Publications 2023
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PublicationA quadruplet 3-D laser scribed graphene/MoS2 functionalised N2-doped graphene quantum dots and lignin-based Ag-nanoparticles for biosensing( 2023-12-31)Troponin I is a protein released into the human blood circulation and a commonly used biomarker due to its sensitivity and specificity in diagnosing myocardial injury. When heart injury occurs, elevated troponin Troponin I levels are released into the bloodstream. The biomarker is a strong and reliable indicator of myocardial injury in a person, with immediate treatment required. For electrochemical sensing of Troponin I, a quadruplet 3D laser-scribed graphene/molybdenum disulphide functionalised N2-doped graphene quantum dots hybrid with lignin-based Ag-nanoparticles (3D LSG/MoS2/N-GQDs/L-Ag NPs) was fabricated using a hydrothermal process as an enhanced quadruplet substrate. Hybrid MoS2 nanoflower (H3 NF) and nanosphere (H3 NS) were formed independently by varying MoS2 precursors and were grown on 3D LSG uniformly without severe stacking and restacking issues, and characterized by morphological, physical, and structural analyses with the N-GQDs and Ag NPs evenly distributed on 3D LSG/MoS2 surface by covalent bonding. The selective capture of and specific interaction with Troponin I by the biotinylated aptamer probe on the bio-electrode, resulted in an increment in the charge transfer resistance. The limit of detection, based on impedance spectroscopy, is 100 aM for both H3 NF and H3 NS hybrids, with the H3 NF hybrid biosensor having better analytical performance in terms of linearity, selectivity, repeatability, and stability.
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PublicationMicro-interdigitated electrodes genosensor based on Au-deposited nanoparticles for early detection of cervical cancer( 2023-12-31)Genosensor-based electrodes mediated with nanoparticles (NPs) have tremendously developed in medical diagnosis. Herein, we report a facile, rapid, low cost and highly sensitive biosensing strategy for early detection of HPV 18 using gold-nanoparticles (AuNPs) deposited on micro-IDEs. This study represents surface charge transduction of micro-interdigitated electrodes (micro-IDE) alumina insulated with silica, independent and mini genosensor modified with colloidal gold NPs (AuNPs), and determination of gene hybridization for early detection of cervical cancer. The surface of AuNPs deposited micro-IDE functionalized with optimized 3-aminopropyl-triethoxysilane (APTES) followed by hybridization with deoxyribonucleic acid (DNA) virus to develop DNA genosensor. The results of ssDNA hybridization with the ssDNA target of human papillomavirus (HPV) 18 have affirmed that micro-IDE functionalized with colloidal AuNPs resulted in the lowest detection at 0.529 aM. Based on coefficient regression, micro-IDE functionalized with AuNPs produces better results in the sensitivity test (R2 = 0.99793) than unfunctionalized micro-IDE.
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PublicationEncapsulation of Dicranopteris linearis extract using cellulose microparticles for antiulcer medication( 2023-12-31)Dicranopteris linearis (DL) is a fern in the Gleicheniaceae family, locally known as resam by the Malay community. It has numerous pharmacological benefits, with antiulcer and gastroprotective properties. Peptic ulcer is a chronic and recurring disease that significantly impacts morbidity and mortality, affecting nearly 20 % of the world's population. Despite the effectiveness of peptic ulcer drugs, there is no perfect treatment for the ailment. Encapsulation is an advanced technique that can treat peptic ulcers by incorporating natural sources. This work aims to encapsulate DL extract using different types of cellulose particles by the solvent displacement technique for peptic ulcer medication. The extract was encapsulated using methyl cellulose (MC), ethyl cellulose (EC), and a blend of ethyl methyl cellulose through a dialysis cellulose membrane tube and freeze-dried to yield a suspension of the encapsulated DL extracts. The microencapsulated methyl cellulose chloroform extract (MCCH) has a considerably greater level of total phenolic (84.53 ± 6.44 mg GAE/g), total flavonoid (84.53 ± 0.54 mg GAE/g), and antioxidant activity (86.40 ± 0.63 %). MCCH has the highest percentage of antimicrobial activity against Escherichia coli (2.42 ± 107 × 0.70 CFU/mL), Bacillus subtilis (5.21 ± 107 × 0.90 CFU/mL), and Shigella flexneri (1.25 ± 107 × 0.66 CFU/mL), as well as the highest urease inhibitory activity (50.0 ± 0.21 %). The MCCH particle size was estimated to be 3.347 ± 0.078 μm in diameter. It has been proven that DL elements were successfully encapsulated in the methyl cellulose polymer in the presence of calcium (Ca). Fourier transform infrared (FTIR) analysis indicated significant results, where the peak belonging to the C[dbnd]O stretch of the carbonyl groups of methyl cellulose (MC) shifted from 1638.46 cm−1 in the spectrum of pure MC to 1639.10 cm−1 in the spectrum of the MCCH extract. The shift in the wavenumbers was due to the interactions between the phytochemicals in the chloroform extract and the MC matrix in the microcapsules. Dissolution studies in simulated gastric fluid (SGF) and model fitting of encapsulated chloroform extracts showed that MCCH has the highest EC50 of 6.73 ± 0.27 mg/mL with R2 = 0.971 fitted by the Korsmeyer-Peppas model, indicating diffusion as the mechanism of release.
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PublicationZeolite nanomaterial-modified dielectrode oxide surface for diagnosing Alzheimer’s disease by dual molecular probed impedance sensor( 2023-12-01)Objectives: Alzheimer’s disease (AD) is an irreversible and progressive neurogenerative disorder, which affects the learning part of brain. It mainly affects the aged population and becoming a global health issue, expecting to increase more in near future. Late diagnosis of AD worsens the situation and difficult to treat the patient. Various biosensing techniques with suitable biomarkers have been developed by researchers to diagnose the earlier stages of AD. Methods: This research was focused to develop a highly sensitive zeolite-dual probe-modified impedance biosensor for identifying AD biomarker, Aβ Oligomer (AβO). The sensing surface was initially modified with zeolite through the chemical linker and then a dual probe of anti-AβO aptamer and anti-AβO antibody were attached to the surface of the zeolite. Results: On these dual probe-modified surfaces, AβO was quantified to diagnose AD. Further, AβO spiked artificial CSF was identified by dual probes without any interference, indicating the selective identification of AβO. In addition, control experiments with non-immune, complementary, and control proteins failed to show the increment of responses, confirming the specific detection of AβO. Conclusions: This zeolite-dual probe-modified biosensor helps to lower the limit of detection to 0.1 pM and diagnose AD at the earlier stages.
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PublicationNanomaterials in food industry for the protection from mycotoxins: an update( 2023-02-01)The storage of food grains against the fungal infection has been a great challenge to the farmers, but nanotechnology provides a solution to address this problem. The application of nanotechnology for the storage of food grains replaces synthetic fungicides in agriculture. Inorganic nanoparticles such as silver and zinc oxide are well-known for their antifungal activity. Green synthesized nanoparticles show enhanced antimicrobial activity than the chemically synthesized nanoparticles. Extracts and essential oils derived from plants exhibit very good antifungal properties. The synthesized nanoparticles can be impregnated in packaging materials, which are used to store food grains. Natural materials are having advantages like non-toxicity and easier to degrade and are suitable for food safety. This overview discusses the nanomaterials-mediated protection of food materials from mycotoxin and its releases into the open environment.
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