Nur Syakimah Ismail
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Preferred name
Nur Syakimah Ismail
Official Name
Nur Syakimah, Ismail
Alternative Name
Nur, Syakimah Ismail
Ismail, N. Syakimah
Ismail, Nur Syakimah Binti
Ismail, N. S.
Main Affiliation
Scopus Author ID
56402634600
Researcher ID
HKN-0608-2023

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Fabrication of electrolyte-gate nanocrystalline diamond-based field effect transistor (NCD-EGFET) for HIV-1 Tat protein detection

2020-03-18 , Ahmad, Nurul Atiqah , Ruslinda A. Rahim , Nur Syakimah Ismail , Rezek B.

In this paper, we reported on the fabrication process of electrolyte-gate field effect transistor using nanocrystalline diamond as a sensing transducer. The fabrication procedure was begin with the growth of nanocrystalline diamond thin film on silicon/silicon dioxide (Si/SiO2) substrate using microwave plasma-enhanced chemical vapour deposition (CVD). Then the photolithography process was performed in order to design and pattern the field effect transistor device with the active gate channel of 60 m length and 20 m width. Each device consists of three active gate channel which connecting to three different pairs of source and drain contact. The surface morphology of fabricated NCD-EGFET was characterized using Scanning Electron Microscope to clarify the active gate channel of the device and the grain size of nanocrystaline diamond. The current-voltage (I-V) measurement of the device were carried out to study the electrical behaviour for HIV-1 Tat protein detection via RNA aptamer as sensing probe.

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Extraction, preparation and application of anthocyanin pigments from mulberry using polar solvent in various pH as photosensitizer for dye-sensitized solar cells

2021-12 , Suriati Suhaimi , Nur Syakimah Ismail , Zaliman Sauli

The purpose of this study is to evaluate the effect of polar solvent acetone and ethanol towards Morus nigra L. (Mulberry) anthocyanin dye extraction and suitable solvent sensitization of the same extracted dye on mesoporous titanium dioxide (TiO2) for dye-sensitized solar cells (DSSCs) applications. Polar extraction solvent, namely acetone, ethanol and combination of polar protic and polar aprotic solvent of acetone and ethanol which containing of 0.5% and 1% hydrochloric acid (HCl) were employed to extract anthocyanin natural dye from Mulberry. The dye extraction effectiveness and dye active component was analysed using-ultraviolet-visible spectroscopy and fourier transform infrared. Then, the extracted dye sensitization over TiO2 was monitored with current-voltage characteristic to obtain the cell power conversion efficiency. The DSSCs equipped with Mulberry extraction achieved the conversion efficiency in ranged of 0.0003% to 0.30%. Open circuit voltage and current densities obtained ranged from 0.024 to 0.574 V and 0.0023 to 0.352 mAcm-2. The performance of the fabricated cells was investigated at various pH values in presence of acidic environment in Mulberry dye extractions. This work provide an insight into the importance of choosing a right medium for photosensitizer as well as the favourable solvent for mulberry anthocyanin dye adsorption on TiO2 photoanode.

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Electrochemical study of TiO2 thin film on aluminium electrode for glucose detection

2020-01-08 , Yen F.S. , Halim N.H.A. , Norhayati Sabani , Ruslinda A. Rahim , Nur Syakimah Ismail

This paper presents the fabrication of Interdigitated Electrodes (IDEs) towards the detection of glucose. The transducer is constructed based on IDE because of its single layer electrode structure. Majority of IDE used metal such as gold and nickel as the electrodes because of their excellent electrical performances. However, in this paper, aluminium is applied as metal of electrodes not only because of its stable material but also trying to investigate the interaction between aluminium metal and Titanium dioxide, TiO2 with glucose detection. Titanium dioxide has been utilized as thin film on the deposited aluminium electrodes to increase the interaction between aluminium electrodes with different concentration of glucose solution. The designs of IDEs interdigitated array (IDBA) and interdigitated ring array (IDRA) are performed by using AUTOCAD and it is printed on a transparency paper as a mask. Customary photolithography methods with positive resist are applied to transfer the pattern on a silicon wafer in this fabrication process. Then, the fabricated IDEs are viewed and examined under Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) to verify the surface morphology and topology. The electrochemical performance of IDEs is observed through cyclic voltammogram characteristics performed using potentiostat. In the nut shell, both IDBA and IDRA are tested within 0 to 100 mM range of glucose concentration.

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Electrochemiluminescence of carbon dots and nitrogen-doped carbon dots from a microwave-assisted method

2023-10 , Nurul Izzati Akmal Mohd Azman , Muhammad Amirul Afiq Abdul Halim , Nur Syakimah Ismail , Nur Hamidah Abdul Halim , Nurjuliana Juhari , Norhayati Sabani , Siti Aisyah Shamsudin , Eiichi Tamiya

This research focuses on the use of carbon dots (CDs) and nitrogen-doped carbon dots (NCDs) synthesized using a microwave-assisted method as electrochemiluminescence (ECL) luminophores. CDs have been synthesized using citric acid, while various concentrations of nitrogen-doped CDs have been successfully obtained by varying the amount of urea from 1 to 3 g with citric acid to produce NCD1, NCD,2 and NCD3. The ECL mechanism of CDs and NCDs on screen-printed electrodes has been studied using cyclic voltammetry (CV). ECL emission from as-prepared CDs and NCDs was observed in PBS with potassium persulfate (K2S2O8) as a co-reactant. The addition of potassium chloride (KCl) as a supporting electrolyte displays fast electroreduction of CDs and K2S2O8 to expedite the generation of CDs and peroxydisulfate radicals that simultaneously increase ECL intensity. Furthermore, as the concentration of nitrogen-doped CDs increases, so does the intensity of the ECL. NCD3 shows the highest ECL intensity by an increment of 86.4% in comparison to CDs in PBS with the addition of K2S2O8 and KCl. Finally, optimization of ECL measurement was carried out in terms of CV potential range, concentration of luminophore, supporting electrolyte, and co-reactant using NCD3 luminophore. The CV potential range at 0 to -2 V shows 50 mV of early CV reverse onset potential that resulted in an increase of 52.9% ECL intensity. Meanwhile, 30x dilution of NCD3, 0.1 M of supporting electrolyte KCl, and 0.1 M of co-reactant K2S2O8 show the optimum value to obtain high ECL intensity.

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Fabrication of Graphene Electrode via Graphene Transfer Method for Bisphenol A (BPA) Detection

2021-01-01 , Shukri N.I.B.A. , Norhayati Sabani , Ruslinda A. Rahim , Mohamad Faris Mohamad Fathil , Syarifah Norfaezah Sabki , Nur Hamidah Abdul Halim , Nur Syakimah Ismail

Exposure of BPA is a concern as BPA can seep into food or beverages from containers and can possibly effects on human health especially endocrine systems. An electrochemical-based aptasensor utilizing graphene was developed in detecting endocrine disrupting compound Bisphenol A (BPA, 4,4'-(propane-2,2-diyl) diphenol). The graphene modified electrode was developed via graphene transfer. Fabrication and characterization of graphene transfer was studied in this paper using Scanning Electron Microscopy (SEM) and High-Power Microscope (HPM). In this research, the investigation of interfacial characteristic modified graphene with aptasensor and recognition of BPA with aptasensor had been done using electrochemical impedance spectroscopy (EIS). The increment of charge transfer resistance (Rct) before and after recognition of BPA denoting the accumulation of charge at the electrode surface in this research.

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Optimization of gold nanoparticles electrodeposition duration on screen printed electrode to enhance electrochemiluminescence of nitrogen-doped carbon dots

2023-12 , Nurul Izzati Akmal Mohd Azman , Nur Syakimah Ismail , Nur Hamidah Abdul Halim , Nurjuliana Juhari , Norhayati Sabani , Toibah Abd Rahim , Siti Aisyah Shamsudin , Eiichi Tamiya

In this work, the electrodeposition method was utilized to form gold nanoparticles on a carbon screen-printed electrode (SPE) using chronoamperometry at -0.4 V with various durations from 50 to 200 seconds. Scanning Electron Microscopy (SEM) images have proven that the electrodeposition method is capable of uniformly forming AuNPs on SPE (AuNPs- SPE). Apart from that, electrodeposition durations have increased the size of AuNPs by up to 66% based on average size measurements using ImageJ software. It can be observed that long electrodeposition durations permit the agglomeration of AuNPs on the electrode surface. The effect of electrodeposition duration on electrocatalytic performance in potassium ferricyanide and electrochemiluminescence (ECL) intensity of nitrogen-doped carbon dots (NCDs) was evaluated. Cyclic voltammetry (CV) of ferricyanide demonstrates that as the electrodeposition duration increases, AuNPs-SPE shows better electrochemical performance than bare SPE. ECL of NCDs displays that 100 s electrodeposition durations give the highest ECL intensity of 184% compared to bare SPE and have been chosen as the optimum parameter. The ECL mechanisms of bare SPE and AuNPs-SPE reveal that AuNPs- SPE has greater electrochemical and ECL performance than bare SPE, as evidenced by the CV of AuNPs-SPE having a faster reduction current, which rises to 87.2% ECL intensity and 510 mV faster ECL occurrence. These phenomena confirmed that the electrodeposition of AuNPs has improved the conductivity of SPE.

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Electrochemical detection of heavy metal ions using gold nanoparticles on carbon dots extracted from curry leaves

2024-06 , Nur Syakimah Ismail , Aidil Safiy Kamarul Ariffin , Nurul Izzati Akmal Mohd Azman , Nur Hamidah Abdul Halim , Norhayati Sabani , Nurjuliana Juhari , Siti Aisyah Shamsudin

Carbon dots (CDs) have attracted attention due to their versatility in electronic and optical properties based on precursor and type of synthesis process. Recently, many researchers have focused on using natural resources or wastes to form CDs. Four samples of CDs have been synthesized from curry leaves using a microwave-assisted approach at heating powers of 700 and 800 V with durations of 5 and 8 minutes. UV-Vis and FTIR spectra reveal the existence of carbon graphitic elements with carboxyl and hydroxyl functional groups on the surfaces of CDs. CVs of AuNPs/CDs/GS electrodes in ferricyanide disclosed that as-synthesized CDs produced using a lower heating power of 700 W exhibit pronounced electrocatalytic activity with sluggish electron transfer kinetics. Conversely, as-synthesized CDs created with a higher heating power of 800 W demonstrate reduced electrocatalytic activity but rapid electron transfer kinetics. Electrochemical detection of Pb2+ ions was observed through a sharp peak around -0.42 to -0.438 V, while detection of Hg2+ ions was observed through two anodic peaks around +0.334 to +0.408 V during a forward scan in acetate buffer (pH 4.5) on AuNPs/CDs/GS electrodes when tested individually. These distinct peaks also appeared in mixture solutions, with a slight reduction in peak current density that suggests the selectivity of the AuNPs/CDs/GS electrodes towards Pb2+ and Hg2+ ion detection. The optimum AuNPs/CDs/GS electrode for sensitive and selective detection of Pb2+ and Hg2+ was recorded using CDs D as a functional supporting matrix for AuNPs that was synthesized using a heating power of 800 W for 8 minutes.

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Effect of heating power towards synthesis of carbon dots through microwave pyrolysis method for optical-based biosensor

2020-01-08 , Nur Syakimah Ismail , Husain, Umi Shahirah , Selvan S. , Mordani, Nor Afnia , Nurjuliana Juhari , Nur Hamidah Abdul Halim

This study focuses on the effect of heating power in producing carbon dots (CDs) using microwave-assisted pyrolysis from glucose and PEG-200. Glucose is one type of saccharide that contains carbon atom in their structure while PEG-200 is a polymer that acts as a stabilizer. Synthesis of CDs was carried out by using a domestic microwave at different heating power ranging from 300 to 600 Watts. Produced CDs were subjected to dilution, filtering and dialysis procedure for purification purpose. UV-Vis was carried out using PerkinElmer Lambda 35 Spectrophotometer to prove the present of carbon dots in the sample solution. Photoluminescence intensity was observed using Horiba FluoroLog Spectrophotometer together with Horiba iHR550 Imaging Spectrometer to show the emission wavelength and the emission color of CDs prepared. UV-Vis results show the present of CDs in each sample from absorption peaks in the range between 240 nm until 260 nm. The photoluminescence testing shows the emission wavelength of prepared CDs solution is around 430 nm to 570 nm which represent emission color of green-yellow luminescence. From this experiment, CDs that were prepared using a heating power of 450 Watt in 2 minutes and went through the filtering process produce the best luminescence properties. Prepared CDs display electrochemiluminescence (ECL) properties in the presence of co-reactant potassium peroxydisulfate using cyclic voltammetry to pave the way for optical-based biosensor application.

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Design of arrayed waveguide grating (AWG) demultiplexer based PMMA for narrow channel spacing

2020-01-08 , Nurjuliana Juhari , Yusof, Muhammad Fadzliazuan , Mohamad Halim Abd. Wahid , Nur Syakimah Ismail

Arrayed Waveguide Grating (AWG) based PMMA polymer that functioning as multiplexer/demultiplexer (mux/de-mux) having good potential in WDM system and interferometer optical sensor. Besides, AWG is suitable for larger count optical signals and good filter response devices. AWG demultiplexer based polymer was simulated using Beam Propagation Method (BPM) under TE mode with 1550 nm central wavelength. This work explores the performance of polymer-based AWG with straight waveguide structure that capable to produce 16-channels AWG device for 100 GHz (0.8 nm) channel spacing. The 16-channels AWG based polymer produces low insertion loss of 3.430 dB and low crosstalk of -24.763 dB. The central wavelength for each output port gives almost similar values with the standard ITU-T DWDM wavelength grid with the smallest difference of 0.5 nm. This proposed device also capable to solve the demand on higher channel capacity especially to support internet usage and the needs of the best communication system.

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