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  • Publication
    Integration of bacteria-imprinted polymer with aluminium transducers: polymeric electrical behaviour to ionic species
    (Elsevier, 2025-06)
    Sing-Mei Tan
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    Mohd Luqman Hakim Abdul Ghani
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    Hemavathi Krishnan
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    Jia-Chun Lim
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    Emily M.Y. Chow
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    Pachaiappan Raman
    Background: Confronted with escalating public health issues exacerbated by bacterial infections, introducing a cost-effective and reliable approach for rapid bacteria detection is imperative. Methods: In this research, bacteria-imprinted polymers (BIPs) technology targeting Bacillus subtilis was developed and characterised with Raman Spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The BIPs were then incorporated into our newly designed capsula capacitive proximity electrode (CapCPE) sensor. Successful deposition of BIPs was validated by scanning electron microscopy (SEM), while the average thickness of the BIP coating was recorded as ∼ 3.0 µm. The current responses of both the bare device and BIP-CapCPE to different pH levels were examined. Significant Findings: The results revealed that the bare device generated a maximum current of 7.55×10−4 A in a highly acidic medium. In contrast, the BIP-coated device exhibited a maximum current of 1.0 × 10−4 A in a highly alkaline medium, attributed to increased charge carrier density from the carboxyl group deprotonation in recognition cavities. Moreover, the mechanistic insights into the impact of strong electrolytes on BIP-coated electronic sensors were further proposed and elucidated. Electrochemical impedance spectroscopy (EIS) was additionally employed to reveal the impedimetric and capacitive behaviours of the devices in varied pH media.
  • Publication
    Augmented sensitivity in electrolyte determination for sweat analysis: Rapid amperometric quantification by self-induced gold nanorods aggregation
    (Elsevier, 2025-03)
    Jia-Chun Lim
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    Sing-Mei Tan
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    Emily M.Y. Chow
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    Yeng Chen
    Background: In this research, different strategies for leveraging gold nanorods (GNRs) were proposed to augment the sensitivity of a fabricated aluminum interdigitated electrodes (IDE) biosensor for detecting sodium chloride (NaCl) at millimolar concentrations. Methods: The sensitivity of the electronic biosensor in detecting NaCl was evaluated by examining the linear relationships between current changes and salt concentrations established at specific voltages. Significant Findings: The results presented that current signals were enhanced when incorporating the catalysts into the detection. At 2.0 V, the biosensor whose surface was functionalized with immobilized GNRs generated prominent electrical responses, with a sensitivity value of 0.0596 mA mM−1 cm−2. However, the performance of NaCl quantification recorded a further enhancement of 87.92 % when the mixture consisting of aggregated GNRs induced by the NaCl sample was pipetted onto the bare biosensor. The mechanisms for both application strategies of GNRs were introduced and discussed. This study provides insight into the detection of low concentrations of NaCl and potentially contributes to the ‘sweat test’ for screening health complications, such as cystic fibrosis (CF)
  • Publication
    Binding dynamics and conformational stability of graphene-based nanomaterials with Mutant LOX-1: Insights from molecular docking and dynamics simulations in atherosclerosis
    (Springer, 2024-12)
    Farizah Hanim Lat
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    Ahmad Naqib Shuid
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    Mohd Yusmaidie Aziz
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    Rafeezul Mohamed
    Oxidized low-density lipoprotein (oxLDL) is a critical factor in endothelial dysfunction and serves as an important biomarker for oxidative stress. Recent research has focused on lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a receptor for oxLDL that plays a significant role in atherosclerosis progression. Mutant LOX-1 may show changes in its binding affinity for oxLDL, potentially leading to variations in oxLDL uptake and foam cell formation. Our previous investigation into graphene-based nanomaterials and their interactions with atherosclerosis-related proteins, including LOX-1, provided important insights into their binding characteristics. In this study, we delve deeper into the binding dynamics between graphene-based nanomaterials and mutant LOX-1, aiming to clarify their implications for atherosclerotic development. Using molecular docking techniques with AutodockVina and active site predictions from P2Rank, we evaluated the binding affinities of graphene, graphene oxide (GO), and reduced graphene oxide (rGO) to mutant LOX-1. Notably, all docking scores were below -5 kcal/mol, indicating strong interactions with the receptor. To investigate the dynamics of these interactions further, we performed molecular dynamics (MD) simulations using the CHARMM force field. Our simulations revealed significant conformational changes within the first 100 ns, particularly in the mutant LOX-1 and GO complex, which suggested improved binding stability. These results enhance our understanding of how graphene-based nanomaterials interact with mutant forms of LOX-1, offering potential avenues for targeted therapies in atherosclerosis management related to LOX-1 dysregulation.
  • Publication
    Selective detection of alpha synuclein amyloid fibrils by faradaic and non-faradaic electrochemical impedance spectroscopic approaches
    (Elsevier B.V., 2025-02)
    Hussaini Adam
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    Hemavathi Krishnan
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    Makram A. Fakhri
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    Evan T. Salim
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    A. Shamsher
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    Sreeramanan Subramaniam
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    Yeng Chen
    This study utilized faradaic and non-faradaic electrochemical impedance spectroscopy to detect alpha synuclein amyloid fibrils on gold interdigitated tetraelectrodes (AuIDTE), providing valuable insights into electrochemical reactions for clinical use. AuIDE was purchased, modified with zinc oxide for increased hydrophobicity. Functionalization was conducted with hexacyanidoferrate and carbonyldiimidazole. Faradaic electrochemical impedance spectroscopy has been extensively explored in clinical diagnostics and biomedical research, providing information on the performance and stability of electrochemical biosensors. This understanding can help develop more sensitive, selective, and reliable biosensing platforms for the detection of clinically relevant analytes like biomarkers, proteins, and nucleic acids. Non-faradaic electrochemical impedance spectroscopy measures the interfacial capacitance at the electrode–electrolyte interface, eliminating the need for redox-active species and simplifying experimental setups. It has practical implications in clinical settings, like real-time detection and monitoring of biomolecules and biomarkers by tracking changes in interfacial capacitance. The limit of detection (LOD) for normal alpha synuclein in faradaic mode is 2.39-fM, The LOD for aggregated alpha synuclein detection is 1.82-fM. The LOD for non-faradaic detection of normal alpha synuclein is 2.22-fM, and the LOD for nonfaradaic detection of aggregated alpha synuclein is 2.40-fM. The proposed EIS-based AuIDTEs sensor detects alpha synuclein amyloid fibrils and it is highly sensitive.
  • Publication
    Microwave welding with SiCNW/PMMA nanocomposite thin films: enhanced joint strength and performance
    (Institute of Physic, 2025-01)
    Phey Yee Foong
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    ; ;
    Foo Wah Low
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    ; ; ;
    Veeradasan Perumal
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    Most previously reported susceptors for microwave welding are in powder form. In this study, a thin-film susceptor was employed due to its uniform heating rate and ease of handling. Silicon carbide nanowhisker (SiCNW) were incorporated into a poly(methyl methacrylate) (PMMA) matrix to create a nanocomposite thin film, which served as the susceptor. The microwave welding process involved three straightforward steps: fabrication of the PMMA/SiCNW nanocomposite thin film, application of the nanocomposite film to the target area, and subsequent microwave heating. Upon cooling, a robust microwave-welded joint was formed. The mechanical properties and microstructure of the welded joints were characterized using single-lap shear tests, three-point bending tests, and scanning electron microscopy. Results demonstrated that the shear strength and elastic modulus of the welded joints were optimized with increased heating time and SiCNW filler loading. This optimization is attributed to the formation of a SiCNW-filled polypropylene (PP) nanocomposite layer of increasing thickness at the welded joint interface. However, the incorporation of SiCNW also constrained the mobility of the PP chains, reducing the joint’s flexibility. Furthermore, the welded joint formed with the PMMA/SiCNW nanocomposite thin-film susceptor exhibited an 18.82% improvement in shear strength compared to joints formed with a powdered SiCNW susceptor. This study not only demonstrates the potential of PMMA/SiCNW nanocomposite thin films as efficient susceptors for microwave welding but also paves the way for developing high-performance polymer-based composite joints with improved mechanical properties for applications in the automotive, aerospace, and construction industries.