Prabakaran A/L Poopalan
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Prabakaran A/L Poopalan
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Prabakaran, A/L Poopalan
Alternative Name
Poopalan, P.
Poopalan, Prabakaran A.L.
Poopalan, Prabakaran
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Scopus Author ID
7003686974

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  • Publication
    Thickness dependent nanostructural, morphological, optical and impedometric analyses of Zinc Oxide-Gold hybrids : Nanoparticle to thin film
    ( 2015)
    Veeradasan Perumal
    ;
    Uda Hashim
    ;
    Subash Chandra Bose Gopinath
    ;
    R. Haarindraprasad
    ;
    Liu Wei Wen
    ;
    Prabakaran A/L Poopalan
    ;
    S. R. Balakrishnan
    ;
    V. Thivina
    ;
    Ruslinda A. Rahim
    ;
    Yogendra Kumar Mishra
    The creation of an appropriate thin film is important for the development of novel sensing surfaces, which will ultimately enhance the properties and output of high-performance sensors. In this study, we have fabricated and characterized zinc oxide (ZnO) thin films on silicon substrates, which were hybridized with gold nanoparticles (AuNPs) to obtain ZnO-Au x (x = 10, 20, 30, 40 and 50 nm) hybrid structures with different thicknesses. Nanoscale imaging by field emission scanning electron microscopy revealed increasing film uniformity and coverage with the Au deposition thickness. Transmission electron microscopy analysis indicated that the AuNPs exhibit an increasing average diameter (5–10 nm). The face center cubic Au were found to co-exist with wurtzite ZnO nanostructure. Atomic force microscopy observations revealed that as the Au content increased, the overall crystallite size increased, which was supported by X-ray diffraction measurements. The structural characterizations indicated that the Au on the ZnO crystal lattice exists without any impurities in a preferred orientation (002). When the ZnO thickness increased from 10 to 40 nm, transmittance and an optical bandgap value decreased. Interestingly, with 50 nm thickness, the band gap value was increased, which might be due to the Burstein-Moss effect. Photoluminescence studies revealed that the overall structural defect (green emission) improved significantly as the Au deposition increased. The impedance measurements shows an increasing value of impedance arc with increasing Au thicknesses (0 to 40 nm). In contrast, the 50 nm AuNP impedance arc shows an increased value compared to lower sputtering thicknesses, which indicated the presence of larger sized AuNPs that form a continuous film, and its ohmic characteristics changed to rectifying characteristics. This improved hybrid thin film (ZnO/Au) is suitable for a wide range of sensing applications.
  • Publication
    Low temperature annealed zinc oxide nanostructured thin film-based transducers: Characterization for sensing applications
    ( 2015)
    R. Haarindraprasad
    ;
    Uda Hashim
    ;
    Subash Chandra Bose Gopinath
    ;
    Muhammad Kashif
    ;
    P. Veeradasan
    ;
    S. R. Balakrishnan
    ;
    Foo Kai Loong
    ;
    Prabakaran A/L Poopalan
    The performance of sensing surfaces highly relies on nanostructures to enhance their sensitivity and specificity. Herein, nanostructured zinc oxide (ZnO) thin films of various thicknesses were coated on glass and p-type silicon substrates using a sol-gel spin-coating technique. The deposited films were characterized for morphological, structural, and optoelectronic properties by high-resolution measurements. X-ray diffraction analyses revealed that the deposited films have a c-axis orientation and display peaks that refer to ZnO, which exhibits a hexagonal structure with a preferable plane orientation (002). The thicknesses of ZnO thin films prepared using 1, 3, 5, and 7 cycles were measured to be 40, 60, 100, and 200 nm, respectively. The increment in grain size of the thin film from 21 to 52 nm was noticed, when its thickness was increased from 40 to 200 nm, whereas the band gap value decreased from 3.282 to 3.268 eV. Band gap value of ZnO thin film with thickness of 200 nm at pH ranging from 2 to 10 reduces from 3.263eV to 3.200 eV. Furthermore, to evaluate the transducing capacity of the ZnO nanostructure, the refractive index, optoelectric constant, and bulk modulus were analyzed and correlated. The highest thickness (200 nm) of ZnO film, embedded with an interdigitated electrode that behaves as a pH-sensing electrode, could sense pH variations in the range of 2-10. It showed a highly sensitive response of 444 μAmM-1cm-2 with a linear regression of R2 =0.9304. The measured sensitivity of the developed device for pH per unit is 3.72μA/pH.
  • Publication
    A Point-of-Care immunosensor for human chorionic gonadotropin in clinical urine samples using a cuneated polysilicon nanogap Lab-on-Chip
    ( 2015)
    S. R. Balakrishnan
    ;
    Uda Hashim
    ;
    Subash Chandra Bose Gopinath
    ;
    Prabakaran A/L Poopalan
    ;
    H. R. Ramayya
    ;
    M. Iqbal Omar
    ;
    R. Haarindraprasad
    ;
    P. Veeradasan
    Human chorionic gonadotropin (hCG), a glycoprotein hormone secreted from the placenta, is a key molecule that indicates pregnancy. Here, we have designed a cost-effective, label-free, in situ point-of-care (POC) immunosensor to estimate hCG using a cuneated 25 nm polysilicon nanogap electrode. A tiny chip with the dimensions of 20.5 × 12.5 mm was fabricated using conventional lithography and size expansion techniques. Furthermore, the sensing surface was functionalized by (3-aminopropyl)triethoxysilane and quantitatively measured the variations in hCG levels from clinically obtained human urine samples. The dielectric properties of the present sensor are shown with a capacitance above 40 nF for samples from pregnant women; it was lower with samples from non-pregnant women. Furthermore, it has been proven that our sensor has a wide linear range of detection, as a sensitivity of 835.88 μA mIU-1 ml-2 cm-2 was attained, and the detection limit was 0.28 mIU/ml (27.78 pg/ml). The dissociation constant Kd of the specific antigen binding to the anti-hCG was calculated as 2.23 ± 0.66 mIU, and the maximum number of binding sites per antigen was Bmax = 22.54 ± 1.46 mIU. The sensing system shown here, with a narrow nanogap, is suitable for high-throughput POC diagnosis, and a single injection can obtain triplicate data or parallel analyses of different targets.
  • Publication
    Thickness dependent nanostructural, morphological, optical and impedometric analyses of Zinc Oxide-Gold Hybrids: Nanoparticle to thin film
    ( 2015)
    Veeradasan Perumal
    ;
    Uda Hashim
    ;
    Subash Chandra Bose Gopinath
    ;
    R. Haarindraprasad
    ;
    Liu Wei Wen
    ;
    Prabakaran A/L Poopalan
    ;
    S. R. Balakrishnan
    ;
    V. Thivina
    ;
    Ruslinda A. Rahim
    The creation of an appropriate thin film is important for the development of novel sensing surfaces, which will ultimately enhance the properties and output of high-performance sensors. In this study, we have fabricated and characterized zinc oxide (ZnO) thin films on silicon substrates, which were hybridized with gold nanoparticles (AuNPs) to obtain ZnO-Aux (x = 10, 20, 30, 40 and 50 nm) hybrid structures with different thicknesses. Nanoscale imaging by field emission scanning electron microscopy revealed increasing film uniformity and coverage with the Au deposition thickness. Transmission electron microscopy analysis indicated that the AuNPs exhibit an increasing average diameter (5–10 nm). The face center cubic Au were found to co-exist with wurtzite ZnO nanostructure. Atomic force microscopy observations revealed that as the Au content increased, the overall crystallite size increased, which was supported by X-ray diffraction measurements. The structural characterizations indicated that the Au on the ZnO crystal lattice exists without any impurities in a preferred orientation (002). When the ZnO thickness increased from 10 to 40 nm, transmittance and an optical bandgap value decreased. Interestingly, with 50 nm thickness, the band gap value was increased, which might be due to the Burstein-Moss effect. Photoluminescence studies revealed that the overall structural defect (green emission) improved significantly as the Au deposition increased. The impedance measurements shows a decreasing value of impedance arc with increasing Au thicknesses (0 to 40 nm). In contrast, the 50 nm AuNP impedance arc shows an increased value compared to lower sputtering thicknesses, which indicated the presence of larger sized AuNPs that form a continuous film, and its ohmic characteristics changed to rectifying characteristics. This improved hybrid thin film (ZnO/Au) is suitable for a wide range of sensing applications.
  • Publication
    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.
  • Publication
    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.
  • Publication
    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).
  • Publication
    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.
  • Publication
    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.
  • Publication
    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.