Voon Chun Hong
Thumbnail Image
Preferred name
Voon Chun Hong
Official Name
Hong, Voon Chun
Alternative Name
Voon, C. H.
Voon, Chun Hong
Hong, Voon Chun
Hong, V. C.
Main Affiliation
Scopus Author ID
55334719400
Researcher ID
D-2050-2015

Research Output

Filters

47
Reset filters

Settings
Now showing 1 - 10 of 47
Thumbnail Image
Publication

Sustainable production of graphene oxide with ascorbic acid reduction characterization and insights

2024-10 , Thaddeus Lee , Chun Hui Tan , Chai Yan Ng , Foo Wah Low , Hing Wah Lee , Voon Chun Hong

In this study, graphene oxide (GO) was synthesized from graphite powder using KMnO4 and a concentrated mixture of H2SO4/H3PO4. The obtained GO was subsequently reduced using ascorbic acid. The ratios of H2SO4 to H3PO4 and KMnO4 to graphite powder were kept constant. The synthesized GO and reduced graphene oxide (rGO) were evaluated using UV-visible spectroscopy, FT-IR spectroscopy, XRD, SEM, and EDX. The findings showed that processing graphite powder with KMnO4 at 60 °C for 12 hours resulted in a high degree of oxidation and minimal defects. Furthermore, ascorbic acid, an alternative to highly toxic hydrazine, aided in eliminating oxygen-containing functional groups in the rGO. This study focuses on the properties of GO produced using the improved Hummer's method, and the changes observed after chemical reduction.

View
Thumbnail Image
Publication

Effect of solvent on mechanical and physical properties of PMMA/Sic composite films

2024-12 , Auni Fakhira Che Baharudin , Lim Bee Ying , Voon Chun Hong , Teh Pei Leng , Tan Soo Jin

The selection of solvent in solution casting is crucial as it may affect the morphology and properties of the resulting composite films. In this study, the effect of solvent on the properties of poly(methyl methacrylate)/silicon carbide (PMMA/SiC) composite films was investigated. By using acetone, the solution casting was carried out at various solvent-to-solid (S/S) ratio, from 4:1 to 10:1 at room temperature. It was found that the increasing S/S ratio enhanced the tensile strength and modulus of elasticity of pristine PMMA films but deteriorated its elongation at break, up to 8:1 ratio. The crystallinity of the PMMA films was found to increase with S/S ratio, as confirmed by the higher peak intensity in X-Ray Diffraction (XRD) patterns and the SEM micrographs. In the second part of the study, by using S/S ratio of 8:1, the nano sized SiC (0.25 wt%) was added as a filler into PMMA and toluene with different ratio was added as a secondary solvent. The addition of SiC has increased the tensile strength and modulus of elasticity of PMMA/SiC but decreased its elongation at break. However, the presence of toluene reduced the tensile strength of the PMMA/SiC composite films and resulting in rougher tensile fracture surfaces as shown in SEM micrographs. The toluene with nonpolar nature had affected the distribution of SiC in PMMA. It can be concluded that the properties of the PMMA composites films can be tailored according to the needs of applications.

View
Thumbnail Image
Publication

Fabrication of Integrated Electrode for pH Sensor Application

2021-01-01 , Mohd Akhir F.S. , Foo Kai Loong , Jin T.S. , Uda Hashim , Voon Chun Hong , Azman Abu Hassan M.

Integrated Electrode (IDEs), as a sensor, is a pervasive device in modern electronics and future hopes for producing a highly sensitive and selective sensor. In this work, a simple method of conventional photolithography for the fabrication of interdigitated electrodes is presented in detail. The structural of highly uniform IDEs device was optically characterized using high power microscope (HPM) and scanning electron microscope (SEM). Besides, the fabricated IDEs device was undergone electrical measurement with different pH. The result shows the highest current at 96 nA when the IDEs was tested with pH 10. Overall, our study establishes a correlation between structural and electrical properties of Al IDEs thin films with different pH

View
Thumbnail Image
Publication

Facile electrical DNA genosensor for human papillomavirus (HPV 58) for early detection of cervical cancer

2023-07 , F. Nadhirah Jaapar , Nor Azizah Parmin , Nur Hamidah Abdul Halim , Uda Hashim , Subash Chandra Bose Gopinath , Ruslinda A. Rahim , Sh. Nadzirah , Voon Chun Hong , Muhammad Nur Aiman Uda , Wei Chern Ang , Iffah Izzati Zakaria , Zulida Rejali , Amilia Afzan , Azrul Azlan Hamzah , Chang Fu Dee , F. Syakirah Halim

For decades, a Pap smear test has been applied as a conventional method in detecting Human Papillomavirus caused cervical cancer. False-positive results were also recorded while using it as conventional method. Current biosensor such as Hybrid (II) Capture resulted in higher time consumption and cost. s Meanwhile, in this study we provided facile, mini, rapid, highly sensitive, eco-friendly, and cost-effective sensing system focusing on HPV strain 58 (HPV58) in a nano-size lab-on-chip technology genosensor. 30-mer of virus ssDNA designed and analyzed as a probe via bioinformatics tools such as GenBank, Basic Local Alignment Searching Tools (BLAST) and ClustalW. Nanotechnology-developed colloidal Gold-nanoparticles (AuNPs) are used in the biosensor fabrication to produce high stability and electron efficient transmission during electrical measurement. AuNPs-APTES modified on active sites of IDEs, followed by immobilization of specific probe ssDNA for HPV 58. Hydrogen binding during hybridization with its target produce electrical signals measured by KEITHLEY 2450 (Source Meter). The genosensor validated with different types of targets such as complimentary, non-complementary and single mismatch oligonucleotides. The serial dilution of target concentration has been experimented triplicate (n=3) range from 1fM to 10μM. The slope of calibration curve resulted 2.389E-0 AM-1 with regression coefficient (R2) = 0.97535.

View
Thumbnail Image
Publication

Potentials of MicroRNA in Early Detection of Ovarian Cancer by Analytical Electrical Biosensors

2022-01-01 , Nor Azizah Parmin , Uda Hashim , Subash Chandra Bose Gopinath , Nadzirah S. , Salimi M.N. , Voon Chun Hong , Muhammad Nur Aiman Uda , Muhammad Nur Afnan Uda , Rozi S.K.M. , Rejali Z. , Afzan A. , Azan M.I.A. , Yaakub A.R.W. , Hamzah A.A. , Dee C.F.

The importance of nanotechnology in medical applications especially with biomedical sensing devices is undoubted. Several medical diagnostics have been developed by taking the advantage of nanomaterials, especially with electrical biosensors. Biosensors have been predominantly used for the quantification of different clinical biomarkers toward detection, screening, and follow-up the treatment. At present, ovarian cancer is one of the severe complications that cannot be identified until it becomes most dangerous as the advanced stage. Based on the American Cancer Society, 20% of cases involved in the detection of ovarian cancer are diagnosed at an early stage and 80% diagnosed at the later stages. The patient just has a common digestive problem and stomach ache as early symptoms and people used to ignore these symptoms. Micro ribonucleic acid (miRNA) is classified as small non-coding RNAs, their expressions change due to the association of cancer development and progression. This article reviews and discusses on the currently available strategies for the early detection of ovarian cancers using miRNA as a biomarker associated with electrical biosensors. A unique miRNA-based biomarker detections are specially highlighted with biosensor platforms to diagnose ovarian cancer.

View
Thumbnail Image
Publication

Functionalized carbon black in epoxy composites: effect of single- and dual-matrix systems

2022-07-01 , Phua J.L. , Teh Pei Leng , Yeoh C.K. , Voon Chun Hong

Functionalized carbon black (CB) using three different surface modification methods: wet oxidation, epoxy monomer impregnation, and air oxidation, in single-epoxy composites and dual-matrix epoxy/poly(methyl methacrylate) PMMA composites at 15 vol% of CB content was studied in this research. The characterization on the surface modification CB was done via Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller (BET), and thermal gravimetric analysis. The phenol or ether, carboxylic acid, and epoxide functional groups were found on CB after surface modifications, along with a change in structure and BET surface area. Thermal degradation of CB was different after surface modification. This study further investigated the effect of the addition of surface-modified CB into epoxy resin, where the state of dispersion and distribution was observed under scanning electron microscopy. After surface modification, the mechanical testing via flexural and fracture toughness was done, where improvement was observed. A minor decrease in the electrical bulk conductivity of the composites was measured, which was due to a reduction in the degree of agglomeration. Both the thermal stability and CTE of surface-modified CB-filled epoxy composites show a decrement. Graphic abstract: Chemical modification of CB using air oxidation, wet oxidation, and epoxy monomer impregnation methods.[Figure not available: see fulltext.]

View
Thumbnail Image
Publication

Oil palm lignin-derived laser scribed graphene in neutral electrolyte for high-performance microsupercapacitor application

2023-10-01 , Remesh S. , Vasudevan M. , Perumal V. , Ovinis M. , Karuppanan S. , Edison T.N.J.I. , Raja P.B. , Ibrahim M.N.M. , Voon Chun Hong , Arumugam N. , Kumar R.S.

Lignin is a renewable natural resource that could be derived from oil palm empty fruit bunches. It has generated significant interest as a precursor in synthesizing graphene as anode and cathode material for supercapacitors. In this paper, we report the synthesis of 3D hierarchical Laser Scribed Graphene (LSG) on a flexible polyimide substrate from lignin extracted from empty fruit bunches (EFB) of oil palm for microsupercapacitor applications. The intensity and speed of the laser have been tuned to yield densely compacted oil palm lignin LSG at a laser power of 70% and a speed of 30% (OPL-LSG 7030). OPL-LSG 7030 possessed lower equivalent series resistance of 60.1 Ω and a larger crystalline size of ∼31 nm than the rest of the tested samples. It exhibited exceptional areal capacitance of 30.77 mFcm−2 at a current density of 0.08 mAcm−2, an energy density of 0.00176 mWhcm−2 and a power density of 0.25 mWcm−2 when using a unique neutral PAAS/K2SO4 gel electrolyte. It achieved excellent capacitance retention of 88.4% after 5000 charge/discharge cycles and remarkable mechanical stability of 95% after 400 bending cycles. Furthermore, electrochemical studies revealed the redox properties of readily available quinone/ hydroquinone in the oil palm lignin, which could be inherited in graphene electrodes through a feasible and affordable approach for flexible green energy storage applications.

View
Thumbnail Image
Publication

Voltammetric DNA Biosensor for Human Papillomavirus (HPV) Strain 18 Detection

2020-07-09 , Mhd Akhir M.A. , Nor Azizah Parmin , Uda Hashim , Subash Chandra Bose Gopinath , Rejali Z. , Afzan A. , Muhammad Nur Aiman Uda , Muhammad Nur Afnan Uda , Voon Chun Hong

This research was developed to focus on the study of the voltammetric DNA biosensor for the detection of HPV strain 18. In this research, electrical DNA biosensor was expected to detect HPV strain 18 more efficiently by using electrical characterization. In this project, device inspection was conducted to make sure the functional of the gold interdigitated electrode (IDE) by using Scanning Electron Microscope (SEM). 3-Aminopropyl Triethoxysilane (APTES) solution was used for the process of surface modification to form the amine group on the surface of the device to facilitate the attachment of the DNA probe. In this project, synthetic DNA sample and DNA from the saliva of several Biosystems Engineering students were used as the target DNA. The current-voltage (I-V) electrical characterization was conducted to detect the presence of HPV strain 18 in both DNA samples. As the results, perfect alignment between the electrodes on the IDE was detected under SEM. Surface modification of the biosensor successfully conducted which is the covalent bond between APTES and DNA probe increase the electrical. Synthetic DNA shows the presence of HPV strain 18 while there was no HPV strain 18 detected in the DNA from saliva samples.

View
Thumbnail Image
Publication

Gold-Nanohybrid Biosensors for Analyzing Blood Circulating Clinical Biomacromolecules: Current Trend toward Future Remote Digital Monitoring

2022-01-01 , Letchumanan I. , Subash Chandra Bose Gopinath , Mohd Khairuddin Md Arshad , Mohamed Saheed M.S. , Perumal V. , Voon Chun Hong , Uda Hashim

Mortality level is worsening the situation worldwide thru blood diseases and greatly jeopardizes the human health with poor diagnostics. Due to the lack of successful generation of early diagnosis, the survival rate is currently lower. To overcome the present hurdle, new diagnostic methods have been choreographed for blood disease biomarkers analyses with the conjunction of ultra-small ideal gold nanohybrids. Gold-hybrids hold varieties of unique features, such as high biocompatibility, increased surface-to-volume ratio, less-toxicity, ease in electron transfer and have a greater localized surface plasmon resonance. Gold-nanocomposites can be physically hybrid on the sensor surface and functionalize with the biomolecules using appropriate chemical conjugations. Revolutionizing biosensor platform can be prominently linked for the nanocomposite applications in the current research on medical diagnosis. This review encloses the new developments in diagnosing blood biomarkers by utilizing the gold-nanohybrids. Further, the current state-of-the-art and the future envision with digital monitoring for facile telediagnosis were narrated.

View
Thumbnail Image
Publication

Effect of zinc oxide suspension on the overall filler content of the PLA/ZnO composites and cPLA/ZnO composites

2023-01-01 , Tan M.A. , Yeoh Cheow Keat , Teh P.L. , Nor Azura Abdul Rahim , Song C.C. , Voon Chun Hong

This work aimed to study the effect of zinc oxide (ZnO) filler suspension on the mechanical, electrical, and thermal properties of polylactic acid (PLA)/ZnO and cPLA/ZnO. Fused deposition modelling, one of the additive manufacturing methods, was used to fabricate the PLA specimen. PLA was used as the main material in this project, and the ZnO suspension was added during the printing process. The speed of the dispenser (low speed = 1,000 rpm, medium speed = 1,400 rpm, and high speed = 1,800 rpm) was the parameter that was varied to control the filler content of the composite. All the samples underwent a tensile test to determine the mechanical properties, followed by the scanning electron microscopy (SEM) test to analyse the fracture surface properties of the tensile test. SEM observations showed the PLA samples' inherent smooth appearance, but the PLA/ZnO composite showed a rougher surface. PLA and cPLA composites showed an enhanced storage modulus but lower loss modulus than the pure samples. Because of the high thermal and electrical conductivity of carbon black and ZnO, cPLA composites had higher electrical and thermal conductivity than PLA composites.

View