scholarly journals Enzymatic Low Volume Passive Sweat Based Assays for Multi-Biomarker Detection

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 13 ◽  
Author(s):  
Ashlesha Bhide ◽  
Sarah Cheeran ◽  
Sriram Muthukumar ◽  
Shalini Prasad
Keyword(s):  
Dynamic Range ◽  
Low Cost ◽  
Simultaneous Detection ◽  
Porous Membrane ◽  
Zno Films ◽  
Current Response ◽  
Biomarker Detection ◽  
High Concentration ◽  
Sensor Performance ◽  
Stable Current

Simultaneous detection of correlated multi-biomarkers on a single low-cost platform in ultra-low fluid volumes with robustness is in growing demand for the development of wearable diagnostics. A non-faradaic biosensor for the simultaneous detection of alcohol, glucose, and lactate utilizing low volumes (1–5 μL) of sweat is demonstrated. Biosensing is implemented using nanotextured ZnO films integrated on a flexible porous membrane to achieve enhanced sensor performance. The ZnO sensing region is functionalized with enzymes specific for the detection of alcohol, glucose, and lactate in the ranges encompassing their physiologically relevant levels. A non-faradaic chronoamperometry technique is used to measure the current changes associated with interactions of the target biomarkers with their specific enzyme. The specificity performance of the biosensing platform was established in the presence of cortisol as the non-specific molecule. Biosensing performance of the platform in a continuous mode performed over a 1.5-h duration showed a stable current response to cumulative lifestyle biomarker concentrations with capability to distinguish reliably between low, mid, and high concentration ranges of alcohol (0.1, 25, 100 mg/dL), glucose (0.1, 10, 50 mg/dL), and lactate (1, 50, 100 mM). The low detection limits and a broader dynamic range for the lifestyle biomarker detection are quantified in this research demonstrating its suitability for translation into a wearable device.

scholarly journals Simultaneous Detection of Viability and Concentration of Microalgae Cells Based on Chlorophyll Fluorescence and Bright Field Dual Imaging

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 896
Author(s):  
Yanjuan Wang ◽  
Junsheng Wang ◽  
Tianqi Wang ◽  
Chengxiao Wang
Keyword(s):  
Chlorophyll Fluorescence ◽  
Ballast Water ◽  
Low Cost ◽  
Simultaneous Detection ◽  
Prototype System ◽  
Detection Accuracy ◽  
High Concentration ◽  
Bright Field ◽  
Microscopy Imaging ◽  
Ship Ballast Water

Ship ballast water contains high concentration of plankton, bacteria, and other microorganisms. If the huge amount of ballast water is discharged without being inactivated, it will definitely spell disaster to the marine environment. Microalgae is the most common species exiting in ballast water, so the detection of the concentration and viability of microalgae is a very important issue. The traditional methods of detecting microalgae in ballast water were costly and need the help of bulky equipment. Herein, a novel method based on microalgae cell intracellular chlorophyll fluorescence (CF) imaging combines with cell bright field (BF) microscopy was proposed. The geometric features of microalgae cells were obtained by BF image, and the cell viability was obtained by CF image. The two images were fused through the classic image registration algorithm to achieve simultaneous detection of the viability and concentration of microalgae cells. Furthermore, a low-cost, miniaturized CF/BF microscopy imaging prototype system based on the above principles was designed. In order to verify the effectiveness of the proposed method, four typical microalgae in ballast water (Platymonas, Pyramimonas sp., Chrysophyta, and Prorocentrum lima) were selected as the samples. The experimental results show that the self-developed prototype can quickly and accurately determine the concentration and the viability of microalgae cells in ship ballast water based on the dual images of BF and CF, and the detection accuracy is equivalent to that of commercial microscope. It was the first time to simultaneously detect the viability and concentration of microalgae cells in ship ballast water using the method that combining the fluorescence and bright field images; moreover, a miniaturized microscopic imaging prototype was developed. Those findings expected to contribute to the microalgae detection and ship ballast water management.

Graphene Modified Molecular Imprinting Electrochemical Sensor for Determining the Content of Dopamine

2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long
Keyword(s):  
Electrochemical Sensor ◽  
Molecular Imprinting ◽  
Neurological Disorders ◽  
Room Temperature ◽  
Low Cost ◽  
Differential Pulse ◽  
Current Response ◽  
Specific Selectivity ◽  
Pulse Voltammetry

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.

Improved photocatalytic conversion of high−concentration ammonia in water by low−cost Cu/TiO2 and its mechanism study

Chemosphere ◽  
2021 ◽  
Vol 274 ◽  
pp. 129689
Author(s):  
Jianpei Feng ◽  
Xiaolei Zhang ◽  
Guan Zhang ◽  
Ji Li ◽  
Wei Song ◽  
...  
Keyword(s):  
Low Cost ◽  
Mechanism Study ◽  
High Concentration

scholarly journals Synthesis of poly (n-butyl acrylate) with tempo by nitroxide mediated polymerization method

2021 ◽  
pp. 096739112110245
Author(s):  
Amrita Sharma ◽  
PP Pande
Keyword(s):  
Butyl Acrylate ◽  
Low Cost ◽  
Polymerization Process ◽  
Polymerization Reaction ◽  
High Concentration ◽  
Acrylate Monomer ◽  
Controlled Polymerization ◽  
Acrylate Monomers ◽  
Nitroxide Mediated Polymerization ◽  
Polymerization Method

It has been observed that acrylate monomers are very difficult to polymerize with the low cost nitroxide catalyst 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO). Therefore, costly acyclic nitroxides such as N-tert-butyl-N-(1-diethylphosphono-2,2-dimethyl)-N-oxyl, (SG1), 2,2,5-Trimethyl-4-phenyl-3-azahexane-3-nitroxide (TIPNO) and TIPNO derivatives have to be used for the polymerization of the acrylic acid derivatives. There are very few reports on the use of TEMPO-derivatives toward the polymerization of n-butyl acrylate. Generally different reducing agents viz. glucose, ascorbic acid, hydroxyacetone etc. have been used to destroy excess TEMPO during the polymerization reaction. The acrylate polymerizations fail in the presence of TEMPO due to the strong C–O bond formed between the acrylate chain end and nitroxide. To the best of our knowledge, no literature report is available on the use of TEMPO without reducing agent or high temperature initiators, toward the polymerization of n-butyl acrylate. The present study has been carried out with a view to re-examine the application of low cost nitroxide TEMPO, so that it can be utilized towards the polymerization of acrylate monomers (e.g. n-butyl acrylate). We have been able to polymerize n-butyl acrylate using the nitroxide TEMPO as initiator (via a macroinitiator). In this synthesis, a polystyrene macroinitiator was synthesized in the first step from TEMPO, after this TEMPO end-capped styrene macroinitiator (PSt-TEMPO) is used to polymerize n-butyl acrylate monomer. The amount of macroinitiator taken was varied from 0.05% to 50% by weight of n-butyl acrylate monomer. The polymerization was carried out at 120°C by bulk polymerization method. The experimental findings showed a gradual increase in molecular weight of the polymer formed and decrease in the polydispersity index (PDI) with increase in amount of PSt-TEMPO macroinitiator taken. In all experiments conversion was more than 80%. These results indicate that the polymerization takes place through controlled polymerization process. Effect of different solvents on polymerization has also been investigated. In the following experiments TEMPO capped styrene has been used as macroinitiator leading to the successful synthesis of poly n-Butyl acrylate. It has been found that styrene macroinitiator is highly efficient for the nitroxide mediated polymerization, even in very small concentration for the synthesis of poly n-butyl acrylate. High concentration of macroinitiator results in the formation of block copolymers of polystyrene and poly ( n-butyl acrylate) viz. polystyrene-block-poly-( n-butyl acrylate). The use of TEMPO toward controlled polymerization is of much importance, because it is the nitroxide commercially available at the lowest cost.

scholarly journals Flow Control in Porous Media: From Numerical Analysis to Quantitative μPAD for Ionic Strength Measurements

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3328
Author(s):  
Pouya Mehrdel ◽  
Hamid Khosravi ◽  
Shadi Karimi ◽  
Joan Antoni López Martínez ◽  
Jasmina Casals-Terré
Keyword(s):  
Porous Media ◽  
Limit Of Detection ◽  
Fluid Dynamic ◽  
Porous Membrane ◽  
External Pressure ◽  
Paper Substrate ◽  
Sensor Performance ◽  
Food Applications ◽  
Substrate Nature

Microfluidic paper-based analytical devices (µPADs) are a promising technology to enable accurate and quantitative in situ assays. Paper’s inherent hydrophilicity drives the fluids without the need for external pressure sources. However, controlling the flow in the porous medium has remained a challenge. This study addresses this problem from the nature of the paper substrate and its design. A computational fluid dynamic model has been developed, which couples the characteristics of the porous media (fiber length, fiber diameter and porosity) to the fluidic performance of the diffusion-based µPAD sensor. The numerical results showed that for a given porous membrane, the diffusion, and therefore the sensor performance is affected not only by the substrate nature but also by the inlets’ orientation. Given a porous substrate, the optimum performance is achieved by the lowest inlets’ angle. A diffusion-based self-referencing colorimetric sensor was built and validated according to the design. The device is able to quantify the hydronium concentration in wines by comparison to 0.1–1.0 M tartaric acid solutions with a 41.3 mM limit of detection. This research showed that by proper adjustments even the simplest µPADs can be used in quantitative assays for agri-food applications.

scholarly journals An Electrochemical Strategy for the Simultaneous Detection of Doxorubicin and Simvastatin for Their Potential Use in the Treatment of Cancer

Biosensors ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Iulia Rus ◽  
Mihaela Tertiș ◽  
Cristina Barbălată ◽  
Alina Porfire ◽  
Ioan Tomuță ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Electrolyte Solution ◽  
Electrode Material ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Simultaneous Detection ◽  
Linear Sweep Voltammetry ◽  
Pharmaceutical Formulations ◽  
Promising Tool ◽  
Scan Rate

The aim of this study was to develop a disposable, simple, fast, and sensitive sensor for the simultaneous electrochemical detection of doxorubicin (DOX) and simvastatin (SMV), which could be used in preclinical studies for the development of new pharmaceutical formulations for drug delivery. Firstly, the electrochemical behavior of each molecule was analyzed regarding the influence of electrode material, electrolyte solution, and scan rate. After this, the proper electrode material, electrolyte solution, and scan rate for both active substances were chosen, and a linear sweep voltammetry procedure was optimized for simultaneous detection. Two chronoamperometry procedures were tested, one for the detection of DOX in the presence of SMV, and the other one for the detection of DOX and SMV together. Finally, calibration curves for DOX and SMV in the presence of each other were obtained using both electrochemical methods and the results were compared. The use of amperometry allowed for a better limit of detection (DOX: 0.1 μg/mL; SMV: 0.7 μg/mL) than the one obtained in voltammetry (1.5 μg/mL for both drugs). The limits of quantification using amperometry were 0.5 μg/mL for DOX (dynamic range: 0.5–65 μg/mL) and 2 μg/mL for SMV (dynamic range: 2–65 μg/mL), while using voltammetry 1 μg/mL was obtained for DOX (dynamic range: 1–100 μg/mL) and 5 μg/mL for SMV (dynamic range: 5–100 μg/mL). This detection strategy represents a promising tool for the analysis of new pharmaceutical formulations for targeted drug delivery containing both drugs, whose association was proven to bring benefits in the treatment of cancer.

scholarly journals MnO2@Reduced Graphene Oxide Nanocomposite-Based Electrochemical Sensor for the Simultaneous Determination of Trace Cd(II), Zn(II) and Cu(II) in Water Samples

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 517
Author(s):  
Siyamthanda Hope Mnyipika ◽  
Tshimangadzo Saddam Munonde ◽  
Philiswa Nosizo Nomngongo
Keyword(s):  
Heavy Metals ◽  
Electrochemical Sensor ◽  
Simultaneous Determination ◽  
Rapid Detection ◽  
Electrochemical Sensors ◽  
Simultaneous Detection ◽  
Cyclic Voltammograms ◽  
Current Response ◽  
Mno2 Nanoparticles

The rapid detection of trace metals is one of the most important aspect in achieving environmental monitoring and protection. Electrochemical sensors remain a key solution for rapid detection of heavy metals in environmental water matrices. This paper reports the fabrication of an electrochemical sensor obtained by the simultaneous electrodeposition of MnO2 nanoparticles and RGO nanosheets on the surface of a glassy carbon electrode. The successful electrodeposition was confirmed by the enhanced current response on the cyclic voltammograms. The XRD, HR-SEM/EDX, TEM, FTIR, and BET characterization confirmed the successful synthesis of MnO2 nanoparticles, RGO nanosheets, and MnO2@RGO nanocomposite. The electrochemical studies results revealed that MnO2@RGO@GCE nanocomposite considerably improved the current response on the detection of Zn(II), Cd(II) and Cu(II) ions in surface water. These remarkable improvements were due to the interaction between MnO2 nanomaterials and RGO nanosheets. Moreover, the modified sensor electrode portrayed high sensitivity, reproducibility, and stability on the simultaneous determination of Zn(II), Cd(II), and Cu(II) ions. The detection limits of (S/N = 3) ranged from 0.002–0.015 μg L−1 for the simultaneous detection of Zn(II), Cd(II), and Cu(II) ions. The results show that MnO2@RGO nanocomposite can be successfully used for the early detection of heavy metals with higher sensitivity in water sample analysis.

scholarly journals New Compact Wearable Metamaterials Circular Patch Antennas for IoT, Medical and 5G Applications

2020 ◽  
Vol 3 (4) ◽  
pp. 42
Author(s):  
Albert Sabban
Keyword(s):  
Communication Systems ◽  
Dynamic Range ◽  
Low Cost ◽  
Patch Antennas ◽  
Antenna Feed ◽  
Circular Patch ◽  
Wearable Antenna ◽  
Wearable Antennas ◽  
Feed Network ◽  
Line Design

The development of compact passive and active wearable circular patch metamaterials antennas for communication, Internet of Things (IoT) and biomedical systems is presented in this paper. Development of compact efficient low-cost wearable antennas are one of the most significant challenges in development of wearable communication, IoT and medical systems. Moreover, the advantage of an integrated compact low-cost feed network is attained by integrating the antenna feed network with the antennas on the same printed board. The efficiency of communication systems may be increased by using efficient passive and active antennas. The system dynamic range may be improved by connecting amplifiers to the printed antenna feed line. Design, design considerations, computed and measured results of wearable circular patch meta-materials antennas with high efficiency for 5G, IoT and biomedical applications are presented in this paper. The circular patch antennas electrical parameters on the human body were analyzed by using commercial full-wave software. The circular patch metamaterial wearable antennas are compact and flexible. The directivity and gain of the antennas with Circular Split-Ring Resonators (CSRR) is higher by 2.5dB to 3dB than the antennas without CSRR. The resonant frequency of the antennas without CSRR is higher by 6% to 9% than the antennas with CSRR. The computed and measured bandwidth of the stacked circular patch wearable antenna with CSRR for IoT and medical applications is around 12%, for S11 lover than −6dB. The gain of the circular patch wearable antenna with CSRR is around 8dBi.

Low cost, trouble-free disposable pencil graphite electrode sensor for the simultaneous detection of hydroquinone and catechol

2021 ◽  
pp. 125663
Author(s):  
T.S. Sunil Kumar Naik ◽  
Arul Varman Kesavan ◽  
B.E. Kumara Swamy ◽  
Simranjeet Singh ◽  
Amith G. Anil ◽  
...  
Keyword(s):  
Graphite Electrode ◽  
Low Cost ◽  
Simultaneous Detection ◽  
Pencil Graphite Electrode ◽  
Electrode Sensor

scholarly journals Automated Low Cost Method of Quantification of Hepatitis C Virus

2015 ◽  
Vol 14 (3) ◽  
pp. 247-253
Author(s):  
Faiz MMT Marikar ◽  
Dammika Senevirathna ◽  
Neil Fernandopulle
Keyword(s):  
Viral Load ◽  
Hepatitis C ◽  
Blood Donors ◽  
Low Cost ◽  
Medical Science ◽  
Simultaneous Detection ◽  
Plasma Samples ◽  
Rt Pcr ◽  
Viral Genomes ◽  
Post Therapy

This paper describes the development of a Dig-dUTP based multiplex real time RT-PCR for the simultaneous detection of HCV viral amount in plasma samples. Viral genomes were identified in the same sample by Dig-dUTP PCR 216 bp region. Analysis of known scalar concentrations of reference plasma indicated that the multiplex procedure detects at least 500 copies/ml of HCV. In addition, we also assayed HCV viral load in eighty co-infected patients and in fifteen blood donors, confirming the sensitivity and specificity of the assay. This method may represent a useful alternative method for the detection of HCV co-infection, reliable for a rapid and relatively inexpensive screening of blood donors. The assay may be used to determine post-therapy viral clearance.Bangladesh Journal of Medical Science Vol.14(3) 2015 p.247-253

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