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1 – 10 of 154Dinesh Ramkrushna Rotake, Anand Darji and Nitin S. Kale
This paper aims to report an insightful portable microfluidic system for rapid and selective sensing of Hg2+ in the picomolar (pM) concentration using microcantilever-based…
Abstract
Purpose
This paper aims to report an insightful portable microfluidic system for rapid and selective sensing of Hg2+ in the picomolar (pM) concentration using microcantilever-based piezoresistive sensor. The detection time for various laboratory-based techniques is generally 12–24 h. The majority of modules used in the proposed platform are battery oriented; therefore, they are portable and handy to carry-out on-field investigations.
Design/methodology/approach
In this study, the authors have incorporated the benefit of three technologies, i.e. thin-film, nanoparticles (NPs) and micro-electro-mechanical systems, to selectively capture the Hg2+ at the pM concentration. The morphology and topography of the proposed sensor are characterized using field emission scanning electron microscopy and verification of the experimental results using energy dispersive X-ray.
Findings
The proposed portable microfluidic system is able to perform the detection in 5 min with a limit of detection (LOD) of 0.163 ng (0.81 pM/mL) for Hg2+, which perfectly describes its excellent performance over other reported techniques.
Research limitations/implications
A microcantilever-based technology is perfect for on-site detection, and a LOD of 0.163 ng (0.81 pM/mL) is outstanding compared to other techniques, but the fabrication of microcantilever sensor is complex.
Originality/value
Many researchers used NPs for heavy metal ions sensing, but the excess usage and industrialization of NPs are rapidly expanding harmful consequences on the human life and nature. Also, the LOD of the NPs-based method is limited to nanomolar concentration. The suggested microfluidic system used the benefit of thin-film and microcantilever devices to provide advancement over the NPs-based approach and it has a selective sensing in pM concentration.
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Dinesh Ramkrushna Rotake, Anand Darji and Jitendra Singh
The purpose of this paper is a new thin-film based sensor proposed for sensitive and selective detection of mercury (Hg2+) ions in water. The thin-film platform is easy to use and…
Abstract
Purpose
The purpose of this paper is a new thin-film based sensor proposed for sensitive and selective detection of mercury (Hg2+) ions in water. The thin-film platform is easy to use and quick for heavy metal ions (HMIs) detection in the picomolar range. Ion-selective self-assembled monolayer's (SAM) of thiol used for the detection of HMIs above the Au/Ti top surface.
Design/methodology/approach
A thin-film based platform is suitable for the on-field experiments and testing of water samples. HMIs (antigen) and thiol-based SAM (antibody) interaction results change in surface morphology and topography. In this study, the authors have used different characterization techniques to check the selectivity of the proposed method. This change in the morphology and topography of thin-film sensor checked with Fourier-transform infrared spectroscopy, surface-enhanced Raman scattering spectroscopy, atomic force microscopy and scanning electron microscopy with energy dispersive x-ray analysis used for high-resolution images.
Findings
This thin-film based platform is straightforward to use and suitable for real-time detection of HMIs at the picomolar range. This thin-film based sensor platform capable of achieving a lower limit of detection (LOD) 27.42 ng/mL (136.56 pM) using SAM of Homocysteine-Pyridinedicarboxylic acid to detect Hg2+ ions.
Research limitations/implications
A thin-film based technology is perfect for real-time testing and removal of HMIs, but the LOD is higher as compared to microcantilever-based devices.
Originality/value
The excessive use and commercialization of nanoparticle (NPs) are quickly expanding their toxic impact on health and the environment. The proposed method used the combination of thin-film and NPs, to overcome the limitation of NPs-based technique and have picomolar (136.56 pM) range of HMIs detection. The proposed thin-film-based sensor shows excellent repeatability and the method is highly reliable for toxic Hg2+ ions detection. The main advantage of the proposed thin-film sensor is its ability to selectively remove the Hg2+ ions from water samples just like a filter and a sensor for detection at picomolar range makes this method best among the other current-state of the art techniques.
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Dinesh Ramkrushna Rotake, Anand D. Darji and Nitin S. Kale
This paper aims to propose a new microfluidic portable experimental platform for quick detection of heavy metal ions (HMIs) in picomolar range. The experimental setup uses a…
Abstract
Purpose
This paper aims to propose a new microfluidic portable experimental platform for quick detection of heavy metal ions (HMIs) in picomolar range. The experimental setup uses a microfabricated piezoresistive sensor (MPS) array of eight cantilevers with ion-selective self-assembled monolayer's (SAM).
Design/methodology/approach
Most of the components used in this experimental setup are battery operated and, hence, portable to perform the on-field experiments. HMIs (antigen) and thiol-based SAM (antibody) interaction start bending the microcantilever. This results in a change of resistance, which is directly proportional to the surface stress produced due to the mass of targeted HMIs. The authors have used Cysteamine and 4-Mercaptobenzoic acid as a thiol for creating SAM to test the sensitivity and identify the suitable thiol. Some of the cantilevers are blocked using acetyl chloride to use as a reference for error detection.
Findings
The portable experimental platform achieves very small detection time of 10-25 min with a lower limit of detection (LOD) 0.762 ng (6.05 pM) for SAM of Cysteamine and 4-Mercaptobenzoic acid to detect Mn2+ ions. This technique has excellent potential and capability to selectively detect Hg2+ ions as low as 2.43 pM/mL using SAM of Homocysteine (Hcys)-Pyridinedicarboxylic acid (PDCA).
Research limitations/implications
As microcantilever is very thin and fragile, it is challenging to apply a surface coating to have selective detection using Nanadispenser. Some of the cantilevers get broken during this process.
Originality/value
The excessive use and commercialization of NPs are quickly expanding their toxic impact on health and the environment. Also, LOD is limited to nanomolar range. The proposed method used the combination of thin-film, NPs, and MEMS-based technology to overcome the limitation of NPs-based technique and have picomolar range of HMIs detection.
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Mulayam Singh Gaur, Rajni Yadav, Mamta Kushwah and Anna Nikolaevna Berlina
This information will be useful in the selection of materials and technology for the detection and removal of mercury ions at a low cost and with high sensitivity and selectivity…
Abstract
Purpose
This information will be useful in the selection of materials and technology for the detection and removal of mercury ions at a low cost and with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity. The purpose of this study is to provide the useful information for selection of materials and technology to detect and remove the mercury ions from water with high sensitivity and selectivity.
Design/methodology/approach
Different nano- and bio-materials allowed for the development of a variety of biosensors – colorimetric, chemiluminescent, electrochemical, whole-cell and aptasensors – are described. The materials used for their development also make it possible to use them in removing heavy metals, which are toxic contaminants, from environmental water samples.
Findings
This review focuses on different technologies, tools and materials for mercury (heavy metals) detection and remediation to environmental samples.
Originality/value
This review gives up-to-date and systemic information on modern nanotechnology methods for heavy metal detection. Different recognition molecules and nanomaterials have been discussed for remediation to water samples. The present review may provide valuable information to researchers regarding novel mercury ions detection sensors and encourage them for further research/development.
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Ionut Nicolae, Dana Miu and Cristian Viespe
The detection of H2 concentrations in concentrations undetectable by the conventional detection method of surface acoustic wave (SAW) sensors based on frequency shift, by…
Abstract
Purpose
The detection of H2 concentrations in concentrations undetectable by the conventional detection method of surface acoustic wave (SAW) sensors based on frequency shift, by correlating analyte presence with Fourier spectra components.
Design/methodology/approach
Fast Fourier Transform (FFT) and autocorrelation analysis of phase noise in a SnO2-coated SAW sensor was performed. Fourier spectra were obtained by FFT from the SAW sensor resonance frequency instability, in the absence of analyte, and for H2 concentrations between 0.08 and 0.4 per cent.
Findings
All analyte concentrations are below the sensor limit of detection, which is 0.8 per cent for H2. Although these analyte concentrations caused no significant change in the resonance frequency of the SAW resonator, the FFT spectra presented several modifications, namely, the appearance of a new peak and the decrease of randomness. The authors consider that the effect is because of the chaotic behavior of the temporal dependence of the SAW resonance frequency. This explanation is substantiated by the decrease observed in the SAW oscillator autocorrelation function, which is an indication for a chaotic behavior.
Practical implications
As chaotic systems are extremely sensitive to perturbation, measurement methods based on chaos diagnosis could potentially greatly improve the SAW detection.
Originality/value
Fourier spectra components were correlated with analyte presence in concentrations undetectable by the conventional SAW detection method based on frequency shift.
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Bjorn John Stephen, Surabhi Suchanti, Devendra Jain, Harshdeep Dhaliwal, Vikram Sharma, Ramandeep Kaur, Rajeev Mishra and Abhijeet Singh
Neglected tropical diseases (NTDs) are a set of infectious diseases that primarily affect low-income countries situated near the equator. Effective diagnostic tools hold the key…
Abstract
Purpose
Neglected tropical diseases (NTDs) are a set of infectious diseases that primarily affect low-income countries situated near the equator. Effective diagnostic tools hold the key to stemming the spread of these infectious diseases. However, specificity is a major concern associated with current diagnostic protocols. In this regard, electrochemical deoxyribonucleic acid (DNA) biosensors could play a crucial role, as highlighted by renewed interest in their research. The purpose of this study was to highlight the current scenario for the design and development of biosensors for the detection of NTDs related pathogens. This review highlights the different types of factors involved and the modifications used to enhance sensor properties.
Design/methodology/approach
The authors discuss the potential of electrochemical DNA biosensors as efficient, affordable diagnostic tools for the detection of pathogens associated with NTDs by reviewing available literature. This study discusses the biosensor components, mainly the probe selection and type of electrodes used, and their potential to improve the overall design of the biosensor. Further, this study analyses the different nanomaterials used in NTD-based electrochemical DNA biosensors and discusses how their incorporation could improve the overall sensitivity and specificity of the biosensor design. Finally, this study examines the impact such techniques could have in the future on mass screening of NTDs.
Findings
The findings provide an in-depth analysis of electrochemical DNA biosensors for the detection of pathogens associated with NTDs.
Originality/value
This review provides an update on the different types and modifications of DNA biosensors that have been designed for the diagnosis of NTD-related pathogens.
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Leila Snani, Saida Zougar, Fatiha Benamia and Ilhem Ghodbane
The purpose of this paper is to study the immobilization of porcine pancreatic lipase (PPL), in an organic matrix by a covalent cross-linking method to sense propylparaben (PP…
Abstract
Purpose
The purpose of this paper is to study the immobilization of porcine pancreatic lipase (PPL), in an organic matrix by a covalent cross-linking method to sense propylparaben (PP) present in aqueous solution.
Design/methodology/approach
PPL immobilization was performed by the covalent cross-linking method, using bovine serum albumin (BSA) in the presence of saturated glutaraldehyde vapor (GA). The preparation of the enzymatic membrane involves the incorporation of porcine pancreatic lipase (PPL), bovine serum albumin (BSA) and glycerol into a phosphate buffer solution (PBS). Characterization of this sensor was performed by impedance spectroscopy (EIS) and scanning electron microscope (SEM). The effect of experimental conditions such as PPL activity, potential, scan rate, PP concentration, pH and presence of interfering elements were studied by cyclic voltammetry.
Findings
Under the optimal experimental conditions, a number of significant factors were optimized. The method exhibited good linearity in the range of 10–14 to 10–9 mol/L with a good correlation coefficient of 0.957, detection limit (LOD) of 3.66 × 10–15 mol/L and high sensitivity of 1.086 mA mol−1L. The authors also obtained a very good coverage rate of the surface equal to 91.44%, and hydrolytic activity of lipase is evaluated to 26.64 mmol min−1. The stability and the interference were also evaluated. The equivalent circuit used to explain the electrochemical behavior of modified electrode is a Randle circuit.
Practical implications
The main application of biosensors is the detection of biomolecules that are either indicators of a disease. For example, electrochemical biosensing techniques can be used as clinical tools to detect breast tumors, because these compounds (PP) were found in breast tumors.
Originality/value
The result registered in this paper indicates that the developed sensor is an efficient, fast, simple and inexpensive analytical tool that can be used for the analysis of water containing PP.
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Reetu Yadav, Mamta Kushwah, Anna Nikolaevna Berlina and Mulayam Singh Gaur
The purpose of this study is determination of cadmium using silver-gold bimetallic nanoparticles (Ag-Au BMNPs) and an aptamer modified glassy carbon electrode.
Abstract
Purpose
The purpose of this study is determination of cadmium using silver-gold bimetallic nanoparticles (Ag-Au BMNPs) and an aptamer modified glassy carbon electrode.
Design/methodology/approach
The maximum response of modified electrode was obtained with, 50 mV pulse amplitude, 20 mV/s scan rate in phosphate buffer of pH 4.0. Ag-Au BMNPs, as the mediators improved electron transmit during the entire electron transfer process and the aptasensor response. Herein, the authors used aptamer as the capture probe to prepare an aptasensor with enhanced stability.
Findings
The proposed aptasensor exhibited a wide linearity to cadmium in the range of 0.001–0.100 µg/L with a low detection limit of 0.005×10−3 µg/L. The glassy carbon electrodes with Ag-Au BMNPs showed a lower detection limit.
Originality/value
This aptasensor has good reproducibility, stability and repeatability and is cost-effective to regenerate. The specificity and selectivity of the novel modified electrode is tested in the presence of other interfering metal ions such as Fe2+, Mn2+, Mg2+, Sb3+ and Bi3+. The aptasensor shows 10 times more sensitivity and selectivity for Cd2+ ions.
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Zhang Lei, Yingshan Chen, Zhiwen Liu, Wenjin Ji and Suqing Zhao
In this study, a highly sensitive and quantitative analysis method using surface-enhanced Raman scattering (SERS)-labeled immunoassay is adopted for bisphenol A bisphenol A (BPA…
Abstract
Purpose
In this study, a highly sensitive and quantitative analysis method using surface-enhanced Raman scattering (SERS)-labeled immunoassay is adopted for bisphenol A bisphenol A (BPA) detection in water samples.
Design/methodology/approach
Primarily, an excellent SERS immuno-nanoprobe is prepared, which relays on Au/Ag core-shell nanoparticles tagged 4-mercaptobenzoic acid (4MBA) and labeled with specific antibody against BPA. Second, the coating antigen of 4,4-Bis(4-hydroxyphenol) valeric acid (BVA) coupling poly-L-lysine (PLL) conjugate (BVA-PLL) is fastened on the substrate. Based on competitive immunoassay, the antibody labeled on SERS immuno-nanoprobe will bind with the free BPA and BVA-PLL competitively.
Findings
A calibration curve was obtained by plotting the intensity of SERS signal of 4MBA at 1007 cm−1 versus the concentration of BPA. The results indicated that the limit of detection (LOD) for BPA is 1 ng/mL and present a great capacity for higher sensitivity. Furthermore, the method was able to quantitatively detect BPA in water samples, which was validated by high performance liquid chromatography (HPLC).
Originality/value
The method was developed based on competitive immunoassay, and the conjugate (BVA-PLL) was chosen as the coating antigen. Au/Ag core-shell nanoparticles played as the SERS active substrate and were labeled with Raman reporter. The value of this paper is supplying a wide potential for analysis of target analytes in the environmental monitoring and food safety.
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Hosein Nikpooyan, Ali Mohamadi Sani and Nafise Zavezad
The aim of this study was to test the presence of lead in raw milk from different regions of Mashhad (north‐east of Iran) through atomic absorption spectrometry (AAS).
Abstract
Purpose
The aim of this study was to test the presence of lead in raw milk from different regions of Mashhad (north‐east of Iran) through atomic absorption spectrometry (AAS).
Design/methodology/approach
A total of 60 samples of raw cow's milk were collected from the bulk holding tanks of 20 dairy farms of Mashhad and analysed immediately.
Findings
The mean level of lead content was 4.07 ng/ml, with a range from 0.02 to 44 ng/ml and a standard deviation of 7.54 ng/ml. The Pb concentration of one sample exceeded 20 ng/ml (maximum concentration accepted by Codex). Lead residue in 70 per cent of the samples was below 5 ng/ml and the Pb concentration in 10, 9.18 and 9.18 per cent of the samples was, respectively, in the range of 5‐10, 10‐15 and 15‐20 ng/ml. The results obtained for limit of detection (LOD) and limit of quantification (LOQ) in μgkg−1 were, respectively, 0.65 and 2.1 while for the recovery 94.47 per cent.
Social implications
The results reduce the public concern about lead contamination in milk in this region.
Originality/value
No research had been done to detect lead residue in raw milk in this region. Milk is not a major source for lead poisoning in Mashhad.
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