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 A Phosphorescence Quenching-Based Intelligent Dissolved Oxygen Sensor on an Optofluidic Platform

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 281
Author(s):  
Fang Wang ◽  
Longfei Chen ◽  
Jiaomeng Zhu ◽  
Xuejia Hu ◽  
Yi Yang
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Sensor ◽  
Continuous Measurement ◽  
Limit Of Detection ◽  
Oxygen Sensing ◽  
High Sensitivity ◽  
Microfluidic Channels ◽  
Phosphorescence Quenching ◽  
Intelligent Sensor ◽  
Sensing Membrane

Continuous measurement of dissolved oxygen (DO) is essential for water quality monitoring and biomedical applications. Here, a phosphorescence quenching-based intelligent dissolved oxygen sensor on an optofluidic platform for continuous measurement of dissolved oxygen is presented. A high sensitivity dissolved oxygen-sensing membrane was prepared by coating the phosphorescence indicator of platinum(II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) on the surface of the microfluidic channels composed of polydimethylsiloxane (PDMS) microstructure arrays. Then, oxygen could be determined by its quenching effect on the phosphorescence, according to Stern–Volmer model. The intelligent sensor abandons complicated optical or electrical design and uses a photomultiplier (PMT) counter in cooperation with a mobile phone application program to measure phosphorescence intensity, so as to realize continuous, intelligent and real-time dissolved oxygen analysis. Owing to the combination of the microfluidic-based highly sensitive oxygen sensing membrane with a reliable phosphorescent intensity detection module, the intelligent sensor achieves a low limit of detection (LOD) of 0.01 mg/L, a high sensitivity of 16.9 and a short response time (22 s). Different natural water samples were successfully analyzed using the intelligent sensor, and results demonstrated that the sensor features a high accuracy. The sensor combines the oxygen sensing mechanism with optofluidics and electronics, providing a miniaturized and intelligent detection platform for practical oxygen analysis in different application fields.

scholarly journals Development of a Ratiometric Fluorescent Glucose Sensor Using an Oxygen-Sensing Membrane Immobilized with Glucose Oxidase for the Detection of Glucose in Tears

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 86 ◽  
Author(s):  
Hong Dinh Duong ◽  
Ok-Jae Sohn ◽  
Jong Il Rhee
Keyword(s):  
Glucose Oxidase ◽  
Glucose Concentration ◽  
Glucose Sensor ◽  
Oxygen Sensing ◽  
Sol Gel ◽  
Glucose Sensing ◽  
Glucose Biosensor ◽  
Detection Range ◽  
Fluorescence Measurements ◽  
Sensing Membrane

Glucose concentration is an important parameter in biomedicine since glucose is involved in many metabolic pathways in organisms. Many methods for glucose detection have been developed for use in various applications, particularly in the field of healthcare in diabetics. In this study, ratiometric fluorescent glucose-sensing membranes were fabricated based on the oxygen levels consumed in the glucose oxidation reaction under the catalysis of glucose oxidase (GOD). The oxygen concentration was measured through the fluorescence quenching effect of an oxygen-sensitive fluorescent dye like platinum meso-tetra (pentafluorophenyl) porphyrin (PtP) by oxygen molecules. Coumarin 6 (C6) was used as a reference dye in the ratiometric fluorescence measurements. The glucose-sensing membrane consisted of two layers: The first layer was the oxygen-sensing membrane containing polystyrene particles (PS) doped with PtP and C6 (e.g., PS@C6^PtP) in a sol–gel matrix of aminopropyltrimethoxysilane and glycidoxypropyltrimethoxysilane (GA). The second layer was made by immobilizing GOD onto one of three supporting polymers over the first layer. These glucose-sensing membranes were characterized in terms of their response, reversibility, interferences, and stability. They showed a wide detection range to glucose concentration in the range of 0.1 to 10 mM, but high sensitivity with a linear detection range of 0.1 to 2 mM glucose. This stable and sensitive ratiometric fluorescent glucose biosensor provides a reliable way to determine low glucose concentrations in blood serum by measuring tear glucose.

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.

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 A Ratiometric Fluorescent Aptamer Homogeneous Biosensor Based on Hairpin Structure Aptamer for AFB1 Detection

2022 ◽  
Author(s):  
Beibei Feng ◽  
Fei Zhao ◽  
Min Wei ◽  
Yong Liu ◽  
Xinyu Ren ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Resonance Energy Transfer ◽  
Fluorescence Emission ◽  
Resonance Energy ◽  
Hairpin Structure ◽  
Fluorescence Signal ◽  
Detection Range ◽  
Quenching Effect ◽  
Double Stranded Dna ◽  
Aflatoxin B

Abstract On the basis of aptamer (Apt) with hairpin structure and fluorescence resonance energy transfer (FRET), a ratio fluorescent aptamer homogeneous sensor was prepared for the determination of Aflatoxin B1 (AFB1). Initially, the Apt labeled simultaneously with Cy5, BHQ2, and cDNA labeled with Cy3 were formed a double-stranded DNA through complementary base pairing. The fluorescent aptamer sensor demonstrates a weak fluorescence emission of Cy3 and a high fluorescence emission of Cy5 due to the quenching effect of BHQ2. The double-stranded DNA structure will be disintegrated in the presence of AFB1, resulting the removal of Cy3 and the close of Cy5 with BHQ2. The fluorescence signal of Cy3 and Cy5 were restored and quenched respectively. Thus, the ratio change of FCy3 to FCy5 was used to realized the detection of AFB1 with wider detection range and lower limit of detection (LOD). The response of the optimized protocol for AFB1 detection was wider linear range from 0.05 ng/mL to 100 ng/mL and the LOD was 12.6 pg/mL. The sensor designed in this strategy has the advantages of simple preparation and fast signal response. It has been used for the detection of AFB1 in labeled corn and wine, indicating it had good application potential in practical samples.

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.

scholarly journals Ratiometric and selective fluorescent nanosensor for the detection of glucose

2021 ◽  
Vol 01 ◽  
Author(s):  
Shengda Qi
Keyword(s):  
Limit Of Detection ◽  
Blue Emission ◽  
Glucose Sensing ◽  
Excitation Wavelength ◽  
Dual Emission ◽  
Fluorescent Intensity ◽  
Quenching Effect ◽  
Color Evolution ◽  
Nanocomposite System ◽  
Dual Emissions

Background and Methods: Dual-emission fluorescent nanosensor for the detection of glucose has been developed by simply mixing the blue-emission C-dots (CDs) with red-emission glutathione modified CdTe QDs. Results and Discussion: The ratiometric fluorescence system exhibits dual emissions peak at 442nm and 600 nm under a single excitation wavelength (365 nm). Due to the strong quenching effect of hydrogen peroxide to the quantum dots, the fluorescence of the QDs in the nanocomposite system could be selectively quenched by H2O2, while the fluorescence of the CDs remained constant, resulting in a distinguishable fluorescence color evolution (from red to blue) of the nanosensor which could be observed obviously by the naked eye. When this nanosensor mixed with glucose oxidase, H2O2 can be produced by the enzyme catalysis reaction, which could quench the fluorescent intensity of QDs. So this system can be used to detect glucose. The limit of detection of this present method was as low as 0.1 μM. Conclusion: the result for glucose was satisfying, suggesting its potential application for glucose sensing.

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.

scholarly journals Vertically Ordered Mesoporous Silica-Nanochannel Film-Equipped Three-Dimensional Macroporous Graphene as Sensitive Electrochemiluminescence Platform

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiawei Gong ◽  
Hongliang Tang ◽  
Xuan Luo ◽  
Huaxu Zhou ◽  
Xueting Lin ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Self Assembly ◽  
Limit Of Detection ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Ordered Mesoporous Silica ◽  
3D Graphene ◽  
Quenching Effect ◽  
Sensing Platform ◽  
Ordered Mesoporous

Three-dimensional (3D) electrochemiluminescence (ECL) platform with high sensitivity and good anti-fouling is highly desirable for direct and sensitive analysis of complex samples. Herein, a novel ECL-sensing platform is demonstrated based on the equipment of vertically ordered mesoporous silica-nanochannel films (VMSF) on monolithic and macroporous 3D graphene (3DG). Through electrografting of 3-aminopropyltriethoxysilane (APTES) onto 3DG as molecular glue, VMSF grown by electrochemically assisted self-assembly (EASA) method fully covers 3DG surface and displays high stability. The developed VMSF/APTES/3DG sensor exhibits highly sensitized ECL response of tris(2,2′-bipyridyl) ruthenium (Ru (bpy)32+) taking advantages of the unique characteristics of 3DG (high active area and conductivity) and VMSF nanochannels (strong electrostatic enrichment). The VMSF/APTES/3DG sensor is applied to sensitively detect an important environmental pollutant (4-chlorophenol, with limit of detection or LOD of 30.3 nM) in term of its quenching effect (ECL signal-off mode) toward ECL of Ru (bpy)32+/tri-n-propylamine (TPrA). The VMSF/APTES/3DG sensor can also sensitively detect the most effective antihistamines chlorpheniramine (with LOD of 430 nM) using ECL signal-on mode because it acts as co-reactant to promote the ECL of Ru (bpy)32+. Combined with the excellent antifouling ability of VMSF, the sensor can also realize the analysis of actual environmental (lake water) and pharmaceutical (pharmacy tablet) samples. The proposed 3D ECL sensor may open new avenues to develop highly sensitive ECL-sensing platform.

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