scholarly journals Simple fluorescence optosensing probe for spermine based on ciprofloxacin-Tb3+ complexation

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251306
Author(s):  
Nguyen Ngoc Nghia ◽  
Bui The Huy ◽  
Pham Thanh Phong ◽  
Jin Sol Han ◽  
Dae Hyun Kwon ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Positive Charge ◽  
Detection Method ◽  
Limit Of Detection ◽  
Green Emission ◽  
High Sensitivity ◽  
Paper Strip ◽  
Serum Samples ◽  
Lanthanide Coordination Polymer ◽  
Strip Test

We developed a facile detection method of spermine based on the fluorescence (FL) quenching of the ciprofloxacin-Tb3+ complex, which shows astrong green emission. Ciprofloxacin (CP) makes efficient bondings to Tb3+ ion as a linker molecule through carboxylic and ketone groups to form a kind of lanthanide coordination polymer. The addition of spermine that competes with Tb3+ ions for the interaction with CP due to its positive charge brings about weakened coordination linkage of CP and Tb3+. The probe exhibited high sensitivity, selectivity, and good linearity in the range of 2–180 μM with a low limit of detection of 0.17 μM. Moreover, we applied this method on the paper strip test (PST), along with the integration of a smartphone and Arduino-based device. The practical reliability of the developed probe was evaluated on human serum samples with acceptable analytical results.

Lanthanide coordination polymer-based biosensor for citrate detection in urine

2019 ◽  
Vol 11 (10) ◽  
pp. 1405-1409 ◽  
Author(s):  
Haoshuang Shen ◽  
Baoxia Liu ◽  
Daosheng Liu ◽  
Xu Zhu ◽  
Xiuhua Wei ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
High Sensitivity ◽  
Lanthanide Coordination Polymer ◽  
Sensitivity And Selectivity

GMP ligand based LCP sensor for Cit with high sensitivity and selectivity was constructed.

scholarly journals Non-enzymatic sensor for determination of glucose based on PtNi nanoparticles decorated graphene

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Risheng Li ◽  
Xu Deng ◽  
Longfei Xia
Keyword(s):  
Limit Of Detection ◽  
High Sensitivity ◽  
Glucose Detection ◽  
Serum Samples ◽  
Time Curve ◽  
Current Time ◽  
Glass Carbon ◽  
Graphene Glass ◽  
Ptni Alloy

Abstract Diabetes has become a universal epidemic in recent years. Herein, the monitoring of glucose in blood is of importance in clinical applications. In this work, PtNi alloy nanoparticles homogeneously dispersed on graphene (PtNi alloy-graphene) was synthesized as a highly effective electrode material for glucose detection. Based on the modified PtNi alloy-graphene/glass carbon (PtNi alloy-graphene/GC) electrode, it is found that the PtNi alloy-graphene/GC electrode exhibited excellent electrocatalytic performance on glucose oxidation. Furthermore, the results from amperometric current–time curve show a good linear range of 0.5–15 mM with the limit of detection of 16 uM (S/N = 3) and a high sensitivity of 24.03 uAmM−1 cm−2. On account of the good selectivity and durability, the modified electrode was successfully applied on glucose detection in blood serum samples.

scholarly journals Detection of Melamine Based on the Fluorescence Changes of Nitrogen-Doped Carbon Dots

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Wenzhi Yin ◽  
Chaoqun Ma ◽  
Tuo Zhu ◽  
Jiao Gu ◽  
Chun Zhu ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Detection Method ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Mercury Ions ◽  
Measuring Range ◽  
Nitrogen Doped ◽  
One Step ◽  
Doped Carbon Dots ◽  
Nitrogen Doped Carbon

In order to determine the concentration of melamine, nitrogen-doped carbon dots (NCDs) were synthesized in one step as a fluorescent probe. Uric acid and diethylenetriamine were used as carbon source and nitrogen source, respectively. The experimental results showed that the fluorescence of NCDs can be quenched by mercury ions (Hg2+). Due to the strong coordination affinity between the carbon-nitrogen heterocyclic of melamine and Hg2+, part of Hg2+ coordinated with melamine when melamine was mixed with Hg2+. Then, the fluorescence of the added NCDs was quenched by the remaining Hg2+. Therefore, the concentration of melamine could be determined. The results show that the method has high sensitivity in wide measuring range that the linear ranges are 50–400 μg/L and 800–2500 μg/L, and the R2 is 0.997 and 0.988, respectively, with the limit of detection (LOD) of 21.76 μg/L. The NCDs are easy to fabricate, and the detection method is easy to implement. In this study, a new method for melamine detection was established, and the proposed method for melamine detection can provide some insights for food safety detection.

scholarly journals Dispersed Conducting Polymer Nanocomposites with Glucose Oxidase and Gold Nanoparticles for the Design of Enzymatic Glucose Biosensors

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2173
Author(s):  
Natalija German ◽  
Almira Ramanaviciene ◽  
Arunas Ramanavicius
Keyword(s):  
Glucose Oxidase ◽  
Conducting Polymer ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Serum Samples ◽  
Glucose Determination ◽  
Constant Potential ◽  
Good Repeatability ◽  
Graphite Rod

Biosensors for the determination of glucose concentration have a great significance in clinical diagnosis, and in the food and pharmaceutics industries. In this research, short-chain polyaniline (PANI) and polypyrrole (Ppy)-based nanocomposites with glucose oxidase (GOx) and 6 nm diameter AuNPs (AuNPs(6 nm)) were deposited on the graphite rod (GR) electrode followed by the immobilization of GOx. Optimal conditions for the modification of GR electrodes by conducting polymer-based nanocomposites and GOx were elaborated. The electrodes were investigated by cyclic voltammetry and constant potential amperometry in the presence of the redox mediator phenazine methosulfate (PMS). The improved enzymatic biosensors based on GR/PANI-AuNPs(6 nm)-GOx/GOx and GR/Ppy-AuNPs(6 nm)-GOx/GOx electrodes were characterized by high sensitivity (65.4 and 55.4 μA mM−1 cm−2), low limit of detection (0.070 and 0.071 mmol L−1), wide linear range (up to 16.5 mmol L−1), good repeatability (RSD 4.67 and 5.89%), and appropriate stability (half-life period (τ1/2) was 22 and 17 days, respectively). The excellent anti-interference ability to ascorbic and uric acids and successful practical application for glucose determination in serum samples was presented for GR/PANI-AuNPs(6 nm)-GOx/GOx electrode.

scholarly journals Ratiometric Probe for Rapid Naked Eye Detection of Toxic Hydrazine: Real Time Application in Strip Test, Spray Test and Soil Analysis

2021 ◽  
Author(s):  
Natarajan Vijay ◽  
Sivan Velmathi
Keyword(s):  
Real Time ◽  
Soil Analysis ◽  
Colour Change ◽  
High Sensitivity ◽  
Water Soluble ◽  
Paper Strip ◽  
Naked Eye ◽  
Strip Test ◽  
Ratiometric Probe ◽  
Real Time Application

Abstract Striking colorimetric probe (CynH) for abrupt detection of hydrazine under complete aqueous solution was achieved. The water soluble probe was designed with electron “push-pull” strategy by coupling of 4-hydroxy benzaldehyde and 2, 3, 3-trimethylindolinine. The positively charged N-propylated indolinine make the probe completely soluble in water. The probe yields eye catching selective detection of hydrazine over other competing analytes with high sensitivity. Obvious colour change was observed from colourless to appearance of bright pink colour with hydrazine. It reacts quickly with hydrazine within 2 minutes and makes the probe an effective candidate for practical application. The real time application was demonstrated using paper strip to detect hydrazine vapour. This probe is superior to earlier reported probes because of its effective sensing of hydrazine displayed with various applications including real-time strip based sensing, spray test and soil analysis. In all the examinations, the probe yields distinct response with rapid naked eye colour change this overcomes the drawbacks of previous reports.

scholarly journals Exploiting a new europium(III) coordination polymer based on a zwitterionic ligand as a fluorescent probe for uranyl cations

2020 ◽  
pp. 174751982093226
Author(s):  
Bin Cai ◽  
Yu-Ning Meng ◽  
Meng-En Zhu ◽  
Youming Yang
Keyword(s):  
Infrared Spectroscopy ◽  
Thermogravimetric Analysis ◽  
Coordination Polymer ◽  
High Selectivity ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Fast Response ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
X Ray

Two new isostructural lanthanide(III) coordination polymers based on an unreported zwitterionic ligand, namely, [Ln(ox)(L)]n (ox = oxalate, HL = N,N'-dipropionic acid imidazolium, Ln = Eu or La), are synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. The fluorescence properties of the europium coordination polymer are investigated. In addition, the europium-based coordination polymer is utilized for specific sensing of UO22+ ions, showing high selectivity, a fast response time (8 min) and high sensitivity with noticeable quenching ( Ksv = 6.19 × 104 M−1) and limit of detection of 1.95 µM.

scholarly journals A Novel, Inexpensive In-House Immunochromatographic Strip Test for Cryptococcosis Based on the Cryptococcal Glucuronoxylomannan Specific Monoclonal Antibody 18B7

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 758
Author(s):  
Pakornswit Sathongdejwisit ◽  
Kritsada Pruksaphon ◽  
Akarin Intaramat ◽  
Pisinee Aiumurai ◽  
Nitat Sookrung ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Lower Limit ◽  
Limit Of Detection ◽  
Latex Agglutination ◽  
Specific Monoclonal Antibody ◽  
Serum Samples ◽  
Immunochromatographic Strip ◽  
Strip Test ◽  
Sensitivity Specificity ◽  
Capsular Antigens

The aim of this study was to develop a novel lateral flow immunochromatoghaphic strip test (ICT) for detecting cryptococcal polysaccharide capsular antigens using only a single specific monoclonal antibody, mAb 18B7. The mAb 18B7 is a well characterized antibody that specifically binds repeating epitopes displayed on the cryptococcal polysaccharide glucuronoxylomannan (GXM). We validated the immunoreactivities of mAb 18B7 against capsular antigens of different cryptococcal serotypes. The mAb 18B7 ICT was constructed as a sandwich ICT strip and the antibody serving in the mobile phase (colloidal gold conjugated mAb 18B7) to bind one of the GXM epitopes while the stationary phase antibody (immobilized mAb18B7 on test line) binding to other remaining unoccupied epitopes to generate a positive visual readout. The lower limit of detection of capsular antigens for each of the Cryptococcus serotypes tested was 0.63 ng/mL. No cross-reaction was found against a panel of antigens isolated from cultures of other pathogenic fungal, except the crude antigen of Trichosporon sp. with the lower limit of detection of 500 ng/mL (~800 times higher than that for cryptococcal GXM). The performance of the mAb 18B7 ICT strip was studied using cerebrospinal fluid (CSF) and serum and compared to commercial diagnostic kits (latex agglutination CALAS and CrAg IMMY). The sensitivity, specificity and accuracy of the mAb18B7 ICT with CSF from patients with confirmed cryptococcal meningitis were 92.86%, 100% and 96.23%, respectively. No false positives were observed with samples from non-cryptococcosis patients. With serum samples, the mAb 18B7 ICT gave a sensitivity, specificity and accuracy of 96.15%, 97.78% and 96.91%, respectively. Our results show that the mAb 18B7 based ICT was reliable, reproducible, and cost-effective as a point-of-care immunodiagnostic test for cryptococcosis. The mAb 18B7 ICT may be particularly useful in countries where commercial kits are not available or affordable.

scholarly journals Label-Free Surface Enhanced Raman Scattering (SERS) on Centrifugal Silver Plasmonic Paper (CSPP): A Novel Methodology for Unprocessed Biofluids Sampling and Analysis

Biosensors ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 467
Author(s):  
Alessandro Esposito ◽  
Alois Bonifacio ◽  
Valter Sergo ◽  
Stefano Fornasaro
Keyword(s):  
High Sensitivity ◽  
Absolute Intensity ◽  
Clinical Samples ◽  
Paper Strip ◽  
Molecular Fingerprinting ◽  
Label Free ◽  
Serum Samples ◽  
Gold Colloids ◽  
Analytical Technique ◽  
Plasmonic Paper

Label-free SERS is a powerful bio-analytical technique in which molecular fingerprinting is combined with localized surface plasmons (LSPs) on metal surfaces to achieve high sensitivity. Silver and gold colloids are among the most common nanostructured substrates used in SERS, but since protein-rich samples such as serum or plasma can hinder the SERS effect due to protein–substrate interactions, they often require a deproteinization step. Moreover, SERS methods based on metal colloids often suffer from a poor reproducibility. Here, we propose a paper-based SERS sampling method in which unprocessed human serum samples are first soaked on paper strips (0.4 × 2 cm2), and then mixed with colloidal silver nanoparticles by centrifugation to obtain a Centrifugal Silver Plasmonic Paper (CSPP). The CSPP methodology has the potential to become a promising tool in bioanalytical SERS applications: it uses common colloidal substrates but without the need for sample deproteinization, while having a good reproducibility both in terms of overall spectral shape (r > 0.96) and absolute intensity (RSD < 10%). Moreover, this methodology allows SERS analysis more than one month after serum collection on the paper strip, facilitating storage and handling of clinical samples (including shipping from clinical sites to labs).

scholarly journals Rapid, Quantitative, and High-Sensitivity Detection of Anti-Phospholipase A2 Receptor Antibodies Using Novel Cdse/Zns-Based Fluorescence Immunosorbent Assay

2020 ◽  
Author(s):  
Chenxi Li ◽  
Manyun Qian ◽  
Qiaozhen Hong ◽  
Xiaohong Xin ◽  
Zichun Sun ◽  
...  
Keyword(s):  
Phospholipase A2 ◽  
Immunosorbent Assay ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Detection Sensitivity ◽  
Response To Treatment ◽  
Enzyme Linked Immunosorbent Assay ◽  
The Novel ◽  
Serum Samples ◽  
Phospholipase A2 Receptor

Abstract Autoantibodies against M-type phospholipase A2 receptor (PLA2R) are specific biomarkers for idiopathic membranous nephropathy (IMN) and their quantification has been helpful to monitor disease activity. In this study, we describe a highly sensitive and rapid quantum dots-based immunochromatography assay (QD-ICA) for quantifying PLA2R autoantibodies. Serum samples from 135 biopsy-confirmed patients with nephrotic syndrome were analyzed for PLA2R autoantibodies using the novel QD-ICA as well as enzyme-linked immunosorbent assay (ELISA). The detection sensitivity and specificity of QD-ICA (80.9 and 100%, respectively) exceeded those of ELISA (72.1 and 98.5%, respectively). The optimum cut-off value of QD-ICA was 18.18 RU/mL and limit of detection was 2.86 relative units/mL. The novel QD-ICA outperforms ELISA in detecting PLA2R autoantibodies, with shorter detection time, fewer steps, smaller equipment size, and broader testing application, suggesting its capability to improve IMN diagnosis and monitor patient response to treatment.

scholarly journals A Simple Fluorescent Aptasensing Platform Based on Graphene Oxide for Dopamine Determination

2021 ◽  
Author(s):  
Ahlem Teniou ◽  
amina rhouati ◽  
Gaëlle Catanante
Keyword(s):  
Graphene Oxide ◽  
Limit Of Detection ◽  
Rapid Determination ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
High Sensitivity ◽  
Fluorescence Recovery ◽  
Serum Samples ◽  
Experimental Conditions ◽  
Minor Response

Abstract Dopamine (DA) is a catecholamine neurotransmitter playing an important role in different biological functions including central nervous, renal, cardiovascular, and hormonal systems. The sensitive and selective detection of this neurotransmitter plays a key role in the early diagnosis of various diseases related to abnormal levels of dopamine. Therefore, it is of great importance to explore rapid, simple, and accurate methods for detection of dopamine with high sensitivity and specificity. We propose in this work, a fluorescent aptasensor based on graphene oxide (GO) as a quencher, for the rapid determination of dopamine. The principle of this aptasensor is based on fluorescence resonance energy transfer (FRET), where GO was used as energy donor, and a carboxyfluorescein (FAM)-labeled aptamer as acceptor. In the absence of DA, FAM-aptamer was adsorbed on the surface of GO through π-π stacking interactions between nucleotide bases and the carbon network, leading to a weak FRET and a quenching of the FAM fluorescence. However, by adding the target, the aptamer undergoes a conformational change to bind to DA with high affinity, resulting in a fluorescence recovery. Under the optimal experimental conditions, the fluorescence recovery was linearly proportional to the concentration of DA in the range of 3-1680 nM, with a limit of detection of 0.031 nM. Moreover, the developed assay exhibited minor response in the presence of various interferents and it revealed a satisfactory applicability in human serum samples.

Sign in / Sign up

Export Citation Format

Share Document