- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Silanized quantum dots as labels in lateral flow test strips for C-reactive protein
摘要： The paper describes the first use of silanized semiconductor core-shell quantum dots as fluorescent labels for macromolecule, C-reactive protein determination in blood plasma. The controlled synthesis of CdSe cores, with successive shells of CdS, CdZnS, ZnS and coating with transparent, stable, and inert silica shell, provides quantum dots with a narrow emission band, high quantum yield, and prolonged signal stability. Finally, the quantum dots were conjugated with specific antibodies via carboxylic groups on the silica surface. The method was further used for the immunochromatographic assay of C-reactive protein, a diagnostically important inflammatory biomarker. Assays with both the fluorescent QDs and a widely used colloidal gold label were developed in parallel and compared. The silanized quantum dots provide a more sensitive assay with a detection limit of 1 ng/mL for C-reactive protein in standard solutions, whereas the common assay has a detection limit of 10 ng/mL. The possibility of quantitative evaluation of analyte content by a portable device was demonstrated; the accuracy of the measurements was in the range of 5%–10%. The tests were used to determine C-reactive proteins in human plasma samples. The selected optimized protocol for these samples is based on a 4-fold dilution. The final working range of the assay, 4–1,200 ng/mL, covers practically all important interval of C-reactive protein values for the characterization of acute, chronic, and local inflammatory processes. Due to their high physical stability and inertness as well as intense, stable, and reproducible fluorescence, silanized quantum dots may be applied for high-sensitive assays for different analytes.
关键词： C-reactive protein,Quantum dots,silanization,lateral flow immunoassay
更新于2025-11-19 16:46:39
-
Smartphone-Based Fluorescent Lateral Flow Immunoassay Platform for Highly Sensitive Point-of-Care Detection of Zika Virus Nonstructural Protein 1
摘要： Simple, inexpensive, and rapid diagnostic tests in low-resource settings with limited laboratory equipment and technical expertise are instrumental in reducing morbidity and mortality from epidemic infectious diseases. We developed a smartphone-based fluorescent lateral flow immunoassay (LFIA) platform for the highly sensitive point-of-care detection of Zika virus nonstructural protein 1 (ZIKV NS1). An attachment was designed and 3D-printed to integrate the smartphone with external optical and electrical components, enabling the miniaturization of the instrument and reduction in cost and complexity. Quantum dot microspheres were utilized as probes in fluorescent LFIA because of their extremely bright fluorescence signal. This approach can achieve quantitative point-of-care detection of ZIKV NS1 within 20 min. Limits of detection (LODs) in buffer and serum were 0.045 and 0.15 ng mL-1, respectively. Despite the high structural similarity, a high-level Dengue virus NS1 as interferent showed limited cross-reactivity. Furthermore, this assay was successfully applied to detecte ZIKV NS1 and virions spiked in complex biological samples, indicating its practical application capability. Given its low cost, compact size, and excellent analytical performance, the proposed smartphone-based fluorescent LFIA platform holds considerable potential in rapid and accurate point-of-care detection of ZIKV NS1 and provides new insight into the design and application of molecular diagnostic methods in low-resource settings.
关键词： Quantum dot microsphere,Smartphone,Lateral flow immunoassay,Zika virus nonstructural protein 1,Point-of-care
更新于2025-09-23 15:23:52
-
Ultrasensitive detection of avian influenza A (H7N9) virus using surface-enhanced Raman scattering-based lateral flow immunoassay strips
摘要： The development of biosensors that are portable, low-cost, and quantitative has long been sought for rapid, on-site, and timely detection of avian influenza virus (AIV). In this study, an antibody-based Raman lateral flow immunoassay strip was developed to detect AIV H7N9. This LFIA strip used a novel core-shell structure material, AuAg4(cid:3)ATP@AgNPs, as a Raman probe. An antibody specific for AIV and goat anti-mouse IgG antibody were immobilized on a nitrocellulose membrane as the test and control lines, respectively. Accumulation of antibody-virus-antibody-Raman probe complex at the test line could be visualized by the naked eye, and the Raman signal could be quantified using a portable Raman instrument. The testing process for the SERS-based LFIA strips could be completed in 20 min, which avoided the time-cost of current methods for AIV analysis. In our SERS-based biosensor, we estimated the limit of detection (LOD) for H7N9 to be 0.0018 HAU. This value is approximately three orders of magnitude more sensitive than the corresponding HA assays. When testing real sample, the results of the strip test were in accordance with those from real-time PCR testing. In conclusion, the SERS-based LFIA strip proposed in this study shows tremendous potential to detect targets quickly and sensitively using an elegantly simple method.
关键词： AuAg4(cid:3)ATP@AgNPs,Surface-enhanced Raman scattering,Avian influenza virus,Lateral flow immunoassay strips
更新于2025-09-23 15:23:52
-
[IEEE 2018 IEEE Life Sciences Conference (LSC) - Montreal, QC, Canada (2018.10.28-2018.10.30)] 2018 IEEE Life Sciences Conference (LSC) - Assay Development and Storage for Fluorescence-Based Lateral Flow Immunoassay
摘要： Point-of-care medical diagnostics can provide efficient, cost-effective medical care, and have the potential to fundamentally change our current approach to global health. There have been substantial efforts in developing lateral flow assays for serologic testing, but most of the existing approaches have limited portability, are expensive, and offer limited analytical sensitivity. In this paper, we demonstrated an assay for the detection of antibodies in plasma to Epstein-Barr Nuclear Antigen-1 (EBNA-1) protein and optimization of the assay including washing and blocking conditions. We also investigated the effect of the storage on the assay strips. Using our optimized conditions, we were able to detect anti-Human Papilloma Virus (HPV)-16 E7 antibodies after three weeks of storage. Our goal is to adapt this system to detect HPV biomarkers for cervical cancers in low and middle-income countries.
关键词： storage,immunoassay,sensitivity,Lateral flow assay,fluorescence,point-of-care
更新于2025-09-23 15:22:29
-
Data on characterization and validation of assays for ultrasensitive quantitative detection of small molecules: Determination of free thyroxine with magnetic and interferometric methods
摘要： The presented data refer to optimization and quantitative characterization of a rapid lateral flow assay based on high-affinity bifunctional ligand and magnetic nanolabels, which was developed for detection of small molecules of thyroid hormones. The results were obtained by including the magnetic particle quantification method, spectral-correlation interferometry and spectral-phase interferometry, dynamic light scattering, enzyme linked immunosorbent assay. The long-term stability of "antibody – magnetic nanoparticle" conjugates is shown. The assay specificity is confirmed, and verification of successful combination of magnetic particles and antibodies is demonstrated. The kinetic and equilibrium dissociation constants are determined for interactions between thyroxine and monoclonal antibodies. The obtained data could be used for design of other platforms for detection of small molecules.
关键词： ELISA,Lateral flow assay,Small molecules,Ultrasensitive detection,Free thyroxine,Interferometry,Magnetic nanolabels,Dynamic light scattering
更新于2025-09-23 15:22:29
-
Ultra-sensitive method based on time-resolved fluorescence immunoassay for detection of sulfamethazine in raw milk
摘要： A novel lateral flow assay (LFA) was developed by introducing Eu (III)-doped polystyrene nanoparticles (EuNPs) for rapid and ultra-sensitive detection of sulfamethazine (SM2) in raw milk. The limit of detection and linear range of the proposed method were 0.0045 and 0.05–10 ng/mL, respectively. The recovery of LFA for the detection of SM2 in raw milk was 96.1–108.2%. The proposed LFA provides a rapid and convenient strategy for fast and ultra-sensitive screening of SM2 in raw milk. EuNP-LFA may be a remarkable method for the detection of other targets at low concentrations to ensure food safety.
关键词： Lateral flow assay,sulfamethazine,raw milk,Eu (III)-doped polystyrene nanoparticle
更新于2025-09-23 15:21:21
-
Immunochromatographic System for Serodiagnostics of Cattle Brucellosis Using Gold Nanoparticles and Signal Amplification with Quantum Dots
摘要： In this article, we describe an immunochromatographic test system developed for rapid serodiagnostics of cattle brucellosis using two markers: Gold nanoparticles (GNPs) and quantum dots (QDs). The test system was compared with immunochromatographic serodiagnostics systems that use only one marker. The approbation of the test system was conducted on samples of cattle sera with low, but diagnostically significant titers of specific antibodies. We show that when two conjugates are used, the intensity of the detectable signal increases by 2–3 times compared with the test system using the QD conjugate and by more than nine times compared with the system using the GNP conjugate.
关键词： signal enhancement,cow diseases,rapid tests,lateral flow tests,functionalized nanoparticles,veterinary diagnostics
更新于2025-09-23 15:19:57
-
Signal amplification and quantification on lateral flow assays by laser excitation of plasmonic nanomaterials
摘要： Lateral flow assay (LFA) has become one of the most widely used point-of-care diagnostic methods due to its simplicity and low cost. While easy to use, LFA suffers from its low sensitivity and poor quantification, which largely limits its applications for early disease diagnosis and requires further testing to eliminate false-negative results. Over the past decade, signal enhancement strategies that took advantage of the laser excitation of plasmonic nanomaterials have pushed down the detection limit and enabled quantification of analytes. Significantly, these methods amplify the signal based on the current LFA design without modification. This review highlights these strategies of signal enhancement for LFA including surface enhanced Raman scattering (SERS), photothermal and photoacoustic methods. Perspectives on the rational design of the reader systems are provided. Future translation of the research toward clinical applications is also discussed.
关键词： gold nanoparticles,lateral flow assay,nanoparticle heating,signal amplification and quantification,SERS
更新于2025-09-23 15:19:57
-
Simple geometrical modifications for substantial color intensity and detection limit enhancements in lateral-flow immunochromatographic assays
摘要： One of the ongoing challenges in lateral flow Immunochromatographic assays (LFIA), is lowering the limit of detection and enhancing their signal quality, i.e. the color intensity. There are a number of rather costly and complicated processes for this aim, such as the use of functionalized materials/membranes and additional spectroscopic readout units. Nonetheless, there are simple and easy to practice alternatives, to be uncovered by analyzing the essential parameters of immunological reactions. The color intensity of the test line is a function of analytes flow velocity and their reaction rate. Detection pad width and test line position impact the flow velocity and reaction rate kinetics, examined in this paper for the limit of detection (LOD) and test-line color intensity. Firstly, the impact of width on the LOD was examined for human chorionic gonadotropin (pregnancy biomarker). Test line color intensity was measured using five different widths of the detection pad (trapezoidal) and four different test line positions, and the trends observed were explained according to the measured evolution of the velocity along the chromatography paper. With a constant width absorbent pad, LOD was cut by half to 5 mIU/ml by using a narrowing width detection pad, which keeps the wicking velocity higher than normal strips, and compared to them, color intensity increase between 55-150%, depending on the concentration. Nevertheless, a widening detection pad might cut the color intensity up to 150%, compared to normal strips, due to a profound decline of the analyte to ligand ratio at the test line. In addition, adequately sending the test line away from the conjugate pad yields the highest possible color intensity, for up to 400% of increase, in lower concentrations and narrowing test pads. However, further distancing the test line downfalls the color intensity.
关键词： Lateral Flow Immunochromatographic Assays,Trapezoidal Geometry,Limit of Detection,Detection Pad,Capillary Flow Velocity,Porous Medium,Color Intensity,Test Line Displacement
更新于2025-09-19 17:15:36
-
A quantum dot-based lateral flow immunoassay for the rapid, quantitative, and sensitive detection of specific IgE for mite allergens in sera from patients with allergic rhinitis
摘要： The prevalence of allergic rhinitis (AR) is increasing worldwide. However, the current systems used to measure levels of immunoglobulin E (IgE) in sera are associated with several disadvantages that limit their further application. Consequently, there is a need to develop novel highly sensitive strategies that can rapidly detect IgE in a quantitative manner. The development of such systems will significantly enhance our ability to diagnose, treat, and even prevent AR. Herein, we describe our experience of using quantum dot-based lateral flow immunoassay (QD-LFIA), combined with a portable fluorescence immunoassay chip detector (PFICD), to detect serum-specific IgE against Dermatophagoides pteronyssinus (Der-p) and Dermatophagoides farinae (Der-f), two common mite allergens in China. Our data showed that our system could detect serum-specific levels of IgE against Der-p and Der-f as low as 0.093 IU/mL and 0.087 IU/mL, respectively. We also established a standard curve to determine serum-specific IgE concentrations that correlated well with the clinical BioIC microfluidics system. The sensitivity of our assay was 96.7% for Der-p and 95.5% for Der-f, while the specificity was 87.2% for Der-p and 85.3% for Der-f. Collectively, our results demonstrate that QD-LFIA is a reliable system that could be applied to detect serum-specific IgE in accordance with clinical demands. This QD-LFIA strategy can be applied at home, in hospitals, and in pharmacies, with reduced costs and time requirements when compared with existing techniques. In the future, this system could be developed to detect other types of allergens and in different types of samples (for example, whole blood).
关键词： Quantum dots,Lateral flow immunoassay,Immunoglobulin E,Allergic rhinitis
更新于2025-09-19 17:13:59