Subash Chandra Bose Gopinath
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Preferred name
Subash Chandra Bose Gopinath
Official Name
Subash Chandra Bose, Gopinath
Alternative Name
Gopinath, S.
Gopinath, S. C.B
Subash Gopinath, C. B.
Subash, Gopinath
Subash C. B. Gopinath
Main Affiliation
Scopus Author ID
7006558013
Researcher ID
D-2953-2015

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Titanium dioxide–mediated resistive nanobiosensor for E. coli O157:H7

2020-04-01 , Nadzirah S. , Uda Hashim , Subash Chandra Bose Gopinath , Nor Azizah Parmin , Hamzah A.A. , Yu H.W. , Dee C.F.

A titanium dioxide nanoparticle (TiO2 NP)–mediated resistive biosensor is described for the determination of DNA fragments of Escherichia coli O157:H7 (E. coli O157:H7). The sol-gel method was used to synthesize the TiO2 NP, and microlithography was applied to fabricate the interdigitated sensor electrodes. Conventional E. coli DNA detections are facing difficulties in long-preparation-and-detection-time (more than 3 days). Hence, electronic biosensor was introduced by measuring the current-voltage (I–V) DNA probe without amplification of DNA fragments. The detection scheme is based on the interaction between the electron flow on the sensor and the introduction of negative charges from DNA probe and target DNA. The biosensor has a sensitivity of 1.67 × 1013 Î©/M and a wide analytical range. The limit detection is down to 1 × 10−11 M of DNA. The sensor possesses outstanding repeatability and reproducibility and is cabable to detect DNA within 15 min in a minute-volume sample (1 Î¼L). [Figure not available: see fulltext.].

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The study of sensing elements parameters optimization for developed biosensor of SARS-CoV-2 detection

2023-04 , Fatin Syakirah Halim , Nor Azizah Parmin , Uda Hashim , Subash Chandra Bose Gopinath , Farrah Aini Dahalan , Iffah Izzati Zakaria , Wei Chern Ang , Nurfareezah Nadhirah Jaapar

New advancements in developing sensitive and selective biosensors have demonstrated outstanding potential for Deoxyribonucleic Acid (DNA biosensors). The detection mode of DNA biosensors primary depends on a particular DNA hybridization that precisely occurs on the surface of the physical transducer that can only be detected using high-performance assays due to slight current changes. The analytical performance (sensitivity) of the DNA biosensor is conclusively rely on the confluence constructing of the sensing surface, which must be optimized. Thus, in this study, the sensing elements of the developed biosensors were optimized for detecting RNA of SARS-CoV-2. This optimization included concentration of nanomaterials (carbon quantum dots), probe density (concentration of DNA probe) and concentration of linker (APTES). It was observed that 0.15 % V/V of concentration CQD, 0.1μM of DNA probe and 36% V/V of APTES were the optimum parameters which provided their maximum response during electrical measurements and increased the sensitivity of the developed biosensor for SARS-CoV-2 detection

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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.

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A potent anticoagulant hybrid of snake venom derived FIX-binding protein and anti-factor IX RNA aptamer: Assessed by in-silico and electrochemical analyses

2023-08-30 , Krishnan H. , Subash Chandra Bose Gopinath

Anticoagulant therapies are crucial in the management of surgical complications as well as the prophylaxis of thrombosis. Many studies are being conducted on the Habu snake-venom anticoagulant, FIX-binding protein (FIX-Bp), for its greater potency and strong affinity to FIX clotting factor. On the other hand, the capacity to promptly reverse such acute anticoagulation is equally important. Combining a reversible anticoagulant with FIX-Bp may be advantageous in maintaining the balance between adequate anticoagulation and repealing when necessary. In this study, authors integrated FIX-Bp and RNA aptamer-based anticoagulants into a single target, FIX clotting factor, in order to achieve a robust anticoagulant effect. An in-silico and electrochemical approach were used to investigate the combination of FIX-Bp and RNA aptamers as a bivalent anticoagulant and to verify the competing or predominant binding sites of each anticoagulant. The in-silico analysis discovered that both the venom- and aptamer-anticoagulant had a strong affinity for the FIX protein at the Gla-domain and EGF-1 domain by holding 9 conventional hydrogen bonds with the binding energy of −34.859 kcal/mol. The electrochemical technique verified that both anticoagulants had different binding sites. The impedance load upon RNA aptamer binding to FIX protein was 14 %, whereas the addition of FIX-Bp caused a significant impedance rise of 37 %. This indicates that the addition of aptamers prior to FIX-Bp is a promising strategy for the conception of a hybrid anticoagulant.

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Preliminary studies on antimicrobial activity of extracts from aloe vera leaf, citrus hystrix leaf, zingiber officinale and Sabah snake grass against bacillus subtilis

2018 , Muhammad Nur Aiman Uda , Subash Chandra Bose Gopinath , Nur Hulwani Ibrahim , Mohd Khairul Rabani Hashim , Nuradibah Mohd Amer , Midhat Nabil Ahmad Salimi , Tan Ewe Shen , Ong Yee Fen , Maisara Azad Mat Akhir , Uda Hashim

Herbal plants have several potential antimicrobial activities either as antifungal or antibacterial to fight against the disease and pathogen that attack the plants. The extractions of the Aloe vera leaf, Citrus hystrix leaf, Zingiber officinale rhizome and Sabah snake grass were selected in this study to fight against Bacillus subtilis. B. subtilis is a Gram-positive bacterium, rodshaped and catalase-positive that lives on decayed organic material. It is known as Gram-positive bacteria because of its thick peptidoglycan and would appear purple when subjected to Gram test. This species is commonly found in the upper layers of the soil, in meat or vegetables, in pastry, cooked meat, in bread or poultry products. The extracts of Sabah Snake Grass found to be most effective than A.vera leaf, Z. officinale, and C. hystrix against the B. subtilis.

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Integration of Aluminium Interdigitated Electrodes with Zinc Oxide as Nanocomposite for Selectively Detect Alpha-Synuclein for Parkinson's Disease Diagnosis

2021-12-14 , Adam H. , Subash Chandra Bose Gopinath , Uda Hashim

Parkinson's disease is associated with motor and non-motor symptoms, mostly a motor symptom such as tremor is said to be an early indication for Parkinson's disease development. Because of higher demands for faster and more precise diagnostic methods, it has sparked trends in the development of a biosensor for the diagnosis of Parkinson's disease. Therefore, this study has fabricated a biosensor that is capable of detecting a specific Parkinson's disease biomarker such as aggregation of alpha synuclein and this is crucial in reducing the burden of Parkinson's disease and to be able to detect the disease at the earlier stage. Finding the inconsistent aggregation of alpha-synuclein is a promising method for the early detection of Parkinson's disease. Using conventional photographic process, aluminium interdigitated electrodes (ALIDEs) have been fabricated and employed with sensitive electrochemical strategy for the specific detection of the Parkinson's disease antigen (alpha synuclein). The microelectrode was developed based on aluminium electrode sputtered on silicon substrate. Further, zinc oxide (ZnO) was deposited by sputtering on the working electrode of the ALIDEs using a spin-coating method. The ZnO nanocomposite onto aluminium microelectrode surface provides a favourable platform for efficient loading of antibody via binding with antigen alpha synuclein. The effective loading of the biomolecules (antibody and antigen) on the ZnO nanocomposite surface modified aluminium microelectrode was observed by SEM, AFM and 3D Profilometer. The current flow for each concentration of alpha synuclein was observed at 7.5×10−6 A (10 fM), 8.8×10−6 A (100 fM), and 8.5×10−6 A (1 pM) respectively.

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Spinal cord injury immunosensor: Sensitive detection of S100β on interdigitated electrode sensor

2023-09-01 , Zhang H. , Subash Chandra Bose Gopinath , Hu Y.

A spinal cord injury is damage to the nerves and cells that receive and provide a signal from the brain to the rest of the body. Spinal injury causes changes in movement, sensation, and strength, affect the body functions near the injury site, and may lead to paralysis. S100β was found as a suitable biomarker for identifying spinal cord injury and its causing problem. Herein, S100β immunoassay was developed on interdigitated electrode sensor to diagnose spinal cord injury. For effective anti-S100β antibody immobilization, the antibody was premixed with 3-Aminopropyl)triethoxsilane and then attached to the hydroxylated interdigitated electrode surface. This method of antibody immobilization enhanced the antibody attachment two-times than the method without premix. Antibody-attached surfaces increased current responses as S100 concentrations increased, and the limit of detection was seen to be 1 pg/mL on the linearity until 3000 pg/mL at an R2 value of 0.9907 [y = 7x - 6.4667]. Further, biofouling experiments with glial fibrillary acidic protein and γ-aminobutyric acid failed to enhance the current response, indicating the specific detection of S100β. This immunoassay identifies S100β at its lower level and helps to diagnose spinal cord injury and its related problem.

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Essential semiconductor films in micro-/nano-biosensors: Current scenarios

2021-10-01 , Subash Chandra Bose Gopinath , Ramanathan S. , Mohd Najib Mohd Yasin , Shapiai M.I. , Ismail Z.H. , Subramaniam S.

Background: Engineering nanoscale matter in a controlled functional system has expanded the area of science in the state-of-art of nanotechnology. The urgency in introducing real-time health monitoring sensors and rapid diagnostic tools in medical health is indeed high and crucial to date. The efforts are accompanied by nanotechnology to improve the sensors performances. In this line, semiconductor materials (Silicon/Silica) have been in well-focus to develop micro-/nano-sensors. Methods: Further, additional layering such as metal oxide and graphene material have elevated the current scenario in biosensor developments. Among these, two-dimensional graphene nanomaterial owns its remarkable mechanical, electronic, electrochemical, and optical properties, has excited the medical field to develop graphene-based biosensors for human health diagnosis and monitoring. The oxygen rich graphene materials enhance the bio-functionalization of recognition bio-elements for excellent graphene-based biosensor development. Significance: This review encloses the excellence of semiconductor materials in conjunction with biosensors for monitoring health and diagnosis. The advances and challenges encountered with developing semiconductors for nanobiosensors from laboratory set-up to the novel hand-held device for rapid and accurate human health care are outlined.

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Production and characterization of graphene from carbonaceous rice straw by cost-effect extraction

2021-05-01 , Muhammad Nur Aiman Uda , Subash Chandra Bose Gopinath , Uda Hashim , Halim N.H. , Nor Azizah Parmin , Muhammad Nur Afnan Uda , Anbu P.

This paper describes the synthesis of graphene-based activated carbon from carbonaceous rice straw fly ash in an electrical furnace and the subsequent potassium hydroxide extraction. The produced graphene has a proper morphological structure; flakes and a rough surface can be observed. The average size of the graphene was defined as up to 2000 nm and clarification was provided by high-resolution microscopes (FESEM and FETEM). Crystallinity was confirmed by surface area electron diffraction. The chemical bonding from the graphene was clearly observed, with –C=C– and O–H stretching at peaks of 1644 cm−1 and 3435 cm−1, respectively. Impurities in the graphene were found using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The measured size, according to zeta-potential analysis, was 8722.2 ± 25 nm, and the average polydispersity index was 0.576. The stability of the mass reduction was analyzed by a thermogravimetric at 100 Â°C, with a final reduction of ~ 11%.

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Optical properties of gallium nitride heterostructures grown on quartz using pulse laser deposition method

2024-06 , Abeer R. Abbasa , Makram A. Fakhri , Ali A. Alwahib , Motahher A. Qaeed , Subash Chandra Bose Gopinath

An optical analysis was conducted on a Gallium nitride (GaN) thin film grown on a quartz substrate using the physical vapor deposition technique (PVD), specifically, pulsed laser deposition (PLD). The film was grown using different laser wavelengths (1064, 532, and 355) nm from a Q-switch neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, all performed under a vacuum pressure of 10-2 m bar. The absorption coefficient of the GaN thin film was determined by performing UV-Vis diffused spectroscopy at room temperature and measuring wavelengths ranging from 200 to 1000 nm. The absorption peak occurs at 227 nm when the wavelength is 1064 nm, at 217 nm when the wavelength is 532 nm, and at 222 nm when the wavelength is 355 nm. The optical energy gap is a crucial statistic for analyzing the properties of thin films and assessing their potential as gas sensors. The value of the direct energy gap (Eg) for the prepared films was established by analyzing the graph that shows the relationship between (α h) and the energy gap (ev) values at different wavelengths. The energy values were determined to be 3.36 eV, 3.62 eV, and 3.7 eV for 1064, 532, and 355 nm wavelengths, respectively.

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