Electrical and Electronic Engineering, Biophysics, Bioengineering, Surfaces, Coatings and Films
99
Scopus Publications
Scopus Publications
Surface Functionalized Plasmonic Sensors for Uric Acid Detection With Gold-Graphene Stacked Nanocomposites Olabisi Abdullahi Onifade, Dinie Dayana Mohamad Azri, Muhammad Hafiz Abu Bakar, Mohammed Thamer Alresheedi, Eng Khoon Ng, Mohd Adzir Mahdi, Ahmad Shukri Muhammad Noor Photonic Sensors, 2025 This study presented a surface-functionalized sensor probe using 3-aminopropyltriethoxysilane (APTES) self-assembled monolayers on a Kretschmann-configured plasmonic platform. The probe featured stacked nanocomposites of gold (via sputtering) and graphene quantum dots (GQD, via spin-coating) for highly sensitive and accurate uric acid (UA) detection within the physiological ranges. Characterization encompassed the field emission scanning electron microscopy for detailed imaging, energy-dispersive X-ray spectroscopy for elemental analysis, and Fourier transform infrared spectroscopy for molecular identification. Surface functionalization increased sensor sensitivity by 60.64%, achieving 0.0221 °/(mg/dL) for the gold-GQD probe and 0.035 5 °/(mg/dL) for the gold-APTES-GQD probe, with linear correlation coefficients of 0.8249 and 0.8509, respectively. The highest sensitivity was 0.070 6 °/(mg/dL), with a linear correlation coefficient of 0.993 and a low limit of detection of 0.2 mg/dL. Furthermore, binding affinity increased dramatically, with the Langmuir constants of 14.29 µM −1 for the gold-GQD probe and 0.000 1 µM −1 for the gold-APTES-GQD probe, representing a 142 900-fold increase. The probe demonstrated notable reproducibility and repeatability with relative standard deviations of 0.166% and 0.013%, respectively, and exceptional temporal stability of 99.66%. These findings represented a transformative leap in plasmonic UA sensors, characterized by enhanced precision, reliability, sensitivity, and increased surface binding capacity, synergistically fostering unprecedented practicality.
Impact of diameter on D-shaped POF sensors for salt detection Abdul Ali Khan, Punithavathi M. Thirunavakkarasu, Norazlina bte Saidin, Ahmad Shukri Muhammad Noor, Nawaf Waqas Journal of Physics Conference Series, 2025 This study investigates the relationship between the diameter of a D-shaped plastic optical fiber (POF) sensor and its optical response as a function of varying salt concentrations. A simple and efficient dry etching polishing technique was employed to create D-shaped POF sensors with a range of diameters. All the fabricated sensors were carefully developed to maintain a consistent length of 20 cm with a sensing region of 1cm. To evaluate the optical intensity response, each sensor, with its respective diameter, was examined with the salt concentration ranging from (0 to 5%) examination utilizing a spectrometer. The sensor response was characterized by quantifying the variations observed in the intensity of the optical signal propagating through the sensing region. The sensors having a diameter of 500 μm, 700 μm, and 900 μm had a sensitivity of 149 A.U/%salt, 66 A.U/%salt, and 11.2 A.U/%salt respectively. The sensitivity of the 500 μm diameter sensor increased 13 times approximately as compared to the sensor having diameter of 900 μm.
Hybrid SPR-LSPR Uric Acid Sensor: An Innovative Framework for Ultrasensitive, Selective, and Stable Biomolecular Detection Olabisi Abdullahi Onifade, Mundzir Abdullah, Muhammad Hafiz Abu Bakar, Mohd Adzir Mahdi, Ahmad Shukri Muhammad Noor IEEE Sensors Letters, 2025 Accurate and sensitive biomarker detection is vital for modern diagnostics, especially in point-of-care testing (POCT), where real-time analysis is essential. Uric acid (UA), a key indicator of metabolic disorders including gout, nephropathy, and cardiovascular disease, requires precise quantification across physiologically relevant ranges in complex matrices. Conventional UA detection methods suffer from instability, poor selectivity, and susceptibility to interference. This study presents an innovative non-enzymatic hybrid surface plasmon resonance–localized surface plasmon resonance (SPR-LSPR) sensor that combines the long-range sensitivity of SPR with the near-field enhancement of LSPR. The platform incorporates a nanostructured gold-3-aminopropyltriethoxysiane-gold nanoparticle-graphene quantum dots (Au-APTES-AuNP-GQD) matrix, leveraging gold thin films, amine-functionalized AuNP, and GQD to enhance plasmonic confinement and molecular recognition. Structural and optical characterizations confirmed its nanoscale integrity. The sensor achieved a sensitivity of 0.1828°/(mg/dL), a low detection limit of 0.1658 mg/dL, and linearity (R² = 0.8655) across a 1–9 mg/dL UA physiological range. It demonstrated high selectivity, with a 1.1757° shift and 90.1% relative response to UA in the presence of common interferents. This label-free, real-time, and scalable sensor is highly suited for POCT and continuous UA monitoring, with modular adaptability for broader clinical biomarker detection.
An IoT-Based Hygiene Monitoring System in the Restroom F. I. Azman, N. L. Saleh, F. Hashim, A. Sali, A. M. Ali, A. S. M. Noor IEEE Access, 2025 Public restroom hygiene is a critical factor influencing public health and user comfort. Traditional maintenance approaches, which rely on manual labour and fixed cleaning schedules, are often inefficient and costly, requiring janitors regardless of actual conditions. This research presents an Internet of Things (IoT)-based restroom hygiene monitoring system designed to optimise cleaning by dispatching staff only when hygiene thresholds are exceeded, particularly during periods of elevated ammonia levels and poor Indoor Air Quality (IAQ). The system enables remote, continuous cleanliness assessment by monitoring ammonia levels and analyzing IAQ through humidity and gas resistance metrics. Alerts are triggered based on correlations among humidity, temperature, and occupancy data, enabling timely interventions. The system utilises the InfluxDB time-series database and the Message Queuing Telemetry Transport (MQTT) protocol over Wi-Fi to support real-time monitoring and long-term trend analysis, providing actionable insights for effective hygiene management. A five-month focused analysis within a two-year monitoring period (January 2023 to December 2024) revealed ammonia concentration spikes ranging from 0 ppm to 13 × 10¹² ppm. These peaks were linked to sewer issues and cleaning without detergent, while poor IAQ levels (up to 466 × 10³ ppm) were associated with excessive use of detergent and air fresheners. Statistical analysis revealed a strong inverse correlation (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> = –0.91) between humidity and temperature regarding ammonia, as well as a moderate inverse correlation (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</i> = –0.45) between humidity and gas resistance. Despite 274 users recorded in a single day, effective ventilation was maintained at safe ammonia levels. These findings suggest that overuse of cleaning agents may worsen air quality. The study demonstrates the potential of IoT-enabled systems for responsive, data-driven, and cost-effective restroom hygiene management.
Salivary Uric Acid Detection with Graphene-Gold Bilayers Surface Plasmon Resonance Olabisi Abdullahi Onifade, Zal-Hazmi Bin Mohammad Zin, Muhammad Hafiz Bin Abu Bakar, Mohammed Thamer Alresheedi, Mohd Adzir Mahdi, Ahmad Shukri Bin Muhammad Noor IEEE Sensors Journal, 2023 This article proposes a Kretschmann configuration surface plasmon resonance (SPR) sensor setup incorporating gold and graphene quantum dot (GQD) bilayers for the detection of uric acid (UA) solution. The confirmation of the deposition of gold and GQD films onto the sensor substrate was accomplished through the utilization of a field emission scanning electron microscope (FESEM) and energy-dispersive X-ray (EDX) spectroscopy. Analysis revealed an average film thickness of 55.4 nm for the gold film and 5.8 nm for the GQD film. Different concentrations of UA solution were tested with the proposed setup and the performance was evaluated in terms of sensitivity, linearity, limit of detection (LOD), binding affinity, full width at half maximum (FWHM), detection accuracy (DA), signal-to-noise ratio (SNR), and figure of merit (FOM). The sensitivities achieved for the SPR sensors were 0.23 and 3.77 %/(mg/dL) with correlation coefficients of 0.0318 and 0.825 for gold and gold–GQD, respectively. The corresponding LODs were 32.85 and 4.74 mg/dL, with binding affinity constants of 91.87 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$89.18\,\,\mu \text {M}^{-1}$ </tex-math></inline-formula> , respectively. Adding GQD to the gold film increased the sensitivity of the SPR sensor substantially while demonstrating excellent reproducibility, repeatability, and reusability, exalted DA and SNR, constricted FWHM, and superlative FOM. These outcomes harbor the potential to spark a proficient and modest technique that enables the detection of UA in saliva, thus expediting near-patient testing.
Residential College's Smart Restroom Monitoring System F. I. Azman, M. S. F. M. Fazdli, N. L. Saleh, A. S. M. Noor, A.M. Ali 2023 International Conference on Smart Applications Communications and Networking Smartnets 2023, 2023 This paper presents the recent development in remote and smart monitoring of restroom cleanliness. This was achieved by incorporating Lora and Raspberry Pi together with physical sensors, which allow the transition from a predefined periodic cleaning to a usage-based approach. This allows measures to track the real-time use of restrooms and then derive longer-term patterns of usage.
Carbon Nanotubes Enhancement of Fiber Bragg Grating Surface Plasmon Resonance Sensor Punithavathi Thirunavakkarasu, Abdul Ali Khan, Arafat Shabaneh, Norazlina Bte Saidin, Muhammad Syahnizam Sulaiman, Ahmad Shukri Muhammad Noor Ies 2023 International Electronics Symposium Unlocking the Potential of Immersive Technology to Live A Better Life Proceeding, 2023
Fabrication of silver nanoparticles in pomegranate seed oil with thermal properties by laser ablation technique Digest Journal of Nanomaterials and Biostructures, 2015
Modelling of light photons detection in scintillation camera S. F. Md Ali, D. Xianling, A. S. Muhammad Noor, F. Z. Rokhani, S. Hashim, M. I. Saripan IEEE Icsipa 2013 IEEE International Conference on Signal and Image Processing Applications, 2013
