Now showing 1 - 10 of 45
  • Publication
    Molecular-imprinting assisted polydopamine-aptasensor on carbon and gold nanomaterials construct for the haemophilia B biomarker detection
    ( 2024-06)
    Hemavathi Krishnan
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    ; ;
    Makram A. Fakhri
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    Evan T. Salim
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    Narendra Patil
    The study presents a comprehensive approach for enhancing the performance of a spiral micro-interdigitated electrode (spiral-μIDE) sensor for the detection of FIX protein. Electropolymerization using dopamine resulted in a molecular-imprinted polymer (polyDOP-μIDE-MIP) layer, which encapsulated the aptamer-FIX complex and was later leached to create cavities. Cyclic and linear-sweep voltammetry techniques were utilized for the MIP development and rebinding assessment. Linear sweep voltammetry demonstrated a linear relationship between FIX concentration and peak current reduction, with a limit of detection (LOD) of 0.250 picomolar. The sensor's sensitivity was determined as 2.613E-10 A.fM-1.μm-2. This work highlights the importance of nanomaterials integration, and electropolymerization in improving sensor performance. The integration of carbon and gold nanomaterials and the use of molecular imprinting contribute to the sensor's enhanced sensitivity and selective detection of FIX protein.
  • Publication
    Arthropods-mediated green synthesis of Zinc oxide nanoparticles using cellar spider extract a biocompatible remediation for environmental approach
    ( 2024-06) ; ;
    M. A. R. Irfan
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    ; ; ;
    MRM Huzaifah
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    Maimunah Mohd Ali
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    Nur Hulwani Ibrahim
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    Muaz Mohd Zaini Makhtar
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    ; ; ; ; ;
    Mahfuz Affif Mohd Ruslan
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    This study presents an eco-friendly approach to synthesizing zinc oxide nanoparticles (ZnO NPs) using extracts from cellar spiders, addressing environmental and health concerns associated with conventional methods. The spider extract efficiently reduced zinc acetate dihydrate, and the synthesized ZnO NPs underwent comprehensive quantitative characterization, including size, shape, morphology, surface chemistry, thermal stability, and optical properties using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), zeta potential measurements, thermogravimetric analysis (TGA), and UV-vis spectroscopy. The nanoparticles exhibited intended characteristics, and their adsorption capability for methylene blue (MB) was quantitatively assessed using the Freundlich isotherm model and pseudo-second-order kinetic model, providing numerical insights into MB removal efficiency. The study demonstrates the potential of these green-synthesized ZnO NPs for applications in environmental remediation, wastewater treatment, and antibacterial therapies, contributing to both sustainable nanomaterial development and quantitative understanding of their functional properties.
  • Publication
    Silica and graphene mediate arsenic detection in mature rice grain by a newly patterned current–volt aptasensor
    ( 2021)
    M. N. A. Uda
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    ; ;
    N. H. Halim
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    N. A. Parmin
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    M. N. Afnan Uda
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    ;
    Periasamy Anbu
    Arsenic is a major global threat to the ecosystem. Here we describe a highly accurate sensing platform using silica nanoparticles/graphene at the surface of aluminum interdigitated electrodes (Al IDE), able to detect trace amounts of arsenic(III) in rice grain samples. The morphology and electrical properties of fabricated Al IDEs were characterized and standardized using AFM, and SEM with EDX analyses. Micrometer scale Al IDEs were fabricated with silicon, aluminum, and oxygen as primary elements. Validation of the bare Al IDE with electrolyte fouling was performed at different pH levels. The sensing surface was stable with no electrolyte fouling at pH 7. Each chemical modification step was monitored with current–volt measurement. The surface chemical bonds were characterized by fourier transform infrared spectroscopy (FTIR) and revealed different peaks when interacting with arsenic (1600–1000 cm−1). Both silica nanoparticles and graphene presented a sensitive limit of detection as measured by slope calibration curves at 0.0000001 pg/ml, respectively. Further, linear regression was established using ΔI (A) = 3.86 E−09 log (Arsenic concentration) [g/ml] + 8.67 E−08 [A] for silica nanoparticles, whereas for graphene Y = 3.73 E−09 (Arsenic concentration) [g/ml] + 8.52 E−08 on the linear range of 0.0000001 pg/ml to 0.01 pg/ml. The R2 for silica (0.96) and that of graphene (0.94) was close to the maximum (1). Modification with silica nanoparticles was highly stable. The potential use of silica nanoparticles in the detection of arsenic in rice grain extract can be attributed to their size and stability.
  • Publication
    Analysis on silica and graphene nanomaterials obtained from rice straw for antimicrobial potential
    This study focuses on the encapsulation of silica and graphene nanoparticles and their potential applications. The encapsulation enhances the properties and effectiveness of these nanoparticles, with silica providing stability and graphene contributing to high surface area and electrical conductivity. Characterization of silica-graphene nanoparticles was conducted using various techniques including High Power Microscope (HPM), Scanning Electron Microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS), and 3D Nano Profiler. The antimicrobial activity of silica, graphene, and silica-graphene nanoparticles was evaluated using a disc diffusion assay against E. coli and B. subtilis at varying concentrations. Results showed significant antimicrobial activity, with the inhibition zone being directly proportional to the concentration. Silica-graphene nanoparticles demonstrated higher efficacy against E. coli compared to B. subtilis, attributed to differences in cell wall structure. Statistical analysis using ANOVA confirmed significant differences in antimicrobial activity among the tested components.
  • Publication
    Integration of microfluidic channel on electrochemical-based nanobiosensors for monoplex and multiplex analyses: An overview
    ( 2023-05-01)
    Adam H.
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    ; ; ; ; ;
    Fakhri M.A.
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    Subramaniam S.
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    Chen Y.
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    Sasidharan S.
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    Wu Y.S.
    Background: Microfluidic devices have evolved into low-cost, simple, and powerful analytical tool platforms. Herein, an electrochemically-based microfluidic nanobiosensor array for monoplex and multiplex detection of physiologically relevant analytes is reviewed. Unlike other analyte detection methods, microfluidics-based embedded electrochemical nanobiosensors are portable, custom electrochemical readers for signal reading. Methods: Microfluidic devices and electrochemical sensors can be integrated into monoplex or multiplex systems. The integrated system is simple to use and sensitive, and so has great potential as a powerful tool for profiling immune-mediated treatment responses in real time. It may also be developed further as a point-of-care diagnostic device for conducting near-patient tests using biological samples. Therefore, using mutiplex analysis, a biosensor array may detect multiple analytes in a sample solution and provide different outputs for each analyte. A microfluidic electrochemical nanobiosensor, for example, can detect urine glucose, lactate, and uric acid. The microfluidic array of integrated nanobiosensors and electrochemical sensors enables fast and cost-effective selection of high-quality and statistically significant diagnostic data at the point of care. The multiplex analytical test is an important molecular tool for academic research as well as clinical diagnosis. Although key approaches for analysing numerous analytes have been developed, none of them are suitable for point-of-care diagnostics, especially in situations with limited resources. Significant findings: In this study, monoplex and multiplex microfluidic assays for rapid measurement of single and multiple analytes at the point of care are presented. Since this test can analyse both single and multiple analytes, it is exceptionally specific, easy to use, and inexpensive. The ability of integrated electrochemical-based microfluidic devices with single channel and multiple channels systems to perform monoplex and multiplex analysis simultaneously and independently is the novelty of this review.
      2
  • Publication
    Plant-based green synthesis of silver nanoparticle via chemical bonding analysis
    ( 2023-01-01)
    Azwatul H.M.
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    ; ;
    Arsat Z.A.
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    Abdullah F.
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    Muttalib M.F.A.
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    Hashim M.K.R.
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    ; ;
    Uda M.N.A.
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    Radi Wan Yaakub A.
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    Ibrahim N.H.
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    Parmin N.A.
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    Nanotechnology that involves the biological synthesis of nanoparticles is a relatively recent subject with advantages over chemical and physical synthesis procedures with respect to the economics and the environment. This study is the first to use the brown sea algae Sargassum muticum (S. muticum) as a reducing agent to generate nanostructured silver particles (AgNP). Using FTIR, XRD, and UV–vis spectroscopy, the structure, shape, and optical features of the synthesized nanoparticles have been exhaustively characterized. Using a UV–visible spectrophotometer, a clear absorption peak at 390 nm demonstrated the synthesis of AgNP. By crystallizing chemicals, nanoparticles were formed. The XRD pattern validated the results.
      1  10
  • Publication
    Magnetic induction tomography for brain tissue imaging based on conductivity distribution for parkinson’s disease diagnosis
    Parkinson's disease is a prevalent neurodegenerative complication defined by the accumulation of alpha synuclein lewy bodies in the brain. Misdiagnosis results widespread of Parkinson’s disease because clinical diagnosis is challenging, underlining a need of a better detection technique, such as non-invasive magnetic induction tomography (MIT) technique. Non-invasive techniques for biological tissues imaging are becoming popular in biomedical engineering field. Therefore, MIT technology as a non-invasive technique has been encouraged in a medical field due to its advancement of technology in diagnosing diseases. The measurement parameters in MIT are passive electromagnetic properties (conductivity, permittivity, permeability) for biological tissue and the most dominant parameter in MIT is conductivity properties. It is uses a phase shift between a primary magnetic field and an induced field caused by a target object's conductivity. As a function of conductivity, the phase shift between the applied and secondary fields is expressed. Thus, the phase shift can be used to characterize the conductivity of a target object. The phase shift between the excitation and induced magnetic fields (EMF and IMF) reflects the change in conductivity in biological tissues. This paper focuses on the virtual simulation by using COMSOL Multi-physics for the design and development of MIT system that emphasizes on single channel magnetic induction tomography for biological tissue (bran tissue) imaging based on conductivity distribution for Parkinson’s disease diagnosis. The develop system employs the use of excitation coils to induce an electromagnetic field (e.m.f) in the brain tissue, which is then measured at the receiving side by sensors. The proposed system is capable of indicating Parkinson’s disease based on conductivity distribution. This method provides the valuable information of the brain abnormality based on differences of conductivities of normal brain and Parkinson’s disease brain tissues.
      2  16
  • Publication
    Gold nanogap impedimetric biosensor for precise and selective Ganoderma boninense detection
    Ganoderma species are common wood-rotting fungi that cause root and stem rot in most monocots, dicots, and gymnosperms. It influences plantation crops such as oil palm and rubber in Malaysia, but the effects vary greatly within the genus. Because of the complex chemistry of Ganoderma, extracting and identifying the physiologically active chemicals is often time-consuming and necessitates extensive bioassays. This study investigated the specific identification of the most infectious Ganoderma species using a sub-20-nm gold electrode. Three electrodes were created using chemically controlled etching (2, 10, and 20 nm). An AutoCAD mask containing nanogap pad electrodes was used to create a chrome glass surface, which was then translated and built. Following the successful construction of the device, the sensor was evaluated using a combination of conventional photolithography and a size reduction technique to imprint the nanogap design onto the gold surface. Ganoderma boninense target DNA was synthesised and surface-modified to enable interaction at extremely low molecular concentrations. The proposed device has a detection limit of 0.001 mol/L, which is seven times lower than the detection limits of currently available devices. The capacitance, conductivity, and permittivity of complementary, non-complementary, single mismatched, and targeted biomolecules changed during hybridization. This sensor correctly differentiated between all samples. The sensor's performance is further validated by comparing experimental data from the sensor to theoretical data from the sensor's corresponding circuit model. The two data sets are very similar.
      3
  • Publication
    Comparative Analysis on Aluminium Interdigitated Electrode Surface: Influence of Ionic Strength and Electrolytes Changes
    ( 2024-06-01)
    Adam H.
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    ; ;
    Fakhri M.A.
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    Salim E.T.
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    The field of generating surface thin films in sensing applications is emerging, and the incorporation of thin film technology into sensor development for enhanced sensing is becoming increasingly significant in various industries such as healthcare, environmental monitoring, and food safety. However, in order to achieve higher specificity in biosensing, advances in nanomaterial biofunctionalization are crucial. This research focuses on the fabrication and characterization of nanobiosensors with surface modification using two different sensing materials: zinc oxide and gold nanorod nanocomposites. The aim of this study was to enhance the sensing capabilities of nanobiosensors by incorporating surface modification with different sensing materials. The fabrication of nanobiosensors involved using silicon as the base material and conventional photolithography to fabricate aluminium interdigitated electrodes with three different structures and gap sizes. AutoCAD software was utilized to create three different photo masks with varying gap sizes. Physical characterization of the fabricated ALIDEs was conducted using atomic force microscope, high power microscope, scanning electron microscope, and 3D-profilormeter. The electrical characterization of the ALIDEs was performed using a Keithley 6487 picoammeter. I-V measurements were conducted on bare ALIDEs as well as surface modified ALIDEs with zinc oxide and gold nanorod. I-V measurements were also performed for pH scouting. The I-V measurements on bare ALIDEs revealed that ALIDEs modified with gold nanorod conducted the least current compared to ALIDEs modified with zinc oxide. Furthermore, the ALIDEs modified with gold nanorod were found to be stable under various electrolytes environments after undergoing pH scouting.
      4