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Öğe Acetylsalicylic acid assisted hydrothermal growth of NiO, CuO and Co3O4 nanostructures and their application in the electro-catalytic determination of nalbuphine hydrochloride(ELSEVIER SCIENCE SA, 2017) Kalwar, Nazar Hussain; Tunesi, Mawada Mohamed; Soomro, Razium Ali; Amir, Md.; Avci, Ahmet; Hallam, Keith Richard; Kilislioglu, AybenThis study describes the hydrothermal synthesis of NiO, CuO and Co3O4 nanostructures using acetylsalicylic acid (ASA) as a growth-controlling/directing agent. The as-synthesised nanostructures were shown to possess unique structural features and distinct morphologies, portraying the efficiency of ASA as a suitable growth modifier. The formed metal oxide nanostructures, when used for electrode modification purposes, exhibited excellent electrocatalytic capabilities against the oxidation of nelbuphine hydrochloride (NAL) in aqueous buffer solution. The modified electrodes exhibited distinct electrochemical characteristics, with CuO-based electrodes exhibiting a superior signal sensitivity and lower over-potential value compared to the NiO and Co3O4 nanostructures. The study further explores the variation in the observed electro-catalytic oxidation signal referenced to the distinct morphologies of the metal oxides nanostructures. The CuO-based electrode was selected for the sensitive quantification of NAL in aqueous solution over the linear range 0.001-2.25 mu M. The electrode demonstrated excellent working linearity, with signal sensitivity achieved down to 1 x 10(-4) mu M. Moreover, the successful quantification of NAL in complex matrices, such as human urine and clinical waste water, further reflected the analytical capability of the proposed sensor.Öğe Enzyme-free colorimetric sensing of glucose using L-cysteine functionalized silver nanoparticles(SPRINGER INTERNATIONAL PUBLISHING AG, 2019) Adnan, Sumaira; Kalwar, Nazar Hussain; Abbas, Malik Waseem; Soomro, Razium Ali; Saand, Mumtaz Ali; Awan, Fazli Rabbi; Avcı, Ahmet; Pehlivan, Erol; Bajwa, SadiaThe study demonstrates an efficient, simple and on-site viable approach for sensitive determination of blood glucose using colorimetric sensing approach. The devised colorimetric sensor works based on cysteine functionalized silver nanoparticles. The as-synthesized Ag NPs were elaborately characterized using advanced analytical techniques such as ultra-violet visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, atomic force microscopy and X-ray diffraction. The detection of glucose was carried under ambient air conditions where change in the optical characteristics of Ag NPs and subsequent interaction between glucose and functional moiety (i.e. surface bind cysteine) of Ag NPs was considered as the signal response. This interaction led to direct detection of glucose in the concentration range between 0.01 to 0.17 mu M with limit of detection up to 1 x 10(-4) mu M. It is worthwhile mentioning that success of the assay lies in application of the developed colorimetric sensor in real blood glucose measurements, which also proved its capability for field based analysis. In addition its simple design, low cost, and more reliability signifies the usefulness of colorimetric sensor and it can be extended monitor other biologically important molecules.Öğe Functionalised CuO nanostructures for the detection of organophosphorus pesticides: A non-enzymatic inhibition approach coupled with nano-scale electrode engineering to improve electrode sensitivity(ELSEVIER SCIENCE SA, 2018) Tunesi, Mawada Mohamed; Kalwar, Nazar; Abbas, Malik Waseem; Karakus, Selcan; Soomro, Razium Ali; Kilislioglu, Ayben; Abro, Muhammad IshaqThis study explores the potential of a newly-developed indium tin oxide (ITO) based electrode for the development of an electro-catalytic inhibition sensor system for organophosphorus pesticides. The sensor relies on the redox signal inhibition of pralidoxime chloride (PAM) immobilised over the pimelic acid functionalised CuO nanostructures grown in-situ over an ITO substrate. The in-situ growth enabled on-pot modification and functionalisation of ITO electrodes with the formation of uniform nanostructures possessing high surface area and excellent interface contact. The versatility of the proposed electrode was evident from its excellent electrochemical characteristics evaluated in comparison to bare and slurry-driven glassy carbon electrodes (GCEs). The high structural uniformity and greater surface coverage achieved by in-situ growth provided a uniform surface environment for electrode-analyte interaction, leading to good inhibition signal sensitivity and repeatability. The developed sensor was successful in detecting chlorpyrifos, fenthion and methyl parathion within the concentration range of 0.01-0.16 mu M with signal sensitivity reaching down to 1.6 x 10(-9), 2.5 x 10(-9) and 6.7 x 10(-9) M respectively. Moreover, the proposed sensor demonstrated excellent applicability when tested for chlorpyrifos from vegetable extracts using a standard addition method. (c) 2018 Elsevier B.V. All rights reserved.Öğe In-situ growth of NiWO4 saw-blade-like nanostructures and their application in photo-electrochemical (PEC) immunosensor system designed for the detection of neuron-specific enolase(ELSEVIER ADVANCED TECHNOLOGY, 2019) Soomro, Razium Ali; Kalwar, Nazar Hussain; Avci, Ahmet; Pehlivan, Erol; Hallam, Keith Richard; Willander, MagnusThis study describes the construction of highly-sensitive photo-electrochemical (PEC) immunosensor for the detection of neuron-specific enolase (NSE). The biosensing platform is comprised of photo-active NiWO4 nanostructures, in-situ-grown over a conductive substrate (indium tin oxide) using a low-temperature template-based co-precipitation approach. The discussed approach enables the formation of discrete, yet morphologically-analogous, nanostructures with complete coverage (pinhole-free) of the electrode surface. The in-situ-grown nanostructure possess dense population with sharp saw-blade like morphological features that can support substantial immobilisation of anti-NSE agent. The constructed platform demonstrated excellent photo-catalytic activity towards uric acid (UA) which served as the base for the Electrochemical -mechanism (EC) based PEC inhibition sensing. The detection of NSE, relied on its obstruction in analytical signal observed for the photo-oxidation of UA after binding to the electrode surface via protein-antibody interaction. The constructed PEC immunosensor exhibits signal sensitivity up to 0.12 ng mL(-1) of NSE with excellent signal reproducibility and electrode replicability. Moreover, the constructed platform was successfully used for NSE determination in human serum samples.Öğe L-lysine derived nickel nanoparticles for reductive degradation of organic dyes(VBRI Press, 2016) Khaskheli, Abdul Rauf; Naz, Saba; Soomro, Razium Ali; Özül, Faruk; Aljabour, Abdalaziz; Kalwar, Nazar Hussain; Mahesar, Abdul Waheed; Patır, Hatay İmren; Ersöz, MustafaThis report demonstrates a facile and green fabrication method for the nickel nanoparticles using L-lysine as an efficient protecting agent. The application of green amino acid (L-lysine) enabled formation highly spherical and well-dispersed nanoparticles with average diameter in the range of 10 ±2.5 nm. UV-Vis spectroscopy was used as a primary tool to elaborately study and optimize the necessary experimental condition for the developed synthetic protocol. Fourier transform infrared spectroscopy (FTIR) was used to confirm the surface protection of Ni NPs via L-lysine molecules whereas; atomic force microscopy (AFM) and scanning electron microscopy (SEM) provided morphological and topographical view of the as-synthesized Ni NPs. In addition, small angle X-ray scattering (SAXS) and X-ray diffraction (XRD) were used to evaluate compositional characteristics of fabricated L-lysine protected Ni NPs. The as-synthesized Ni NPs demonstrated excellent catalytic potential when utilized as heterogeneous catalyst for reduction of methylene Blue (MB) in the presence of sodium borohydride (NaBH4). The observed catalytic reaction was determined to follow pseudo first order kinetics with rate constant (K) and turn over frequency (TOF) determined to be 0.0224 and TOF value of 0.00411 s-1 respectively. © 2016 VBRI Press.Öğe Tartaric acid assisted in-situ growth of CuO nanostructures over ITO substrate for the electrocatalytic detection of Sudan I(ELSEVIER SCI LTD, 2018) Tunesi, Mawada Mohamed; Kalwar, Nazar Hussain; Soomro, Razium Ali; Karakus, Selcan; Jawaid, Sana; Abro, Muhammad IshaqThe study explores the potential of newly developed ITO based electrode for the electro-catalytic detection of Sudan I. The ITO based electrode utilizes a dense layer of 2D CuO nanostructures as an effective electron-transfer facilitator which promotes the electro-catalytic sensing of Sudan I in aqueous solution. The in-situ growth of CuO nanostructures was achieved using simple hydrothermal route with the assistance of tartaric acid utilized as an effective template. The in-situ grown layer comprises of 2D CuO nanostructures with morphological features similar to flowers composed of sharp-flake like features. The electro-catalytic oxidation of Sudan I over the described electrode system demonstrated low-over potential value and excellent working stability with good analytical linearity in the range of 0.001-1.56 mu M. The ITO based electrode was found highly selective and sensitive towards Sudan I with limit of detection determined to be 1.2 x 10(-4) mu M (S/N = 3).
