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Surface charge transduction enhancement on nano-silica and - Alumina integrated planar electrode for hybrid DNA determination

2021-06-01 , Ramanathan S. , Prabakaran A/L Poopalan , Subash Chandra Bose Gopinath , Mohd Khairuddin Md Arshad , Anbu P. , Lakshmipriya T. , Salimi M.N. , Pandian K.

This study represents the surface charge transduction, an efficient and inexpensive biosensor with modifications by silica-alumina entities and determination of gene sequence hybridization. The sensing surface was made by the planar aluminium interdigitated electrode on silicon substrate. Silica and alumina nanoparticles were engineered on the planar transducer surface and the device sensitivity was investigated. The morphology of silica and alumina particles was characterized through the high-resolution election microscopic analyses and revealed the spherical shaped nanoscale sizes at the range of 45–100 nm. The elemental compositions of silica and alumina nanomaterial were affirmed through energy disperse spectroscopy as prominent peaks of Si, Al and O were observed. Selected area electron diffraction analysis of silica and alumina justified their crystalline and amorphous nature, respectively. XRD analysis revealed the expending cristobalite state of silica crystal and γ-alumina for planar electrode surface enhancement. Fourier transform infrared spectroscopy peak observed at 1094 cm−1 revealed the asymmetric stretching of silica nanoparticles whereas the projecting peak observed at 806 cm−1. Additionally, Al–O stretch and Al–O–Al bending modes were justified with the peaks at 585 and 825 cm−1, respectively. Band gap values of silica and alumina computed were 6.75 eV and 3.20 eV, respectively. The results of DNA probe immobilization and complementation have affirmed that silica modified transducer shows the lowest detection at 10 aM whereas alumina modified transducer displayed insignificant current signal and failed to detect DNA hybridization. To investigate the effect of silica entity and its nanocomposite in detecting DNA hybridization, aluminosilicate nanocomposite was deposited on transducer and attained highly sensitive gene detection. Based on the coefficient regression value, aluminosilicate nanocomposite modified planar transducer has shown good device sensitivity (R2 = 0.96) in contrast to silica and alumina entities.

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Nanostructured aluminosilicate from fly ash: Potential approach in waste utilization for industrial and medical applications

2020-04-20 , Ramanathan S. , Subash Chandra Bose Gopinath , Arshad M. , Prabakaran A/L Poopalan

Fly ash is found as a significant solid waste released from power plants to the atmosphere, but its qualitative and quantitative consumptions for the sustainability are ambiguous. The main issues aroused with the disposal of fly ash are the requirement of a large land area for landfills, cause toxicity and pollution to the soil and groundwater due to the accumulation of heavy metals. Although fly ash is highly recommended for soil amelioration and cement manufacturing, the ultimate usage of the solid waste causes unsatisfactory effect to the ground system and cementitious product, respectively. Apart from direct utilization and disposal of fly ash, it has been well reported in literature for the synthesis of nanosized particles due to its enrichment in silica, kaolin, iron, and alumina. With this regard, aluminosilicates have been acknowledged as one of the prospective nanocomposites synthesized from fly ash. It has proven that naturally occurring geopolymerization of fly ash under alkaline medium results is in the formation of aluminosilicates. As such, synthetic aluminosilicates were highly encouraged to extract from fly ash in large scale due to their excellent physiochemical properties and applications. This overview intends to fill-up the knowledge gap through critically reviewing about fly ash waste for the synthesis of aluminosilicate nanocomposite. The applications of fly ash derived aluminosilicates in industries such as wastewater treatment, agriculture system and as antioxidants are gleaned. Besides the heavy industrial potential, this review encompasses the prospective alternative consumption of fly ash for the production of nanostructured aluminosilicates and their comprehensive assessment in medical applications, especially in drug carrier and drug delivery systems, bone engineering, biosensors, hemodialysis, and intestinal therapeutics.

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Nanoparticle synthetic methods: Strength and limitations

2020-01-01 , Ramanathan S. , Subash Chandra Bose Gopinath , Mohd Khairuddin Md Arshad , Prabakaran A/L Poopalan , Perumal V.

Nanoparticles (NPs) are produced through nanotechnology development by reducing the metal to its nuclear size. NP synthesis includes a few techniques, such as physical, chemical, and biological techniques. Physical methods avoid NP solvent contamination but it is not negligible to consume a large quantity of energy for condensation and evaporation of particles. In addition, extremely high modulation of temperature and pressure indirectly expends the cost of NPs synthesis. In the chemical technique, reducing agents and protective agents are used to synthesize NP and prevent agglomeration in order to synthesize high purity and stable NP. High intake of strong chemicals leads to contamination of the synthetic NP. In comparison to NP’s synthesis by chemical and physical techniques, the interest in NP biological synthesis has concentrated on its ecofriendly and effective technique. The biological technique used under green synthesis differs with the type of reduction agent used as microorganisms (bacteria and fungi) and plants and their extracts. Exclusion in the consumption of powerful chemical agents and set-up of high-energy reactions highlights the significant benefits of biological technique in NP synthesis. Thus, the synthesis of NP with plant extracts by biological method is the appealing technique for a large-scale production of NP and has a higher potential in significant medicinal applications.

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Aptasensing nucleocapsid protein on nanodiamond assembled gold interdigitated electrodes for impedimetric SARS-CoV-2 infectious disease assessment

2022-02-01 , Ramanathan S. , Subash Chandra Bose Gopinath , Ismail Z.H. , Mohd Khairuddin Md Arshad , Prabakaran A/L Poopalan

In an aim of developing portable biosensor for SARS-CoV-2 pandemic, which facilitates the point-of-care aptasensing, a strategy using 10 μm gap-sized gold interdigitated electrode (AuIDE) is presented. The silane-modified AuIDE surface was deposited with ∼20 nm diamond and enhanced the detection of SARS-CoV-2 nucleocapsid protein (NCP). The characteristics of chemically modified diamond were evidenced by structural analyses, revealing the cubic crystalline nature at (220) and (111) planes as observed by XRD. XPS analysis denotes a strong interaction of carbon element, composed ∼95% as seen in EDS analysis. The C–C, C[dbnd]C, C[dbnd]O, C[dbnd]N functional groups were well-refuted from XPS spectra of carbon and oxygen elements in diamond. The interrelation between elements through FTIR analysis indicates major intrinsic bondings at 2687-2031 cm−1. The aptasensing was evaluated through electrochemical impedance spectroscopy measurements, using NCP spiked human serum. With a good selectivity the lower detection limit was evidenced as 0.389 fM, at a linear detection range from 1 fM to 100 pM. The stability, and reusability of the aptasensor were demonstrated, showing ∼30% and ∼33% loss of active state, respectively, after ∼11 days. The detection of NCP was evaluated by comparing anti-NCP aptamer and antibody as the bioprobes. The determination coefficients of R2 = 0.9759 and R2 = 0.9772 were obtained for aptamer- and antibody-based sensing, respectively. Moreover, the genuine interaction of NCP aptamer and protein was validated by enzyme linked apta-sorbent assay. The aptasensing strategy proposed with AuIDE/diamond enhanced sensing platform is highly recommended for early diagnosis of SARS-CoV-2 infection.

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Nanoparticle synthetic methods: Strength and limitations

2020-01-01 , Ramanathan S. , Subash Chandra Bose Gopinath , Mohd Khairuddin Md Arshad , Prabakaran A/L Poopalan , Perumal V.

Nanoparticles (NPs) are produced through nanotechnology development by reducing the metal to its nuclear size. NP synthesis includes a few techniques, such as physical, chemical, and biological techniques. Physical methods avoid NP solvent contamination but it is not negligible to consume a large quantity of energy for condensation and evaporation of particles. In addition, extremely high modulation of temperature and pressure indirectly expends the cost of NPs synthesis. In the chemical technique, reducing agents and protective agents are used to synthesize NP and prevent agglomeration in order to synthesize high purity and stable NP. High intake of strong chemicals leads to contamination of the synthetic NP. In comparison to NP’s synthesis by chemical and physical techniques, the interest in NP biological synthesis has concentrated on its ecofriendly and effective technique. The biological technique used under green synthesis differs with the type of reduction agent used as microorganisms (bacteria and fungi) and plants and their extracts. Exclusion in the consumption of powerful chemical agents and set-up of high-energy reactions highlights the significant benefits of biological technique in NP synthesis. Thus, the synthesis of NP with plant extracts by biological method is the appealing technique for a large-scale production of NP and has a higher potential in significant medicinal applications.

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Aluminosilicate Nanocomposites from Incinerated Chinese Holy Joss Fly Ash: A Potential Nanocarrier for Drug Cargos

2020-02-25 , Ramanathan S. , Subash Chandra Bose Gopinath , Mohd Khairuddin Md Arshad , Prabakaran A/L Poopalan , Anbu P. , Lakshmipriya T.

An incredible amount of joss fly ash is produced from the burning of Chinese holy joss paper; thus, an excellent method of recycling joss fly ash waste to extract aluminosilicate nanocomposites is explored. The present research aims to introduce a novel method to recycle joss fly ash through a simple and straightforward experimental procedure involving acidic and alkaline treatments. The synthesized aluminosilicate nanocomposite was characterized to justify its structural and physiochemical characteristics. A morphological analysis was performed with field-emission transmission electron microscopy, and scanning electron microscopy revealed the size of the aluminosilicate nanocomposite to be ~25 nm, while also confirming a uniformly spherical-shaped nanostructure. The elemental composition was measured by energy dispersive spectroscopy and revealed the Si to Al ratio to be 13.24 to 7.96, showing the high purity of the extracted nanocomposite. The roughness and particle distribution were analyzed using atomic force microscopy and a zeta analysis. X-ray diffraction patterns showed a synthesis of faceted and cubic aluminosilicate crystals in the nanocomposites. The presence of silica and aluminum was further proven by X-ray photoelectron spectroscopy, and the functional groups were recognized through Fourier transform infrared spectroscopy. The thermal capacity of the nanocomposite was examined by a thermogravimetric analysis. In addition, the research suggested the promising application of aluminosilicate nanocomposites as drug carriers. The above was justified by an enzyme-linked apta-sorbent assay, which claimed that the limit of the aptasensing aluminosilicate-conjugated ampicillin was two-fold higher than that in the absence of the nanocomposite. The drug delivery property was further justified through an antibacterial analysis against Escherichia coli (gram-negative) and Bacillus subtilis (gram-positive).

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Alkalinized extraction of silica-aluminium nanocomposite from traditional Chinese joss paper: Optical characterizations

2020-03-01 , Ramanathan S. , Subash Chandra Bose Gopinath , Mohd Khairuddin Md Arshad , Prabakaran A/L Poopalan , Anbu P. , Lakshmipriya T. , Lee C.G.

The Chinese traditional joss paper has been recycled and silica and aluminium nanocomposite production is reported in the current research, using an alkalinization procedure. Characterization of silica and aluminium nanocomposite extracted was performed using field-emission transmission electron microscope (FETEM), field-emission scanning electron microscope (FESEM), UV–visible spectroscopy, high-power optical microscopy (HPM) and 3D nano profiler, indicates the size, shape and particle distribution, eventually reveals the purity of silica and aluminium nanocomposite synthesized. The silica-aluminium nanocrystal synthesized from joss paper waste was found to be ~15 nm size range under FETEM analysis and FESEM analysis revealed the uniform spherical shape. The energy disperse spectroscopy (EDX) data attained from FESEM analysis affirmed the synthesis of silica-aluminium nanocomposite with greater purity since the ratio of silicon to aluminium observed in EDX spectra was 13.24 to 7.96. HPM indicated the size of agglomerated aluminosilicate is 36.74 μm whereas 3D nano profiler has proven that the height of nanocrystal synthesized from joss paper waste is 234.37 μm. Band gap value of 3.84 eV, calculated using UV–vis absorbance readings further affirmed the size of nanocomposite which is in good agreement with presented results.