Displaying publications 81 - 100 of 366 in total

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  1. Arshad MKM, Adzhri R, Fathil MFM, Gopinath SCB, N M NM
    J Nanosci Nanotechnol, 2018 Aug 01;18(8):5283-5291.
    PMID: 29458578 DOI: 10.1166/jnn.2018.15419
    The development of electrical biosensor towards device miniaturization in order to achieve better sensitivity with enhanced electrical signal has certain limitations especially complexity in fabrication process and costs. In this paper, an alternative technique with minor modification in the device structure is presented for signal amplification by implementing ambipolar conduction in the biosensor itself. We demonstrated the field-effect transistor (FET)-based biosensor coupled back-gate for attaining a higher sensitivity with the detection of lower target abundance. To utilize the coupled back-gate as a pre-amplifier, silicon-on-insulator wafer with thicknesses of top-silicon and buried oxide (BOX) layers of 70 nm and 145 nm, respectively were desired. Titanium dioxide (TiO2) nanomaterial was deposited using sol-gel method on the channel which acts as a transducer. Surface functionalization on TiO2 thin film allowed an effective immobilization of anti-cardiac troponin I antibody to interact cardiac troponin I (cTnI). Binding events at each step was validated by X-ray photoelectron spectroscopy (XPS) analysis. Further, electrical characterization (Id-Vd) confirms the potentiality of FET-based biosensor to detect cTnI (represents acute myocardial infarction disease) with the concentration ranges from 10 μg/ml down to 1 fg/ml. The sensitivity of 459.2 nA (g/ml)-1 and lower detection limit of 1 fg/ml were achieved at Vbg = -5 V and Vd = 5 V. The designed device demonstrates its ability to detect lower level of cTnI with pre-amplified electrical signal by back-gate biasing.
    Matched MeSH terms: Biosensing Techniques*
  2. Siew QY, Pang EL, Loh HS, Tan MTT
    Biosens Bioelectron, 2021 Mar 15;176:112895.
    PMID: 33358432 DOI: 10.1016/j.bios.2020.112895
    This study reports on the development of a novel impedimetric immunosensor design using plant-derived antigenic glycoprotein for the detection of dengue virus (DENV) IgG antibodies. The electrochemical immunosensor platform was constructed using screen-printed carbon electrode (SPCE) modified with graphene/titanium dioxide (G/TiO2) nanocomposite to improve the electrode in terms electrochemical performance and specific surface area. A plant-derived dengue envelope domain III (EDIII) protein was used as the antigenic probe protein in this immunosensing strategy. Under optimised sensing conditions, the immunosensor demonstrated high sensitivity towards DENV IgG in a wide linear working range (62.5-2000 ng/mL), with a limit of detection of 2.81 ng/mL. The immunosensor showed high specificity for discriminating DENV IgG against antibodies of other infectious disease, including the closely related Zika virus (ZIKV). The reliability of the immunosensor in serological diagnosis was verified by challenging the immunosensor against serum samples, compared to conventional enzyme-linked immunosorbent assay (ELISA). As shown by its remarkable performance throughout the study, the devised immunosensor is proposed as a reliable and practical diagnostic tool for the serological detection of dengue in realistic applications.
    Matched MeSH terms: Biosensing Techniques*
  3. Rashid JIA, Kannan V, Ahmad MH, Mon AA, Taufik S, Miskon A, et al.
    Mater Sci Eng C Mater Biol Appl, 2021 Jan;120:111625.
    PMID: 33545813 DOI: 10.1016/j.msec.2020.111625
    Multidrug resistant Pseudomonas aeruginosa (P. aeruginosa) is known to be a problematic bacterium for being a major cause of opportunistic and nosocomial infections. In this study, reduced graphene oxide decorated with gold nanoparticles (AuNPs/rGO) was utilized as a new sensing material for a fast and direct electrochemical detection of pyocyanin as a biomarker of P. aeruginosa infections. Under optimal condition, the developed electrochemical pyocyanin sensor exhibited a good linear range for the determination of pyocyanin in phosphate-buffered saline (PBS), human saliva and urine at a clinically relevant concentration range of 1-100 μM, achieving a detection limit of 0.27 μM, 1.34 μM, and 2.3 μM, respectively. Our developed sensor demonstrated good selectivity towards pyocyanin in the presence of interfering molecule such as ascorbic acid, uric acid, NADH, glucose, and acetylsalicylic acid, which are commonly found in human fluids. Furthermore, the developed sensor was able to discriminate the signal with and without the presence of pyocyanin directly in P. aeruginosa culture. This proposed technique demonstrates its potential application in monitoring the presence of P. aeruginosa infection in patients.
    Matched MeSH terms: Biosensing Techniques*
  4. Białobrzeska W, Dziąbowska K, Lisowska M, Mohtar MA, Muller P, Vojtesek B, et al.
    Biosensors (Basel), 2021 Jun 07;11(6).
    PMID: 34200338 DOI: 10.3390/bios11060184
    The detection of cancer antigens is a major aim of cancer research in order to develop better patient management through early disease detection. Many cancers including prostate, lung, and ovarian secrete a protein disulfide isomerase protein named AGR2 that has been previously detected in urine and plasma using mass spectrometry. Here we determine whether a previously developed monoclonal antibody targeting AGR2 can be adapted from an indirect two-site ELISA format into a direct detector using solid-phase printed gold electrodes. The screen-printed gold electrode was surface functionalized with the anti-AGR2 specific monoclonal antibody. The interaction of the recombinant AGR2 protein and the anti-AGR2 monoclonal antibody functionalized electrode changed its electrochemical impedance spectra. Nyquist diagrams were obtained after incubation in an increasing concentration of purified AGR2 protein with a range of concentrations from 0.01 fg/mL to 10 fg/mL. In addition, detection of the AGR2 antigen can be achieved from cell lysates in medium or artificial buffer. These data highlight the utility of an AGR2-specific monoclonal antibody that can be functionalized onto a gold printed electrode for a one-step capture and quantitation of the target antigen. These platforms have the potential for supporting methodologies using more complex bodily fluids including plasma and urine for improved cancer diagnostics.
    Matched MeSH terms: Biosensing Techniques*
  5. Chang KM, Chun YT, Chen SH, Lu L, Su HT, Liang HM, et al.
    Sensors (Basel), 2016 Jul 20;16(7).
    PMID: 27447641 DOI: 10.3390/s16071126
    Chan Ding training is beneficial to health and emotional wellbeing. More and more people have taken up this practice over the past few years. A major training method of Chan Ding is to focus on the ten Mailuns, i.e., energy points, and to maintain physical stillness. In this article, wireless wearable accelerometers were used to detect physical stillness, and the created physical stillness index (PSI) was also shown. Ninety college students participated in this study. Primarily, accelerometers used on the arms and chest were examined. The results showed that the PSI values on the arms were higher than that of the chest, when participants moved their bodies in three different ways, left-right, anterior-posterior, and hand, movements with natural breathing. Then, they were divided into three groups to practice Chan Ding for approximately thirty minutes. Participants without any Chan Ding experience were in Group I. Participants with one year of Chan Ding experience were in Group II, and participants with over three year of experience were in Group III. The Chinese Happiness Inventory (CHI) was also conducted. Results showed that the PSI of the three groups measured during 20-30 min were 0.123 ± 0.155, 0.012 ± 0.013, and 0.001 ± 0.0003, respectively (p < 0.001 ***). The averaged CHI scores of the three groups were 10.13, 17.17, and 25.53, respectively (p < 0.001 ***). Correlation coefficients between PSI and CHI of the three groups were -0.440, -0.369, and -0.537, respectively (p < 0.01 **). PSI value and the wearable accelerometer that are presently available on the market could be used to evaluate the quality of the physical stillness of the participants during Chan Ding practice.
    Matched MeSH terms: Biosensing Techniques/methods*
  6. Fathil MF, Md Arshad MK, Ruslinda AR, Nuzaihan M N M, Gopinath SC, Adzhri R, et al.
    Anal Chim Acta, 2016 Sep 07;935:30-43.
    PMID: 27543013 DOI: 10.1016/j.aca.2016.06.012
    A real-time ability to interpret the interaction between targeted biomolecules and the surface of semiconductors (metal transducers) into readable electrical signals, without biomolecular modification involving fluorescence dyes, redox enzymes, and radioactive labels, created by label-free biosensors has been extensively researched. Field-effect transistor (FET)- and capacitor-based biosensors are among the diverse electrical charge biosensing architectures that have drawn much attention for having charge transduction; thus, enabling the early and rapid diagnosis of the appropriate cardiac biomarkers at lower concentrations. These semiconducting material-based transducers are very suitable to be integrated with portable electronic devices for future online collection, transmission, reception, analysis, and reporting. This overview elucidates and clarifies two major electrical label-free systems (FET- and capacitor-based biosensors) with cardiac troponin (cTn) biomarker-mediated charge transduction for acute myocardial infarction (AMI) diagnosis. Advances in these systems are highlighted by their progression in bridging the laboratory and industry; the foremost technologies have made the transition from benchtop to bedside and beyond.
    Matched MeSH terms: Biosensing Techniques*
  7. Ibau C, Md Arshad MK, Gopinath SCB
    Biosens Bioelectron, 2017 Dec 15;98:267-284.
    PMID: 28689113 DOI: 10.1016/j.bios.2017.06.049
    Early cancer diagnosis remains the holy-grail in the battle against cancers progression. Tainted with debates and medical challenges, current therapeutic approaches for prostate cancer (PCa) lack early preventive measures, rapid diagnostic capabilities, risk factors identification, and portability, i.e. the inherent attributes offered by the label-free biosensing devices. Electronic assisted immunosensing systems inherit the high sensitivity and specificity properties due to the predilection of the antigen-antibody affinity. Bioelectronic immunosensor for PCa has attracted much attentions among the researchers due to its high-performance, easy to prepare, rapid feedback, and possibility for miniaturization. This review explores the current advances on bioelectronic immunosensors for the detection of PCa biomarker revealed in the past decade. The research milestones and current trends of the immunosensors are reported to project the future visions in order to propel their "lab-to-market" realization.
    Matched MeSH terms: Biosensing Techniques*
  8. Ong CC, Siva Sangu S, Illias NM, Chandra Bose Gopinath S, Saheed MSM
    Biosens Bioelectron, 2020 Apr 15;154:112088.
    PMID: 32056954 DOI: 10.1016/j.bios.2020.112088
    Deoxynivalenol (DON), a cosmopolitan mycotoxin found in agricultural commodities causes serious health maladies to human and animals when accidently consumed even at a low quantity. It necessitates selective and sensitive devices to analyse DON as the conventional methods are complex and time-consuming. This study is focused on developing a selective biosensing system using iron nanoflorets graphene nickel (INFGN) as the transducer and a specific aptamer as the biorecognition element. 3D-graphene is incorporated using a low-pressure chemical vapour deposition followed by the decoration of iron nanoflorets using electrochemical deposition. INFGN enables a feasible bio-capturing due to its large surface area. The X-ray photoelectron spectroscopy analysis confirms the presence of the hydroxyl groups on the INFGN surface, which acts as the linker. Clear Fourier-transform infrared peak shifts affirm the changes with surface chemical modification and biomolecular assembly. The limit of detection attained is 2.11 pg mL-1 and displays high stability whereby it retains 30.65% of activity after 48 h. The designed INFGN demonstrates remarkable discrimination of DON against similar mycotoxins (zearalenone and ochratoxin A). Overall, the high-performance biosensor shown here is an excellent, simple and cost-effective alternative for detecting DON in food and feed samples.
    Matched MeSH terms: Biosensing Techniques*
  9. Ahmad N, Colak B, Gibbs MJ, Zhang DW, Gautrot JE, Watkinson M, et al.
    Biomacromolecules, 2019 07 08;20(7):2506-2514.
    PMID: 31244015 DOI: 10.1021/acs.biomac.9b00245
    Inflammatory conditions are frequently accompanied by increased levels of active proteases, and there is rising interest in methods for their detection to monitor inflammation in a point of care setting. In this work, new sensor materials for disposable single-step protease biosensors based on poly(2-oxazoline) hydrogels cross-linked with a protease-specific cleavable peptide are described. The performance of the sensor material was assessed targeting the detection of matrix metalloproteinase-9 (MMP-9), a protease that has been shown to be an indicator of inflammation in multiple sclerosis and other inflammatory conditions. Films of the hydrogel were formed on gold-coated quartz crystals using thiol-ene click chemistry, and the cross-link density was optimized. The degradation rate of the hydrogel was monitored using a quartz crystal microbalance (QCM) and showed a strong dependence on the MMP-9 concentration. A concentration range of 0-160 nM of MMP-9 was investigated, and a lower limit of detection of 10 nM MMP-9 was determined.
    Matched MeSH terms: Biosensing Techniques*
  10. Abd Rahman SF, Md Arshad MK, Gopinath SCB, Fathil MFM, Sarry F, Ibau C
    Chem Commun (Camb), 2021 Sep 23;57(76):9640-9655.
    PMID: 34473143 DOI: 10.1039/d1cc03080a
    Prostate cancer is currently diagnosed using the conventional gold standard methods using prostate-specific antigen (PSA) as the selective biomarker. However, lack of precision in PSA screening has resulted in needless biopsies and delays the treatment of potentially fatal prostate cancer. Thus, identification of glycans as novel biomarkers for the early detection of prostate cancer has attracted considerable attention due to their reliable diagnostic platform compared with the current PSA systems. Therefore, biosensing technologies that provide point-of-care diagnostics have demonstrated the ability to detect various analytes, including glycosylated micro- and macro-molecules, thereby enabling versatile detection methodologies. This highlight article discusses recent advances in the biosensor-based detection of prostate cancer glycan biomarkers and the innovative strategies for the conjugation of nanomaterials adapted to biosensing platforms. Finally, the article is concluded with prospects and challenges of prostate cancer biosensors and recommendations to overcome the issues associated with prostate cancer diagnosis.
    Matched MeSH terms: Biosensing Techniques*
  11. Faheem M, Butt RA, Raza B, Alquhayz H, Abbas MZ, Ngadi MA, et al.
    Sensors (Basel), 2019 Nov 20;19(23).
    PMID: 31757104 DOI: 10.3390/s19235072
    The importance of body area sensor networks (BASNs) is increasing day by day because of their increasing use in Internet of things (IoT)-enabled healthcare application services. They help humans in improving their quality of life by continuously monitoring various vital signs through biosensors strategically placed on the human body. However, BASNs face serious challenges, in terms of the short life span of their batteries and unreliable data transmission, because of the highly unstable and unpredictable channel conditions of tiny biosensors located on the human body. These factors may result in poor data gathering quality in BASNs. Therefore, a more reliable data transmission mechanism is greatly needed in order to gather quality data in BASN-based healthcare applications. Therefore, this study proposes a novel, multiobjective, lion mating optimization inspired routing protocol, called self-organizing multiobjective routing protocol (SARP), for BASN-based IoT healthcare applications. The proposed routing scheme significantly reduces local search problems and finds the best dynamic cluster-based routing solutions between the source and destination in BASNs. Thus, it significantly improves the overall packet delivery rate, residual energy, and throughput with reduced latency and packet error rates in BASNs. Extensive simulation results validate the performance of our proposed SARP scheme against the existing routing protocols in terms of the packet delivery ratio, latency, packet error rate, throughput, and energy efficiency for BASN-based health monitoring applications.
    Matched MeSH terms: Biosensing Techniques/methods*
  12. Ariffin EY, Zakariah EI, Ruslin F, Kassim M, Yamin BM, Heng LY, et al.
    Sci Rep, 2021 04 12;11(1):7883.
    PMID: 33846405 DOI: 10.1038/s41598-021-86939-z
    Ferrocene or ferrocenium has been widely studied in the field of organometallic complexes because of its stable thermodynamic, kinetic and redox properties. Novel hexaferrocenium tri[hexa(isothiocyanato)iron(III)]trihydroxonium (HexaFc) complex was the product from the reaction of ferrocene, maleic acid and ammonium thiocyanate and was confirmed by elemental analysis CHNS, FTIR and single crystal X-ray crystallography. In this study, HexaFc was used for the first time as an electroactive indicator for porcine DNA biosensor. The UV-Vis DNA titrations with this compound showed hypochromism and redshift at 250 nm with increasing DNA concentrations. The binding constant (Kb) for HexaFc complex towards CT-DNA (calf-thymus DNA) was 3.1 × 104 M-1, indicated intercalator behaviour of the complex. To test the usefulness of this complex for DNA biosensor application, a porcine DNA biosensor was constructed. The recognition probes were covalently immobilised onto silica nanospheres (SiNSs) via glutaraldehyde linker on a screen-printed electrode (SPE). After intercalation with the HexaFc complex, the response of the biosensor to the complementary porcine DNA was measured using differential pulse voltammetry. The DNA biosensor demonstrated a linear response range to the complementary porcine DNA from 1 × 10-6 to 1 × 10-3 µM (R2 = 0.9642) with a limit detection of 4.83 × 10-8 µM and the response was stable up to 23 days of storage at 4 °C with 86% of its initial response. The results indicated that HexaFc complex is a feasible indicator for the DNA hybridisation without the use of a chemical label for the detection of porcine DNA.
    Matched MeSH terms: Biosensing Techniques/methods*
  13. Gan Z, Roslan MAM, Abd Shukor MY, Halim M, Yasid NA, Abdullah J, et al.
    Biosensors (Basel), 2022 Oct 25;12(11).
    PMID: 36354431 DOI: 10.3390/bios12110922
    Aptamers are a group of synthetic single-stranded nucleic acids. They are generated from a random library of single-stranded DNA or RNA by a technology named systematic evolution of ligands by exponential enrichment (SELEX). SELEX is a repetitive process to select and identify suitable aptamers that show high affinity and specificity towards target cells. Great strides have been achieved in the design, construction, and use of aptamers up to this point. However, only a small number of aptamer-based applications have achieved widespread commercial and clinical acceptance. Additionally, finding more effective ways to acquire aptamers with high affinity remains a challenge. Therefore, it is crucial to thoroughly examine the existing dearth and advancement in aptamer-related technologies. This review focuses on aptamers that are generated by SELEX to detect pathogenic microorganisms and mammalian cells, as well as in cell-internalizing SELEX for diagnostic and therapeutic purposes. The development of novel aptamer-based biosensors using optical and electrical methods for microbial detection is reported. The applications and limitations of aptamers are also discussed.
    Matched MeSH terms: Biosensing Techniques*
  14. Li X, Gopinath SCB, Peng X, Lv J
    J Biomed Nanotechnol, 2021 Dec 01;17(12):2495-2504.
    PMID: 34974872 DOI: 10.1166/jbn.2021.3213
    An aptasensor was developed on an interdigitated microelectrode (IDME) by current-volt sensing for the diagnosis of ulcerative colitis by detecting the biomarker lipocalin-2. Higher immobilization of the anti-lipocalin-2 aptamer as a probe was achieved by using sodium dodecyl benzenesulfonate-aided zeolite particles. FESEM and FETEM observations revealed that the size of the zeolite particles was <200 nm, and they displayed a uniform distribution and spherical shape. XPS analysis attested the occurrence of Si, Al, and O groups on the zeolite particles. Zeolite particles were immobilized on IDME by a (3-aminopropyl)-trimethoxysilane amine linker, and then, the aptamer as the probe was tethered on the zeolite particles through a biotin-streptavidin strategy assisted by a bifunctional aldehyde linker. Due to the high occupancy of the aptamer and the efficient electric transfer from zeolite particles, higher changes in current can be observed upon interaction of the aptamer with lipocalin-2. The lower detection of lipocalin-2 was noted as 10 pg/mL, with a linear range from 10 pg/mL to 1 μg/mL and a linear regression equation of y=8E-07x+8E-08; R² = 0.991. Control experiments with complementary aptamer and matrix metalloproteinase-9 indicate the specific detection of lipocalin-2. Furthermore, spiking lipocalin-2 in human serum does not interfere with the identification.
    Matched MeSH terms: Biosensing Techniques*
  15. Ravikumar A, Panneerselvam P, Radhakrishnan K, Morad N, Anuradha CD, Sivanesan S
    J Fluoresc, 2017 Nov;27(6):2101-2109.
    PMID: 28819702 DOI: 10.1007/s10895-017-2149-4
    A label -free DNAzyme amplified biosensor is found to be highly selective and sensitive towards fluorescent detection of Pb2+ ions in aqueous media. The DNAzyme complex has designed by the hybridization of the enzyme and substrate strand. In the presence of Pb2+, the DNAzyme activated and cleaved the substrate strand of RNA site (rA) into two oligonucleotide fragments. Further, the free fragment was hybridized with a complementary strand on the surface of MBs. After magnetic separation, SYBER Green I was added and readily intercalate with the dsDNA to gives a bright fluorescence signal with intensity directly proportional to the concentration of Pb2+ions. A detection limit of 5 nM in Pb2+ the detection range 0 to 500 nM was obtained. This label- free fluorescent biosensor has been successfully applied to the determination of environmental water samples. Then results open up the possibility for real-time quantitative detection of Pb2+ with convenient potential applications in the biological and environmental field. Graphical Abstract.
    Matched MeSH terms: Biosensing Techniques/methods*
  16. Foo ME, Gopinath SCB
    Biomed Pharmacother, 2017 Oct;94:354-361.
    PMID: 28772213 DOI: 10.1016/j.biopha.2017.07.122
    Nanotechnology is the developing field, bringing the materials in the nanoscale level, has been applied in the interdisciplinary sciences. Different nanomaterials, such as gold, silver, zinc, copper and graphene are shown to have a wide range of applications. Among these, graphene is one of the faster upcoming two-dimensional nanomaterials utilized in various fields due to its positive features including the properties of thermal, electrical, strength and elasticity. Biomedical applications of graphene have been widely attested to be popular among academician and industrial partners for creating next generation medical systems and therapies. In this review, we selectively revealed the current applications of graphene in the interdisciplinary medical sciences.
    Matched MeSH terms: Biosensing Techniques/methods*
  17. Nik Mansor NN, Leong TT, Safitri E, Futra D, Ahmad NS, Nasuruddin DN, et al.
    Sensors (Basel), 2018 Feb 26;18(3).
    PMID: 29495352 DOI: 10.3390/s18030686
    A tri-enzyme system consisting of choline kinase/choline oxidase/horseradish peroxidase was used in the rapid and specific determination of the biomarker for bacterial sepsis infection, secretory phospholipase Group 2-IIA (sPLA2-IIA). These enzymes were individually immobilized onto the acrylic microspheres via succinimide groups for the preparation of an electrochemical biosensor. The reaction of sPLA2-IIA with its substrate initiated a cascading enzymatic reaction in the tri-enzyme system that led to the final production of hydrogen peroxide, which presence was indicated by the redox characteristics of potassium ferricyanide, K₃Fe(CN)₆. An amperometric biosensor based on enzyme conjugated acrylic microspheres and gold nanoparticles composite coated onto a carbon-paste screen printed electrode (SPE) was fabricated and the current measurement was performed at a low potential of 0.20 V. This enzymatic biosensor gave a linear range 0.01-100 ng/mL (R² = 0.98304) with a detection limit recorded at 5 × 10-3 ng/mL towards sPLA2-IIA. Moreover, the biosensor showed good reproducibility (relative standard deviation (RSD) of 3.04% (n = 5). The biosensor response was reliable up to 25 days of storage at 4 °C. Analysis of human serum samples for sPLA2-IIA indicated that the biosensor has potential for rapid bacterial sepsis diagnosis in hospital emergency department.
    Matched MeSH terms: Biosensing Techniques*
  18. Hashim H, Maruyama H, Masuda T, Arai F
    Sensors (Basel), 2016 Dec 01;16(12).
    PMID: 27916931
    Manipulation and injection of single nanosensors with high cell viability is an emerging field in cell analysis. We propose a new method using fluorescence nanosensors with a glass nanoprobe and optical control of the zeta potential. The nanosensor is fabricated by encapsulating a fluorescence polystyrene nanobead into a lipid layer with 1,3,3-trimethylindolino-6'-nitrobenzopyrylospiran (SP), which is a photochromic material. The nanobead contains iron oxide nanoparticles and a temperature-sensitive fluorescent dye, Rhodamine B. The zeta potential of the nanosensor switches between negative and positive by photo-isomerization of SP with ultraviolet irradiation. The positively-charged nanosensor easily adheres to a negatively-charged glass nanoprobe, is transported to a target cell, and then adheres to the negatively-charged cell membrane. The nanosensor is then injected into the cytoplasm by heating with a near-infrared (NIR) laser. As a demonstration, a single 750 nm nanosensor was picked-up using a glass nanoprobe with optical control of the zeta potential. Then, the nanosensor was transported and immobilized onto a target cell membrane. Finally, it was injected into the cytoplasm using a NIR laser. The success rates of pick-up and cell immobilization of the nanosensor were 75% and 64%, respectively. Cell injection and cell survival rates were 80% and 100%, respectively.
    Matched MeSH terms: Biosensing Techniques/methods*
  19. Mohd Sukri SA, Heng LY, Abd Karim NH
    J Fluoresc, 2017 May;27(3):1009-1023.
    PMID: 28224358 DOI: 10.1007/s10895-017-2035-0
    The platinum(II) salphen complex N,N'-Bis-4-(hydroxysalicylidene)-phenylenediamine-platinum(II); (1) and its two derivatives containing hydroxyl functionalized side chains N,N'-bis-[4-[[1-(2-hydroxyethoxy)] salicylidene] phenylenediamine-platinum(II); (2) and N,N'-bis-[4-[[1-(3-hydroxypropoxy)] salicylidene] phenylenediamine-platinum(II); (3) were synthesized and characterized. The structures of the complexes were confirmed by 1H and 13C NMR spectroscopy, FTIR, ESI-MS and CHN elemental analyses. The effects of the hydroxyl substituent on the spectral properties and the DNA binding behaviors of the Pt(II) complexes were explored. The binding mode and interactions of these complexes with duplex DNA (calf thymus DNA and porcine DNA) and also single-stranded DNA were studied by UV-Vis and emission DNA titration. The complexes interact with DNA by intercalation binding mode with the binding constants in the order of magnitude (Kb = 104 M-1, CT-DNA) and (Kb = 105 M-1, porcine DNA). The intercalation of the complex in the DNA structure was proposed to happen by π-π stacking due to its square-planar geometry and aromatic rings structure. The phosphorescence emission spectral characteristics of Pt(II) complexes when interacted with DNA have been studied. Also, the application of the chosen hydroxypropoxy side chains complex (3) as an optical DNA biosensor, specifically for porcine DNA was investigated. These findings will be valuable for the potential use of the platinum(II) salphen complex as an optical DNA biosensor for the detection of porcine DNA in food products.
    Matched MeSH terms: Biosensing Techniques/methods*
  20. Said FA, Menon PS, Rajendran V, Shaari S, Majlis BY
    IET Nanobiotechnol, 2017 Dec;11(8):981-986.
    PMID: 29155398 DOI: 10.1049/iet-nbt.2017.0051
    In this study, the authors investigated the effects of a single layer graphene as a coating layer on top of metal thin films such as silver, gold, aluminum and copper using finite-difference time domain method. To enhance the resolution of surface plasmon resonance (SPR) sensor, it is necessary to increase the SPR reflectivity and decrease the full-width-half maximum (FWHM) of the SPR curve so that there is minimum uncertainty in the determination of the resonance dip. Numerical data was verified with analytical and experimental data where all the data were in good agreement with resonance angle differing in <10% due to noise present in components such as humidity and temperature. In further analysis, reflectivity and FWHM were compared among four types of metal with various thin film thicknesses where graphene was applied on top of the metal layers, and data was compared against pure conventional metal thin films. A 60 nm-thick Au thin film results in higher performance with reflectivity of 92.4% and FWHM of 0.88° whereas single layer graphene-on-60 nm-thick Au gave reflectivity of 91.7% and FWHM of 1.32°. However, a graphene-on-40 nm-thick Ag also gave good performance with narrower FWHM of 0.88° and reflection spectra of 89.2%.
    Matched MeSH terms: Biosensing Techniques/instrumentation*
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