Now showing 1 - 3 of 3
  • 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
    ;
    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
    Cyclic and differential pulse voltammetric measurements on fibrils formation of alpha synuclein in Parkinson's disease by a gold interdigitated tetraelectrodes
    ( 2024-01-01)
    Adam Hussaini
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    Krishnan Hemavathi
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    Mohammed M.
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    Perumal V.
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    Fakhri M.A.
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    Salim E.T.
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    Raman P.
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    Subramaniam, Sreeramanan
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    Chen Y.
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    Sasidharan S.
    Parkinson's disease is a neurodegenerative disorder characterized by the aggregation and deposition of alpha-synuclein protein, which are pathological hallmarks. To understand the fibril formation of alpha-synuclein in Parkinson's disease, this study uses cyclic and differential pulse voltammetric measurements. These measurements analyze the electrochemical properties and behavior of alpha-synuclein during its fibril formation process. By applying a potential sweep or pulse to the alpha-synuclein sample, it is possible to gain insights into its redox activity and structural changes during fibril formation. This could lead to the development of therapeutic strategies to prevent or disrupt this pathological event in Parkinson's disease. To detect Parkinson's disease, a 15 nm sized gold conjugated antibody was used as the probe and seeded on gold interdigitated tetraelectrodes (AuIDTE). Alpha synuclein variations (fibriled and non-fibriled) were detected using phosphate-buffer saline and glycine buffer based on cyclic voltammetry and differential pulse voltammetry techniques. Discriminated by Tau protein measurement that was employed as a control. The linear regression for detecting alpha synuclein aggregation using differential pulse voltammetry was R2 = 0.9987 [y = 9E-06x - 4E-07], with a limit of detection of 10 aM, on a linear range of 1 aM-1 pM. Cyclic voltammetry determined the limit of detection of aggregated alpha synuclein to be 100 aM, with a linear relationship of R2 = 0.9939 [y = 7E-06x - 2E-06]. The sensor has excellent analytical performance in terms of detection limit, sensitivity, selectivity, repeatability, and stability.
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  • Publication
    Application of Nanobiosensor engineering in the diagnosis of neurodegenerative disorders
    (Elsevier, 2024)
    Thikra S. Dhahi
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    Alaa Kamal Yousif Dafhalla
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    A. Wesam Al-Mufti
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    ; ;
    Neurodegenerative diseases like Alzheimer's disease and Parkinson's disease are hard to diagnose and treat early. They are characterised by progressive loss of neuronal function and structure leading to crippling cognitive, motor and psychiatric impairments. In recent years, nanobiosensor engineering has emerged as a promising way to address the limitations of traditional diagnostic methods for neurodegenerative diseases. Nanobiosensors which combine nanotechnology and biosensing principles can detect disease specific biomarkers with high sensitivity and specificity to enable early and accurate diagnosis. One of the key advantages of nanobiosensors in diagnosing neurodegenerative diseases is their ability to detect and quantify specific proteins or molecules that are biomarkers for these conditions. For example, accumulation of amyloid beta peptides and hyperphosphorylation of tau protein are hallmarks of Alzheimer's disease. Nanobiosensors can be designed to selectively bind to these biomarkers providing rapid and non-invasive method for early disease detection. This enables more targeted and personalized treatment approaches. Furthermore, nanomaterials have shown potential in biosensing applications due to their unique physical, optical, and electrical properties. Their small size, large surface-to-volume ratio, and tunable properties enable them to interact with biological molecules in remarkable ways. One notable property is their ability to be functionalized with molecular beacons, reporter molecules, pacification layers, and targeting biomolecules, creating highly sensitive and specific biofunctional nanoprobes. This review aims to explore the promising role of nanobiosensor engineering in the early diagnosis and management of neurodegenerative disorders.