Cds nanocrystal enhanced TiO2photoelectrochemical aptasensor for sensitive detection of cytochrome c

A CdS nanocrystal enhanced TiO2 nanotubes (CdS@TiO2 NATs) photoelectrode was prepared via successive ionic layer adsorption and reaction (SILAR) of CdS on the surface of TiO2 NATs. A HS-aptamer owing a specific binding toward cytochrome c was modified onto the CdS@TiO2 NATs, which resulting a decrease in the photoelectrical current intensity. Cytochrome c is therefore quantified based on the decrease in photoelectrical current. High specificity and high sensitivity were obtained with a linear range from 3 pM to 80 nM, and a limit of detection of 2.53 pM.

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SARS-CoV-2 Direct Detection Without RNA Isolation With Loop-Mediated Isothermal Amplification (LAMP) and CRISPR-Cas12

Frontiers in Medicine ◽

10.3389/fmed.2021.627679 ◽

2021 ◽

Vol 8 ◽

Author(s):

Alfredo Garcia-Venzor ◽

Bertha Rueda-Zarazua ◽

Eduardo Marquez-Garcia ◽

Vilma Maldonado ◽

Angelica Moncada-Morales ◽

...

Keyword(s):

Limit Of Detection ◽

Direct Detection ◽

Direct Method ◽

Rna Extraction ◽

Rna Isolation ◽

High Sensitivity ◽

High Specificity ◽

Isothermal Amplification ◽

Clinical Samples ◽

Loop Mediated Isothermal Amplification

As to date, more than 49 million confirmed cases of Coronavirus Disease 19 (COVID-19) have been reported worldwide. Current diagnostic protocols use qRT-PCR for viral RNA detection, which is expensive and requires sophisticated equipment, trained personnel and previous RNA extraction. For this reason, we need a faster, direct and more versatile detection method for better epidemiological management of the COVID-19 outbreak. In this work, we propose a direct method without RNA extraction, based on the Loop-mediated isothermal amplification (LAMP) and Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated protein (CRISPR-Cas12) technique that allows the fast detection of SARS-CoV-2 from patient samples with high sensitivity and specificity. We obtained a limit of detection of 16 copies/μL with high specificity and at an affordable cost. The diagnostic test readout can be done with a real-time PCR thermocycler or with the naked eye in a blue-light transilluminator. Our method has been evaluated on a small set of clinical samples with promising results.

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A Highly Sensitive Cell-Based TLR Reporter Platform for the Specific Detection of Bacterial TLR Ligands

Frontiers in Immunology ◽

10.3389/fimmu.2021.817604 ◽

2022 ◽

Vol 12 ◽

Author(s):

Katharina Radakovics ◽

Claire Battin ◽

Judith Leitner ◽

Sabine Geiselhart ◽

Wolfgang Paster ◽

...

Keyword(s):

Limit Of Detection ◽

Ectopic Expression ◽

High Sensitivity ◽

High Specificity ◽

Reporter System ◽

Specificity And Sensitivity ◽

Highly Sensitive ◽

Definition Of ◽

The Individual ◽

Allergen Extracts

Toll-like receptors (TLRs) are primary pattern recognition receptors (PRRs), which recognize conserved microbial components. They play important roles in innate immunity but also in the initiation of adaptive immune responses. Impurities containing TLR ligands are a frequent problem in research but also for the production of therapeutics since TLR ligands can exert strong immunomodulatory properties even in minute amounts. Consequently, there is a need for sensitive tools to detect TLR ligands with high sensitivity and specificity. Here we describe the development of a platform based on a highly sensitive NF-κB::eGFP reporter Jurkat JE6-1 T cell line for the detection of TLR ligands. Ectopic expression of TLRs and their coreceptors and CRISPR/Cas9-mediated deletion of endogenously expressed TLRs was deployed to generate reporter cell lines selectively expressing functional human TLR2/1, TLR2/6, TLR4 or TLR5 complexes. Using well-defined agonists for the respective TLR complexes we could demonstrate high specificity and sensitivity of the individual reporter lines. The limit of detection for LPS was below 1 pg/mL and ligands for TLR2/1 (Pam3CSK4), TLR2/6 (Fsl-1) and TLR5 (flagellin) were detected at concentrations as low as 1.0 ng/mL, 0.2 ng/mL and 10 pg/mL, respectively. We showed that the JE6-1 TLR reporter cells have the utility to characterize different commercially available TLR ligands as well as more complex samples like bacterially expressed proteins or allergen extracts. Impurities in preparations of microbial compounds as well as the lack of specificity of detection systems can lead to erroneous results and currently there is no consensus regarding the involvement of TLRs in the recognition of several molecules with proposed immunostimulatory functions. This reporter system represents a highly suitable tool for the definition of structural requirements for agonists of distinct TLR complexes.

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Highly Sensitive Detection of Benzoyl Peroxide Based on Organoboron Fluorescent Conjugated Polymers

Polymers ◽

10.3390/polym11101655 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1655 ◽

Cited By ~ 2

Author(s):

Mingyuan Yin ◽

Caiyun Zhang ◽

Jing Li ◽

Haijie Li ◽

Qiliang Deng ◽

...

Keyword(s):

Conjugated Polymers ◽

Benzoyl Peroxide ◽

Boronic Acid ◽

Limit Of Detection ◽

Fluorescence Emission ◽

High Sensitivity ◽

Ammonium Persulfate ◽

Sensitive Detection ◽

Polymerization Reaction ◽

Charge Transfer Complexes

The method capable of rapid and sensitive detection of benzoyl peroxide (BPO) is necessary and receiving increasing attention. In consideration of the vast signal amplification of fluorescent conjugated polymers (FCPs) for high sensitivity detection and the potential applications of boron-containing materials in the emerging sensing fields, the organoboron FCPs, poly (3-aminophenyl boronic acid) (PABA) is directly synthesized via free-radical polymerization reaction by using the commercially available 3-aminophenyl boronic acid (ABA) as the functional monomer and ammonium persulfate as the initiator. PABA is employed as a fluorescence sensor for sensing of trace BPO based on the formation of charge-transfer complexes between PABA and BPO. The fluorescence emission intensity of PABA demonstrates a negative correlation with the concentration of BPO. And a linear range of 8.26 × 10−9 M–8.26 × 10–4 M and a limit of detection of 1.06 × 10–9 M as well as a good recovery (86.25%–111.38%) of BPO in spiked real samples (wheat flour and antimicrobial agent) are obtained. The proposed sensor provides a promising prospective candidate for the rapid detection and surveillance of BPO.

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Highly sensitive detection of nitrite by using gold nanoparticle-decorated α-Fe2O3 nanorod arrays as self-supporting photo-electrodes

Inorganic Chemistry Frontiers ◽

10.1039/c9qi00176j ◽

2019 ◽

Vol 6 (6) ◽

pp. 1432-1441 ◽

Cited By ~ 2

Author(s):

Shenghong Kang ◽

Haimin Zhang ◽

Guozhong Wang ◽

Yunxia Zhang ◽

Huijun Zhao ◽

...

Keyword(s):

Gold Nanoparticle ◽

Limit Of Detection ◽

High Sensitivity ◽

Sensitive Detection ◽

Nanorod Arrays ◽

Highly Sensitive ◽

Highly Sensitive Detection

Gold nanoparticle (Au NP)-decorated-Fe2O3 nanorod arrays (AuNPs-Fe2O3) as a photoelectrode are applied to the detection of nitrite solution with a low limit of detection and high sensitivity.

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An isothermal method for sensitive detection of Mycobacterium tuberculosis complexes using CRISPR/Cas12a cis- and trans-cleavage

10.1101/2020.02.03.933101 ◽

2020 ◽

Author(s):

Haipo Xu ◽

Xiaolong Zhang ◽

Zhixiong Cai ◽

Xiuqing Dong ◽

Geng Chen ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Limit Of Detection ◽

Clinical Performance ◽

High Specificity ◽

Culture Method ◽

Sensitive Detection ◽

Clinical Samples ◽

Target Sequence ◽

Guide Rna ◽

Specificity And Sensitivity

AbstractTuberculosis is still one of the most serious infectious diseases resulting in lethal death worldwide. The traditional method is still not enough to meet the clinical requirements of rapid diagnosis, high specificity and sensitivity. Fast, sensitive and accurate detection of mycobacterium tuberculosis (MTB) is an urgent need for the treatment and control of tuberculosis disease. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated proteins (Cas12a) exhibits strongly nonspecific degradation ability of exogenous single-strand nucleic acid (trans-cleavage) after specific recognition of target sequence. We purified Cas12a protein and selected a proper guide RNA (gRNA) based on conserved sequences of MTB from gRNA library we designed. Then, we proposed a novel method based on recombinase polymerase amplification (RPA) and CRISPR/Cas12a nuclease system for specific and sensitive detection of MTB DNA. The assay based on fluorescence detection pattern showed 4.48 fM of limit of detection (LOD) and good linear correlation of concentration and fluorescence value (R2=0.9775). Also, it showed good performance in distinguishing other bacteria. Furthermore, its clinical performance was evaluated by 193 samples and showed sensitivity of 99.29% (139/140) and specificity of 100% (53/53) at 99% confidence interval, respectively, compared with culture method. The CRISPR/Cas12a system showed good specificity, excellent sensitivity and accuracy for MTB detection, and it meets requirements of MTB detection in clinical samples and has great potential for clinical translation.

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A Label-Free Liquid Crystal Biosensor Based on Specific DNA Aptamer Probes for Sensitive Detection of Amoxicillin Antibiotic

Micromachines ◽

10.3390/mi12040370 ◽

2021 ◽

Vol 12 (4) ◽

pp. 370

Author(s):

Duy Khiem Nguyen ◽

Chang-Hyun Jang

Keyword(s):

Liquid Crystal ◽

Specific Binding ◽

Water Environment ◽

Polarized Light ◽

High Specificity ◽

Dna Aptamer ◽

Sensitive Detection ◽

Label Free ◽

Homeotropic Orientation ◽

Optical Appearance

We developed a liquid crystal (LC) aptamer biosensor for the sensitive detection of amoxicillin (AMX). The AMX aptamer was immobilized onto the surface of a glass slide modified with a mixed self-assembled layer of dimethyloctadecyl [3-(trimethoxysilyl) propyl] ammonium chloride (DMOAP) and (3-aminopropyl) triethoxysilane (APTES). The long alkyl chains of DMOAP maintained the LC molecules in a homeotropic orientation and induced a dark optical appearance under a polarized light microscope (POM). In the presence of AMX, the specific binding of the aptamer and AMX molecules induced a conformational change in the aptamers, leading to the disruption of the homeotropic orientation of LCs, resulting in a bright optical appearance. The developed aptasensor showed high specificity and a low detection limit of 3.5 nM. Moreover, the potential application of the developed aptasensor for the detection of AMX in environmental samples was also demonstrated. Therefore, the proposed aptasensor is a promising platform for simple, rapid, and label-free monitoring of AMX in an actual water environment with high selectivity and sensitivity.

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A Novel Graphene Oxide-Based Aptasensor for Amplified Fluorescent Detection of Aflatoxin M1 in Milk Powder

Sensors ◽

10.3390/s19183840 ◽

2019 ◽

Vol 19 (18) ◽

pp. 3840 ◽

Cited By ~ 3

Author(s):

Xiaodong Guo ◽

Fang Wen ◽

Qinqin Qiao ◽

Nan Zheng ◽

Matthew Saive ◽

...

Keyword(s):

Graphene Oxide ◽

Dynamic Range ◽

Limit Of Detection ◽

Milk Powder ◽

High Sensitivity ◽

High Specificity ◽

Fluorescent Detection ◽

Aflatoxin M1 ◽

Powder Samples ◽

Infant Milk Powder

In this paper, a rapid and sensitive fluorescent aptasensor for the detection of aflatoxin M1 (AFM1) in milk powder was developed. Graphene oxide (GO) was employed to quench the fluorescence of a carboxyfluorescein-labelled aptamer and protect the aptamer from nuclease cleavage. Upon the addition of AFM1, the formation of an AFM1/aptamer complex resulted in the aptamer detaching from the surface of GO, followed by the aptamer cleavage by DNase I and the release of the target AFM1 for a new cycle, which led to great signal amplification and high sensitivity. Under optimized conditions, the GO-based detection of the aptasensor exhibited a linear response to AFM1 levels in a dynamic range from 0.2 to 10 μg/kg, with a limit of detection (LOD) of 0.05 μg/kg. Moreover, the developed aptasensor showed a high specificity towards AFM1 without interference from other mycotoxins. In addition, the technique was successfully applied for the detection of AFM1 in infant milk powder samples. The aptasensor proposed here offers a promising technology for food safety monitoring and can be extended to various targets.

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Laboratory and Clinical Evaluation of DNA Microarray for the Detection of Carbapenemase Genes in Gram-Negative Bacteria from Hospitalized Patients

BioMed Research International ◽

10.1155/2019/8219748 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13

Author(s):

Yi Song ◽

Fengna Dou ◽

Sha He ◽

Yu Zhou ◽

Qiqi Liu

Keyword(s):

Dna Microarray ◽

High Throughput ◽

Sanger Sequencing ◽

Limit Of Detection ◽

High Sensitivity ◽

High Specificity ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Specificity And Sensitivity ◽

Global Threat

Background. The prevalence of a variety of carbapenemases in Gram-negative bacteria (GNB) has posed a global threat on clinical control and management. Monitoring and controlling the carbapenemase-producing GNB became imperative tasks for many healthcare centers. The aim of this study was to develop a high-throughput, specific, sensitive, and rapid DNA microarray-based method for the diagnosis, phenotypic confirmation, and molecular epidemiological study of carbapenemase genes. Methods. We targeted a panel of eight carbapenemase genes, including blaKPC, blaNDM-1, blaOXA-23, blaOXA-48, blaOXA-51, blaIMP, blaVIM, and blaDIM for detection. Ultrasensitive chemiluminescence (CL) detection method was developed and used to simultaneously detect eight carbapenemase genes, and plasmids were established as positive or limit of detection (LOD) reference materials. Antibiotic susceptibility was determined by disk diffusion according to Clinical and Laboratory Standards Institute (CLSI) guidelines in order to screen clinical isolates resistant to carbapenem antibiotics as well as Sanger sequencing which was used to confirm the reliability of the results presented by DNA microarray. Results. Eight carbapenemase genes could be detected with high sensitivity and specificity. The absolute LOD of this strategy to detect serially diluted plasmids of eight carbapenemase genes was 102- 103copies/μL. Then, 416 specimens collected from hospital were detected and the results showed 96.6% concordance between the phenotypic and microarray tests. Compared with Sanger sequencing, a specificity and sensitivity of 100% were recorded for blaNDM-1, blaIMP, blaVIM, and blaDIM genes. The specificity for blaKPC, blaOXA-23, blaOXA-48, and blaOXA-51 genes was 100% and the sensitivity was 98.5%, 97.6%, 95.7%, and 97.9%, respectively. The overall consistency rate between the sequencing and microarray is 97.8%. Conclusions. The proposed ultrasensitive CL imaging DNA hybridization has high specificity, sensitivity, and reproducibility and could detect and differentiate clinical specimens that carried various carbapenemase genes, suggesting that the method can conveniently be customized for high-throughput detection of the carbapenemase-producing GNB and can be easily adapted for various clinical applications.

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A potential reusable fluorescent aptasensor based on magnetic nanoparticles for ochratoxin A analysis

Open Chemistry ◽

10.1515/chem-2019-0140 ◽

2019 ◽

Vol 17 (1) ◽

pp. 1301-1308 ◽

Cited By ~ 1

Author(s):

Pinzhu Qin ◽

Dawei Huang ◽

Zihao Xu ◽

Ying Guan ◽

Yongxin Bing ◽

...

Keyword(s):

Magnetic Property ◽

Ochratoxin A ◽

Cost Reduction ◽

Environmental Samples ◽

Limit Of Detection ◽

Specific Binding ◽

High Sensitivity ◽

Capture Probe ◽

Real Samples ◽

Fluorescent Aptasensor

AbstractAn aptasensor for the detection of ochratoxin A (OTA) in environmental samples was developed. It displayed high sensitivity and good selectivity. Factors such as specific binding between a FAM (5-carboxyfluorescein)-labeled aptamer (f-RP) and OTA, and a magnetic property of a streptavidin magbeads-modified capture probe (bm-CP) resulted in aptasensor’s linear relationship between fluorescence intensity and the concentration of OTA. This characteristic is present at the OTA concentration ranges from 0.100 μM to 25.00 μM with a LOD (limit of detection) of 0.0690 μM. The bm-CP can be reused through melting, washing and magnetic separation, which contributes to cost reduction. In addition, the proposed method is simple and detection process is fast. The aptasensor can be used in real samples.

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Nonenzymatic Glucose Biosensor Based on NiNPs/Nafion/Graphene Film for Direct Glucose Determination in Human Serum

NANO ◽

10.1142/s1793292018500753 ◽

2018 ◽

Vol 13 (07) ◽

pp. 1850075 ◽

Cited By ~ 2

Author(s):

Parviz Sukhrobov ◽

Sodik Numonov ◽

Sanshuang Gao ◽

Xamxikamar Mamat ◽

Thomas Wagberg ◽

...

Keyword(s):

Human Serum ◽

Glucose Oxidation ◽

Limit Of Detection ◽

Graphene Film ◽

High Sensitivity ◽

Linear Range ◽

Signal To Noise ◽

Serum Samples ◽

Coefficient Of Correlation ◽

Glucose Determination

This study describes a type of novel nickel nanoparticles (NiNPs) decorated on Nafion-graphene composite film by using the electrochemical deposition method. It was used to fabricate electrochemical biosensors for sensitive nonenzymatic glucose detection. Compared with the Nafion–graphene film and NiNPs-modified glassy carbon electrode (NiNPs-GCE), the NiNPs/Nafion/graphene/GCE showed the best electrocatalytic activity towards glucose oxidation in alkaline medium. The NiNPs/Nafion/graphene/GCE at an applied potential of [Formula: see text]0.55[Formula: see text]V in a linear range of 1–200[Formula: see text][Formula: see text]M presented a high sensitivity of 3437.25[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text] with coefficient of correlation [Formula: see text]; and in a linear range of 200–10[Formula: see text]800[Formula: see text][Formula: see text]M it performed the best sensitivity of 2848.6[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text] with coefficient of correlation [Formula: see text] towards glucose oxidation. For a concentration up to 200[Formula: see text][Formula: see text]M, a linear range was obtained with a limit of detection of 0.6[Formula: see text][Formula: see text]M (signal to noise [Formula: see text] 3) and as much as 10[Formula: see text]800[Formula: see text][Formula: see text]M with a limit of detection of 0.82[Formula: see text][Formula: see text]M (signal to noise [Formula: see text] 3). The time of responses was about 1–1.5[Formula: see text]s with the addition of 0.1–1[Formula: see text]mM glucose. In addition, NiNPs/Nafion/graphene/GCE also has a high anti-interference ability toward common oxidative interfering species, such as uric acid, ascorbic acid and dopamine. More importantly, NiNPs/Nafion/graphene/GCE was successfully used for the determination of glucose concentration in human serum samples in comparison with a local hospital. The NiNPs/Nafion/graphene/GCE exhibited high sensitivity, low working potential, good stability, excellent electrical properties, enhanced selectivity and fast amperometric responses to glucose oxidation. Thus, as a nonenzymatic sensor, it is promising for future glucose determination development.

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