- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Detection and Quantification of HspX Antigen in Sputum Samples Using Plasmonic Biosensing: Toward a Real Point-of-Care (POC) for Tuberculosis Diagnosis
摘要： Advances occurred during the last years in the diagnosis of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis infection, have prompted increased survival rates of patients. However, limitations related to the inefficiency of an early detection still remain: some techniques and laboratory methods do not have enough specificity, most instruments are expensive, and require handling by trained staff. In order to contribute to a prompt and effective diagnosis of tuberculosis, we report the development of a portable, user-friendly and low-cost biosensor device for its early detection. By using a label-free Surface Plasmon Resonance (SPR) biosensor, we have established a direct immunoassay for the direct detection and quantification of the Heat shock protein X (HspX) of Mtb, a well-established biomarker of this pathogen, directly in pre-treated sputum samples. The method relies on highly specific monoclonal antibodies which are previously immobilized on the plasmonic sensor surface. This technology allows the direct detection of the biomarker without amplification steps, showing a Limit of Detection (LOD) of 0.63 ng mL-1 and a Limit of Quantification (LOQ) of 2.12 ng mL-1. The direct analysis in pre-treated sputum shows significant differences in the HspX concentration in patients with tuberculosis (with concentration levels in the order of 116-175 ng mL-1) compared with non-tuberculosis infected patients (values below the LOQ of the assay).
关键词： SPR Immunosensor,Tuberculosis diagnosis,HspX recombinant protein,human sputum samples,Point-of-Care device
更新于2025-09-19 17:13:59
-
Perylenetetracarboxylic Dianhydride and Aniline Assembled Supramolecular Nanomaterial with Multi-color Electrochemiluminescence for Highly Sensitive Label-free Immunoassay
摘要： Most electrochemiluminescence (ECL) studies were focused on the single emission of luminophore, which was severely limited the development of multi-color ECL fundamental theory and applications. Herein, we prepared a multi-color ECL supramolecular nanomaterial self-assembled by 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) and aniline (An) through hydrogen bonding. This PTCDA-An supramolecular nanomaterial simultaneously produced multi-color emission peaked at 486, 692 and 760 nm with K2S2O8 as coreactant. And the multi-emissions were assigned to excitated PTCDA monomer (486 nm), H-dimer (692 nm) and J-dimer (760 nm). The simultaneously increased dual-color ECL intensity significantly enhanced the total ECL intensity of PTCDA-An. And this high efficient ECL nanomaterial was further used as ECL platform to construct label-free immunosensor for tumor markers carcinoembryonic antigen (CEA) detection. The total ECL intensity of immunosensor exhibited a sensitive decrease due to the simultaneously decreased ECL of multi-emissions. And this immunosensor exhibited wide linear range from 1 pg mL-1 to 10 μg mL-1 with low detection limit of 0.23 pg mL-1. Multi-color ECL from the same luminophore PTCDA in this work also provided a new perspective for multi-color ECL biomaterial’s design.
关键词： supramolecular nanomaterial,multi-color ECL,electrochemiluminescence,aniline,PTCDA,CEA detection,label-free immunosensor
更新于2025-09-19 17:13:59
-
Direct culture-free electrochemical detection of cells in milk based on quantum dots-modified nanostructured dendrons
摘要： With regard to global food safety and preventing the spread of diseases caused by foodborne pathogens or their toxins, there is an increasing need for simple and rapid methods for the screening of such pathogens. We aimed to develop a fast and efficient biosensor for the screening of milk samples contaminated by Salmonella spp. and provide a quick and cost-effective method as an alternative to the time-consuming conventional cultivation- or PCR-based approaches. We exploited a simple but highly specific technique whereby bacterial cells were separated immunomagnetically, with subsequent reaction with conjugate; i.e. specific IgG molecule labelled with an electrochemically potent indicator. The unique structure of this indicator exploits the benefits of hyperbranched dendron molecules and heavy metal–derived quantum dots (QDs). Square-wave anodic stripping voltammetry (SWASV) using of screen-printed carbon electrodes with in situ formed Bi(III) film (BiSPCE) was used for the detection and quantification of metal ions released from the QDs (CdTe) after their acidic dissolution. The metal ion signals proportionally correlate with the amount of captured bacteria cells. By this method, the presence of Salmonella spp. was proven in 2.5 hours even in minimal number of bacterial cells (4 CFU) in 1 mL of the sample.
关键词： Salmonella spp.,Electrochemical immunosensor,Quantum dots,Stripping voltammetry,Foodborne pathogen,Nanostructured dendrons
更新于2025-09-19 17:13:59
-
Rapid screening and quantification of multi-class antibiotic pollutants in water using a planar waveguide immunosensor
摘要： Rapid screening and quantification of multi-class antibiotic pollutants in water using a planar waveguide immunosensor
关键词： immunosensor,antibiotics,planar waveguide,detection,water
更新于2025-09-16 10:30:52
-
[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Immunosensor Based On Cladding-etched Excessively Tilted Fiber Grating Coated With Graphene Oxide
摘要： In this work, a bovine serum albumin (BSA) immunosensor based on graphene oxide (GO) modified cladding-etched excessively tilted fiber grating (ExTFG) is proposed, and the basic principle and sensing characteristics of the sensor are analyzed. Refractive index (RI) sensitivity of ExTFG is increased by 77.17% by etching to 80μm. The cladding-etched ExTFG is coated with GO, and then BSA anti-monoclonal antibody (anti-MABs) are immobilized on its surface, so as to realize the special detection for BSA. Experimental results show that the sensitivity is about five times of that of the un-etched GO-coated ExTFG, the limit of detection (LOD) is ~0.165 nM by using optical spectrum analyzer with a resolution of 0.03nm.
关键词： Graphene oxide (GO),Cladding etching,Excessively tilted fiber grating (ExTFG),Immunosensor
更新于2025-09-16 10:30:52
-
Electrochemiluminescence resonance energy transfer system between non-toxic SnS2 quantum dots and ultrathin Ag@Au nanosheets for chloramphenicol detection
摘要： Herein, an efficient electrochemiluminescence energy resonance transfer (ECL-RET) system was first applied in an immunosensor for the detection of chloramphenicol (CAP). SnS2 quantum dots (SnS2 QDs) has an extremely narrow electrochemical emission spectrum, which was used as donor. Compared with conventional quantum dots, toxic-element-free SnS2 QDs exhibit superior environmental friendliness and biocompatibility. Ultrathin Ag@Au nanosheets (Ag@Au NSs) was selected as acceptor due to its excellent structure and controllable UV-vis absorption range. Furthermore, ZnO nanoflowers (ZnO NFs) was employed to modify the electrode surface to provide stable luminescent environment and support more SnS2 QDs. Taking these advantages, the absorption spectra of Ag@Au NSs and the ECL emission spectra of SnS2 QDs are highly matched which ensures the occurrence of ECL-RET. When the CAP analyte were absent, Ag@Au NSs was immobilized on the electrode, and its ultrathin thickness effectively shortens the path of ECL-RET to produce the weak ECL intensity. Inversely, CAP analyte would compete with coating antigen for the certain amount of antibody to remove excess Ag@Au NSs and cause relatively high ECL intensity. As a result, the proposed immunosensor performed satisfactory sensitivity with a wide linear range from 0.005 to 1000 ng mL?1 and a low detection limit (1.7 pg mL?1).
关键词： Chloramphenicol,Electrochemiluminescence energy resonance transfer,Ag@Au nanosheets,SnS2 quantum dots,Immunosensor
更新于2025-09-12 10:27:22
-
Electrochemical synthesis of phosphorus and sulfur co-doped graphene quantum dots as efficient electrochemiluminescent immunomarkers for monitoring okadaic acid
摘要： In this study, water-dispersed, uniform-sized phosphorus and sulfur co-doped graphene quantum dots (P, S-GQDs) were prepared by the one-step electrolysis of a graphite rod in an alkaline solution containing sodium phytate and sodium sulfide. Compared with GQDs and mono-doped GQDs (P-GQDs and S-GQDs), the P, S-GQDs dramatically improved the electrochemiluminescence (ECL) performance. Therefore, they were used as bright ECL signaling markers through conjugation with a monoclonal antibody against okadaic acid (anti-OA-MAb). Moreover, as an effective matrix for OA immobilization, the carboxylated multiwall carbon nanotubes-poly(diallyldimethylammonium) chloride-Au nanocluster (CMCNT-PDDA-AuNCs) composite promoted electron transfer and enlarged the surface area. Owing to the multiple amplifications, a competitive indirect ECL immunosensor for highly sensitive quantitation of OA has been developed. Under the optimized conditions, the 50% inhibitory concentration (IC50) of the immunosensor was 0.25 ng mL-1, and its linear range was 0.01–20 ng mL-1 with a low detection limit of 0.005 ng mL-1. Finally, the proposed ECL sensor was successfully utilized to detect OA contents in mussel samples. Therefore, this study provides new insights into the designation of ECL luminophores and expands application of co-doped GQDs in fabrication of ECL immunosensors for shellfish toxin determination.
关键词： immunosensor,electrolysis,okadaic acid,electrochemiluminescence,phosphorus and sulfur co-doped graphene quantum dots
更新于2025-09-12 10:27:22
-
Ratiometric fluorescent sensing system for drug residue analysis: Highly sensitive immunosensor using dual-emission quantum dots hybrid and compact smartphone based-device
摘要： Immunoassays such as the enzyme-linked immunosorbent assay (ELISA) are utilized extensively for detecting protein biomarkers and small molecules in healthcare, environmental monitoring, and food analysis. Unfortunately, the current strategies for immunoassays often require sophisticated apparatus such as a microplate reader, which might not be available in resource-limited areas. To mitigate this problem, we designed a compact smartphone based-device and a multicolor response immunosensor. First, we designed a compact and cost-effective 3D-printed attachment, where a light-emitting diode was used as a light excitation source and a smartphone captured the fluorescent emission signals. Second, by combining quantum dots hybrid and chemical redox reaction, multiple color responses were displayed in the presence of the analyte at different concentrations. Third, solutions with distinct tonality could be readily distinguished by the naked eye and they were suitable for quantitative analysis using the hue-saturation-lightness color space based on a smartphone application. The versatility of the proposed sensing system was demonstrated by implementing an indirect competitive ELISA for analyzing trace drug residues in foodstuffs. The multicolor response of this sensing strategy allows us to visually quantify drug residues in foodstuffs. Moreover, the smartphone-based immunosensor can assess the exact concentration of the analyte by using a self-designed mobile application. The proposed assay provides a highly sensitive performance that the limit of detection was 0.37 ng/mL by visual detection and 0.057 ng/mL using the compact device. Due to its advantages in terms of portability, straightforward visual detection, high sensitivity, and cost effectiveness, the proposed immunosensor has great potential for applications in areas without access to laboratories or expensive infrastructure.
关键词： Quantum Dots Hybrid,Compact Device,Visual Readout,Immunosensor,Residue Analysis
更新于2025-09-12 10:27:22
-
Polydopamine nanospheres loaded with l-cysteine-coated cadmium sulfide quantum dots as photoelectrochemical signal amplifier for PSA detection
摘要： A sandwich-type photoelectrochemical (PEC) immunosensor was constructed for sensitive detection of prostate specific antigen (PSA). It was based on electrochemically reduced graphene oxide-TiO2 (ERGO-TiO2) as photoelectrochemical platform to immobilize capture antibody (Ab1). Then, quinone-rich polydopamine nanospheres (PDANS) loaded detection antibody (Ab2) and photocurrent signal label, L-cysteine-coated cadmium sulfide quantum dots (CdSQDs). ERGO-TiO2 displayed greatly improved photocurrent response to white light. CdSQDs conjugated with PDANS further amplified photocurrent signal because of the good conductivity of PDANS and ERGO. The increased photocurrent showed a linear correlation with PSA in the concentration range from 0.02 pg mL?1 to 200 ng mL?1 with the detection limit of 6.8 fg mL?1. It also revealed high selectivity and good stability.
关键词： Electrochemically reduced graphene oxide-TiO2,Polydopamine nanospheres,Photoelectrochemical immunosensor,L-cysteine-coated cadmium sulfide quantum dots,Prostate specific antigen
更新于2025-09-12 10:27:22
-
Quantum dot nanoconjugates for immuno-detection of circulating cell-free miRNAs
摘要： Argonaute protein (AGO2) bound circulating cell-free miRNAs (ccf-miRs), in the recent years, has attracted great attention due to their differential abundance in biological fluids. In the present work, a selective and technically uncomplicated quantum dot (QD) nanoconjugate has been fabricated combining the specific affinity of the antibody and fluorescent property of QDs for the precise immuno-detection of AGO2-bound ccf-miRs in plasma samples. The electrophoretic mobility assay confirmed the conjugation of antibody with QDs. The detection methodology involves a highly specific antigen-antibody reaction between the AGO2 proteins of miRNA-induced silencing complex and the anti-AGO2 antibody conjugated with QDs. The recognition efficiency of QD-Ab nanoconjugates was analysed using flow cytometry and fluorometry.The flow cytometry results demonstrated a significant change in the fluorescence intensity of the prepared nanoconjugates upon capture of ccf-miRs in the plasma samples with respect to the samples devoid of any miRNAs. Fluorometry measurements exhibited corroboration with the flow cytometry results indicating the selectivity and reproducibility of the developed method. Current research highlights the translational significance of the methodology as a novel flow cytometry based immunoassay for detection of differentially expressed AGO2-bound miRNAs in clinical and field settings.
关键词： Immunosensor,Circulating nucleic acids,Translational research,Point-of-care assay
更新于2025-09-11 14:15:04