade signal amplification, this newly designed protocol provides an ultrasensitive electrochemical detection of LPS down to the femtogram level (8.7 fg mL-1) with a linear range of 6 orders of magnitude (from 10 fg mL-1 to 50 ng mL-1). Moreover, the high sensitivity and specificity make this method versatile for the detection of other biomolecules by changing the corresponding sequences of the capture probe and the assistant probe.

  10. A signal-on electrochemical aptasensor for ultrasensitive detection of endotoxin using three-way DNA junction-aided enzymatic recycling and graphene nanohybrid for amplification.

    PubMed

    Bai, Lijuan; Chai, Yaqin; Pu, Xiaoyun; Yuan, Ruo

    2014-03-07

    Endotoxin, also known as lipopolysaccharide (LPS), is able to induce a strong immune response on its internalization into mammalian cells. To date, aptamer-based biosensors for LPS detection have been rarely reported. This work describes a new signal-on electrochemical aptasensor for the ultrasensitive detection of LPS by combining the three-way DNA hybridization process and nanotechnology-based amplification. With the help of DNA1 (associated with the concentration of target LPS), the capture probe hybridizes with DNA1 and the assistant probe to open its hairpin structure and form a ternary "Y" junction structure. The DNA1 can be released from the structure in the presence of nicking endonuclease to initiate the next hybridization process. Then a great deal of cleaved capture probe produced in the cyclic process can bind with DNA2-nanocomposite, which contains the electroactive toluidine blue (Tb) with the amplification materials graphene (Gra) and gold nanoparticles (AuNPs). Thus, an enhanced electrochemical signal can be easily read out. With the cascade signal amplification, this newly designed protocol provides an ultrasensitive electrochemical detection of LPS down to the femtogram level (8.7 fg mL(-1)) with a linear range of 6 orders of magnitude (from 10 fg mL(-1) to 50 ng mL(-1)). Moreover, the high sensitivity and specificity make this method versatile for the detection of other biomolecules by changing the corresponding sequences of the capture probe and the assistant probe.

  11. Glucose biosensor based on the immobilization of glucose oxidase on electrochemically synthesized polypyrrole-poly(vinyl sulphonate) composite film by cross-linking with glutaraldehyde.

    PubMed

    Colak, Ozlem; Yaşar, Ahmet; Cete, Servet; Arslan, Fatma

    2012-10-01

    In this study, a novel amperometric glucose biosensor was developed by immobilizing glucose oxidase (GOX) by cross-linking via glutaraldehyde on electrochemically polymerized polypyrrole-poly(vinyl sulphonate) (PPy-PVS) films on the surface of a platinum (Pt) electrode. Electropolymerization of pyrrole and poly(vinyl sulphonate) on the Pt surface was carried out with an electrochemical cell containing pyrrole and poly(vinyl sulphonate) by cyclic voltammetry between -1.0 and + 2.0 V (vs.Ag/AgCl) at a scan rate of 50 mV/s upon the Pt electrode. The amperometric determination was based on the electrochemical detection of H(2)O(2) generated in enzymatic reaction of glucose. Determination of glucose was carried out by the oxidation of enzymatically produced H(2)O(2) at 0.4 V vs. Ag/AgCl. The effects of pH and temperature were investigated and optimum parameters were found to be 7.5 and 65°C, respectively. The effect of working potential was investigated and optimum potential was determined to be 0.4 V. The operational stability of the enzyme electrode was also studied. The response of the PPy/PVS-GOX glucose biosensor exhibited good reproducibility with a relative standard deviation (RSD) of 2.48%. The glucose biosensor retained 63% of initial activity after 93 days when stored in 0.1 M phosphate buffer solution of pH 7.5 at 4°C. With the low operating potential, the biosensor demonstrated little interference from the possible interferants.

  12. DNA-functionalized upconversion nanoparticles as biosensors for rapid, sensitive, and selective detection of Hg(2+) in complex matrices.

    PubMed

    Huang, Li-Jiao; Yu, Ru-Qin; Chu, Xia

    2015-08-07

    We have developed a facile one-step approach to make hydrophilic and DNA-functionalizable upconversion nanoparticles (UCNPs), which are used to act as a biosensor for determining Hg(2+) in complex matrices. The proposed approach is simple and exhibits low background interference, high sensitivity and rapid response.

  13. Porous silicon biosensor: current status.

    PubMed

    Dhanekar, Saakshi; Jain, Swati

    2013-03-15

    Biosensing technologies cater to modern day diagnostics and point of care multi-specialty clinics, hospitals and laboratories. Biosensors aggregate the sensitivity of detection methodologies and constitutional selectivity of biomolecules. Endeavors to develop highly sensitive, fast, stable and low cost biosensors have been made possible by extensive and arduous research. Immense research work is going on for detection of molecules using various materials as immobilization substrate and sensing elements. Amongst materials being used as bio-sensing substrates, nano-porous silicon (PS) has amassed attention and gained popularity in recent years. It has captivating and tunable features like ease of fabrication, special optico-physico properties, tailored morphological structure and versatile surface chemistry enhancing its prospects as transducer for fabricating biosensors. The present review describes the fabrication of PS and its biosensing capabilities for detection of various analytes including, but not limited to, glucose, DNA, antibodies, bacteria and viruses. Attention has been consecrated on the various methodologies such as electrical, electrochemical, optical and label free techniques along with the performances of these biosensors. It concludes with some future prospects and challenges of PS based biosensors.

  14. Electrochemical biosensors for rapid determination of pesticide residues in agricultural products

    NASA Astrophysics Data System (ADS)

    Jiang, Xuesong; Wang, Jianping; Ying, Yibin; Ye, Zunzhong; Li, Yanbin

    2005-11-01

    The biosensors, consisting of immobilized antibodies which were for specific recognition to target molecules and electrodes which were able to convert the binding event between antigen and antibody to a detectable signal, were developed for rapid detection of organophosphate (OPs) pesticides. Anti-OPs antibodies were immobilized onto indium-tin-oxide (ITO) coated interdigitated microsensor electrodes (IMEs). The Faradaic impedance spectra, presented as Nyquist plots (Z' vs Z'') and Bode diagrams, (impedance vs frequency) were recorded in the frequency range from 1Hz to 100 kHz respectively. A linear relationship between the electron-transfer resistance and concentrations of OPs pesticide was found ranging from 0.1 ppm to 100 ppm. The regression equations were Y = 658 X +1861, with the correlation coefficient of 0.977. The biosensing procedure was simple and rapid, and could be completed within 1 h.

  15. Electrochemical biosensor for protein kinase A activity assay based on gold nanoparticles-carbon nanospheres, phos-tag-biotin and β-galactosidase.

    PubMed

    Zhou, Yunlei; Yin, Huanshun; Li, Xue; Li, Zhi; Ai, Shiyun; Lin, Hai

    2016-12-15

    A sensitive and selective electrochemical biosensor was fabricated for protein kinase A (PKA) activity assay. Multiple signal amplification techniques were employed including the nanocomposite of gold nanoparticles and carbon nanospheres (Au@C), the biocomposite of SiO2 and streptavidin (SiO2-SA), the composite of AuNPs and biotinylated β-galactosidase (AuNPs-B-Gal) and in situ enzymatic generation of electrochemical activity molecule of p-aminophenol. After peptides were assembled on Au@C modified electrode surface, they were phosphorylated by PKA in the presence of ATP. Then, biotinylated Phos-tag was modified on electrode surface through the specific interaction between Phos-tag and phosphate group. Finally, SiO2-SA and AuNPs-B-Gal were captured through the specific interaction between biotin and streptavidin. Because the electrochemical response of p-aminophenol was directly related to PKA concentration, an innovative electrochemical assay could be realized for PKA detection. The detection limit was 0.014unit/mL. The developed method showed high detection sensitivity and selectivity. In addition, the fabricated biosensor can be also applied to detect PKA in human normal gastricepithelial cell line and human gastric carcinoma cell line with satisfactory results.

  16. Architecture of a modular, multichannel readout system for dense electrochemical biosensor microarrays

    NASA Astrophysics Data System (ADS)

    Ramfos, Ioannis; Blionas, Spyridon; Birbas, Alexios

    2015-01-01

    The architecture of a modular, multichannel readout system for dense electrochemical microarrays, targeting Lab-on-a-Chip applications, is presented. This approach promotes efficient component reusability through a hybrid multiplexing methodology, maintaining high levels of sampling performance and accuracy. Two readout modes are offered, which can be dynamically interchanged following signal profiling, to cater for both rapid signal transitions and weak current responses. Additionally, functional extensions to the described architecture are discussed, which provide the system with multi-biasing capabilities. A prototype integrated circuit of the proposed architecture’s analog core and a supporting board were implemented to verify the working principles. The system was evaluated using standard loads, as well as electrochemical sensor arrays. Through a range of operating conditions and loads, the prototype exhibited a highly linear response and accurately delivered the readout of input signals with fast transitions and wide dynamic ranges.

  17. Real-time monitoring of strand-displacement DNA amplification by a contactless electrochemical microsystem using interdigitated electrodes.

    PubMed

    Fang, Xinxin; Zhang, Huanqian; Zhang, Feng; Jing, Fengxiang; Mao, Hongju; Jin, Qinghui; Zhao, Jianlong

    2012-09-07

    This paper reports the design and implementation of a contactless conductivity detection system which combines a thermal control cell, a data processing system and an electrochemical (EC) cell for label-free isothermal nucleic acid amplification and real-time monitoring. The EC cell consists of a microchamber and interdigitated electrodes as the contactless conductivity biosensor with a cover slip as insulation. In our work, contactless EC measurements, the effects of trehalose on amplification, and chip surface treatment are investigated. With the superior performance of the biosensor, the device can detect the amount of pure DNA at concentrations less than 0.1 pg μl(-1). The EC cell, integrated with a heater and a temperature sensor, has successfully implemented nicking-based strand-displacement amplification at an initial concentration of 2.5 μM and the yields are monitored directly (dismissing the use of probes or labels) on-line. This contactless detector carries important advantages: high anti-interference capability, long detector life, high reusability and low cost. In addition, the small size, low power consumption and portability of the detection cell give the system the potential to be highly integrated for use in field service and point of care applications.

  18. Electrochemical Glucose Sensors—Developments Using Electrostatic Assembly and Carbon Nanotubes for Biosensor Construction

    PubMed Central

    Harper, Alice; Anderson, Mark R.

    2010-01-01

    In 1962, Clark and Lyons proposed incorporating the enzyme glucose oxidase in the construction of an electrochemical sensor for glucose in blood plasma. In their application, Clark and Lyons describe an electrode in which a membrane permeable to glucose traps a small volume of solution containing the enzyme adjacent to a pH electrode, and the presence of glucose is detected by the change in the electrode potential that occurs when glucose reacts with the enzyme in this volume of solution. Although described nearly 50 years ago, this seminal development provides the general structure for constructing electrochemical glucose sensors that is still used today. Despite the maturity of the field, new developments that explore solutions to the fundamental limitations of electrochemical glucose sensors continue to emerge. Here we discuss two developments of the last 15 years; confining the enzyme and a redox mediator to a very thin molecular films at electrode surfaces by electrostatic assembly, and the use of electrodes modified by carbon nanotubes (CNTs) to leverage the electrocatalytic effect of the CNTs to reduce the oxidation overpotential of the electrode reaction or for the direct electron transport to the enzyme. PMID:22163652

  19. Electrochemical glucose sensors--developments using electrostatic assembly and carbon nanotubes for biosensor construction.

    PubMed

    Harper, Alice; Anderson, Mark R

    2010-01-01

    In 1962, Clark and Lyons proposed incorporating the enzyme glucose oxidase in the construction of an electrochemical sensor for glucose in blood plasma. In their application, Clark and Lyons describe an electrode in which a membrane permeable to glucose traps a small volume of solution containing the enzyme adjacent to a pH electrode, and the presence of glucose is detected by the change in the electrode potential that occurs when glucose reacts with the enzyme in this volume of solution. Although described nearly 50 years ago, this seminal development provides the general structure for constructing electrochemical glucose sensors that is still used today. Despite the maturity of the field, new developments that explore solutions to the fundamental limitations of electrochemical glucose sensors continue to emerge. Here we discuss two developments of the last 15 years; confining the enzyme and a redox mediator to a very thin molecular films at electrode surfaces by electrostatic assembly, and the use of electrodes modified by carbon nanotubes (CNTs) to leverage the electrocatalytic effect of the CNTs to reduce the oxidation overpotential of the electrode reaction or for the direct electron transport to the enzyme.

  20. Electrochemical Biosensor Based on Nanoporous Au/CoO Core-Shell Material with Synergistic Catalysis.

    PubMed

    Zhang, Chao; Huang, Bin; Qian, Lihua; Yuan, Songliu; Wang, Shuai; Chen, Rong

    2016-01-04

    An ultrathin CoO layer is deposited on the skeleton surfaces of a nanoporous gold (NPG) film by using atomic layer deposition, creating a flexible electrode. Detailed characterization demonstrates the superior performance of the flexible NPG/CoO hybrids for electrochemical catalysis. The NPG/CoO hybrid not only achieves high catalytic activity for glucose oxidation and H2O2 reduction, but also exhibits a linear dependence of the electrical signal on the concentration of glucose and H2O2 molecules in the electrolyte. Meanwhile, the sensitivity for H2O2 reduction can be as high as 62.5 μA mm(-1)  cm(-2) with linear dependence on the concentration in the range of 0.1-92.9 mm. The high sensitivity is proposed to result from the synergistic effect of Au and CoO at the interfaces, and the high conductivity of the gold skeleton with a large surface area. The superior electrochemical performance of this hybrid electrode is promising for future potential applications in various transitional-metal-oxide-based electrochemical electrodes.

  1. Diagnostics Strategies with Electrochemical Affinity Biosensors Using Carbon Nanomaterials as Electrode Modifiers

    PubMed Central

    Campuzano, Susana; Yáñez-Sedeño, Paloma; Pingarrón, José M.

    2016-01-01

    Early diagnosis is often the key to successful patient treatment and survival. The identification of various disease signaling biomarkers which reliably reflect normal and disease states in humans in biological fluids explain the burgeoning research field in developing new methodologies able to determine the target biomarkers in complex biological samples with the required sensitivity and selectivity and in a simple and rapid way. The unique advantages offered by electrochemical sensors together with the availability of high affinity and specific bioreceptors and their great capabilities in terms of sensitivity and stability imparted by nanostructuring the electrode surface with different carbon nanomaterials have led to the development of new electrochemical biosensing strategies that have flourished as interesting alternatives to conventional methodologies for clinical diagnostics. This paper briefly reviews the advantages of using carbon nanostructures and their hybrid nanocomposites as electrode modifiers to construct efficient electrochemical sensing platforms for diagnosis. The review provides an updated overview of some selected examples involving attractive amplification and biosensing approaches which have been applied to the determination of relevant genetic and protein diagnostics biomarkers. PMID:28035946

  2. Enhancing the sensitivity of localized surface plasmon resonance (LSPR) biosensors using nanorods and DNA aptamers

    NASA Astrophysics Data System (ADS)

    Chuang, Po-Chun; Liao, Pei-Chen; Chen, Yih-Fan

    2015-03-01

    Localized surface plasmon resonance (LSPR) biosensors have drawn much attention for their promising application in point-of-care diagnostics. While surface plasmon resonance (SPR) biosensing systems have been well developed, LSPR systems have the advantages of simpler and more compact setups. The LSPR peak shifts caused by the binding of molecules to the LSPR substrates, however, are usually smaller than 1 nm if no signal amplification mechanism is used. When using nanoparticles to enhance the sensitivity of LSPR biosensors, because of the short field penetration depth, the nanoparticles should be very close to the LSPR substrate to induce significant shifts in the LSPR peak position. In this study, we used DNA aptamers and gold nanorods to significantly increase the change in the LSPR peak position with the concentration of the target molecules. We have successfully used the proposed mechanism to detect 0.1 nM interferongamma (IFN-γ), a biomarker related to the diagnosis of latent tuberculosis infection. The calibration curves obtained in pure buffers and serum-containing buffers show that accurate detection can be achieved even when the sample is from complex biological fluids such as serum. Because of the enhancement in the sensitivity by the proposed sensing scheme, it is possible to use a low-cost spectrometer to build a LSPR biosensing system.

  3. Electrodeposition of flower-like platinum on electrophoretically grown nitrogen-doped graphene as a highly sensitive electrochemical non-enzymatic biosensor for hydrogen peroxide detection

    NASA Astrophysics Data System (ADS)

    Tajabadi, M. T.; Sookhakian, M.; Zalnezhad, E.; Yoon, G. H.; Hamouda, A. M. S.; Azarang, Majid; Basirun, W. J.; Alias, Y.

    2016-11-01

    An efficient non-enzymatic biosensor electrode consisting of nitrogen-doped graphene (N-graphene) and platinum nanoflower (Pt NF) with different N-graphene loadings were fabricated on indium tin oxide (ITO) glass using a simple layer-by-layer electrophoretic and electrochemical sequential deposition approach. N-graphene was synthesized by annealing graphene oxide with urea at 900 °C. The structure and morphology of the as-fabricated non-enzymatic biosensor electrodes were determined using X-ray diffraction, field emission electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectra. The as-fabricated Pt NF-N-graphene-modified ITO electrodes with different N-graphene loadings were utilized as a non-enzymatic biosensor electrode for the detection of hydrogen peroxide (H2O2). The behaviors of the hybrid electrodes towards H2O2 reduction were assessed using chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy analysis. The Pt NF-N-graphene-modified ITO electrode with a 0.05 mg ml-1 N-graphene loading exhibited the lowest detection limit, fastest amperometric sensing, a wide linear response range, excellent stability and reproducibility for the non-enzymatic H2O2 detection, due to the synergistic effect between the electrocatalytic activity of the Pt NF and the high conductivity and large surface area of N-graphene.

  4. Functionalized poly (ionic liquid) as the support to construct a ratiometric electrochemical biosensor for the selective determination of copper ions in AD rats.

    PubMed

    Yu, Yanyan; Yu, Chao; Yin, Tianxiao; Ou, Shanshan; Sun, Xiaoyu; Wen, Xiangru; Zhang, Lin; Tang, Daoquan; Yin, Xiaoxing

    2017-01-15

    An efficient ratiometric electrochemical biosensor for Cu(2+) determination was constructed using dual hydroxyl-functionalized poly (ionic liquid) (DHF-PIL) as the catalyst support. The DHF-PIL exhibited typical macroporous structure, which provided a high surface area of 39.31m(2)/g for the sufficient loading of biomolecules. The specific recognition of Cu(2+) was accomplished by employing neurokinin B (NKB) for the first time, which could bind to Cu(2+) to form a [Cu(II)(NKB)2] complex with high specificity. Meanwhile, a common redox mediator, 2, 2'-Azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) was modified into DHF-PIL by electrostatic interactions to act as an inner reference molecule, which provided a built-in correction for environmental effects and improving the detection accuracy. With this strategy, the developed electrochemical biosensor was capable of determining Cu(2+) with a linear range between 0.9 and 36.1μM and low detection limit (LOD) and quantification limit (LOQ) of 0.24 and 0.6μM, respectively. The sensor also displayed a satisfactory selectivity against a series of interferences in the brain, including metal ions, amino acids and other endogenous compounds. Accordingly, the present biosensor was successfully applied to evaluate Cu(2+) levels in normal and AD rats.

  5. Gold nanoparticles-induced enhancement of the analytical response of an electrochemical biosensor based on an organic-inorganic hybrid composite material.

    PubMed

    Barbadillo, M; Casero, E; Petit-Domínguez, M D; Vázquez, L; Pariente, F; Lorenzo, E

    2009-12-15

    The design and characterization of a new organic-inorganic hybrid composite material for glucose electrochemical sensing are described. This material is based on the entrapment of both gold nanoparticles (AuNPs) and glucose oxidase, which was chosen as a model, into a sol-gel matrix. The addition of spectroscopic grade graphite to this system, which confers conductivity, leads to the development of a material particularly attractive for electrochemical biosensor fabrication. The characterization of the hybrid composite material was performed using atomic force microscopy and scanning electron microscopy techniques. This composite material was applied to the determination of glucose in presence of hydroxymethylferrocene as a redox mediator. The system exhibits a clear electrocatalytic activity towards glucose, allowing its determination at 250 mV vs Ag/AgCl. The performance of the resulting enzyme biosensor was evaluated in terms of sensitivity, detection limit, linear response range, stability and accuracy. Finally, the enhancement of the analytical response of the resulting biosensor induced by the presence of gold nanoparticles was evaluated by comparison with a similar organic-inorganic hybrid composite material without AuNPs.

  6. Hydrogel with chains functionalized with carboxyl groups as universal 3D platform in DNA biosensors.

    PubMed

    Kowalczyk, Agata; Fau, Michal; Karbarz, Marcin; Donten, Mikolaj; Stojek, Zbigniew; Nowicka, Anna M

    2014-04-15

    Application of hydrogel based on N-isopropylacrylamide with carboxyl groups grafted to the chains enabled the immobilization of DNA at an extent exceeding that for flat surfaces by at least one order of magnitude. The probe DNA strands in the 3D platform were fully available for the hybridization process. The examination of the gels containing different amounts of grafted carboxyl groups (1-10%) was done using quartz crystal microbalance, electrochemical impedance spectroscopy, chronoamperometry and ionic coupled plasma with laser ablation. The optimal carboxyl group content was determined to be 5%. A very good agreement of the data obtained with independent techniques on content of DNA in the gel was obtained. In comparison to the other methods of immobilization of DNA the new platform enabled complete removal of DNA after the measurements and analysis and, therefore, could be used many times. After a 10-fold exchange of the DNA-sensing layer the efficiency of hybridization and analytical signal did not change by more than 5%. The sensor response increased linearly with logarithm of concentration of target DNA in the range 1×10(-13)-1×10(-6) M. The obtained detection limit was circa 8×10(-13) M of target DNA in the sample which is a substantial improvement over the planar sensing layers.

  7. Chitosan-cross-linked osmium polymer composites as an efficient platform for electrochemical biosensors.

    PubMed

    Jirimali, Harishchandra Digambar; Nagarale, Rajaram Krishna; Lee, Jong Myung; Saravanakumar, Durai; Shin, Woonsup

    2013-07-22

    A new family of chitosan-cross-linked osmium polymer composites was prepared and its electrochemical properties were examined. The composites were prepared by quaternization of the poly(4-vinylpyridine) osmium bipyridyl polymer (PVP-Os) which was then cross-linked with chitosan, yielding PVP-Os/chitosan. Films made of the composites showed improved mass and electron transport owing to the porous and hydrophilic structure which is derived from the cross-links between the Os polymer and chitosan. The rate for glucose oxidation was enhanced four times when glucose oxidase (GOx) was immobilized on PVP-Os/chitosan compared immobilization on PVP-Os.

  8. Quantification of transcription factor binding in cell extracts using an electrochemical, structure-switching biosensor

    PubMed Central

    Bonham, Andrew J.; Hsieh, Kuangwen; Ferguson, B. Scott; Vallée-Bélisle, Alexis; Ricci, Francesco; Soh, H. Tom; Plaxco, Kevin W.

    2012-01-01

    Transcription factor expression levels, which sensitively reflect cellular development and disease state, are typically monitored via cumbersome, reagent-intensive assays that require relatively large quantities of cells. Here we demonstrate a simple, quantitative approach to their detection based on a simple, electrochemical sensing platform. This sensor sensitively and quantitatively detects its target transcription factor in complex media (e.g., 250 μg/ml crude nuclear extracts) in a convenient, low-reagent process requiring only 10 μl of sample. Our approach thus appears a promising means of monitoring transcription factor levels. PMID:22313286

  9. In vivo Electrochemical Biosensor for Brain Glutamate Detection: A Mini Review

    PubMed Central

    HAMDAN, Siti Kartika; MOHD ZAIN, ainiharyati

    2014-01-01

    Glutamate is one of the most prominent neurotransmitters in mammalian brains, which plays an important role in neuronal excitation. High levels of neurotransmitter cause numerous alterations, such as calcium overload and the dysfunction of mitochondrial and oxidative stress. These alterations may lead to excitotoxicity and may trigger multiple neuronal diseases, such as Alzheimer’s disease, stroke, and epilepsy. Excitotoxicity is a pathological process that damages nerve cells and kills cells via excessive stimulation by neurotransmitters. Monitoring the concentration level of brain glutamate via an implantable microbiosensor is a promising alternative approach to closely investigate in the function of glutamate as a neurotransmitter. This review outlines glutamate microbiosensor designs to enhance the sensitivity of glutamate detection with less biofouling occurrence and minimal detection of interference species. There are many challenges in the development of a reproducible and stable implantable microbiosensor because many factors and limitations may affect the detection performance. However, the incorporation of multiple scales is needed to address the basic issues and combinations across the various disciplines needed to achieve the success of the system to overcome the challenges in the development of an implantable glutamate biosensor. PMID:25941459

  10. Solanum melongena polyphenol oxidase biosensor for the electrochemical analysis of paracetamol.

    PubMed

    Garcia, Luane Ferreira; Benjamin, Stephen Rathinaraj; Antunes, Rafael S; Lopes, Flavio Marques; Somerset, Vernon Sydwill; Gil, Eric de Souza

    2016-11-16

    A new strategy for the construction of a polyphenol oxidase carbon paste biosensor for paracetamol detection is reported. The eggplant (Solanum melongena) was processed to collect the polyphenol oxidase as an enzyme that was incorporated in the carbon paste sensor construction. The constructed sensor displayed high sensitivity and good selection for paracetamol detection and recognition. Optimized conditions included pH 6.0 (highest activity), pH 7.0 (highest stability), pulse amplitude of 50 mV, and 15% of vegetable extract per carbon paste. The sensor displayed a linear range from 20 to 200 µM, with a detection limit of 5 µM. Application of the sensor to paracetamol determination in tablet and oral solutions have shown satisfactory results. The efficiency of the method showed very good repeatability ranging between 1.26 and 1.72% relative standard deviation for interday analysis, while recoveries for paracetamol varied between 97.5 and 99.8% for the voltammetric determination. The strategy for a simple, low cost, and efficient eggplant polyphenol oxidase sensor showcased in this work provides an opportunity for the detection of other phenolic compounds in various matrices.

  11. Development of mercury (II) ion biosensors based on mercury-specific oligonucleotide probes.

    PubMed

    Li, Lanying; Wen, Yanli; Xu, Li; Xu, Qin; Song, Shiping; Zuo, Xiaolei; Yan, Juan; Zhang, Weijia; Liu, Gang

    2016-01-15

    Mercury (II) ion (Hg(2+)) contamination can be accumulated along the food chain and cause serious threat to the public health. Plenty of research effort thus has been devoted to the development of fast, sensitive and selective biosensors for monitoring Hg(2+). Thymine was demonstrated to specifically combine with Hg(2+) and form a thymine-Hg(2+)-thymine (T-Hg(2+)-T) structure, with binding constant even higher than T-A Watson-Crick pair in DNA duplex. Recently, various novel Hg(2+) biosensors have been developed based on T-rich Mercury-Specific Oligonucleotide (MSO) probes, and exhibited advanced selectivity and excellent sensitivity for Hg(2+) detection. In this review, we explained recent development of MSO-based Hg(2+) biosensors mainly in 3 groups: fluorescent biosensors, colorimetric biosensors and electrochemical biosensors.

  12. A label-free electrochemical biosensor for microRNA detection based on catalytic hairpin assembly and in situ formation of molybdophosphate.

    PubMed

    Cai, Wei; Xie, Shunbi; Tang, Ying; Chai, Yaqin; Yuan, Ruo; Zhang, Jin

    2017-01-15

    A label-free electrochemical biosensor for sensitive detection of miRNA-155 was presented by coupling enzyme-catalyzed in situ generation of electronic mediator for signal introduction with catalytic hairpin assembly (CHA) induced target recycling amplification strategy. In this work, alkaline phosphatase (ALP) was adopted to hydrolyze inactive substrate 1-naphthyl phosphate (NPP) to produce phosphate ion (PO4(3-)), which could further react with acidic molybdate to form abundant molybdophosphate anion (PMo12O40(3-)) on the surface of electrode. The produced PMo12O40(3-) could directly generate a strong and stable electrochemical signal for quantitative detection of targets. In addition, CHA induced the cyclic reuse of the target was also employed as an effective strategy for improving the sensitivity of biosensor. This electrochemical method for miRNA-155 detection had achieved a good linear relationship ranging from 10fM to 1nM with a detection limit of 1.64fM. With this assay successfully applied in tumor cell lysates, it holds great potential for early cancer diagnosis by employing miRNA as the effective biomarker.

  13. Molecularly imprinted electrochemical biosensor based on Fe@Au nanoparticles involved in 2-aminoethanethiol functionalized multi-walled carbon nanotubes for sensitive determination of cefexime in human plasma.

    PubMed

    Yola, Mehmet Lütfi; Eren, Tanju; Atar, Necip

    2014-10-15

    The molecular imprinting technique depends on the molecular recognition. It is a polymerization method around the target molecule. Hence, this technique creates specific cavities in the cross-linked polymeric matrices. In present study, a sensitive imprinted electrochemical biosensor based on Fe@Au nanoparticles (Fe@AuNPs) involved in 2-aminoethanethiol (2-AET) functionalized multi-walled carbon nanotubes (f-MWCNs) modified glassy carbon (GC) electrode was developed for determination of cefexime (CEF). The results of X-ray photoelectron spectroscopy (XPS) and reflection-absorption infrared spectroscopy (RAIRS) confirmed the formation of the developed surfaces. CEF imprinted film was constructed by cyclic voltammetry (CV) for 9 cycles in the presence of 80 mM pyrrole in phosphate buffer solution (pH 6.0) containing 20mM CEF. The developed electrochemical biosensor was validated according to the International Conference on Harmonisation (ICH) guideline and found to be linear, sensitive, selective, precise and accurate. The linearity range and the detection limit were obtained as 1.0 × 10(-10)-1.0 × 10(-8)M and 2.2 × 10(-11)M, respectively. The developed CEF imprinted sensor was successfully applied to real samples such as human plasma. In addition, the stability and reproducibility of the prepared molecular imprinted electrode were investigated. The excellent long-term stability and reproducibility of the prepared CEF imprinted electrodes make them attractive in electrochemical sensors.

  14. DNA Nanostructure-based Interfacial engineering for PCR-free ultrasensitive electrochemical analysis of microRNA

    NASA Astrophysics Data System (ADS)

    Wen, Yanli; Pei, Hao; Shen, Ye; Xi, Junjie; Lin, Meihua; Lu, Na; Shen, Xizhong; Li, Jiong; Fan, Chunhai

    2012-11-01

    MicroRNAs (miRNAs) have been identified as promising cancer biomarkers due to their stable presence in serum. As an alternative to PCR-based homogenous assays, surface-based electrochemical biosensors offer great opportunities for low-cost, point-of-care tests (POCTs) of disease-associated miRNAs. Nevertheless, the sensitivity of miRNA sensors is often limited by mass transport and crowding effects at the water-electrode interface. To address such challenges, we herein report a DNA nanostructure-based interfacial engineering approach to enhance binding recognition at the gold electrode surface and drastically improve the detection sensitivity. By employing this novel strategy, we can directly detect as few as attomolar (<1, 000 copies) miRNAs with high single-base discrimination ability. Given that this ultrasensitive electrochemical miRNA sensor (EMRS) is highly reproducible and essentially free of prior target labeling and PCR amplification, we also demonstrate its application by analyzing miRNA expression levels in clinical samples from esophageal squamous cell carcinoma (ESCC) patients.

  15. A regenerated electrochemical biosensor for label-free detection of glucose and urea based on conformational switch of i-motif oligonucleotide probe.

    PubMed

    Gao, Zhong Feng; Chen, Dong Mei; Lei, Jing Lei; Luo, Hong Qun; Li, Nian Bing

    2015-10-15

    Improving the reproducibility of electrochemical signal remains a great challenge over the past decades. In this work, i-motif oligonucleotide probe-based electrochemical DNA (E-DNA) sensor is introduced for the first time as a regenerated sensing platform, which enhances the reproducibility of electrochemical signal, for label-free detection of glucose and urea. The addition of glucose or urea is able to activate glucose oxidase-catalyzed or urease-catalyzed reaction, inducing or destroying the formation of i-motif oligonucleotide probe. The conformational switch of oligonucleotide probe can be recorded by electrochemical impedance spectroscopy. Thus, the difference of electron transfer resistance is utilized for the quantitative determination of glucose and urea. We further demonstrate that the E-DNA sensor exhibits high selectivity, excellent stability, and remarkable regenerated ability. The human serum analysis indicates that this simple and regenerated strategy holds promising potential in future biosensing applications.

  16. Porphyrin-encapsulated metal-organic frameworks as mimetic catalysts for electrochemical DNA sensing via allosteric switch of hairpin DNA.

    PubMed

    Ling, Pinghua; Lei, Jianping; Zhang, Lei; Ju, Huangxian

    2015-04-07

    A sensitive electrochemical sensor is designed for DNA detection based on mimetic catalysis of metal-organic framework (MOF) and allosteric switch of hairpin DNA. The functional MOFs are synthesized as signal probes by a one-pot encapsulation of iron(III) meso-5,10,15,20-tetrakis(4-carboxyphenyl) porphyrin chloride (FeTCPP) into a prototypal MOF, HKUST-1(Cu), and sequentially conjugated with streptavidin (SA) as a recognition element. The resulting FeTCPP@MOF composites can mimetically catalyze the oxidation of o-phenylenediamine (o-PD) to 2,2'-diaminoazobenzene, which is a good electrochemical indicator for signal readout. The presence of target DNA introduces the allosteric switch of hairpin DNA to form SA aptamer, and thus, FeTCPP@MOF-SA probe is brought on the electrode surface via the specific recognition between SA and the corresponding aptamer, resulting in the enhancement of electrochemical signal. The "signal-on" electrochemical sensor can detect target DNA down to 0.48 fM with the linear range of 10 fM to 10 nM. Moreover, the MOF-based electrochemical sensor exhibits acceptable selectivity against even a single mismatched DNA and good feasibility in complex serum matrixes. This strategy opens up a new direction of porphyrin-functionalized MOF for signal transduction in electrochemical biosensing.

  17. Functional Polymers in Protein Detection Platforms: Optical, Electrochemical, Electrical, Mass-Sensitive, and Magnetic Biosensors

    PubMed Central

    Hahm, Jong-in

    2011-01-01

    The rapidly growing field of proteomics and related applied sectors in the life sciences demands convenient methodologies for detecting and measuring the levels of specific proteins as well as for screening and analyzing for interacting protein systems. Materials utilized for such protein detection and measurement platforms should meet particular specifications which include ease-of-mass manufacture, biological stability, chemical functionality, cost effectiveness, and portability. Polymers can satisfy many of these requirements and are often considered as choice materials in various biological detection platforms. Therefore, tremendous research efforts have been made for developing new polymers both in macroscopic and nanoscopic length scales as well as applying existing polymeric materials for protein measurements. In this review article, both conventional and alternative techniques for protein detection are overviewed while focusing on the use of various polymeric materials in different protein sensing technologies. Among many available detection mechanisms, most common approaches such as optical, electrochemical, electrical, mass-sensitive, and magnetic methods are comprehensively discussed in this article. Desired properties of polymers exploited for each type of protein detection approach are summarized. Current challenges associated with the application of polymeric materials are examined in each protein detection category. Difficulties facing both quantitative and qualitative protein measurements are also identified. The latest efforts on the development and evaluation of nanoscale polymeric systems for improved protein detection are also discussed from the standpoint of quantitative and qualitative measurements. Finally, future research directions towards further advancements in the field are considered. PMID:21691441

  18. Functional polymers in protein detection platforms: optical, electrochemical, electrical, mass-sensitive, and magnetic biosensors.

    PubMed

    Hahm, Jong-in

    2011-01-01

    The rapidly growing field of proteomics and related applied sectors in the life sciences demands convenient methodologies for detecting and measuring the levels of specific proteins as well as for screening and analyzing for interacting protein systems. Materials utilized for such protein detection and measurement platforms should meet particular specifications which include ease-of-mass manufacture, biological stability, chemical functionality, cost effectiveness, and portability. Polymers can satisfy many of these requirements and are often considered as choice materials in various biological detection platforms. Therefore, tremendous research efforts have been made for developing new polymers both in macroscopic and nanoscopic length scales as well as applying existing polymeric materials for protein measurements. In this review article, both conventional and alternative techniques for protein detection are overviewed while focusing on the use of various polymeric materials in different protein sensing technologies. Among many available detection mechanisms, most common approaches such as optical, electrochemical, electrical, mass-sensitive, and magnetic methods are comprehensively discussed in this article. Desired properties of polymers exploited for each type of protein detection approach are summarized. Current challenges associated with the application of polymeric materials are examined in each protein detection category. Difficulties facing both quantitative and qualitative protein measurements are also identified. The latest efforts on the development and evaluation of nanoscale polymeric systems for improved protein detection are also discussed from the standpoint of quantitative and qualitative measurements. Finally, future research directions towards further advancements in the field are considered.

  19. Electrochemical Urea Biosensor Based on Sol-gel Derived Nanostructured Cerium Oxide

    NASA Astrophysics Data System (ADS)

    Ansari, Anees A.; Azahar, Md; Malhotra, B. D.

    2012-04-01

    Urease (Urs) and glutamate dehydrogenase (GLDH) have been co-immobilized onto a nanostructured-cerium oxide (Nano-CeO2) film deposited onto a indium-tin-oxide (ITO) coated glass substrate by dip-coating via sol-gel process for urea detection. This nanostructured film has characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning electron microscope (SEM) and electrochemical techniques, respectively. The particle size of the Nano-CeO2 film has been found to be 23 nm. Electrochemcial response (CV) studies show that Ur-GLDH/Nano-CeO2/ITO bioelectrode is found to be sensitive in the 10-80 mg/dL urea concentration range and can detect urea concentration upto 0.1 mg/dL level. The value of Michaelis-Menten constant (Km) estimated using Lineweaver-Burke plot found as 6.09 mg/dL indicates enhancement in the affinity and/or activity of enzyme attached to their nanobiocomposite. This bioelectrode retained 95% of enzyme activity after 6 months at 4°C.

  20. Electrochemically deposited nanostructured ZnO thin films for biosensor applications

    NASA Astrophysics Data System (ADS)

    Bhadane, Hemalata; Samuel, Edmund; Gautam, D. K.

    2014-04-01

    Zinc Oxide thin films have been deposited by electrochemical method on stainless steel using Zinc nitrate hexahydrate as precursor and 0.05 M potassium chloride (KCl) as supporting electrolyte. The paper reveals thorough investigation of effect of concentration of Zinc nitrate. Further, morphological, structural and optical analysis has been carried out using the FESEM, XRD and PL spectroscopy respectively. From FESEM hexagonal shape nanorods ZnO films fabricated for 1 hour using 0.05M and 0.1M concentration are clearly observed. The XRD of ZnO thin films shows strong peaks along c-axis with (0 0 2) orientation of ZnO nanorods which implies deposited nanorods are perpendicular to the substrate surface and wurtzite hexagonal phase. The hexagonal ZnO nanorod grown using a 0.05M zinc nitrate concentration exhibited the sharpest and most intense PL peak in at 382 nm near UV band edge, indicates the enhanced crystalline structure of ZnO film.

  1. An electrochemical biosensor for the assay of alpha-fetoprotein-L3 with practical applications.

    PubMed

    Li, Jinlong; Gao, Tao; Gu, Shiyu; Zhi, Jun; Yang, Jie; Li, Genxi

    2017-01-15

    The detection of alpha-fetoprotein-L3 (AFP-L3) is of great importance for hepatocellular carcinoma (HCC) diagnosis, but remains unsatisfactory owing to poor sensitivity and complex operating steps. In this work, a simple and sensitive method has been proposed for the detection of AFP-L3. Firstly, biotinylated Lens culinaris agglutinin-integrated silver nanoparticles (B-LCA-AgNPs) is fabricated. Owing to the specific interaction between Lens culinaris agglutinin and AFP-L3, AFP-L3 can be detected directly through the electrochemical signal readout of AgNPs, avoiding separated steps used in clinical practice. Furthermore, after the recognition between B-LCA-AgNPs and AFP-L3, large amount of AgNPs can be gathered at the binding site through avidin-biotin interactions, which can amplify the signal. Therefore, detection of AFP-L3 can be sensitively achieved. Moreover, compared with the other approaches, this new method has a better linear correlation (25-15,000pg/mL) and a lower detection limit (12pg/mL). Also, the new method developed in this work has been demonstrated to have good stability and reproducibility for the assay of AFP-L3 in human serum samples, so, it may hold a great application prospect in clinical diagnostics.

  2. Development of an Electrochemical Biosensor for the Detection of Aflatoxin M1 in Milk

    PubMed Central

    Paniel, Nathalie; Radoi, Antonio; Marty, Jean-Louis

    2010-01-01

    We have developed an electrochemical immunosensor for the detection of ultratrace amounts of aflatoxin M1 (AFM1) in food products. The sensor was based on a competitive immunoassay using horseradish peroxidase (HRP) as a tag. Magnetic nanoparticles coated with antibody (anti-AFM1) were used to separate the bound and unbound fractions. The samples containing AFM1 were incubated with a fixed amount of antibody and tracer [AFM1 linked to HRP (conjugate)] until the system reached equilibrium. Competition occurs between the antigen (AFM1) and the conjugate for the antibody. Then, the mixture was deposited on the surface of screen-printed carbon electrodes, and the mediator [5-methylphenazinium methyl sulphate (MPMS)] was added. The enzymatic response was measured amperometrically. A standard range (0, 0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.3, 0.4 and 0.5 ppb) of AFM1-contaminated milk from the ELISA kit was used to obtain a standard curve for AFM1. To test the detection sensitivity of our sensor, samples of commercial milk were supplemented at 0.01, 0.025, 0.05 or 0.1 ppb with AFM1. Our immunosensor has a low detection limit (0.01 ppb), which is under the recommended level of AFM1 [0.05 μg L-1 (ppb)], and has good reproducibility. PMID:22163418

  3. Electrochemical Biosensor for Rapid and Sensitive Detection of Magnetically Extracted Bacterial Pathogens

    PubMed Central

    Setterington, Emma B.; Alocilja, Evangelyn C.

    2012-01-01

    Biological defense and security applications demand rapid, sensitive detection of bacterial pathogens. This work presents a novel qualitative electrochemical detection technique which is applied to two representative bacterial pathogens, Bacillus cereus (as a surrogate for B. anthracis) and Escherichia coli O157:H7, resulting in detection limits of 40 CFU/mL and 6 CFU/mL, respectively, from pure culture. Cyclic voltammetry is combined with immunomagnetic separation in a rapid method requiring approximately 1 h for presumptive positive/negative results. An immunofunctionalized magnetic/polyaniline