scholarly journals Multiformity of Photoelectron Storages in Functionalized Carbon Nitrides Enabling Reversible and Adaptable Colorimetric Sensing

2021 ◽  
Author(s):  
Dan Han ◽  
Hong Yang ◽  
Zhixin Zhou ◽  
Kaiqing Wu ◽  
Jin Ma ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Raw Materials ◽  
High Sensitivity ◽  
Terminal Group ◽  
Blue Color ◽  
Colorimetric Sensing ◽  
Electron Hole ◽  
Detection Range ◽  
Linear Detection ◽  
Easy Operation

Colorimetric sensing has been widely used for centuries across diverse fields, thanks to easy operation with no electricity and uncompromised high sensitivity. However, the limited number of chromogenic systems hampers its broader applications. Here, we reported that carbon nitride (CN), the raw materials-abundant and cheap semiconductors with photoelectron storage capability, can be developed as a new chromogenic platform for colorimetric sensing. Beyond most photoelectron storage materials that only demonstrated blue color in the excited state, CN could also exhibit brown color by terminal group functionalization. The experiments and DFT theoretical calculation revealed the origin of the unusual two types of color switches. Cyano and carbonyl terminal groups in CN elongated the centroids distance of electron/hole and stabilized the excited states through a physical and electrochemical pathway, respectively; meanwhile, the counter cations strengthened these processes. As a result, the CN-derived colorimetric O2 sensors demonstrated excellent reversibility in recycling hundreds of times for detection, and exhibited adaptable limit of detection and linear detection range, which was superior to commercial O2 sensors, especially for complex systems with broad variable concentrations.

Detection of Sodium Ions by SPR Sensor Using Modified Self-Assembled Calix[4]Arene Deravative Monolayer

2015 ◽  
Vol 799-800 ◽  
pp. 915-918
Author(s):  
M. Benounis ◽  
Nicole Jaffrezic ◽  
Isabelle Bonnamour ◽  
Nadhir Messai
Keyword(s):  
Impedance Spectroscopy ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Gold Surface ◽  
Sodium Ions ◽  
Sensor Surface ◽  
Detection Range ◽  
Spr Sensor ◽  
Linear Detection ◽  
Influence Of Ph

A new SPR sensor surface based onself-assembled-Calix [4] arene-derivative-monolayer was proposed for the detection of sodium in water. The immobisation of claixarene onto the gold surface was confirmed by impedance spectroscopy (EIS). Three alkaliions were used K+, Na+and Ca2+and the influence of pH on ions detection was studied and optimized. The Calix [4] arene-gold SPR sensor developed was characterized by low limit of detection (LOD) for about 10-10M, high sensitivity and wide linear detection range between 10-6M and 10-14M.

scholarly journals Ratiometric Fluorescent Biosensors for Glucose and Lactate Using an Oxygen-Sensing Membrane

Biosensors ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 208
Author(s):  
Hong Dinh Duong ◽  
Jong Il Rhee
Keyword(s):  
Limit Of Detection ◽  
Oxygen Sensing ◽  
High Sensitivity ◽  
Glucose Sensing ◽  
Oxidation Reactions ◽  
Lactate Oxidase ◽  
Lactate Oxidation ◽  
Detection Range ◽  
Quenching Effect ◽  
Sensing Membrane

In this study, ratiometric fluorescent glucose and lactate biosensors were developed using a ratiometric fluorescent oxygen-sensing membrane immobilized with glucose oxidase (GOD) or lactate oxidase (LOX). Herein, the ratiometric fluorescent oxygen-sensing membrane was fabricated with the ratio of two emission wavelengths of platinum meso-tetra (pentafluorophenyl) porphyrin (PtP) doped in polystyrene particles and coumarin 6 (C6) captured into silica particles. The operation mechanism of the sensing membranes was based on (i) the fluorescence quenching effect of the PtP dye by oxygen molecules, and (ii) the consumption of oxygen levels in the glucose or lactate oxidation reactions under the catalysis of GOD or LOX. The ratiometric fluorescent glucose-sensing membrane showed high sensitivity to glucose in the range of 0.1–2 mM, with a limit of detection (LOD) of 0.031 mM, whereas the ratiometric fluorescent lactate-sensing membrane showed the linear detection range of 0.1–0.8 mM, with an LOD of 0.06 mM. These sensing membranes also showed good selectivity, fast reversibility, and stability over long-term use. They were applied to detect glucose and lactate in artificial human serum, and they provided reliable measurement results.

scholarly journals Label-Free Electrochemical Biosensor Based on Au@MoS₂–PANI for Escherichia coli Detection

Chemosensors ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 49
Author(s):  
Pushap Raj ◽  
Man Hwan Oh ◽  
Kyudong Han ◽  
Tae Yoon Lee
Keyword(s):  
Escherichia Coli ◽  
Bacterial Infections ◽  
Limit Of Detection ◽  
Bacterial Pathogens ◽  
Cost Effective ◽  
Covalent Immobilization ◽  
Label Free ◽  
Self Assembled Monolayer ◽  
Detection Range ◽  
Linear Detection

Bacterial infections have become a significant challenge in terms of public health, the food industry, and the environment. Therefore, it is necessary to address these challenges by developing a rapid, cost-effective, and easy-to-use biosensor for early diagnosis of bacterial pathogens. Herein, we developed a simple, label-free, and highly sensitive immunosensor based on electrochemical detection using the Au@MoS₂–PANI nanocomposite. The conductivity of the glassy carbon electrode is greatly enhanced using the Au@MoS₂–PANI nanocomposite and a self-assembled monolayer of mercaptopropionic acid on the gold nanoparticle surface was employed for the covalent immobilization of antibodies to minimize the nonspecific adsorption of bacterial pathogens on the electrode surface. The biosensor established a high selectivity and sensitivity with a low limit of detection of 10 CFU/mL, and detected Escherichia coli within 30 min. Moreover, the developed biosensor demonstrated a good linear detection range, practical utility in urine samples, and electrode regenerative studies.

scholarly journals Light-Excited Ag-Doped TiO2−CoFe2O4 Heterojunction Applied to Toluene Gas Detection

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3261
Author(s):  
Wenhao Wang ◽  
Lu Zhang ◽  
Yanli Kang ◽  
Feng Yu
Keyword(s):  
Diffuse Reflectance ◽  
Gas Sensing ◽  
Limit Of Detection ◽  
Electron Hole ◽  
Detection Range ◽  
Response Recovery ◽  
Test Conditions ◽  
Sensing Material ◽  
Starting Point ◽  
Good Starting Point

(1) Background: Toluene gas is widely used in indoor decoration and industrial production, and it not only pollutes the environment but also poses serious health risks. (2) Methods: In this work, TiO2−CoFe2O4−Ag quaternary composite gas-sensing material was prepared using a hydrothermal method to detect toluene. (3) Results: The recombination of electron–hole pairs was suppressed, and the light absorption range was expanded after constructing a heterojunction and doping with Ag, according to ultraviolet–visible (UV–vis) diffuse reflectance spectra and photoluminescence spectroscopy. Moreover, in the detection range of toluene gas (3 ppm–50 ppm), the response value of TiO2−CoFe2O4−Ag increased from 2 to 15, which was much higher than that of TiO2−Ag (1.7) and CoFe2O4−Ag (1.7). In addition, the working temperature was reduced from 360 °C to 263 °C. Furthermore, its response/recovery time was 40 s/51 s, its limit of detection was as low as 10 ppb, and its response value to toluene gas was 3–7 times greater than that of other interfering gases under the same test conditions. In addition, the response value to 5 ppm toluene was increased from 3 to 5.5 with the UV wavelength of 395 nm–405 nm. (4) Conclusions: This is primarily due to charge flow caused by heterojunction construction, as well as metal sensitization and chemical sensitization of novel metal doping. This work is a good starting point for improving gas-sensing capabilities for the detection of toluene gas.

scholarly journals Citric Acid Capped CdS Quantum Dots for Fluorescence Detection of Copper Ions (II) in Aqueous Solution

Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 32 ◽  
Author(s):  
Zhezhe Wang ◽  
Xuechun Xiao ◽  
Tong Zou ◽  
Yue Yang ◽  
Xinxin Xing ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Citric Acid ◽  
Limit Of Detection ◽  
Copper Ions ◽  
High Sensitivity ◽  
Fluorescence Sensor ◽  
Cds Quantum Dots ◽  
Detection Range ◽  
Cds Qds

Citric acid capped CdS quantum dots (CA-CdS QDs), a new assembled fluorescent probe for copper ions (Cu2+), was synthesized successfully by a simple hydrothermal method. In this work, the fluorescence sensor for the detection of heavy and transition metal (HTM) ions has been extensively studied in aqueous solution. The results of the present study indicate that the obtained CA-CdS QDs could detect Cu2+ with high sensitivity and selectivity. It found that the existence of Cu2+ has a significant fluorescence quenching with a large red shifted (from greenish-yellow to yellowish-orange), but not in the presence of 17 other HTM ions. As a result, Cu2S, the energy level below the CdS conduction band, could be formed at the surface of the CA-CdS QDs and leads to the quenching of fluorescence of CA-CdS QDs. Under optimal conditions, the copper ions detection range using the synthesized fluorescence sensor was 1.0 × 10‒8 M to 5.0 × 10‒5 M and the limit of detection (LOD) is 9.2 × 10‒9 M. Besides, the as-synthesized CA-CdS QDs sensor exhibited good selectivity toward Cu2+ relative to other common metal ions. Thus, the CA-CdS QDs has potential applications for detecting Cu2+ in real water samples.

scholarly journals Nanostructured copper selenide as an ultrasensitive and selective non-enzymatic glucose sensor

2021 ◽  
Author(s):  
Siddesh Umapathi ◽  
Harish Singh ◽  
Jahangir Masud ◽  
Manashi Nath
Keyword(s):  
Detection Limit ◽  
High Efficiency ◽  
Glucose Sensor ◽  
High Sensitivity ◽  
Copper Selenide ◽  
Glucose Detection ◽  
Applied Potential ◽  
Detection Range ◽  
Low Detection Limit ◽  
Linear Detection

CuSe nanostructures exhibit high-efficiency for glucose detection with high sensitivity (19.419 mA mM−1 cm−2) and selectivity at low applied potential (0.15 V vs. Ag|AgCl), low detection limit (0.196 μM) and linear detection range (100 nM to 40 μM).

Crystal-Reconstructed BiVO4 Semiconductor Photoelectrochemical Sensor for Ultra-Sensitive Tumor Biomarkers Detection

2022 ◽  
Author(s):  
Yang Li ◽  
Xianying Dai ◽  
Lin He ◽  
Yuyu Bu ◽  
Jin-Ping Ao
Keyword(s):  
Laser Treatment ◽  
Limit Of Detection ◽  
High Energy ◽  
Tumor Biomarkers ◽  
Treatment Technique ◽  
Detection Range ◽  
Linear Detection ◽  
Photoelectrochemical Sensor ◽  
Energy Laser ◽  
High Energy Laser

In this work, we develop a crystal-reconstructed-BiVO4 aptamer photoelectrochemical (PEC) biosensor by high-energy laser treatment technique. This biosensor achieves a limit of detection (LOD) (0.82 ag/mL), linear detection range (1...

scholarly journals Comparative Studies of CPEs Modified with Distinctive Metal Nanoparticle-Decorated Electroactive Polyimide for the Detection of UA

Polymers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 252
Author(s):  
Aamna Bibi ◽  
Sheng-Chieh Hsu ◽  
Wei-Fu Ji ◽  
Yi-Chi Cho ◽  
Karen S. Santiago ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Initial Step ◽  
Differential Pulse ◽  
Metal Nanoparticle ◽  
Carbon Paste ◽  
Detection Range ◽  
Au Nps ◽  
Linear Detection ◽  
Paste Electrode

In this present work, an electrochemical sensor was developed for the sensing of uric acid (UA). The sensor was based on a carbon paste electrode (CPE) modified with electroactive polyimide (EPI) synthesized using aniline tetramer (ACAT) decorated with reduced nanoparticles (NPs) of Au, Pt, and Ag. The initial step involved the preparation and characterization of ACAT. Subsequently, the ACAT-based EPI synthesis was performed by chemical imidization of its precursors 4,4′-(4.4′-isopropylidene-diphenoxy) bis (phthalic anhydride) BPADA and ACAT. Then, EPI was doped with distinctive particles of Ag, Pt and Au, and the doped EPIs were abbreviated as EPIS, EPIP and EPIG, respectively. Their structures were characterized by XRD, XPS, and TEM, and the electrochemical properties were determined by cyclic voltammetry and chronoamperometry. Among these evaluated sensors, EPI with Au NPs turned out the best with a sensitivity of 1.53 uA uM−1 UA, a low limit of detection (LOD) of 0.78 uM, and a linear detection range (LDR) of 5–50 uM UA at a low potential value of 310 mV. Additionally, differential pulse voltammetric (DPV) analysis showed that the EPIG sensor showed the best selectivity for a tertiary mixture of UA, dopamine (DA), and ascorbic acid (AA) as compared to EPIP and EPIS.

Giant Magnetoresistive Based Handheld System for Rapid Detection of Human NT-proBNP

2019 ◽  
Author(s):  
Wei Wang ◽  
Todd Klein ◽  
James Collins
Keyword(s):  
Limit Of Detection ◽  
Detection System ◽  
Point Of Care ◽  
High Sensitivity ◽  
Time Signal ◽  
Point Of Care Testing ◽  
Detection Range ◽  
Further Development ◽  
Signal Readout

In this work, we developed giant magnetoresistive (GMR) based handheld biosensing systems that serve as platform for detecting human NT-proBNP. This assay takes advantages of high sensitivity and real-time signal readout of GMR biosensor. The limit of detection was estimated to be less than 0.01ng/mL, and detection range covered from 0.01 ng/mL to 5 ng/mL was obtained. The assay can be completed within 20 min, which is very important for further development of point-of-care testing. The proposed GMR handheld system is also successfully used for the detection of real NT-proBNP human samples. It can be foreseen that this handheld detection system could become a robust contender in the applications of in vitro biomarker diagnostics.

scholarly journals Hydrogen Peroxide Detection by Super-Porous Hybrid CuO/Pt NP Platform: Improved Sensitivity and Selectivity

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2034
Author(s):  
Rakesh Kulkarni ◽  
Sundar Kunwar ◽  
Rutuja Mandavkar ◽  
Jae-Hun Jeong ◽  
Jihoon Lee
Keyword(s):  
Hydrogen Peroxide ◽  
Physical Vapor Deposition ◽  
Active Sites ◽  
Limit Of Detection ◽  
Synergetic Effect ◽  
High Sensitivity ◽  
Detection Range ◽  
Hydrogen Peroxide Detection ◽  
Sensitivity And Selectivity ◽  
Hybrid Platform

A super-porous hybrid platform can offer significantly increased number of reaction sites for the analytes and thus can offer advantages in the biosensor applications. In this work, a significantly improved sensitivity and selectivity of hydrogen peroxide (H2O2) detection is demonstrated by a super-porous hybrid CuO/Pt nanoparticle (NP) platform on Si substrate as the first demonstration. The super-porous hybrid platform is fabricated by a physiochemical approach combining the physical vapor deposition of Pt NPs and electrochemical deposition of super-porous CuO structures by adopting a dynamic hydrogen bubble technique. Under an optimized condition, the hybrid CuO/Pt biosensor demonstrates a very high sensitivity of 2205 µA/mM·cm2 and a low limit of detection (LOD) of 140 nM with a wide detection range of H2O2. This is meaningfully improved performance as compared to the previously reported CuO-based H2O2 sensors as well as to the other metal oxide-based H2O2 sensors. The hybrid CuO/Pt platform exhibits an excellent selectivity against other interfering molecules such as glucose, fructose, dopamine, sodium chloride and ascorbic acid. Due to the synergetic effect of highly porous CuO structures and underlying Pt NPs, the CuO/Pt architecture offers extremely abundant active sites for the H2O2 reduction and electron transfer pathways.

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