scholarly journals Chitozyme: First Peroxidase-like Activity of Chitosan for Multiplexed Visual Detection of H2O2, Glucose and Lactate on Paper-based Device

2017 ◽  
Author(s):  
Syed Rahin Ahmed ◽  
Xuan Weng ◽  
Suresh Neethirajan
Keyword(s):  
Visual Detection ◽  
Limit Of Detection ◽  
Natural Polymer ◽  
Multiplex Detection ◽  
Practical Applications ◽  
Naked Eye ◽  
Pharmaceutical Technology ◽  
Assay Performance ◽  
Cost Efficient ◽  
Amplification Strategy

AbstractVisual read-out diagnostics tools are promising candidates for field applicable medical devices. Current colorimetric biosensors require introduction of natural enzymes or nanozymes, which has some serious drawbacks for practical applications. Chitosan, a natural polymer, provides safe and efficient compound in medical and pharmaceutical technology. Herein, we report on a simple, cost-efficient, field-portable, environmental friendly and ultra-sensitive multiplex detection platform based on peroxidase-like activity of chitosan in the presence of 3,3’,5,5’-Tetramethylbenzidine (TMBZ) and H2O2. This straight forward signal amplification strategy was successfully applied to detect H2O2, glucose and lactate with the limit of detection (LOD) of 2.64 pM, 0.104 μM and 2.8 nM respectively, represents the lowest LOD of H2O2, glucose and lactate with visual read-out. The chitosan-based assay performance was also retained in complex biological media for glucose and lactate detection. Furthermore, the proposed assay was successfully demonstrated as a paper-based colorimetric biosensor. Most importantly, the simplicity, biocompatibility and sensitivity of the proposed assay will open new doors for instrument free naked eye visual detection of H2O2, glucose and lactate detection.

Naked-Eye Detection of Hg(II) Ions by Visible Light-Induced Polymerization Initiated by a Hg(II)-Selective Photoredox Catalyst

2021 ◽  
Author(s):  
Hyungwook Kim ◽  
Young Jae Jung ◽  
Jungkyu K. Lee
Keyword(s):  
Visible Light ◽  
Signal Amplification ◽  
Eye Detection ◽  
Naked Eye ◽  
Turn On ◽  
Novel Strategy ◽  
Amplification Strategy ◽  
Naked Eye Detection

We developed a novel strategy for signal amplification strategy using a visible light-induced photopolymerization, initiated by a selective turn-on photoredox catalyst. As photoredox catalysts, fluorescein derivatives are able to initiate...

Chromogenic ‘naked eye’ and fluorogenic ‘turn on’ sensor for mercury metal ion using thiophene-based Schiff base

RSC Advances ◽  
2015 ◽  
Vol 5 (81) ◽  
pp. 65731-65738 ◽  
Author(s):  
Divya Singhal ◽  
Neha Gupta ◽  
Ashok Kumar Singh
Keyword(s):  
Schiff Base ◽  
Binding Affinity ◽  
Metal Ion ◽  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Naked Eye ◽  
Turn On

2-((3-Methylthiophen-2-yl)methyleneamino)benzenethiol (Probe 1) is selective for Hg2+. The binding affinity of Hg2+ with Probe 1 was confirmed by DFT and electrochemical behaviour. The limit of detection was 20 μM with 2 : 1 stoichiometry of 1 + Hg2+ complex.

scholarly journals Development of Quantitative Real-Time Polymerase Chain Reaction for Detection of and Discrimination between Erysipelothrix Rhusiopathiae and Other Erysipelothrix Species

2009 ◽  
Vol 21 (5) ◽  
pp. 701-706 ◽  
Author(s):  
Ho To ◽  
Tomohiro Koyama ◽  
Shinya Nagai ◽  
Kotaro Tuchiya ◽  
Tetsuo Nunoya
Keyword(s):  
Polymerase Chain Reaction ◽  
Real Time ◽  
Limit Of Detection ◽  
Enrichment Culture ◽  
Bacterial Species ◽  
Erysipelothrix Rhusiopathiae ◽  
Chain Reaction ◽  
Tissue Samples ◽  
Practical Applications ◽  
Polymerase Chain

Quantitative real-time polymerase chain reaction (qPCR) assays were developed and validated in combination with enrichment culture for the detection and discrimination of Erysipelothrix rhusiopathiae and other Erysipelothrix species from tissue samples. The targets for SYBR green qPCR assays were the 16S ribosomal RNA gene for Erysipelothrix species and a gene involved in capsular formation for E. rhusiopathiae. The specificity of the assays was assessed with Erysipelothrix species and other related bacterial species. The limit of detection was found to be 5 colony-forming units per reaction. Amplification of DNA extracted from spleen and joint samples spiked with increasing quantities of Erysipelothrix cells was shown to be equally sensitive to DNA extracted from a pure bacterial culture. The assays were evaluated with 88 tissue samples from 3 experimentally infected pigs and 50 mice and with 36 tissue samples from 3 naturally infected pigs and 11 noninfected pigs. Results were compared with those of direct qPCR and conventional culture. The qPCR after enrichment increased the diagnostic sensitivity over that of culture and qPCR, thereby significantly reducing the total time taken for the detection of E. rhusiopathiae and other Erysipelothrix species. Therefore, this technique could be used for practical applications.

An ultra-sensitive colorimetric assay for reliable visual detection of telomerase activity

The Analyst ◽  
2017 ◽  
Vol 142 (17) ◽  
pp. 3235-3240 ◽  
Author(s):  
Yaocai Wang ◽  
Luzhu Yang ◽  
Yanjun Wang ◽  
Wei Liu ◽  
Baoxin Li ◽  
...  
Keyword(s):  
Hela Cell ◽  
Visual Detection ◽  
Colorimetric Assay ◽  
Telomerase Activity ◽  
Cell Lysates ◽  
Naked Eye ◽  
Vis Spectroscopy

We proposed a sensitive colorimetric assay for detecting telomerase activity. The telomerase activity of 5 and 20 HeLa cell lysates can be detected via UV-vis spectroscopy and the naked eye, respectively.

A Framework to Evaluate the Benefit of Seismic Upgrading

2019 ◽  
Vol 35 (2) ◽  
pp. 1045-1051 ◽  
Author(s):  
Clotaire Michel ◽  
Blaise Duvernay ◽  
Ehrfried Kölz ◽  
Navid Jamali ◽  
Pierino Lestuzzi
Keyword(s):  
Existing Buildings ◽  
Design Code ◽  
Absolute Level ◽  
Safety Level ◽  
Seismic Code ◽  
Practical Applications ◽  
The Absolute ◽  
Cost Efficient ◽  
The One ◽  
Level Of Risk

The framework to evaluate the benefit of seismic upgrading of Galanis et al. (2018) is compared to that present in the Swiss seismic code for existing buildings since 2004, updated in 2017. To illustrate the comparison, the example building of Galanis et al. (2018) in Zurich is analyzed following the Swiss code. It is shown that the concept of Degree of Seismic Upgrade is not relevant for practical applications. More generally, the approach of Galanis et al. (2018) would be more suited to a risk-based framework (like the Swiss code) than to a performance-based framework like the one they followed. For existing buildings, we claim that it is appropriate to define the retrofitting strategy based on the absolute level of risk, whereas targeting the safety level of the design code is rarely cost-efficient.

scholarly journals Enzyme Method-Based Microfluidic Chip for the Rapid Detection of Copper Ions

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1380
Author(s):  
Binfeng Yin ◽  
Xinhua Wan ◽  
Changcheng Qian ◽  
A. S. M. Muhtasim Fuad Sohan ◽  
Teng Zhou ◽  
...  
Keyword(s):  
Metal Ions ◽  
Microfluidic Chip ◽  
Limit Of Detection ◽  
Copper Ions ◽  
Practical Applications ◽  
Enzyme Method ◽  
In Series ◽  
High Concentrations ◽  
Biochemical Detection ◽  
Seawater Samples

Metal ions in high concentrations can pollute the marine environment. Human activities and industrial pollution are the causes of Cu2+ contamination. Here, we report our discovery of an enzyme method-based microfluidic that can be used to rapidly detect Cu2+ in seawater. In this method, Cu2+ is reduced to Cu+ to inhibit horseradish peroxidase (HRP) activity, which then results in the color distortion of the reaction solution. The chip provides both naked eye and spectrophotometer modalities. Cu2+ concentrations have an ideal linear relationship, with absorbance values ranging from 3.91 nM to 256 μM. The proposed enzyme method-based microfluidic chip detects Cu2+ with a limit of detection (LOD) of 0.87 nM. Other common metal ions do not affect the operation of the chip. The successful detection of Cu2+ was achieved using three real seawater samples, verifying the ability of the chip in practical applications. Furthermore, the chip realizes the functions of two AND gates in series and has potential practical implementations in biochemical detection and biological computing.

scholarly journals Highly sensitive dual mode electrochemical platform for microRNA detection

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Pawan Jolly ◽  
Marina R. Batistuti ◽  
Anna Miodek ◽  
Pavel Zhurauski ◽  
Marcelo Mulato ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Dynamic Range ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Dual Mode ◽  
Electrode Surfaces ◽  
Microrna Detection ◽  
Highly Sensitive ◽  
Detection Mode ◽  
Amplification Strategy

Abstract MicroRNAs (miRNAs) play crucial regulatory roles in various human diseases including cancer, making them promising biomarkers. However, given the low levels of miRNAs present in blood, their use as cancer biomarkers requires the development of simple and effective analytical methods. Herein, we report the development of a highly sensitive dual mode electrochemical platform for the detection of microRNAs. The platform was developed using peptide nucleic acids as probes on gold electrode surfaces to capture target miRNAs. A simple amplification strategy using gold nanoparticles has been employed exploiting the inherent charges of the nucleic acids. Electrochemical impedance spectroscopy was used to monitor the changes in capacitance upon any binding event, without the need for any redox markers. By using thiolated ferrocene, a complementary detection mode on the same sensor was developed where the increasing peaks of ferrocene were recorded using square wave voltammetry with increasing miRNA concentration. This dual-mode approach allows detection of miRNA with a limit of detection of 0.37 fM and a wide dynamic range from 1 fM to 100 nM along with clear distinction from mismatched target miRNA sequences. The electrochemical platform developed can be easily expanded to other miRNA/DNA detection along with the development of microarray platforms.

scholarly journals Naked-eye Detection of Hg2+ in Practical Applications Using a Highly Selective and Sensitive Fluorescent Probe

2018 ◽  
Vol 34 (12) ◽  
pp. 1411-1417 ◽  
Author(s):  
Yushun YANG ◽  
Dajun ZHENG ◽  
Yunjie XU ◽  
Qixing LIU ◽  
Chen XU ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Eye Detection ◽  
Practical Applications ◽  
Naked Eye ◽  
Naked Eye Detection

Naked-Eye Detection of Mercury Ions from Morphological Transition of Silver Nanocubes: Tuning Sensitivity Using Co-Staining Agent

2021 ◽  
Vol 21 (4) ◽  
pp. 2123-2131
Author(s):  
Alagan Jeevika ◽  
Dhesingh Ravi Shankaran
Keyword(s):  
Color Change ◽  
Limit Of Detection ◽  
Low Cost ◽  
Toxic Metal ◽  
Face Centered Cubic ◽  
Mercury Ions ◽  
Eye Detection ◽  
Naked Eye ◽  
Silver Nanocubes ◽  
Naked Eye Detection

A simple, low-cost and highly selective nanosensor was developed for naked-eye detection of mercury ions (Hg2+) based on Eosin/silver nanocubes (Eosin/AgNCbs). Silver nanocubes (AgNCbs) were synthesized by polyol assisted chemical method. HR-TEM result shows the formed AgNCbs have a mean diameter of 84±0.005 nM (diagonally measured) and edge length of 55±0.01 nM. XRD result confirms that the AgNCbs are single crystalline in nature with a phase structure of face centered cubic (FCC) of silver. On interaction of Hg2+, AgNCbs exhibits a color change from gray to black up to 16.67 μM of Hg2+ owed to the formation of solid like bimetallic complex of Ag/Hg amalgam. The selectivity of AgNCbs was evaluated with several other toxic metal ions including, Mg2+, Ba2+, Ca4+, Pb2+, Cd4+, Zn2+, Co2+, Cu2+, K+ and Ni2+ and found good selectivity towards Hg2+. The sensitivity of the AgNCbs sensor system was tuned by using Eosin as a co-staining agent. The Eosin/AgNCbs showed a limit of detection of 60±0.050 nM with the color change from orange to purple. The results suggests that the Eosin/AgNCbs nanosensor exhibits good selectivity, sensitivity, repeatability and rapid response, which could be explored for real-time detection of Hg2+ in environmental and biological samples.

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