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Molecular Technology (Life Innovation) || Self-assembled Monolayers from Carbon-Based Ligands on Metal Surfaces
摘要： Rift Valley fever virus (RVFV) is an arthropod-borne, zoonotic disease endemic to sub-Saharan Africa and the Arabian Peninsula. Outbreaks of Rift Valley fever have had up to 100% mortality rates in fetal and neonatal sheep. Upon infection of ruminant and human hosts alike, RVFV infection causes an at times severe hepatitis and pathology in many other organs. The enveloped virion contains a tripartite, predominantly negative-sense, single-stranded RNA genome, which codes for the proteins the virus needs to replicate both in mammalian hosts and insect vectors. Endemic countries often use attenuated RVFV strains for vaccination of livestock but there are no commercially licensed vaccines for humans or livestock in non-endemic areas. In the laboratory, RVFV can be readily propagated and manipulated in vitro using cell culture systems. Presented in this article are techniques routinely used in RVFV research that have proven successful in our laboratories.
关键词： Rift Valley fever virus,plaque assay,TCID50,virology,bunyaviruses,focus-forming assay,virus quantification,propagation
更新于2025-09-19 17:13:59
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Dual-Functional Plasmonic Photothermal Biosensors for Highly Accurate Severe Acute Respiratory Syndrome Coronavirus 2 Detection
摘要： The ongoing outbreak of the novel coronavirus disease (COVID-19) has spread globally and poses a threat to public health in more than 200 countries. Reliable laboratory diagnosis of the disease has been one of the foremost priorities for promoting public health interventions. The routinely used reverse transcription polymerase chain reaction (RT-PCR) is currently the reference method for COVID-19 diagnosis. However, false-positive or -negative cases, especially in the early stages of the novel virus outbreak. In this work, a dual-functional plasmonic biosensor combining the plasmonic photothermal (PPT) effect and localized surface plasmon resonance (LSPR) sensing transduction provides an alternative and promising solution for the clinical COVID-19 diagnosis. The two-dimensional gold nanoislands (AuNIs) functionalized with complementary DNA receptors can perform a sensitive detection of the selected sequences from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) through nucleic acid hybridization. For better sensing performance, the thermoplasmonic heat is generated on the same AuNIs chip when illuminated at their plasmonic resonance frequency. The localized PPT heat is capable to elevate the in situ hybridization temperature and facilitate the accurate discrimination of two similar gene sequences. Our dual-functional LSPR biosensor exhibits a high sensitivity toward the selected SARS-CoV-2 sequences with a lower detection limit down to the concentration of 0.22 pM and allows precise detection of the specific target in a multigene mixture. This study gains insight into the thermoplasmonic enhancement and its applicability in the nucleic acid tests and viral disease diagnosis.
关键词： plasmonic photothermal effect,RNA virus,coronavirus disease,LSPR,biosensors,nuclei acids,severe acute respiratory syndrome coronavirus 2
更新于2025-09-19 17:13:59
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Sensitive detection of influenza a virus based on a CdSe/CdS/ZnS quantum dot-linked rapid fluorescent immunochromatographic test
摘要： Prevention is the most effective management strategy for influenza A infection in humans. In this study, we developed a CdSe/CdS/ZnS quantum dot (QD) fluorescent dye for rapid and sensitive detection of two common subtypes (H1N1 and H3N2) of influenza A virus, and examined its utility. CdSe/CdS/ZnS QD was conjugated with antibody (Ab) after conjugation with latex, making QD conjugate of QD+Latex+Ab. A stable photoluminescence of QD conjugate and advantage of CdSe/CdS/ZnS QD used was characterized in this study. The performance of a rapid fluorescent immunochromatographic test (FICT) employing QD conjugate (QD-FICT) in detecting influenza A/H1N1 was 8-fold and 64-fold higher than that of a europium nanoparticle-based FICT and a rapid diagnostic test (RDT; Standard Diagnostics BIOLINE Influenza A/B), respectively. For influenza A/H3N2, QD-FICT showed 8-fold and 128-fold higher performance than europium nanoparticle-based FICT and RDT, respectively. In clinical evaluations, QD-FICT showed 93.75% clinical sensitivity [45/48; 95% confidence interval (95% CI): 82.80-98.69], 100% clinical specificity (117/117; 95% CI: 96.90-100.00), and strong correlation (kappa; 0.98) with rRT-PCR (20 ≤ Ct ≤ 40). Europium nanoparticle-linked FICT showed 79.17% clinical sensitivity (38/48; 95% CI: 65.01-89.53) and 100% clinical specificity (117/117; 95% CI: 96.90-100.00), whereas RDT showed 77.08% sensitivity (37/48; 95% CI: 62.69-87.97), 100% specificity (117/117; 95% CI: 96.90-100.00), and reasonably good correlation with rRT-PCR (kappa; 0.93). Water-soluble QDs can therefore be used as an effective material for developing fluorescent diagnostic systems for rapid detection of human influenza A virus in clinical specimens.
关键词： Rapid Fluorescent Immunochromatographic Test,Influenza A Virus,Quantum Dot Fluorescent Dye
更新于2025-09-19 17:13:59
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Fluorometric Sensing Platform Based on Localized Surface Plasmon Resonance using Quantum Dots-Gold Nanocomposites Optimizing the Linker Length Variation
摘要： The successful development of a label free sensing approach using the localized surface plasmon resonance (LSPR), controlling the distance between fluorescent CdZnSeS/ZnSeS quantum dots (QDs) and gold nanoparticles (AuNPs) has been established for the detection of virus. Here, we present a new combination of AuNPs and CdZnSeS/ZnSeS QDs linked with a peptide chain of 18 amino acids after functionalization in its both ends. The synthesized peptide has been used as a linker between these duos and provided the anchoring sides for the antibody conjugation. In the optimized condition, the fluorescent properties of the QDs have been enhanced due to the surface plasmon effect of the adjacent AuNPs. On the basis of the significance on LSPR sensing, we have attempted to detect different concentration of influenza virus in this work. The detection sensitivity has been analyzed by the quenched spectra of the fluorescence of QDs due to the induced steric effect of the attached virus molecule on the LSPR behavior. A detection limit of 26.4 fg mL-1 influenza virus has been obtained in a linear range of 10-14 to 10-9 g mL-1. On the basis of the obtained results and the detection mechanism, this proposed biosensor can be a good option for the detection of general biomolecule by altering the conjugated antibody and analytes, in the various range of sensing application.
关键词： biosensor,localized surface plasmon resonance,influenza virus,gold nanoparticles,quantum dots
更新于2025-09-19 17:13:59
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Wafer‐Scale Polymer‐Based Transparent Nanocorals with Excellent Nanoplasmonic Photothermal Stability for High‐Power and Superfast SERS Imaging
摘要： To understand the mechanism(s) of age-dependent outcomes of hepatitis B virus (HBV) infection in humans, we previously established an age-related HBV mouse model in which 6-week-old (N6W) C3H/HeN mice exhibited virus tolerance whereas 12-week-old (N12W) counterparts presented virus clearance. By investigating the hepatic myeloid cell dynamics in mice of these two ages, we aim to identify factors associated with HBV clearance. C3H/HeN mice were transfected with an HBV plasmid by hydrodynamic injection. Serum HBV markers were monitored weekly. Hepatic leucocyte populations and their cytokine/chemokine productions were examined at baseline, day 3 (D3), day 7 (D7), and day 14 after injection. C-C chemokine receptor type 2 (CCR2) antagonist and clodronate (CLD) were respectively administered to N12W and N6W mice to study the roles of lymphocyte antigen 6 complex, locus C (Ly6C) monocytes and Kupffer cells (KCs) in viral clearance. N12W mice had a significantly higher number of TNF-α–secreting Ly6C monocytes and fewer IL-10–secreting KCs at D3 in the liver than their younger N6W counterparts after HBV transfection. In addition, the elevated number of interferon-γ+ T cells at D7 was only seen in the older cohort. The enhanced Ly6C monocyte induction in N12W mice resulted from elevated C-C motif chemokine ligand 2 (CCL2) secretion by hepatocytes. CCR2 antagonist administration hampered Ly6C monocyte recruitment and degree of KC reduction and delayed HBV clearance in N12W animals. Depletion of KCs by CLD liposomes enhanced Ly6C monocyte recruitment and accelerated HBV clearance in N6W mice. Conclusions: Ly6C monocytes and KCs may, respectively, represent the resistance and tolerance arms of host defenses. These two cell types play an essential role in determining HBV clearance/tolerance. Manipulation of these cells is a promising avenue for immunotherapy of HBV-related liver diseases.
关键词： Hepatitis B virus,monocytes,clearance,immune response,Kupffer cells,tolerance,age-dependent
更新于2025-09-19 17:13:59
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Virus Structures by X-Ray Free-Electron Lasers
摘要： Until recently X-ray crystallography has been the standard technique for virus structure determinations. Available X-ray sources have continuously improved over the decades, leading to the realization of X-ray free-electron lasers (XFELs). They provide high-intensity femtosecond X-ray pulses, which allow for new kinds of experiments by making use of the diffraction-before-destruction principle. By overcoming classical dose constraints, they at least in principle allow researchers to perform X-ray virus structure determination for single particles at room temperature. Simultaneously, the availability of XFELs led to the development of the method of serial femtosecond crystallography, where a crystal structure is determined from the measurement of hundreds to thousands of microcrystals. In the case of virus crystallography this method does not require freezing of the crystals and allows researchers to perform experiments under non-equilibrium conditions (e.g., by laser-induced temperature jumps or rapid chemical mixing), which is currently not possible with electron microscopy.
关键词： structure determination,serial crystallography,XFEL,single particle imaging,virus crystallography,X-ray free-electron laser
更新于2025-09-16 10:30:52
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Progress in the use of an electro-optical sensor for virus detection
摘要： This paper describes, for the first time, the real-time virus detection with an electro-optical (EO) sensor, using transmissible gastroenteritis virus (TGEV) as an example. The possibility of detecting an intact but inactivated TGEV by using specific antibodies is shown. The antibody-aided detection of the TGEV is possible in the presence of extraneous virus particles. The changes in the frequency dependence of the EO signal of virus suspensions before and after the addition of specific antibodies is an optimally informative parameter. The limit for reliable virus detection is 104 virus particles ml?1, and the time of analysis is 10–15 min. The EO sensor is promising for the recording of virus-antibody interactions and for rapid virus detection.
关键词： Electro-optical sensor,Virus,Detection
更新于2025-09-16 10:30:52
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Dual-mode detection of avian influenza virions (H9N2) by ICP-MS and fluorescence after quantum dot labeling with immuno-rolling circle amplification
摘要： Avian influenza virus (AIVs), hosted in poultry, are the pathogens of many poultry diseases and human infections, which bring huge losses to the poultry breeding industry and huge panic to society. Therefore, it is of great significance to establish accurate and sensitive detection methods for AIVs. In this work, a dual-mode detection method based on immuno-rolling circle amplification (immuno-RCA) and quantum dots (QDs) labeling for inductively coupled plasma mass spectrometry (ICP-MS) and fluorescence detection of H9N2 AIV was developed. The dual-mode detection of the QDs by ICP-MS and fluorescence is used to achieve mutual verification within the analysis results, thus improving the accuracy of the method. With the immuno-RCA, the sensitivity of the method was increased by two orders of magnitude. The limit of detection of the proposed method is 17 ng L-1 and 61 ng L-1, and the linear range of the proposed method is 0.05-5 ng mL-1 and 0.1-5 ng mL-1 with ICP-MS and fluorescence detection, respectively. The relative standard deviation (n=7) is 4.9% with ICP-MS detection and 3.1% with fluorescence detection. Furthermore, the proposed method was applied to the analysis of chicken serum samples, no significant different was found for two modes detection and the recoveries of the spiking experiments are acceptable, indicating that the method has good practical potential for real sample analysis.
关键词： ICP-MS,quantum dot,rolling circle amplification,H9N2 avian influenza virus,dual mode detection
更新于2025-09-12 10:27:22
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Fibrin glue to manage flap necrosis secondary to late-onset infectious keratitis after laser in?situ karatomileusis
摘要： A 52-year-old man developed flap necrosis secondary to late-onset infectious keratitis after laser in situ keratomileusis. Management involved a flap lift and irrigation of the interface with fortified antibiotics. The flap was then replaced, and fibrin glue was placed at the flap edges and over the necrotic area to seal it completely. Two months after surgery, the corrected distance visual acuity was 20/20 and a slitlamp examination showed no signs of infection. Localized flap necrosis can be adequately managed with fibrin glue, including in cases of herpes simplex virus keratitis.
关键词： fibrin glue,infectious keratitis,flap necrosis,herpes simplex virus,laser in situ keratomileusis
更新于2025-09-12 10:27:22
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Laser-induced fluorescence (LIF) as a smart method for fast environmental virological analyses: validation on Picornaviruses
摘要： Virological analysis is time-consuming and expensive. The aim of this work is to demonstrate the applicability of laser-induced fluorescence (LIF) to the classification of viruses, reducing the time for this analysis and its costs. Experimental tests were performed in which different viruses were irradiated with a UV laser emitting at 266 nm and the emitted spectra were recorded by a spectrometer. The classification techniques show the possibility of discriminating viruses. Although the application of the LIF technique to biological agents has been thoroughly studied by many researchers over the years, this work aims at validating for the first time its applicability to virological analyses. The development of a fast virological analysis may revolutionize this field, allowing fast responses to epidemiologic events, reducing their risks and improving the efficiency of monitoring environments. Moreover, a cost reduction may lead to an increase in the monitoring frequency, with an obvious enhancement of safety and prevention.
关键词： Laser-induced fluorescence,environmental monitoring,virological analyses,virus classification
更新于2025-09-11 14:15:04