Now showing 1 - 10 of 12
  • Publication
    Integration of Aluminium Interdigitated Electrodes with Zinc Oxide as Nanocomposite for Selectively Detect Alpha-Synuclein for Parkinson's Disease Diagnosis
    Parkinson's disease is associated with motor and non-motor symptoms, mostly a motor symptom such as tremor is said to be an early indication for Parkinson's disease development. Because of higher demands for faster and more precise diagnostic methods, it has sparked trends in the development of a biosensor for the diagnosis of Parkinson's disease. Therefore, this study has fabricated a biosensor that is capable of detecting a specific Parkinson's disease biomarker such as aggregation of alpha synuclein and this is crucial in reducing the burden of Parkinson's disease and to be able to detect the disease at the earlier stage. Finding the inconsistent aggregation of alpha-synuclein is a promising method for the early detection of Parkinson's disease. Using conventional photographic process, aluminium interdigitated electrodes (ALIDEs) have been fabricated and employed with sensitive electrochemical strategy for the specific detection of the Parkinson's disease antigen (alpha synuclein). The microelectrode was developed based on aluminium electrode sputtered on silicon substrate. Further, zinc oxide (ZnO) was deposited by sputtering on the working electrode of the ALIDEs using a spin-coating method. The ZnO nanocomposite onto aluminium microelectrode surface provides a favourable platform for efficient loading of antibody via binding with antigen alpha synuclein. The effective loading of the biomolecules (antibody and antigen) on the ZnO nanocomposite surface modified aluminium microelectrode was observed by SEM, AFM and 3D Profilometer. The current flow for each concentration of alpha synuclein was observed at 7.5×10−6 A (10 fM), 8.8×10−6 A (100 fM), and 8.5×10−6 A (1 pM) respectively.
  • Publication
    MicroRNA of N-region from SARS-CoV-2: Potential sensing components for biosensor development
    ( 2022-08-01)
    Halim F.S.
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    ; ; ;
    Dahalan F.A.
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    Zakaria I.I.
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    Ang W.C.
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    Jaapar N.F.
    An oligonucleotide DNA probe has been developed for the application in the DNA electrochemical biosensor for the early diagnosis of coronavirus disease (COVID-19). Here, the virus microRNA from the N-gene of severe acute respiratory syndrome-2 (SARS-CoV-2) was used for the first time as a specific target for detecting the virus and became a framework for developing the complementary DNA probe. The sequence analysis of the virus microRNA was carried out using bioinformatics tools including basic local alignment search tools, multiple sequence alignment from CLUSTLW, microRNA database (miRbase), microRNA target database, and gene analysis. Cross-validation of distinct strains of coronavirus and human microRNA sequences was completed to validate the percentage of identical and consent regions. The percent identity parameter from the bioinformatics tools revealed the virus microRNAs’ sequence has a 100% match with the genome of SARS-CoV-2 compared with other coronavirus strains, hence improving the selectivity of the complementary DNA probe. The 30 mer with 53.0% GC content of complementary DNA probe 5′ GCC TGA GTT GAG TCA GCA CTG CTC ATG GAT 3′ was designed and could be used as a bioreceptor for the biosensor development in the clinical and environmental diagnosis of COVID-19.
  • Publication
    Impact of buried oxide thickness in substrate-gate integrated silicon nanowire field-effect transistor biosensor performance for charge sensing
    The paper investigated on performance in charge sensing for substrate-gate integrated silicon nanowire field-effect transistor biosensor at different thickness of the buried oxide layer, sandwiched in between the top-silicon and substrate layers. The device structures with different buried oxide thickness ranging from 100 to 200 nm were designed and simulated using the Silvaco ATLAS device simulation software. The increase of buried oxide thickness reduced the strength of induced electric field that contributes to the formation of inversion layer for current flow through the silicon nanowire channel, hence contributed to the increase in threshold voltage. For simulation of charge sensing, the device demonstrated the ability to identify different interface charge values ranging from -5×1010 to -9×1010 e· cm-2 applied on the surface of the silicon nanowire channel to represent target charge biomolecules that bound to the biosensor in actual detection. Significant change in threshold voltage can be observed due to the applied interface charge density values and was evaluated to determine the sensitivity for charge sensing performance. The device shows better performance when designed with buried oxide thickness of 200 nm at sensitivity of 1.151 V/e· cm-2.
  • 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.
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    ; ;
    Ang W.C.
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    Zakaria I.I.
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    Rejali Z.
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    Afzan A.
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    Hamzah A.A.
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    Dee C.F.
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    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
    Annealing Effects on Polycrystalline Silicon Germanium (SiGe) Thin Films grown on Nanostructured Silicon Substrates using Thermal Evaporation Technique
    ( 2022-10-01) ;
    Eop T.S.
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    Sopian K.
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    Zaidi S.H.
    Polycrystalline SiGe thin films have been formed after thermal annealing of formerly vacuum evaporated a-Ge layers. The a-Ge thin films were deposited onto nanostructured Si substrates via low-cost thermal evaporation method. Then, the films were annealed in a furnace at temperatures ranging from 400 °C to 1000 °C resulting in crystal growth of the SiGe layers. In general, the annealing temperature for polycrystalline SiGe is between 600 °C – 800 °C. The crystalline structure of the SiGe layer is improved as a function of increased temperature. This is shown by the low FWHM of about 5.27 as compared to the commercially available Ge substrates where the FWHM value is about 5.06. This method also produces more relax Ge layer where the strain value is 0.261.
      30  2
  • Publication
    Potentials of MicroRNA in Early Detection of Ovarian Cancer by Analytical Electrical Biosensors
    ( 2022-01-01) ; ; ;
    Nadzirah S.
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    Salimi M.N.
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    ; ;
    Muhammad Nur Afnan Uda
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    Rozi S.K.M.
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    Rejali Z.
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    Afzan A.
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    Azan M.I.A.
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    Yaakub A.R.W.
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    Hamzah A.A.
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    Dee C.F.
    The importance of nanotechnology in medical applications especially with biomedical sensing devices is undoubted. Several medical diagnostics have been developed by taking the advantage of nanomaterials, especially with electrical biosensors. Biosensors have been predominantly used for the quantification of different clinical biomarkers toward detection, screening, and follow-up the treatment. At present, ovarian cancer is one of the severe complications that cannot be identified until it becomes most dangerous as the advanced stage. Based on the American Cancer Society, 20% of cases involved in the detection of ovarian cancer are diagnosed at an early stage and 80% diagnosed at the later stages. The patient just has a common digestive problem and stomach ache as early symptoms and people used to ignore these symptoms. Micro ribonucleic acid (miRNA) is classified as small non-coding RNAs, their expressions change due to the association of cancer development and progression. This article reviews and discusses on the currently available strategies for the early detection of ovarian cancers using miRNA as a biomarker associated with electrical biosensors. A unique miRNA-based biomarker detections are specially highlighted with biosensor platforms to diagnose ovarian cancer.
      1  43
  • 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
    Design and fabrication of PDMS microfluidics device for rapid and label-free DNA detection
    Microfluidics explores the manipulation of fluid in small volume, a multidisciplinary field is imperative for DNA extraction. This study offers a simple yet substantial methodology for the fabrication of microfluidics structure-based polydimethylsiloxane (PDMS) biopolymer on a glass substrate with SU-8 photoresist for label-free detection of pathogenic genomic DNA. Two microfluidics designs for DNA detection were based on AutoCAD software, both contain two inlets and one outlet, with dimensions of 28 mm wide, and 18 mm long, and total surface area of 504 mm2. The designs were patterned in such particular sizes and dimensions to test fluid delivery and enhancement in biochemical processes in DNA extraction, while maintaining economical values as a disposable chip. Both microfluidics devices showed no leakage during fluid delivery, have heights of 97.97 and 103.44 Î¼m, and surface roughness of 0.15 and 0.07 Î¼m, respectively. DNA extraction from pathogenic fungus Ganoderma boninense was run on PDMS microfluidic device and UV–Vis analysis confirmed successful extraction with peaks found at 260–280 nm. Current–voltage (I–V) measurement confirmed the accuracy of microfluidic device for the specific pathogen with both real and synthetic samples of G. boninense illustrating the similar graph values of only 0.000005 A difference at 1.0 V after hybridization.
      1  15
  • Publication
    Automated, high-throughput DNA extraction protocol for disposable label free, microfluidics integrating DNA biosensor for oil palm pathogen, Ganoderma boninense
    Basal Stem Rot and Upper Stem Rot diseases caused by pathogenic fungus Ganoderma boninense continue to be a major plight in the palm oil industry. Despite continuous research in combating the problem, resolution remains stagnant. Here, developed an automated, high-throughput DNA extraction protocol on microfluidics device for a quick, disposable, label-free detection, within 2 h of assessment. Microfluidics was designed using AutoCAD software, fabricated on microscopic glass substrate using negative photoresist (SU-8 2015) and molded with a biopolymer silicone, Polydimethylsiloxane. G. boninense and unknown pathogenic fungus isolated from rotten mushroom were grown and fractions of extracted DNA were pooled and analyzed for comparison along with synthetic ssDNA of G. boninense. Results from LPM and HPM show successful fabrication with ≤0.1 mm variance between the dimensions in the design before and after lithography process. The PDMS microfluidics show no leakage when run with DNA samples. Analyses from I-V measurement, UV–vis, FTIR, and PCR show comparable results between extracted and synthetic ssDNA of G. boninense and a contrast with the unknown pathogenic fungus, indicating a successful DNA extraction protocol via microfluidics for label-free identification of G. boninense. Optimization of DNA extraction can be further devised for applicability on lab-on-a-chip devices.
      2  2
  • 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