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Article
Publication date: 5 September 2021

Nur Shahira Abdul Nasir, Revathy Deivasigamani, Muhammad Khairulanwar Abdul Rahim, Siti Nur Ashakirin Mohd Nashruddin, Azrul Azlan Hamzah, M. Farhanulhakim M. Razip Wee and Muhamad Ramdzan Buyong

The purpose of this paper is to visualize protein manipulation using dielectrophoresis (DEP) as a substantial perspective on being an effective protein analysis and…

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Abstract

Purpose

The purpose of this paper is to visualize protein manipulation using dielectrophoresis (DEP) as a substantial perspective on being an effective protein analysis and biosensor method as DEP is able to be used as a means for manipulation, fractionation, pre-concentration and separation. This research aims to quantify DEP using an electrochemical technique known as cyclic voltammetry (CV), as albumin is non-visible without any fluorescent probe or dye.

Design/methodology/approach

The principles of DEP were generated by an electric field on tapered DEP microelectrodes. The principle of CV was analysed using different concentrations of albumin on a screen-printed carbon electrode. Using preliminary data from both DEP and CV methods as a future prospect for the integration of both techniques to do electrical quantification of DEP forces.

Findings

The size of the albumin is known to be 0.027 µm. Engineered polystyrene particle of size 0.05 µm was selected to mimic the DEP actuation of albumin. Positive DEP of the sample engineered polystyrene particle was able to be visualized clearly at 10 MHz supplied with 20 Vpp. However, negative DEP was not able to be visualized because of the limitation of the apparatus. However, albumin was not able to be visualized under the fluorescent microscope because of its translucent properties. Thus, a method of electrical quantification known as the CV technique is used. The detection of bovine serum albumin (BSA) using the CV method is successful. As the concentration of BSA increases, the peak current obtained from the voltammogram decreases. The peak current can be an indicator of DEP response as it correlates to the adsorption of the protein onto the electrodes. The importance of the results from both CV and DEP shows that the integration of both techniques is possible.

Originality/value

The integration of both methods could give rise to a new technique with precision to be implemented into the dialyzers used in renal haemodialysis treatment for manipulation and sensing of protein albumin.

Article
Publication date: 2 May 2017

Siti Kudnie Sahari, Muhammad Kashif, Norsuzailina Mohamed Sutan, Zaidi Embong, Nik Amni Fathi Nik Zaini Fathi, Azrul Azlan Hamzah, Rohana Sapawi, Burhanuddin Yeop Majlis and Ibrahim Ahmad

The quality of GeOx–Ge interface and the equivalent oxide thickness (EOT) are the main issues in fabricating high-k/Ge gate stack due to the low-k of GeOx interfacial…

Abstract

Purpose

The quality of GeOx–Ge interface and the equivalent oxide thickness (EOT) are the main issues in fabricating high-k/Ge gate stack due to the low-k of GeOx interfacial layer (IL). Therefore, a precise study of the formation of GeOx IL and its contribution to EOT is of utmost importance. In this study, the GeOx ILs were formed through post-oxidation annealing of sputtered Al2O3 on the Ge substrate. The purpose of this paper is to report on growth kinetics and composition of IL between Al2O3 and Ge for HCl- and HF-last Ge surface.

Design/methodology/approach

After wet chemical cleaning with HCl or HF, Al2O3 was grown onto the Ge surface by RF sputtering. Thickness and composition of IL formed after post-anneal deposition at 400°C in dry oxygen ambience were evaluated as a function of deposition time by FESEM and characterized by X-ray photoelectron spectroscopy, respectively.

Findings

It was observed that the composition and thickness of IL were dependent on the starting surface and an aluminum germinate-like composition was formed during RF sputtering for both HF- and HCl-last starting surface.

Originality/value

The novelty of this work is to investigate the starting surface of Ge to IL growth between Al2O3/Ge that will lead to the improvement in Ge metal insulator field effect transistors (MISFETs) application.

Details

Microelectronics International, vol. 34 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Abstract

Purpose

This paper aims to present the capacitance characterization of tapered dielectrophoresis (DEP) microelectrodes as micro-electro-mechanical system sensor and actuator device. The application of DEP-on-a-chip (DOC) can be used to evaluate and correlate the capacitive sensing measurement at an actual position and end station of liquid suspended targeted particles by DEP force actuator manipulation.

Design/methodology/approach

The capability of both, sensing and manipulation was analysed based on capacitance changes corresponding to the particle positioning and stationing of the targeted particles at regions of interest. The mechanisms of DEP sensor and actuator, designed in DOC applications were energized by electric field of tapered DEP microelectrodes. The actual DEP forces behaviour has been also studied via quantitative analysis of capacitance measurement value and its correlation with qualitative analysis of positioning and stationing of targeted particles.

Findings

The significance of the present work is the ability of using tapered DEP microelectrodes in a closed mode system to simultaneously sense and vary the magnitude of manipulation.

Originality/value

The integration of DOC platform for contactless electrical-driven with selective detection and rapid manipulation can provide better efficiency in in situ selective biosensors or bio-detection and rapid bio-manipulation for DOC diagnostic and prognostic devices.

Details

Microelectronics International, vol. 37 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 4 September 2020

Muhamad Ramdzan Buyong, Farhad Larki, Celine Elie Caille, Norazreen Abd Aziz, Ahamad Ghadafi Ismail, Azrul Azlan Hamzah and Burhanuddin Yeop Majlis

This paper aims to present the dielectrophoresis (DEP) force (FDEP), defined as microelectrofluidics mechanism capabilities in performing selective detection and rapid…

Abstract

Purpose

This paper aims to present the dielectrophoresis (DEP) force (FDEP), defined as microelectrofluidics mechanism capabilities in performing selective detection and rapid manipulation of blood components such as red blood cells (RBC) and platelets. The purpose of this investigation is to understand FDEP correlation to the variation of dynamic dielectric properties of cells under an applied voltage bias.

Design/methodology/approach

In this paper, tapered design DEP microelectrodes are used and explained. To perform the characterization and optimization by analysing the DEP polarization factor, the change in dynamic dielectric properties of blood components are observed according to the crossover frequency (fxo) and adjustment frequency (fadj) variation for selective detection and rapid manipulation.

Findings

Experimental observation of dynamic dielectric properties change shows clear correlation to DEP polarization factor when performing selective detection and rapid manipulation. These tapered DEP microelectrodes demonstrate an in situ DEP patterning efficiency more than 95%.

Research limitations/implications

The capabilities of tapered DEP microelectrode devices are introduced in this paper. However, they are not yet mature in medical research studies for various purposes such as identifying cells and bio-molecules for detection, isolation and manipulation application. This is because of biological property variations that require further DEP characterization and optimization.

Practical implications

The introduction of microelectrofluidics using DEP microelectrodes operate by selective detecting and rapid manipulating via lateral and vertical forces. This can be implemented on precision health-care development for lab-on-a-chip application in microfluidic diagnostic and prognostic devices.

Originality/value

This study introduces a new concept to understand the dynamic dielectric properties change. This is useful for rapid, label free and precise methods to conduct selective detection and rapid manipulation of mixtures of RBC and platelets. Further, potential applications that can be considered are for protein, toxin, cancer cell and bacteria detections and manipulation. Implementation of tapered DEP microelectrodes can be used based on the understanding of dynamic dielectric properties of polarization factor analysis.

Details

Microelectronics International, vol. 37 no. 4
Type: Research Article
ISSN: 1356-5362

Keywords

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