Publications Archives – Page 2 of 13 – Institute of Nano Electronic Engineering

An investigation on GaN/ porous-Si NO2 gas sensor fabricated by pulsed laser ablation in liquid

June 30, 2022 By Editor

Abstract – Pulsed-laser ablation in liquid was used to prepare GaN nanostructure. The P-type GaN nanostructure was deposited onto the porous-silicon substrate through the drop-casting method for NO2 gas-sensor fabrication. Ablation was performed in ethanol using two laser wavelengths, namely, 532 and 1064 nm. The XRD pattern showed a high and sharp peak at 2θ= 29.49°, indicating enhanced GaN formation using a 532 nm laser wavelength. AFM and FESEM analyses confirmed increased GaN grain growth at the same wavelength. The optical reflectance of the GaN sample showed higher reflectance at 532 nm than at 1064 nm. The optical-energy bandgap was more elevated at 532 nm than at 1064 nm. Photoluminescence analysis revealed that the 532 nm sample had a higher-intensity peak than the 1064 nm one. Device-performance studies showed the most enhanced sensor response (158.49%), highest sensitivity (2.109 ppm), and best response time (13.5 s) at 250 °C for the sample prepared using 532 nm laser wavelength.

Corresponding Author: Prof. Ts. Dr. Uda Hashim
Corresponding Author’s Email: uda@unimap.edu.my

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Link to Publication: https://doi.org/10.1016/j.snb.2022.132163

MiR-133a-3p overexpression-induced elevation of cisplatin-mediated chemosensitivity to non-small cell lung cancer by targeting replication factor C3

December 17, 2021 By Editor

Abstract – Investigated the role of miR-133a-3p expression in NSCLC resistance to cisplatin (DDP) treatment and elucidate the possible mechanisms. MiR-133a-3p expression levels in DDP-resistant cells (SPC-1/DPP and A549/DDP) were measured using quantitative reverse-transcription polymerase chain reaction. Cell proliferation, cell apoptosis, cell cycle distribution, and DDP sensitivity were detected through flow cytometry, Cell Counting Kit-8 (CCK-8) and western blot analysis. In addition, databases were used to predict the miR-133a-3p targets, confirmed by dual-luciferase reporter assay. The miR-133a-3p expression levels obviously decreased in the A549/DDP and SPC-1/DPP cells [**P < 0.01; (n = 3)]. Upregulation of the miR-133a-3p expression notably suppressed cell growth, enhanced cell apoptosis, and resulted in cell cycle arrest in the SPC-1/DPP and A549/DDP cells. CCK-8 assay for the detection of proliferation of the miR-133a-3p mimic-transfected A549/DDP and SPC-A1/DDP cells treated with different DDP doses revealed IC50 values of NC mimic group: 6.85 μg/mL; miR-133a-3p mimic: 3.9 μg/mL and NC mimic group: 6.9 μg/mL; miR-133a-3p mimic: 3.99 μg/mL, respectively]. By contrast, it elevated DDP sensitivity in the A549/DDP cells and DDP resistance in the SPC-1/DPP cells. Mechanically, miR-133a-3p negatively regulated replication factor C3 and promoted DDP sensitivity in the SPC-1/DPP and A549/DDP cells, 94 potential targets that might bind to miR-133a-3p were identified.

Corresponding Author: Assoc. Prof. Dr. Subash C B Gopinath
Corresponding Author’s Email: subash@unimap.edu.my

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Link to Publication: https://doi.org/10.1016/j.procbio.2021.10.026

Fabrication and characterizations of Al nanoparticles doped ZnO nanostructures-based integrated electrochemical biosensor

June 15, 2020 By Editor

Abstract – The benefits of the electrical-based biosensor include cheap production and fast response time of detecting diseases. An interdigitated electrode (IDE) is fabricated using silver (Ag) as a metal contact that is deposited on aliminium (Al) nanoparticles doped with both zinc oxide (ZnO) and Silicon (Si) forming AZO/Si nanostructures by vacuum coater in a thermal evaporator. The electrical properties are studied as a function of frequency and voltage using I–V characteristics. Sol–gel method under annealing temperature, 500 °C is utilized to generate Al nanoparticles doped ZnO nanostructures. UV–vis spectrophotometer, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD) are used for analyzing optical, topographical, morphological and structural studies of AZO nanostructure, respectively. Specific empirical models of optical dielectric constant, bulk modulus and refractive index are also verified.

Corresponding Author: Prof. Dr. Uda Hashim
Corresponding Author’s Email: uda@unimap.edu.my

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Link to Publication: https://doi.org/10.1016/j.jmrt.2019.11.025

Design and fabrication of PDMS microfluidics device for rapid and label-free DNA detection

March 24, 2020 By Editor

Abstract – Microfluidics explores the manipulation of fluid in small volume, a multidisciplinary field is imperative for DNA extraction. This study offers a simple yet substantial methodology for the fabrication of microfluidics structure-based polydimethylsiloxane (PDMS) biopolymer on a glass substrate with SU-8 photoresist for label-free detection of pathogenic genomic DNA. Two microfluidics designs for DNA detection were based on AutoCAD software, both contain two inlets and one outlet, with dimensions of 28 mm wide, and 18 mm long, and total surface area of 504 mm2. The designs were patterned in such particular sizes and dimensions to test fluid delivery and enhancement in biochemical processes in DNA extraction, while maintaining economical values as a disposable chip. Both microfluidics devices showed no leakage during fluid delivery, have heights of 97.97 and 103.44 μm, and surface roughness of 0.15 and 0.07 μm, respectively. DNA extraction from pathogenic fungus Ganoderma boninense was run on PDMS microfluidic device and UV–Vis analysis confirmed successful extraction with peaks found at 260–280 nm. Current–voltage (I–V) measurement confirmed the accuracy of microfluidic device for the specific pathogen with both real and synthetic samples of G. boninense illustrating the similar graph values of only 0.000005 A difference at 1.0 V after hybridization.

Corresponding Author: Prof. Dr. Uda Hashim
Corresponding Author’s Email: uda@unimap.edu.my

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Fabrication of gold nanorod–zinc oxide nanocomposite on gap‑fingered integrated interdigitated aluminum electrodes and their response to electrolytes

December 5, 2019 By Editor

Abstract – This study describes the fabrication of three different gap-fingered aluminum-interdigitated electrodes (AlIDEs) on the silicon substrate based on photolithographic method, followed by integration of the gold nanorod–zinc oxide nanocomposite. The IDE masks were designed using AutoCAD software with the gaps of 10, 20, and 30 μm for design 1, 2, and 3, respectively. The morphological and electrical characterizations were subsequently performed using 3D-nanoprofiler, atomic force microscopy, high-power microscopy (HPM), scanning electron microscopy (SEM), and I–V. Validation of the fabricated surfaces (AlIDEs with/without gold nanorod–zinc oxide nanocomposite) against the electrolytes was performed at different pHs which are ranging from 1 to 12. SEM revealed the following gaps, 18.4, 20, and 40.5 μm for bare 1, 2, and 3, respectively. The measurements on I–V for bare AlIDEs indicated the electrolyte influences at different pH solutions, which were almost similar in terms of current variations except at highly acidic and alkaline. AlIDEs were well fabricated and the smaller the gap displayed the better the sensitivity, hence device 1 AlIDE has a good performance. Using different pH solutions which ranging from pH 1–12, before and after AlIDEs were coated with zinc oxide and gold nanorod. The responses of the devices were similar, fluctuating from highly acidic region to highly alkaline region in the cases of AlIDEs bare 1 and 3. Bare 2 AlIDE displayed similar responses with the AlIDE that was deposited with gold nanorod. With these results, we can conclude that deposition of gold nanorod on the device brought about the orderly response to the different pH and with the increment from acidic to alkaline increases, the proportional changes with the current were noticed.

Corresponding Author: Assoc. Prof. Dr. Subash C B Gopinath
Corresponding Author’s Email: subash@unimap.edu.my

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