Now showing 1 - 10 of 12
  • Publication
    Field-Effect Transistor-based Biosensor Optimization: Single Versus Array Silicon Nanowires Configuration
    ( 2020-01-01)
    Ong C.C.
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    ; ; ; ; ;
    Rafizatul Fitri Abdullah
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    Mohd Hazmi Mohd Ghazali
    ;
    Tamjis N.
    This paper demonstrated the effect of different number of silicon nanowire transducer channels, in other word single, double, and triple channels towards the performance of field-effect transistor-based biosensor through simulation tool. These silicon nanowire field-effect transistor biosensors were designed and simulated in device simulation modelling tool, Silvaco ATLAS with fixed length, width, and height of the silicon nanowire. Different negatively interface charge density values were applied on the transducer channels’ surface of the biosensors to represent as detected target biomolecules that will bind onto the surface of the transducer regions. Based on the results, more negatively interface charges density values presented on the sensing channels had reduced the electron carrier accumulation at the channel’s interface, therefore, reduced drain current flow between the source and drain terminal. With the increase number of the transducer channels, significant change in drain current for every applied negatively interface charges became more apparent and increased the sensitivity of the biosensor. The triple transducer channels silicon nanowire field-effect transistor biosensor had demonstrated highest sensitivity, that is 2.83 µA/e∙cm2, which indicates it has better response for the detection of interface charges, thus increases chances for transducer channels reaction to the target biomolecules during testing or diagnosis.
  • Publication
    Facile electrical DNA genosensor for human papillomavirus (HPV 58) for early detection of cervical cancer
    ( 2023-07)
    F. Nadhirah Jaapar
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    ; ; ; ; ;
    Sh. Nadzirah
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    ; ;
    Wei Chern Ang
    ;
    Iffah Izzati Zakaria
    ;
    Zulida Rejali
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    Amilia Afzan
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    Azrul Azlan Hamzah
    ;
    Chang Fu Dee
    ;
    F. Syakirah Halim
    For decades, a Pap smear test has been applied as a conventional method in detecting Human Papillomavirus caused cervical cancer. False-positive results were also recorded while using it as conventional method. Current biosensor such as Hybrid (II) Capture resulted in higher time consumption and cost. s Meanwhile, in this study we provided facile, mini, rapid, highly sensitive, eco-friendly, and cost-effective sensing system focusing on HPV strain 58 (HPV58) in a nano-size lab-on-chip technology genosensor. 30-mer of virus ssDNA designed and analyzed as a probe via bioinformatics tools such as GenBank, Basic Local Alignment Searching Tools (BLAST) and ClustalW. Nanotechnology-developed colloidal Gold-nanoparticles (AuNPs) are used in the biosensor fabrication to produce high stability and electron efficient transmission during electrical measurement. AuNPs-APTES modified on active sites of IDEs, followed by immobilization of specific probe ssDNA for HPV 58. Hydrogen binding during hybridization with its target produce electrical signals measured by KEITHLEY 2450 (Source Meter). The genosensor validated with different types of targets such as complimentary, non-complementary and single mismatch oligonucleotides. The serial dilution of target concentration has been experimented triplicate (n=3) range from 1fM to 10μM. The slope of calibration curve resulted 2.389E-0 AM-1 with regression coefficient (R2) = 0.97535.
  • Publication
    Facile Electrical DNA Genosensor for Human Papillomavirus (HPV 58) for Early Detection of Cervical Cancer
    ( 2023-07-01)
    Jaapar F.N.
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    ;
    Halim N.H.A.
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    ; ; ;
    Nadzirah S.
    ;
    ; ;
    Ang W.C.
    ;
    Zakaria I.I.
    ;
    Rejali Z.
    ;
    Afzan A.
    ;
    Hamzah A.A.
    ;
    Dee C.F.
    ;
    Halim F.S.
    For decades, a Pap smear test has been applied as a conventional method in detecting Human Papillomavirus caused cervical cancer. False-positive results were also recorded while using it as conventional method. Current biosensor such as Hybrid (II) Capture resulted in higher time consumption and cost. s Meanwhile, in this study we provided facile, mini, rapid, highly sensitive, eco-friendly, and cost-effective sensing system focusing on HPV strain 58 (HPV58) in a nano-size lab-on-chip technology genosensor. 30-mer of virus ssDNA designed and analyzed as a probe via bioinformatics tools such as GenBank, Basic Local Alignment Searching Tools (BLAST) and ClustalW. Nanotechnology-developed colloidal Gold-nanoparticles (AuNPs) are used in the biosensor fabrication to produce high stability and electron efficient transmission during electrical measurement. AuNPs-APTES modified on active sites of IDEs, followed by immobilization of specific probe ssDNA for HPV 58. Hydrogen binding during hybridization with its target produce electrical signals measured by KEITHLEY 2450 (Source Meter). The genosensor validated with different types of targets such as complimentary, non-complementary and single mismatch oligonucleotides. The serial dilution of target concentration has been experimented triplicate (n=3) range from 1fM to 10µM. The slope of calibration curve resulted 2.389E-0 AM-1 with regression coefficient (R2) = 0.97535.
  • Publication
    Electrical simulation on silicon nanowire field-effect transistor biosensor at different substrate-gate voltage bias conditions for charge detection
    In this work, the impact of different substrate-gate voltage bias conditions (below and above the device threshold voltage) on current-voltage characteristics and sensitivity of a silicon nanowire field-effect transistor (SiNW-FET) biosensor was investigated. A 3-dimensional device structure with n-type SiNW channel and a substrate gate electrode was designed and electrically simulated In the Silvaco ATLAS. Next, the SiNW channel was covered with a range of interface charge density to mimic the charged target biomolecule captured by the device. The outcome was translated into a drain current versus interface charge semi-log graph and the device sensitivity was calculated using the linear regression curve’s slope of the plotted data. The device’s electrical characteristic shown higher generation of output drain current values with the increase of negative substrate-gate voltage bias due to the hole carriers’ accumulation that forms a conduction channel in the SiNW. Application of higher negative interface charge density increased the change in drain current, with the device biased with higher substrate-gate voltage shows more significant change in drain current. The device sensitivity increased when biased with higher substrate-gate voltage with highest sensitivity is 75.12 nA/dec at substrate-gate voltage bias of –1.00 V.
      3  62
  • Publication
    Formation of polypropylene nanocomposite joint using silicon carbide nanowhiskers as novel susceptor for microwave welding
    Up to present, no study has reported on the use of silicon carbide nanomaterials (SiCNMs) as susceptor for microwave welding of thermoplastics. Therefore, in this study, silicon carbide nanowhiskers (SiCNWs) was attempted as the microwave susceptor for the microwave welding of polypropylene (PP). It was observed that SiCNWs are capable of absorbing microwave and converting them into heat, leading to a sharp increase in temperature until it reaches the melting point of PP substrates. The microwave welded joint is formed after the molten PP at the interface between PP substrates is cooled under pressure. The effect of microwave heating duration and solid loading of SiCNWs suspension was studied and reported. The formation mechanism of SiCNWs reinforced PP welded joint was proposed in this study. With these remarkable advantages of microwave welding and enhanced mechanical properties of the welded joint, it is believed that this study can provide a new insight into welding of thermoplastic and material processing through short-term microwave heating.
      26  1
  • Publication
    Effective synthesis of silicon carbide nanotubes by microwave heating of blended silicon dioxide and multi-walled carbon nanotube
    Silicon carbide nanotube (SiCNTs) has been proven as a suitable material for wide applications in high power, elevated temperature and harsh environment. For the first time, we reported in this article an effective synthesis of SiCNTs by microwave heating of SiO2 and MWCNTs in molar ratio of 1:1, 1:3, 1:5 and 1:7. Blend of SiO2 and MWCNTs in the molar ratio of 1:3 was proven to be the most suitable for the high yield synthesis of β-SiCNTs as confirmed by X-ray diffraction pattern. Only SiCNTs were observed from the blend of MWCNTs and SiO2 in the molar ratio of 1:3 from field emission scanning electron microscopy imaging. High magnification transmission electron microscopy showed that tubular structure of MWCNT was preserved with the inter-planar spacing of 0.25 nm. Absorption bands of Si-C bond were detected at 803 cm-1 in Fourier transform infrared spectrum. Thermal gravimetric analysis revealed that SiCNTs from ratio of 1:3 showed the lowest weight loss. Thus, our synthetic process indicates high yield conversion of SiO2 and MWCNTs to SiCNTs was achieved for blend of SiO2 and MWCNTs in molar ratio of 1:3.
      4  32
  • Publication
    Thickness dependent nanostructural, morphological, optical and impedometric analyses of Zinc Oxide-Gold hybrids : Nanoparticle to thin film
    ( 2015)
    Veeradasan Perumal
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    ; ;
    R. Haarindraprasad
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    ; ;
    S. R. Balakrishnan
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    V. Thivina
    ;
    ;
    Yogendra Kumar Mishra
    The creation of an appropriate thin film is important for the development of novel sensing surfaces, which will ultimately enhance the properties and output of high-performance sensors. In this study, we have fabricated and characterized zinc oxide (ZnO) thin films on silicon substrates, which were hybridized with gold nanoparticles (AuNPs) to obtain ZnO-Au x (x = 10, 20, 30, 40 and 50 nm) hybrid structures with different thicknesses. Nanoscale imaging by field emission scanning electron microscopy revealed increasing film uniformity and coverage with the Au deposition thickness. Transmission electron microscopy analysis indicated that the AuNPs exhibit an increasing average diameter (5–10 nm). The face center cubic Au were found to co-exist with wurtzite ZnO nanostructure. Atomic force microscopy observations revealed that as the Au content increased, the overall crystallite size increased, which was supported by X-ray diffraction measurements. The structural characterizations indicated that the Au on the ZnO crystal lattice exists without any impurities in a preferred orientation (002). When the ZnO thickness increased from 10 to 40 nm, transmittance and an optical bandgap value decreased. Interestingly, with 50 nm thickness, the band gap value was increased, which might be due to the Burstein-Moss effect. Photoluminescence studies revealed that the overall structural defect (green emission) improved significantly as the Au deposition increased. The impedance measurements shows an increasing value of impedance arc with increasing Au thicknesses (0 to 40 nm). In contrast, the 50 nm AuNP impedance arc shows an increased value compared to lower sputtering thicknesses, which indicated the presence of larger sized AuNPs that form a continuous film, and its ohmic characteristics changed to rectifying characteristics. This improved hybrid thin film (ZnO/Au) is suitable for a wide range of sensing applications.
      1  10
  • Publication
    Thickness dependent nanostructural, morphological, optical and impedometric analyses of Zinc Oxide-Gold Hybrids: Nanoparticle to thin film
    ( 2015)
    Veeradasan Perumal
    ;
    ; ;
    R. Haarindraprasad
    ;
    ; ;
    S. R. Balakrishnan
    ;
    V. Thivina
    ;
    The creation of an appropriate thin film is important for the development of novel sensing surfaces, which will ultimately enhance the properties and output of high-performance sensors. In this study, we have fabricated and characterized zinc oxide (ZnO) thin films on silicon substrates, which were hybridized with gold nanoparticles (AuNPs) to obtain ZnO-Aux (x = 10, 20, 30, 40 and 50 nm) hybrid structures with different thicknesses. Nanoscale imaging by field emission scanning electron microscopy revealed increasing film uniformity and coverage with the Au deposition thickness. Transmission electron microscopy analysis indicated that the AuNPs exhibit an increasing average diameter (5–10 nm). The face center cubic Au were found to co-exist with wurtzite ZnO nanostructure. Atomic force microscopy observations revealed that as the Au content increased, the overall crystallite size increased, which was supported by X-ray diffraction measurements. The structural characterizations indicated that the Au on the ZnO crystal lattice exists without any impurities in a preferred orientation (002). When the ZnO thickness increased from 10 to 40 nm, transmittance and an optical bandgap value decreased. Interestingly, with 50 nm thickness, the band gap value was increased, which might be due to the Burstein-Moss effect. Photoluminescence studies revealed that the overall structural defect (green emission) improved significantly as the Au deposition increased. The impedance measurements shows a decreasing value of impedance arc with increasing Au thicknesses (0 to 40 nm). In contrast, the 50 nm AuNP impedance arc shows an increased value compared to lower sputtering thicknesses, which indicated the presence of larger sized AuNPs that form a continuous film, and its ohmic characteristics changed to rectifying characteristics. This improved hybrid thin film (ZnO/Au) is suitable for a wide range of sensing applications.
      2  17
  • Publication
    Dielectric properties and microwave absorbing properties of silicon carbide nanoparticles and silicon carbide nanowhiskers
    Silicon carbide (SiC) is well known for their outstanding microwave absorbing properties. SiC nanomaterials (SiCNMs) are expected to have better microwave absorption performance due to their high specific surface area. To date, no study was reported to compare the dielectric properties and microwave absorbing properties of different type of SiCNMs. Therefore, the objective of this paper is to compare the dielectric properties and microwave absorption properties of different types of SiCNMs. In this paper, SiC nanoparticles (SiCNPs) and SiC nanowhiskers (SiCNWs) were characterised using SEM and XRD. In addition, their dielectric properties and microwave absorbing properties were measured using network analyser and transmission line theory. It was found that SiCNWs achieved higher dielectric constant and loss factor which are and εr’ =17.94 and εr″ = 2.64 compared to SiCNPs that only achieved εr’ = 2.83 and εr″ = 0.71. For microwave absorbing properties, SiCNWs and SiCNPs attained minimum reflection loss of -10.41 dB and -6.83 dB at 5.68 GHz and 17.68 GHz, respectively. The minimum reflection loss of SiCNPs and SiCNWs obtained in this study is much lower than the nanometer-SiC reported previously. These results suggested that SiCNWs can be an ideal candidate of microwave susceptors for various microwave applications
      1  13
  • Publication
    Designing DNA probe from HPV 18 and 58 in the E6 region for sensing element in the development of genosensor-based gold nanoparticles
    ( 2022-10-01)
    Jaapar F.N.
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    ; ; ; ;
    Halim F.S.
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    ; ; ;
    Muhammad Nur Afnan Uda
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    Nadzirah S.
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    Rejali Z.
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    Afzan A.
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    Zakaria I.I.
    The E6 region has higher protuberant probability annealing than consensus probe focusing on another region in the human papillomavirus (HPV) genome in terms of detection and screening method. Here, we designed the first multiple virus single-stranded deoxyribonucleic acid (ssDNA) for multiple detections in an early phase of screening for cervical cancer in the E6 region and became a fundamental evolution of detection electrochemical HPV biosensor. Gene profiling of the virus ssDNA sequences has been carried by high-end bioinformatics tools such as GenBank, Basic Local Alignment Searching Tools (BLAST), and Clustal OMEGA in a row. The output from bioinformatics tools resulted in 100% of similarities between our virus ssDNA probe and HPV complete genome in the databases. The cross-validation between HPV genome and our designed virus ssDNA provided high specificity and selectivity during screening methods compared with Pap smear. The DNA probe for HPV 18, 5′ COOH-GAT CCA GAA GGT ACA GAC GGG GAG GGC ACG 3′, while 5′COOH-GGG CGC TGT GCA GTG TGT TGG AGA CCC CGA3′ as DNA probe for HPV 58 designed with 66.77% guanine (G) and cytosine (C) content for both. Our virus ssDNA probe for the HPV biosensor promises high sensitivity, specificity, selectivity, repeatability, low fluid consumption, and will be useful in mini-size diagnostic devices for cervical cancer detection.
      1  52