Displaying publications 1 - 20 of 366 in total

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  1. Zia Q, Alawami M, Mokhtar NFK, Nhari RMHR, Hanish I
    Food Chem, 2020 Sep 15;324:126664.
    PMID: 32380410 DOI: 10.1016/j.foodchem.2020.126664
    Authentication of meat products is critical in the food industry. Meat adulteration may lead to religious apprehensions, financial gain and food-toxicities such as meat allergies. Thus, empirical validation of the quality and constituents of meat is paramount. Various analytical methods often based on protein or DNA measurements are utilized to identify meat species. Protein-based methods, including electrophoretic and immunological techniques, are at times unsuitable for discriminating closely related species. Most of these methods have been replaced by more accurate and sensitive detection methods, such as DNA-based techniques. Emerging technologies like DNA barcoding and mass spectrometry are still in their infancy when it comes to their utilization in meat detection. Gold nanobiosensors have shown some promise in this regard. However, its applicability in small scale industries is distant. This article comprehensively reviews the recent developments in the field of analytical methods used for porcine identification.
    Matched MeSH terms: Biosensing Techniques
  2. Zhou D, Gopinath SCB, Mohamed Saheed MS, Siva Sangu S, Lakshmipriya T
    Int J Nanomedicine, 2020;15:10171-10181.
    PMID: 33363373 DOI: 10.2147/IJN.S284752
    Background: In recent years, nanomaterials have justified their dissemination for biosensor application towards the sensitive and selective detections of clinical biomarkers at the lower levels. MXene is a two-dimensional layered transition metal, attractive for biosensing due to its chemical, physical and electrical properties along with the biocompatibility.

    Materials and Methods: This work was focused on diagnosing osteosarcoma (OS), a common bone cancer, on MXene-modified multiple junction triangles by dielectrode sensing. Survivin protein gene is highly correlated with OS, identified on this sensing surface. Capture DNA was immobilized on MXene by using 3-glycidoxypropyltrimethoxysilane as an amine linker and duplexed by the target DNA sequence.

    Results: The limitation and sensitivity of detection were found as 1 fM with the acceptable regression co-efficient value (y=1.0037⨰ + 0.525; R2=0.978) and the current enhancement was noted when increasing the target DNA concentrations. Moreover, the control sequences of single- and triple-mismatched and noncomplementary to the target DNA sequences failed to hybridize on the capture DNA, confirming the specificity. In addition, different batches were prepared with capture probe immobilized sensing surfaces and proved the efficient reproducibility.

    Conclusion: This microgap device with Mxene-modified multiple junction triangles dielectrode surface is beneficial to quantify the survivin gene at its lower level and diagnosing OS complication levels.

    Matched MeSH terms: Biosensing Techniques/methods*
  3. Zheng S, Zhang H, Lakshmipriya T, Gopinath SCB, Yang N
    Biomed Res Int, 2019;2019:9726967.
    PMID: 31380444 DOI: 10.1155/2019/9726967
    Gestational diabetes (hyperglycaemia) is an elevated blood sugar level diagnosed during the period of pregnancy and affects the baby's health. Hyperglycaemia has been found within the gestational weeks between 24 and 28, and the foetus has also the possibility of getting out prior to this test frame; it causes excessive birth weight, early birth, low-blood sugar level, respiratory distress syndrome, and type-2 diabetes to the mother. It creates a mandatory situation to identify the hyperglycaemia at least during the pregnancy weeks from 18 to 20. Further, a continuous monitoring of the level of glucose is necessary for the proper delivery. In this work, a method is introduced for glucose detection at 0.06 mg/mL, assisted by gold nanorod (GNR)-conjugated glucose oxidase (GOx) on interdigitated electrode sensor. In the absence of GNR, GOx shows the limit of glucose detection to be 0.25 mg/mL. Moreover, with GOx-GNR the reactions of all the glucose concentrations have recorded higher levels of the current from the baseline. With the specificity analysis, it was found that the glucose only reacts with GOx-GNR and discriminates other sugars efficiently. This method of detection is useful to diagnose and continuously monitor the glucose level during the pregnancy period.
    Matched MeSH terms: Biosensing Techniques*
  4. Zheng J, Wai JL, Lake RJ, New SY, He Z, Lu Y
    Anal Chem, 2021 08 10;93(31):10834-10840.
    PMID: 34310132 DOI: 10.1021/acs.analchem.1c01077
    DNAzymes have emerged as an important class of sensors for a wide variety of metal ions, with florescence DNAzyme sensors as the most widely used in different sensing and imaging applications because of their fast response time, high signal intensity, and high sensitivity. However, the requirements of an external excitation light source and its associated power increase the cost and size of the fluorometer, making it difficult to be used for portable detections. To overcome these limitations, we report herein a DNAzyme sensor that relies on chemiluminescence resonance energy transfer (CRET) without the need for external light. The sensor is constructed by combining the functional motifs from both Pb2+-dependent 8-17 DNAzyme conjugated to fluorescein (FAM) and hemin/G-quadruplex that mimics horseradish peroxidase to catalyze the oxidation of luminol by H2O2 to yield chemiluminescence. In the absence of Pb2+, the hybridization between the enzyme and substrate strands bring the FAM and hemin/G-quadruplex in close proximity, resulting in CRET. The presence of Pb2+ ions can drive the cleavage on the substrate strand, resulting in a sharp decrease in the melting temperature of hybridization and thus separation of the FAM from hemin/G-quadruplex. The liberated CRET pair causes a ratiometric increase in the donor's fluorescent signal and a decrease in the acceptor signal. Using this method, Pb2+ ions have been measured rapidly (<15 min) with a low limit of detection at 5 nM. By removing the requirement of exogenous light excitation, we have demonstrated a simple and portable detection using a smartphone, making the DNAzyme-CRET system suitable for field tests of lake water. Since DNAzymes selective for other metal ions or targets, such as bacteria, can be obtained using in vitro selection, the method reported here opens a new avenue for rapid, portable, and ratiometric detection of many targets in environmental monitoring, food safety, and medical diagnostics.
    Matched MeSH terms: Biosensing Techniques*
  5. Zhao X, Gopinath SCB, Zhao W
    Biotechnol Appl Biochem, 2023 Apr;70(2):502-508.
    PMID: 35661417 DOI: 10.1002/bab.2372
    Abdominal aortic aneurysm (AAA), a medical complication, occurs when the aortic area becomes swollen and very large. It is mandatory to identify AAA to avoid the breakdown of aneurysms. C-reactive protein (CRP) has been recognized as one of the biomarkers for identifying AAA due to the possibility of CRP produced in vascular tissue, which contributes to the formation of an aneurysm, and it is elevated in patients with a ruptured AAA. This research work was designed to develop an immunosensor on a multiwalled carbon nanotube (MWCNT)-modified surface to quantify the CRP level. Anti-CRP specificity was constructed on the MWCNT surface through a silane linker to interact with CRP. The detection limit of CRP was calculated as 100 pM with an R2 (determination coefficient) value of 0.9855 (y = 2.3446x - 1.9922) on a linear regression graph. The dose-dependent linear pattern was registered from 200 to 3000 pM and attained the saturation level during binding at 3000 pM. Furthermore, serum-spiked CRP showed a clear increase in the current response, proving the specific recognition of CRP in biological samples. This designed biosensor identifies CRP at a lower level and can help diagnose AAA.
    Matched MeSH terms: Biosensing Techniques*
  6. Zhang J, Lakshmipriya T, Gopinath SCB
    ACS Omega, 2020 Oct 13;5(40):25899-25905.
    PMID: 33073115 DOI: 10.1021/acsomega.0c03260
    The primary reasons for myocardial infarction (MI) are pericarditis, arrhythmia, and heart failure, causing predominant deaths worldwide. Patients need a potential diagnostic system and treatment before cardiomyocyte damage. Cardiac biomarkers are released from myocytes immediately after a heart attack. Troponin is an efficient biomarker released from dead cells within a few hours. Aptamers are artificial antibodies used effectively in the biosensor field for biomarker detection. Along with aptamers, the application of nanomaterials is also expected to enhance the detection limits of biosensors. In this investigation, selected aptamers against cardiac troponin I (cTnI) were conjugated with gold nanoparticles (GNPs) to diagnose MI and compared with an aptamer-only control group on an interdigitated electrode surface. Based on electroanalysis, cTnI was detected at concentrations as low as 1 fM, and the detection limit improved to 100 aM when the aptamer was conjugated with GNP. In addition, aptamer-GNP conjugates increased the current level at the tested concentrations of cTnI. Control experiments with noncomplementary aptamers and relevant proteins did not result in notable changes in the current, demonstrating the selective detection of cTnI.
    Matched MeSH terms: Biosensing Techniques
  7. Zen DI, Saidin N, Damanhuri SS, Harun SW, Ahmad H, Ismail MA, et al.
    Appl Opt, 2013 Feb 20;52(6):1226-9.
    PMID: 23434993 DOI: 10.1364/AO.52.001226
    We demonstrate mode locking of a thulium-bismuth codoped fiber laser (TBFL) operating at 1901.6 nm, using a graphene-based saturable absorber (SA). In this work, a single layer graphene is mechanically exfoliated using the scotch tape method and directly transferred onto the surface of a fiber pigtail to fabricate the SA. The obtained Raman spectrum characteristic indicates that the graphene on the core surface has a single layer. At 1552 nm pump power of 869 mW, the mode-locked TBFL self starts to generate an optical pulse train with a repetition rate of 16.7 MHz and pulse width of 0.37 ps. This is a simple, low-cost, stable, and convenient laser oscillator for applications where eye-safe and low-photon-energy light sources are required, such as sensing and biomedical diagnostics.
    Matched MeSH terms: Biosensing Techniques*
  8. Zandi K
    Methods Mol Biol, 2016;1426:255-62.
    PMID: 27233278 DOI: 10.1007/978-1-4939-3618-2_23
    Screening of viral inhibitors through induction of cytopathic effects (CPE) by conventional method has been applied for various viruses including Chikungunya virus (CHIKV), a significant arbovirus. However, it does not provide the information about cytopathic effect from the beginning and throughout the course of virus replication. Conventionally, most of the approaches are constructed on laborious end-point assays which are not capable for detecting minute and rapid changes in cellular morphology. Therefore, we developed a label-free and dynamical method for monitoring the cellular features that comprises cell attachment, proliferation, and viral cytopathogenicity, known as the xCELLigence real-time cell analysis (RTCA). In this chapter, we provide a RTCA protocol for quantitative analysis of CHIKV replication using an infected Vero cell line treated with ribavirin as an in vitro model.
    Matched MeSH terms: Biosensing Techniques
  9. Zambry NS, Awang MS, Beh KK, Hamzah HH, Bustami Y, Obande GA, et al.
    Lab Chip, 2023 Mar 14;23(6):1622-1636.
    PMID: 36786757 DOI: 10.1039/d2lc01159j
    The emergence of coronavirus disease 2019 (COVID-19) motivates continuous efforts to develop robust and accurate diagnostic tests to detect severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Detection of viral nucleic acids provides the highest sensitivity and selectivity for diagnosing early and asymptomatic infection because the human immune system may not be active at this stage. Therefore, this work aims to develop a label-free electrochemical DNA biosensor for SARS-CoV-2 detection using a printed circuit board-based gold substrate (PCBGE). The developed sensor used the nucleocapsid phosphoprotein (N) gene as a biomarker. The DNA sensor-based PCBGE was fabricated by self-assembling a thiolated single-stranded DNA (ssDNA) probe onto an Au surface, which performed as the working electrode (WE). The Au surface was then treated with 6-mercapto-1-hexanol (MCH) before detecting the target N gene to produce a well-oriented arrangement of the immobilized ssDNA chains. The successful fabrication of the biosensor was characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and atomic force microscopy (AFM). The DNA biosensor performances were evaluated using a synthetic SARS-CoV-2 genome and 20 clinical RNA samples from healthy and infected individuals through EIS. The developed DNA biosensor can detect as low as 1 copy per μL of the N gene within 5 minutes with a LOD of 0.50 μM. Interestingly, the proposed DNA sensor could distinguish the expression of SARS-CoV-2 RNA in a patient diagnosed with COVID-19 without any amplification technique. We believe that the proposed DNA sensor platform is a promising point-of-care (POC) device for COVID-19 viral infection since it offers a rapid detection time with a simple design and workflow detection system, as well as an affordable diagnostic assay.
    Matched MeSH terms: Biosensing Techniques*
  10. Zakaria Z, Abdul Rahim R, Mansor MS, Yaacob S, Ayub NM, Muji SZ, et al.
    Sensors (Basel), 2012;12(6):7126-56.
    PMID: 22969341 DOI: 10.3390/s120607126
    Magnetic Induction Tomography (MIT), which is also known as Electromagnetic Tomography (EMT) or Mutual Inductance Tomography, is among the imaging modalities of interest to many researchers around the world. This noninvasive modality applies an electromagnetic field and is sensitive to all three passive electromagnetic properties of a material that are conductivity, permittivity and permeability. MIT is categorized under the passive imaging family with an electrodeless technique through the use of excitation coils to induce an electromagnetic field in the material, which is then measured at the receiving side by sensors. The aim of this review is to discuss the challenges of the MIT technique and summarize the recent advancements in the transmitters and sensors, with a focus on applications in biological tissue imaging. It is hoped that this review will provide some valuable information on the MIT for those who have interest in this modality. The need of this knowledge may speed up the process of adopted of MIT as a medical imaging technology.
    Matched MeSH terms: Biosensing Techniques/instrumentation*
  11. Zakaria N, Ramli MZ, Ramasamy K, Meng LS, Yean CY, Banga Singh KK, et al.
    Anal Biochem, 2018 08 15;555:12-21.
    PMID: 29879415 DOI: 10.1016/j.ab.2018.05.031
    A miniaturized biosensing platform, based on monoclonal amyloid-beta antibodies (mAβab) that were immobilized on a disc-shaped platinum/iridium (Pt/Ir) microelectrode surface coupled with an impedimetric signal transducer, was developed for the label-free and sensitive detection of amyloid-beta peptide fragment 1-40 (Aβ40); a reliable biomarker for early diagnosis of Alzheimer's disease (AD). A Pt/Ir microelectrode was electropolymerized with poly (ortho-phenylenediamine), a conducting free amine-containing aromatic polymer; followed by crosslinking with glutaraldehyde for subsequent coupling of mAβab on the microelectrode surface. This modification strategy efficiently improved the impedimetric detection performance of Aβ40 in terms of charge transfer resistance (∼400-fold difference) and normalized impedance magnitude percentage change (∼40% increase) compared with a passive adsorption-based immobilization method. The sensitivity of the micro-immunosensing assay was found to be 1056 kΩ/(pg/mL)/cm2 and the limit of detection was found to be 4.81 pg/mL with a dynamic range of 1-104 pg/mL (R2 = 0.9932). The overall precision of the assay, as measured by relative standard deviation, ranged from 0.84 to 5.15%, demonstrating its reliability and accuracy; while in respect to assay durability and stability, the immobilized mAβab were able to maintain 80% of their binding activity to Aβ40 after incubation for 48 h at ambient temperature (25 °C). To validate the practical applicability, the assay was tested using brain tissue lysates prepared from AD-induced rats. Results indicate that the proposed impedimetric micro-immunosensing platform is highly versatile and adaptable for the quantitative detection of other disease-related biomarkers.
    Matched MeSH terms: Biosensing Techniques*
  12. Zakaria A, Shakaff AY, Masnan MJ, Ahmad MN, Adom AH, Jaafar MN, et al.
    Sensors (Basel), 2011;11(8):7799-822.
    PMID: 22164046 DOI: 10.3390/s110807799
    The major compounds in honey are carbohydrates such as monosaccharides and disaccharides. The same compounds are found in cane-sugar concentrates. Unfortunately when sugar concentrate is added to honey, laboratory assessments are found to be ineffective in detecting this adulteration. Unlike tracing heavy metals in honey, sugar adulterated honey is much trickier and harder to detect, and traditionally it has been very challenging to come up with a suitable method to prove the presence of adulterants in honey products. This paper proposes a combination of array sensing and multi-modality sensor fusion that can effectively discriminate the samples not only based on the compounds present in the sample but also mimic the way humans perceive flavours and aromas. Conversely, analytical instruments are based on chemical separations which may alter the properties of the volatiles or flavours of a particular honey. The present work is focused on classifying 18 samples of different honeys, sugar syrups and adulterated samples using data fusion of electronic nose (e-nose) and electronic tongue (e-tongue) measurements. Each group of samples was evaluated separately by the e-nose and e-tongue. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) were able to separately discriminate monofloral honey from sugar syrup, and polyfloral honey from sugar and adulterated samples using the e-nose and e-tongue. The e-nose was observed to give better separation compared to e-tongue assessment, particularly when LDA was applied. However, when all samples were combined in one classification analysis, neither PCA nor LDA were able to discriminate between honeys of different floral origins, sugar syrup and adulterated samples. By applying a sensor fusion technique, the classification for the 18 different samples was improved. Significant improvement was observed using PCA, while LDA not only improved the discrimination but also gave better classification. An improvement in performance was also observed using a Probabilistic Neural Network classifier when the e-nose and e-tongue data were fused.
    Matched MeSH terms: Biosensing Techniques
  13. Zainuddin NH, Chee HY, Ahmad MZ, Mahdi MA, Abu Bakar MH, Yaacob MH
    J Biophotonics, 2018 08;11(8):e201700363.
    PMID: 29570957 DOI: 10.1002/jbio.201700363
    This paper presents the development of tapered optical fiber sensor to detect a specific Leptospira bacteria DNA. The bacteria causes Leptospirosis, a deadly disease but with common early flu-like symptoms. Optical single mode fiber (SMF) of 125 μm diameter is tapered to produce 12 μm waist diameter and 15 cm length. The novel DNA-based optical fiber sensor is functionalized by incubating the tapered region with sodium hydroxide (NaOH), (3-Aminopropyl) triethoxysilane and glutaraldehyde. Probe DNA is immobilized onto the tapered region and subsequently hybridized by its complementary DNA (cDNA). The transmission spectra of the DNA-based optical fiber sensor are measured in the 1500 to 1600 nm wavelength range. It is discovered that the shift of the wavelength in the SMF sensor is linearly proportional with the increase in the cDNA concentrations from 0.1 to 1.0 nM. The sensitivity of the sensor toward DNA is measured to be 1.2862 nm/nM and able to detect as low as 0.1 fM. The sensor indicates high specificity when only minimal shift is detected for non-cDNA testing. The developed sensor is able to distinguish between actual DNA of Leptospira serovars (Canicola and Copenhageni) against Clostridium difficile (control sample) at very low (femtomolar) target concentrations.
    Matched MeSH terms: Biosensing Techniques/instrumentation*
  14. Zainol Abidin AS, Rahim RA, Md Arshad MK, Fatin Nabilah MF, Voon CH, Tang TH, et al.
    Sensors (Basel), 2017 May 22;17(5).
    PMID: 28531146 DOI: 10.3390/s17051180
    Anxiety is a psychological problem that often emerges during the normal course of human life. The detection of anxiety often involves a physical exam and a self-reporting questionnaire. However, these approaches have limitations, as the data might lack reliability and consistency upon application to the same population over time. Furthermore, there might be varying understanding and interpretations of the particular question by the participant, which necessitating the approach of using biomarker-based measurement for stress diagnosis. The most prominent biomarker related to stress, hormone cortisol, plays a key role in the fight-or-flight situation, alters the immune response, and suppresses the digestive and the reproductive systems. We have taken the endeavour to review the available aptamer-based biosensor (aptasensor) for cortisol detection. The potential point-of-care diagnostic strategies that could be harnessed for the aptasensing of cortisol were also envisaged.
    Matched MeSH terms: Biosensing Techniques
  15. Zahed FM, Hatamluyi B, Lorestani F, Es'haghi Z
    J Pharm Biomed Anal, 2018 Nov 30;161:12-19.
    PMID: 30142492 DOI: 10.1016/j.jpba.2018.08.004
    A highly efficient electrochemical sensor for the analysis of anticancer drug 5-fluorouracil (5-FU), is fabricated based on silver nanoparticles-polyaniline nanotube (AgNPs@PANINTs). AgNPs@PANINTs nanocomposite has been synthesized by a simple one-step method. Synthesized AgNPs@PANINTs nanocomposite was studied by Fourier transform infrared spectrometry, Scanning Electron Microscopy and Energy Dispersive X-ray. The fabricated PANINTs@AgNPs PGE was applied to the electrochemical sensing of 5-FU. Cyclic voltammetry and differential pulse voltammetry experiments illustrated high electro activity for the AgNPs@PANINTs nanocomposite. The study was explored using the Taguchi experimental design method. Electrochemical measurements using differential pulse voltammetry showed a wide linear relationship between 5-FU concentration and peak height within the range 1.0-300.0 μM with a low detection limit (0.06 μM). Also, the fabricated sensor showed excellent selectivity in the presence of two anticancer drugs and a number of other interfering compounds. The as-prepared sensor showed to be a promising device for a simple, rapid, and direct analysis of 5-FU.
    Matched MeSH terms: Biosensing Techniques/methods*
  16. Yusuf N, Zakaria A, Omar MI, Shakaff AY, Masnan MJ, Kamarudin LM, et al.
    BMC Bioinformatics, 2015;16:158.
    PMID: 25971258 DOI: 10.1186/s12859-015-0601-5
    Effective management of patients with diabetic foot infection is a crucial concern. A delay in prescribing appropriate antimicrobial agent can lead to amputation or life threatening complications. Thus, this electronic nose (e-nose) technique will provide a diagnostic tool that will allow for rapid and accurate identification of a pathogen.
    Matched MeSH terms: Biosensing Techniques
  17. Yuhana Ariffin E, Heng LY, Tan LL, Abd Karim NH, Hasbullah SA
    Sensors (Basel), 2020 Feb 26;20(5).
    PMID: 32111092 DOI: 10.3390/s20051279
    A novel label-free electrochemical DNA biosensor was constructed for the determination of Escherichia coli bacteria in environmental water samples. The aminated DNA probe was immobilized onto hollow silica microspheres (HSMs) functionalized with 3-aminopropyltriethoxysilane and deposited onto a screen-printed electrode (SPE) carbon paste with supported gold nanoparticles (AuNPs). The biosensor was optimized for higher specificity and sensitivity. The label-free E. coli DNA biosensor exhibited a dynamic linear response range of 1 × 10-10 µM to 1 × 10-5 µM (R2 = 0.982), with a limit of detection at 1.95 × 10-15 µM, without a redox mediator. The sensitivity of the developed DNA biosensor was comparable to the non-complementary and single-base mismatched DNA. The DNA biosensor demonstrated a stable response up to 21 days of storage at 4 ℃ and pH 7. The DNA biosensor response was regenerable over three successive regeneration and rehybridization cycles.
    Matched MeSH terms: Biosensing Techniques/methods*
  18. Yu CY, Ang GY, Chua AL, Tan EH, Lee SY, Falero-Diaz G, et al.
    J Microbiol Methods, 2011 Sep;86(3):277-82.
    PMID: 21571011 DOI: 10.1016/j.mimet.2011.04.020
    Cholera is a communicable disease caused by consumption of contaminated food and water. This potentially fatal intestinal infection is characterised by profuse secretion of rice watery stool that can rapidly lead to severe dehydration and shock, thus requiring treatment to be given immediately. Epidemic and pandemic cholera are exclusively associated with Vibrio cholerae serogroups O1 and O139. In light of the need for rapid diagnosis of cholera and to prevent spread of outbreaks, we have developed and evaluated a direct one-step lateral flow biosensor for the simultaneous detection of both V. cholerae O1 and O139 serogroups using alkaline peptone water culture. Serogroup specific monoclonal antibodies raised against lipopolysaccharides (LPS) were used to functionalize the colloidal gold nanoparticles for dual detection in the biosensor. The assay is based on immunochromatographic principle where antigen-antibody reaction would result in the accumulation of gold nanoparticles and thus, the appearance of a red line on the strip. The dry-reagent dipstick format of the biosensor ensure user-friendly application, rapid result that can be read with the naked eyes and cold-chain free storage that is well-suited to be performed at resource-limited settings.
    Matched MeSH terms: Biosensing Techniques/methods*
  19. Yu CY, Ang GY, Yean CY
    Chem Commun (Camb), 2013 Mar 11;49(20):2019-21.
    PMID: 23370051 DOI: 10.1039/c3cc39144b
    We developed a multiplex enzyme-based electrochemical genosensor for sequence-specific detection of multiplex linear-after-the-exponential-PCR amplicons that targeted toxigenic Vibrio cholerae O1 and O139 using novel screen-printed gold electrode bisensors.
    Matched MeSH terms: Biosensing Techniques
  20. Yu CY, Ang GY, Chan KG, Banga Singh KK, Chan YY
    Biosens Bioelectron, 2015 Aug 15;70:282-8.
    PMID: 25835520 DOI: 10.1016/j.bios.2015.03.048
    In this study, we developed a nucleic acid-sensing platform in which a simple, dry-reagent-based nucleic acid amplification assay is combined with a portable multiplex electrochemical genosensor. Preparation of an amplification reaction mix targeting multiple DNA regions of interest is greatly simplified because the lyophilized reagents need only be reconstituted with ultrapure water before the DNA sample is added. The presence of single or multiple target DNAs causes the corresponding single-stranded DNA (ssDNA) amplicons to be generated and tagged with a fluorescein label. The fluorescein-labeled ssDNA amplicons are then analyzed using capture probe-modified screen-printed gold electrode bisensors. Enzymatic amplification of the hybridization event is achieved through the catalytic production of electroactive α-naphthol by anti-fluorescein-conjugated alkaline phosphatase. The applicability of this platform as a diagnostic tool is demonstrated with the detection of toxigenic Vibrio cholerae serogroups O1 and O139, which are associated with cholera epidemics and pandemics. The platform showed excellent diagnostic sensitivity and specificity (100%) when challenged with 168 spiked stool samples. The limit of detection was low (10 colony-forming units/ml) for both toxigenic V. cholerae serogroups. A heat stability assay revealed that the dry-reagent amplification reaction mix was stable at temperatures of 4-56 °C, with an estimated shelf life of seven months. The findings of this study highlight the potential of combining a dry-reagent-based nucleic acid amplification assay with an electrochemical genosensor in a more convenient, sensitive, and sequence-specific detection strategy for multiple target nucleic acids.
    Matched MeSH terms: Biosensing Techniques/instrumentation*
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