Publications Archives – Page 5 of 13 – Institute of Nano Electronic Engineering

Selectivity verification of cardiac troponin monoclonal antibodies for cardiac troponin detection by using conventional ELISA

July 16, 2017 By Editor

Abstract – This paper presents preparation and characterization of conventional enzyme-linked immunosorbent assay (ELISA) for cardiac troponin detection to determine the selectivity of the cardiac troponin monoclonal antibodies. Monoclonal antibodies, used to capture and bind the targets in this experiment, are cTnI monoclonal antibody (MAb-cTnI) and cTnT monoclonal antibody (MAb-cTnT), while both cardiac troponin I (cTnI) and T (cTnT) are used as targets. ELISA is performed inside two microtiter plates for MAb-cTnI and MAb-cTnT. For each plate, monoclonal antibodies are tested by various concentrations of cTnI and cTnT ranging from 0-6400 μg/l. The binding selectivity and level of detection between monoclonal antibodies and antigen are determined through visual observation based on the color change inside each well on the plate. ELISA reader is further used to quantitatively measured the optical density of the color changes, thus produced more accurate reading. The results from this experiment are utilized to justify the use of these monoclonal antibodies as bio-receptors for cardiac troponin detection by using field-effect transistor (FET)-based biosensors coupled with substrate-gate in the future.

Corresponding Author: Ruslinda A. Rahim
Corresponding Author’s Email: ruslinda@unimap.edu.my

Abstract text: PDF

Current and Potential Developments of Cortisol Aptasensing towards Point-of-Care Diagnostics (POTC)

May 27, 2017 By Editor

Abstract – Anxiety is a psychological problem that often emerges during the normal course of human life. The detection of anxiety often involves a physical exam and a self-reporting questionnaire. However, these approaches have limitations, as the data might lack reliability and consistency upon application to the same population over time. Furthermore, there might be varying understanding and interpretations of the particular question by the participant, which necessitating the approach of using biomarker-based measurement for stress diagnosis. The most prominent biomarker related to stress, hormone cortisol, plays a key role in the fight-or-flight situation, alters the immune response, and suppresses the digestive and the reproductive systems. We have taken the endeavour to review the available aptamer-based biosensor (aptasensor) for cortisol detection. The potential point-of-care diagnostic strategies that could be harnessed for the aptasensing of cortisol were also envisaged.

Keywords – anxiety, cortisol, aptasensor, aptamer

Corresponding Author: Ruslinda A. Rahim
Corresponding Author’s Email: ruslinda@unimap.edu.my

Full text: PDF

Substrate-gate coupling in ZnO-FET biosensor for cardiac troponin I detection

March 17, 2017 By Editor

Abstract – Currently, field-effect transistor (FET)-based biosensors have been implemented in several portable sensors with the ultimate application in point-of-care testing (POCT). In this paper, we have designed substrate-gate coupling in FET-based biosensor for the detection of cardiac troponin I (cTnI) biomarker. In the device structure, zinc oxide nanoparticles (ZnO-NPs) thin film were deposited through sol-gel and spin coating techniques on the channel. The p-type silicon was used as a substrate, while ZnO is an n-type nanomaterial, thus creates p-n-p junction between source, channel, and drain. The deposited thin films exhibited hexagonal wurtzite phase of ZnO, suitable for biomolecular interaction as revealed in X-ray diffraction (XRD) analysis. The surface of the thin film was then functionalized with 3-aminopropyltriethoxysilane (APTES), followed by glutaraldehyde (GA) as a bi-functional linker to immobilize the cTnI monoclonal antibody (MAb-cTnI) as bio-receptor for capturing cTnI biomarker and proven by the Fourier transform-infrared (FT-IR) spectra. Lastly, we demonstrated a new strategy, the integration of FET-based biosensors with substrate-gate showed differences between before (immobilization) and after cTnI target biomarker interaction by significant changes in drain current (ID) and change of threshold voltage (VT), which improved the sensitive detection, with the limit of detection down to 3.24 pg/ml.

Keywords – Biosensor, Cardiac troponin I, Electrical-based, Field-effect transistor, Substrate-gate coupling, Zinc oxide nanoparticles

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

Full text: PDF

A direct detection of human papillomavirus 16 genomic DNA using gold nanoprobes

December 8, 2016 By Editor

Abstract – Nanoparticles have been investigated as flagging tests for the sensitive DNA recognition that can be utilized as a part of field applications to defeat restrictions. Gold nanoparticles (AuNPs) have been widely utilized due to its optical property and capacity to get functionalized with a mixed bag of biomolecules. This study exhibits the utilization of AuNPs functionalized with single-stranded oligonucleotide (AuNP-oligo test) for fast the identification of Human Papillomavirus (HPV). This test is displayed on interdigitated electrode sensor and supported by colorimetric assay. DNA conjugated AuNP has optical property that can be controlled for the applications in diagnostics. With its identification abilities, this methodology incorporates minimal effort, strong reagents and basic identification of HPV.

Keywords – Colorimetric detection, DNA detection, Gold nanoparticles, Human Papillomavirus, Interdigitated electrode sensor

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

Full text: PDF

Formation of nanocrystalline GeSn thin film on Si substrate by sputtering and rapid thermal annealing

September 25, 2016 By Editor

Abstract – Nanocrystalline Ge1-xSnx thin films have been formed after rapid thermal annealing of sputtered GeSn layers. The alloy films were deposited onto the Silicon (100) substrate via low cost radio frequency magnetron sputtering. Then, the films were annealed by rapid thermal annealing at 350 °C, 400 °C, and 450 °C for 10 s. The morphological, structural, and optical properties of the layers were investigated with field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and high-resolution X-ray diffraction (HR-XRD). The Raman analysis showed that the only observed phonon mode is attributed to Ge-Ge vibrations. Raman phonon intensities of GeSn thin films were enhanced with increasing the annealing temperature. The results clearly revealed that by increasing the annealing temperature the crystalline quality of the films were improved. The XRD measurements revealed the nanocrystalline phase formation in the annealed films with (111) preferred orientation. The results showed the potentiality of using the sputtering technique and rapid thermal anneal to produce crystalline GeSn layer.

Keywords – Germanium-tin, HR-XRD, Nanocrystalline materials, Raman spectroscopy, Sputtering, Thin films

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

Full text: PDF

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