Publications Archives – Page 7 of 13 – Institute of Nano Electronic Engineering

‘Spotted Nanoflowers’: Gold-seeded Zinc Oxide Nanohybrid for Selective Bio-capture

September 8, 2015 By Editor

Abstract – Hybrid gold nanostructures seeded into nanotextured zinc oxide (ZnO) nanoflowers (NFs) were created for novel biosensing applications. The selected ‘spotted NFs’ had a 30-nm-thick gold nanoparticle (AuNP) layer, chosen from a range of AuNP thicknesses, sputtered onto the surface. The generated nanohybrids, characterized by morphological, physical and structural analyses, were uniformly AuNP-seeded onto the ZnO NFs with an average length of 2–3 μm. Selective capture of molecular probes onto the seeded AuNPs was evidence for the specific interaction with DNA from pathogenic Leptospirosis-causing strains via hybridization and mis-match analyses. The attained detection limit was 100 fM as determined via impedance spectroscopy. High levels of stability, reproducibility and regeneration of the sensor were obtained. Selective DNA immobilization and hybridization were confirmed by nitrogen and phosphorus peaks in an X-ray photoelectron spectroscopy analysis. The created nanostructure hybrids illuminate the mechanism of generating multiple-target, high-performance detection on a single NF platform, which opens a new avenue for array-based medical diagnostics.

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

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Design and fabrication of micro‑mixer with short turns angles for self‑generated turbulent structures

August 27, 2015 By Editor

Abstract – Micro mixing process is one of the most important drugs, synthesis and process technology. Many expectations toward enhanced fluids miscibility, yield and purity, improved safety, and access to new discovery are directed to the micro mixing technology. In microfluidic technology, mixer is the most important component because of its ability to operate either active or passive micro mixing. The study reports a simple inexpensive and cost effective micro mixer design/simulation/fabrication using 4.3a COMSOL Multi-physics software package and homemade photolithography equipment. The micro mixer was fabricated using PDMS and glass substrate with master mold fabricated with SU8 for rapid prototyping and reusability, the micro mixer and the whole mixer were fabricated in less than 20 min. Mixing profiles were observed for the efficiency evaluation by dropping four samples urine through the four inlets and collecting the sample at outlet. Flow rate and mixing efficiency were quantitatively measured by analyzing the recorded flow profiles and values of the image collected from the high powered microscope at inlet and outlet locations. and sample flow and mixing were compared for flowing efficiency and flow rate using different concentrations and the results indicate that the mixing efficiency of 98% was obtained at Reynolds number (Re) <2.

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

Highly sensitive silicon nanowire biosensor with novel liquid gate control for detection of specific single-stranded DNA molecules

June 25, 2015 By Editor

Abstract – The study demonstrates the development of a liquid-based gate-control silicon nanowire biosensor for detection of specific single-stranded DNA (ssDNA) molecules. The sensor was fabricated using conventional photolithography coupled with an inductively coupled plasma dry etching process. Prior to the application of DNA to the device, its linear response to pH was confirmed by serial dilution from pH 2 to pH14. Then, the sensor surface was silanized and directly aminated with (3-aminopropyl) triethoxysilane to create a molecular binding chemistry for biofunctionalization. The resulting Si‒O‒Si‒ components were functionalized with receptor ssDNA, which interacted with the targeted ssDNA to create a field across the silicon nanowire and increase the current. The sensor shows selectivity for the target ssDNA in a linear range from target ssDNA concentrations of 100 pM to 25 nM. With its excellent detection capabilities, this sensor platform is promising for detection of specific biomarkers and other targeted proteins.

Keywords – Nanowire biosensor, APTES, ssDNA, DNA, Photolithography, Liquid gate control

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

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Fully Depletion of Advanced Silicon on Insulator MOSFETs

March 27, 2015 By Editor

Abstract – Scaling of the transistor has been tremendous successful in the beginning with reduction of the
gate oxide thickness and increase of doping concentration. Moving into smaller dimension,
those are not enough to overcome the short channel effect. Starting with changing in
materials and followed by device architecture is needed which require fully depletion
operation. This article reviews the fully-depletion operation of thin body of silicon on
insulator of advanced MOSFETs.

Keywords – fully-depletion, SOI MOSFETs, thin-body and thin-buried oxide (UTBB)

Corresponding Author: Mohd Khairuddin Md Arshad
Corresponding Author’s Email: mohd.khairuddin@unimap.edu.my

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Fabrication of Silicon Nanowires Array Using E-beam Lithography Integrated with Microfluidic Channel for pH Sensing

March 25, 2015 By Editor

Abstract – Silicon nanowires based biosensors have garnered great potential in serving as highly sensitive, label-free and real-time response biosensing application. These biosensors are useful in detecting pH, DNA molecules, proteins and even single viruses. In this paper, we report the geometrical characteristics and performance of silicon nanowires array for pH level detection. The nanowires are designed for 40 nm, 50 nm and 60 nm diameter sizes. Top-Down Nanofabrication (TDN) is utilized in the development of resist mask and nanowires formation from silicon on insulator (SOI) wafer involving scanning electron microscope (SEM) based electron beam lithography (EBL). The smallest silicon nanowires structure achieved is 40 nm width and 30 nm height. The corresponding source and drain are fabricated via two aluminum (Al) electrodes on top of the silicon nanowires array using conventional lithography process. A 100 µm microfluidic channel is attached on the silicon nanowires for the sample solution transportation. pH level detection are performed based on several types of standard aqueous pH buffer solutions (pH 4, pH 7, pH 10 and pH 12) to test the electrical response of the sensor. Morphological and electrical responses have been proposed to verify the characteristics of the silicon nanowires array based pH sensor.

Keywords – Array, E-beam lithography, microfluidic channel, pH sensor, silicon nanowires

Corresponding Author: Mohd Khairuddin Md Arshad
Corresponding Author’s Email: mohd.khairuddin@unimap.edu.my

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