Now showing 1 - 10 of 15
  • Publication
    Advancing COVID-19 detection high-performance RNA biosensing via electrical interactions
    ( 2024-06) ;
    Muhammad Nur Afnan Uda
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    ; ;
    Nur Hulwani Ibrahim
    ;
    Chai Chang Yii
    ;
    Lorita Angeline
    This research paper investigated the detection of COVID-19 using an Aluminum Interdigitated Electrode (Al-IDE) sensor based on electrical conductivity. The silanization process involved the functionalization step, employing (3-Aminopropyl) triethoxysilane (APTES), while the immobilization process was facilitated by the RNA Probe specific to COVID-19. To verify its specificity in detection, the functionalized biosensor was tested against single-base mismatches, non-complementary sequences, and complementary sequences. The physical characteristics of the Al-IDE biosensor were examined using both low-power microscopy (LPM) and high-power microscopy (HPM). Additionally, the morphological properties of the biosensor were assessed using atomic force microscopy (AFM). To assess its diagnostic potential, the biosensor's sensitivity was evaluated by exposing it to a range of complementary targets, spanning from 1 femtomolar (fM) to 1 micromolar (μM). The current-voltage (I-V) characteristics of the biosensor were meticulously analyzed at each stage of functionalization bare Al-IDE, silanization, immobilization, and hybridization. This I-V characterization was carried out using a picoammeter voltage source (Keithley 2450), Kickstart software, and a probe station. The results confirmed the biosensor's capability to effectively detect COVID-19 targets within the nanoampere concentration range, demonstrating its success in detecting specific COVID-19 targets at the nanoampere level.
  • Publication
    MPTES decorated IDE for arsenic (AS) selective detection
    ( 2021-05-03) ; ;
    Mosbah A.B.
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    ;
    Muhammad Nur Afnan Uda
    Heavy metals ions are ions which generally occupied most part water sources such river, sea and other water flow channels such as drainage, water pipe. The exist of the ions in drinking water traces have called the attention researchers due to the recent discovery of the ions problem in both human health and aquatic animal such as fish. Fish come and encounter heavy metals ions in the river and ingest it and subsequently this fish eaten by man. The ions will pass to human and attack some human orgains. Finding the reliable solution to detect traces of heavy metals ions in water is a promising approach to eliminate such problems. This research aim is to enhance detection of heavy sensors, for sensor technology industry using the fabricated MTES surface-modified silicon interdigitated electrode to detect arsenic ion in water, The device was fabricated using conventional photolithography process coupled with deep RIE etching. The fabricated devices was modified surface and characterized by Scanning Electron Microscopy, Atomic Force Microscopy and high-power microscopy. The electrical analysis by applying voltage to measure the device response to the surface modification step and subsequently against arsenic ion as it bonded to the device via MPTES, various MTES concentrations distinguished against the bare device and arsenic concentration. Based on current and voltage analysis, concentration-dependent results were obtained, the detection limit for surface modified IDE to the arsenic detection was 20 pM with the linear response behaviour to the concentration, Thus, with this wonderful detection limits, the devices high high-performance characteristic by selectively distinguish arsenic ions against other foreign elements in the water.
      7
  • Publication
    Quantitative lead (Pb+) ion detection via modified silicon nanowire
    ( 2021-05-03) ; ;
    Nuri A KH Ehfaed
    ;
    Muhammad Nur Afnan Uda
    ;
    The study presented a functionalized silicon with (3-aminopropyl) triethoxysilane (APTES) to serve as a sensor for heavy metal detection. The amino-functionalized Si nanowires were tested against the heavy metal, lead (Pb). Due to the silicon electrochemical response towards the heavy metal ions, linear response to four different sources of water was observed. The results indicated that Pb can be detected with a high precision. Furthermore, confirmation was demonstrated using atomic absorption spectroscopy to determine the level lead content in the collected water source. Tab water (H2O), River H2O, Treated (H2O), DI (deionized) H2O and found the levels of 0.0859 mg/L, 0.0929 mg/L, 0.0052mg/L, 0.0023 mg/L with 5.8pA, 7.2pA, 4.6pA, 3.3pA current responses, respectively. Thus, with this high capability to discriminate water samples, the sensor potential can be employed for effective heavy metal detections and further be extended to a large sensor network in water treatment plant. A new microfluidic bonding material based on SU8 to implement electrical Nano chemical sensors for ions sensing, and an investigation of direct electrical measurement allowed for label free detection.. Thus, the study developed new room temperature bonding method using SU8 as an intermediate adhesive layer. The SU8 modified bonding was compared with non modified. The bond strength of SU8 modified was found to be stronger than ordinary plasma bonding under the same curing conditions. Overnight room temperature curing yields an average burst pressure of 420 kPa, which is more than adequate for many PDMS sensor devices. In contrast, non SU8 coated plasma bonded resulted in a burst pressure of only 174 KPa.
      2
  • Publication
    Determination of silicon nanowire mechanical properties by first principle
    ( 2021-05-03) ; ;
    Muhammad Nur Afnan Uda
    ;
    Electronic and mechanical properties of SiNWs were studied based on First principle method via density functional theory. Effect of orientations on mechanical properties of silicon nanowire were identified. The elastic properties of {110}, {100}, {011} and {111} orientations were calculated. Due to atomic interaction in wires, various mechanical properties of wire changes were noted. The results show for strain 0.1164×10-5, 0.12×10-5 and 0.115×10-5 with modulus of 149.6GPa, 75.5GPa and 85.1GPa respectively.
      1  8
  • Publication
    Capillary Driven Muilti Channels Microfluidic
    ( 2021-12-14) ; ;
    Nuri A KH Ehfaed
    ;
    Muhammad Nur Afnan Uda
    ;
    The paper present design and fabrication of capillary driven muilti channels microfluidic. AutoCAD assisted layout design was conducted and fabricated based on cold photolithography process with precise geometry for capillary flow. The design was bonded with glass to test the flow and bonding integrity. The device was tested for flow and it was found the uniform capillary flow was established with strong bonding energy.
      6
  • Publication
    Silica and graphene mediate arsenic detection in mature rice grain by a newly patterned current–volt aptasensor
    ( 2021-12-01) ; ; ;
    Halim N.H.
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    ;
    Muhammad Nur Afnan Uda
    ;
    Anbu P.
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    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.
      2
  • Publication
    Determination of Silicon Electrical Properties Using First Principles Approach
    ( 2021-12-14) ; ;
    Muhammad Nur Afnan Uda
    ;
    Silicon nanowires have attracted attention as basis for reconfigurable electronics. However, as the size decreases, the electronic properties of the nanowires vary as a result of confinement, strain and crystal topology effects. Thus, at the thin diameter regime the band gap of Silicon nanowires can no longer be derived from a simple extrapolation of the isotropic bulk behaviour. This study compares band gap parameters in sub 10nm nanowires obtained from first-principles density-functional band structure calculations with extrapolations using continuum theory in order to rationalize the changes of the overall conductance, resistance and band gap. The device consists of silicon nanowire of size between 1 nm to 6nm. The results indicate an increase of, both the energy gap and the resistance along with reduced conductivity for the thinnest wires and a dependence on the crystal orientation with gaps reaching up to 4.3 eV along <111>, 4.0 eV along <110>, and 3.7 along <100>.
      5
  • Publication
    Nano humidity and temperature sensors activated water pump agricultural system
    ( 2021-05-03) ; ;
    Thing Y.C.
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    ;
    Muhammad Nur Afnan Uda
    Solar power is absolutely perfect for usage with irrigation systems and field landscape such as golf course, field and especially for planting. This study utilized 12 V Solar Panel, the energy from sun will converted to electrical energy, striking and shining causes the solar panel absorbs the energy of the sun. The designed water pumped was controlled by the humidity sensor, the system turn on the pump at particular preset time to keep the pump running automatically. The system was tested for two consecutive days with optimum generation of flow rate and switched with the humidity is high. Thus, this system is reliable and can be integrated with irrigation farms to support in automatic and constant water supply.
      4
  • Publication
    Green route synthesis of antimicrobial nanoparticles using sewage alga bloom
    ( 2023-01-01)
    H.M A.
    ;
    Muhammad Nur Afnan Uda
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    ;
    Arsat Z.A.
    ;
    Abdullah F.
    ;
    Muttalib M.F.A.
    ;
    Hashim M.K.R.
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    ; ;
    Yaakub A.R.W.
    ;
    Ibrahim N.H.
    ;
    Parmin N.A.
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    Nanoparticles have a large surface area for their size and interact effectively with other particles. AgNPs may be created chemically, physically, or biologically. Biological techniques are considered the safest and cleanest since they use no toxic chemicals. Biological synthesis involves plant extracts, bacteria, fungus, algae, and other organisms. The algal production of AgNPs is of major interest. The abundance of algae and the ease with which it can be grown in a lab are two of the many reasons why it has become so popular as a nanoparticle production source. In this study, algae were employed as nanoparticles and antibacterial inhibitors against microbes.
      2
  • Publication
    Size dependance of mechanical stiffness in silicon nanowire
    ( 2024-03-21) ; ; ;
    Muhammad Nur Afnan Uda
    The present present the effect of orientation of silicon nanowires on its band structure properties based on atomic interaction within SiNWs. It was observed the atomic interaction energy resulted in inducing force which created both repulsive or attractive generating free radicals which produce dynamic behaviour leading to band structure shrinkage. This effect has been observed in various theoretical studies for nanowires. At fixed position, the atom within the silicon significantly interact, resulting in relative molecular vibration.
      1  9