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Site Selective Nucleation and Size Control of Gold Nanoparticle Photothermal Antennae on the Pore Structures of a Virus
摘要： In this article, we show that the surface of the bacteriophage Qβ is equipped with natural ligands for the synthesis of small gold nanoparticles. By exploiting disulfides in the protein secondary structure and the geometry formed from the capsid quaternary structure, we find we can produce regularly arrayed patterns of ~6 nm gold nanoparticles across the surface of the virus-like particle. Experimental and computational analysis provide insight into the formation and stability of this composite. We further show that the entrapped genetic material can hold upwards of 500 molecules of the anti-cancer drug Doxorubicin without leaking and without interfering with the synthesis of the gold nanoparticles. This direct nucleation of nanoparticles on the capsid allows for exceptional conduction of photothermal energy upon nanosecond laser irradiation. As a proof of principle, we demonstrate that this energy is capable of rapidly releasing the drug from the capsid without heating the bulk solution, allowing for highly targeted cell killing in vitro.
关键词： Drug Delivery,Virus-Like Particles,Gold Nanoparticles,Photothermal Release
更新于2025-09-23 15:21:01
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Sensitive Detection of Dengue Virus Type 2 E-Proteins Signals Using Self-Assembled Monolayers/Reduced Graphene Oxide-PAMAM Dendrimer Thin Film-SPR Optical Sensor
摘要： In this work, sensitive detection of dengue virus type 2 E-proteins (DENV-2 E-proteins) was performed in the range of 0.08 pM to 0.5 pM. The successful DENV detection at very low concentration is a matter of concern for targeting the early detection after the onset of dengue symptoms. Here, we developed a SPR sensor based on self-assembled monolayer/reduced graphene oxide-polyamidoamine dendrimer (SAM/NH2rGO/PAMAM) thin film to detect DENV-2 E-proteins. Surface characterizations involving X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirms the incorporation of NH2rGO-PAMAM nanoparticles in the prepared sensor films. The specificity, sensitivity, binding affinity, and selectivity of the SPR sensor were then evaluated. Results indicated that the variation of the sensing layer due to different spin speed, time incubation, and concentration provided a better interaction between the analyte and sensing layer. The linear dependence of the SPR sensor showed good linearity (R2 = 0.92) with the lowest detection of 0.08 pM DENV-2 E-proteins. By using the Langmuir model, the equilibrium association constant was obtained at very high value of 6.6844 TM?1 (R2 = 0.99). High selectivity of the SPR sensor towards DENV-2 E-proteins was achieved in the presence of other competitors.
关键词： optical sensor,E-proteins,SPR sensor,PAMAM dendrimer,reduced graphene oxide,dengue virus,self-assembled monolayer
更新于2025-09-23 15:19:57
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Visualizing Speech-Generated Oral Fluid Droplets with Laser Light Scattering
摘要： Aerosols and droplets generated during speech have been implicated in the person-to-person transmission of viruses, and there is current interest in understanding the mechanisms responsible for the spread of Covid-19 by these means. The act of speaking generates oral fluid droplets that vary widely in size, and these droplets can harbor infectious virus particles. Whereas large droplets fall quickly to the ground, small droplets can dehydrate and linger as “droplet nuclei” in the air, where they behave like an aerosol and thereby expand the spatial extent of emitted infectious particles. We report the results of a laser light-scattering experiment in which speech-generated droplets and their trajectories were visualized.
关键词： Covid-19,speech,virus transmission,laser light-scattering,droplets,aerosols
更新于2025-09-23 15:19:57
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Impedimetric detection of Banana bunchy top virus using CdSe quantum dots for signal amplification
摘要： Banana bunchy top virus is considered to be the most economically destructive pathogens of banana that causes severe economic loss in banana plantations worldwide, including India. In this present study we have developed an improved electrochemical ELISA for detection of Banana bunchy top virus (BBTV). For enhanced and accurate detection we have used cadmium selenide (CdSe) quantum dots (QDs) as signal amplifiers. Experiments in this study were performed using primary antibody raised from recombinant coat protein of BBTV. CdSe QDs could significantly amplify the electrical signals in this assay and make the method appropriate for lab use. The result of electrical conduction showed the difference of impedance between the healthy and diseased sample of the order of ~ 100 Ω. The electrochemical ELISA could detect the virus in plant sap up to dilution of 1:25 as compared to 1:10 of conventional ELISA.
关键词： Faradic impedance spectroscopy,Cadmium selenide quantum dots (CdSe QDs),Banana bunchy top virus
更新于2025-09-23 15:19:57
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Fluorometric virus detection platform using quantum dots-gold nanocomposites optimizing the linker length variation
摘要： In this study, a tunable biosensor using the localized surface plasmon resonance (LSPR), controlling the distance between fluorescent CdZnSeS/ZnSeS quantum dots (QDs) and gold nanoparticles (AuNPs) has been developed for the detection of virus. The distance between the AuNPs and QDs has been controlled by a linkage with a peptide chain of 18 amino acids. In the optimized condition, the fluorescent properties of the QDs have been enhanced due to the surface plasmon effect of the adjacent AuNPs. Successive virus binding on the peptide chain induces steric hindrance on the LSPR behavior and the fluorescence of QDs has been quenched. After analyzing all the possible aspect of the CdZnSeS/ZnSeS QD-peptide-AuNP nanocomposites, we have detected different concentration of influenza virus in a linear range of 10?14 to 10?9 g?mL?1 with detection limit of 17.02?fg?mL?1. On the basis of the obtained results, this proposed biosensor can be a good alternative for the detection of infectious viruses in the various range of sensing application.
关键词： Quantum dots,Localized surface plasmon resonance,Biosensor,Peptide,Influenza virus,Gold nanoparticle
更新于2025-09-23 15:19:57
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Determination of parvovirus retention profiles in virus filter membranes using laser scanning microscopy
摘要： Virus filtration is a highly effective method in the downstream processing of biotherapeutic products to provide effective removal of potential infectious agents based on a size exclusion mechanism. The direct visualization of viruses retained inside the filter membrane represents a valuable tool to get a deeper understanding of the filtration process and to explain observations of virus breakthrough under particular operating conditions. Parvoviruses, which are used as worst-case models in validation studies, were purified and labeled with fluorescent dyes to detect their retention pattern inside the filter membrane using laser scanning microscopy. Critical factors influencing the reproducibility and accuracy of the approach were identified and optimized. The retention profiles revealed detectable differences between viruses, suggesting that the use of bacteriophages or nanoparticles as surrogates is limited in their applicability to accurately predict the behavior of parvoviruses in filter membranes. The established method enables a direct and quantitative analysis of the virus retention profile, adding a valuable tool to the conventional measurement of the viral load reduction to better understand the mechanism underlying the removal of viruses during nanofiltration of biotherapeutic products.
关键词： Parvovirus retention profile,Virus filtration,Nanofiltration,Laser scanning microscopy,Filter membrane
更新于2025-09-23 15:19:57
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Digital Single Virus Immunoassay for Ultrasensitive Multiplex Avian Influenza Virus Detection Based on Fluorescent Magnetic Multifunctional Nanospheres
摘要： Fluorescence method has made great progress in the construction of sensitive sensors, but the background fluorescence of matrix and photobleaching limit its broad application in clinical diagnosis. Here, we propose a digital single virus immunoassay for multiplex virus detection by using fluorescent magnetic multifunctional nanospheres as both capture carriers and signal labels. The superparamagnetism and strong magnetic response ability of nanospheres can realize efficient capture and separation of targets without sample pretreatment. Due to its distinguishable fluorescence imaging and photostability, the nanospheres enable single-particle counting for ultrasensitive multiplexed detection. Furthermore, the integration of digital analysis provided a reliable quantitative strategy for rare targets detection. Based on multifunctional nanospheres and digital analysis, a digital single virus immunoassay was proposed for simultaneous detection of H9N2, H1N1 and H7N9 avian influenza virus (AIV) without complex signal amplification, whose detection limits were 0.02 pg/mL. Owing to its good specificity and anti-interference ability, the method showed great potential in single biomolecules, multiplexed detection and early diagnosis of diseases.
关键词： Multifunctional nanospheres,Digital analysis,Avian influenza virus,Single virus immunoassay,Ultrasensitive multiplexed detection
更新于2025-09-19 17:15:36
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NanoJ: a high-performance open-source super-resolution microscopy toolbox
摘要： Super-resolution microscopy has become essential for the study of nanoscale biological processes. This type of imaging often requires the use of specialised image analysis tools to process a large volume of recorded data and extract quantitative information. In recent years, our team has built an open-source image analysis framework for super-resolution microscopy designed to combine high performance and ease of use. We named it NanoJ - a reference to the popular ImageJ software it was developed for. In this paper, we highlight the current capabilities of NanoJ for several essential processing steps: spatio-temporal alignment of raw data (NanoJ-Core), super-resolution image reconstruction (NanoJ-SRRF), image quality assessment (NanoJSQUIRREL), structural modelling (NanoJ-VirusMapper) and control of the sample environment (NanoJ-Fluidics). We expect to expand NanoJ in the future through the development of new tools designed to improve quantitative data analysis and measure the reliability of fluorescent microscopy studies.
关键词： Virus,Vaccinia,Archaea,Quantitative imaging,Sulfolobus acidocaldarius,Super-resolution microscopy,Fluidics,Modelling,Resolution,Image quality assessment,Pox,Image analysis,ImageJ,Fiji
更新于2025-09-19 17:15:36
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Process Monitoring of Virus-like Particle Reassembly by Diafiltration with UV/Vis Spectroscopy and Light Scattering
摘要： Virus-Like Particles (VLPs) have shown great potential as biopharmaceuticals on the market and in clinics. Non-enveloped, in vivo-assembled VLPs are typically dis- and reassembled in vitro to improve particle stability, homogeneity, and immunogenicity. At industrial scale, Cross-Flow Filtration (CFF) is the method of choice for performing reassembly by diafiltration. Here, we developed an experimental CFF setup with on-line measurement loop for the implementation of Process Analytical Technology (PAT). The measurement loop included an Ultraviolet and Visible (UV/Vis) spectrometer as well as a light-scattering photometer. These sensors allowed for monitoring protein concentration, protein tertiary structure, and protein quaternary structure. The experimental setup was tested with three Hepatitis B core Antigen (HBcAg) variants. With each variant, three reassembly processes were performed at different Transmembrane Pressures (TMPs). While light scattering provided information on the assembly progress, UV/Vis allowed for monitoring the protein concentration and the rate of VLP assembly based on the microenvironment of Tyrosine-132. VLP formation was verified by off-line Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Furthermore, the experimental results provided evidence of aggregate-related assembly inhibition and showed that off-line Size-Exclusion Chromatography (SEC) does not provide a complete picture of the particle content. Finally, a Partial-Least Squares (PLS) model was calibrated to predict VLP concentrations in the process solution. Q2 values of 0.947 to 0.984 were reached for the three HBcAg variants. In summary, the proposed experimental setup provides a powerful platform for developing and monitoring VLP reassembly steps by CFF.
关键词： process analytical technology,self-assembly,cross-flow filtration,virus-like particles,downstream processing,spectroscopy
更新于2025-09-19 17:15:36
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A fluorescence method for homogeneous detection of influenza A (H1N1) DNA sequence based on Guanine(G)‐quadruplex‐ N‐methylmesoporphyrin IX (NMM) complex and Assistance‐DNA (A‐DNA) inhibition
摘要： In this work, we report a fluorescence method for homogeneous detection of influenza A (H1N1) DNA sequence based on G-quadruplex-NMM complex and Assistance DNA (A-DNA) inhibition. The quadruplex-based functional DNA (QBF-DNA), composed of complementary probe to the target H1N1 DNA sequence and G-rich fragment, was designed as the signal DNA. The A-DNA consisted of two parts, one part was complementary to target H1N1 DNA and the other part was complementary to the signal DNA. In the absence of target H1N1 DNA, the G-rich fragment of QBF-DNA can form G-quadruplex-NMM complex, which outputted a fluorescent signal. With the presence of target H1N1 DNA, QBF-DNA and A-DNA can simultaneously hybridize with target H1N1 DNA to form double-helix structure. In this case, the A-DNA partially hybridized with the QBF-DNA, which inhibited the formation of G-quadruplex-NMM complex, leading to the decrease of fluorescent signal. Under the optimum conditions, the fluorescence intensity was inversely proportional to the concentration of target H1N1 DNA over the range from 25pmol/L to 700pmol/L with a detection limit of 8pmol/L. In addition, the method is target specific and practicability, and would become a new diagnostic assay for influenza A (H1N1) DNA sequence and other infectious diseases.
关键词： G-quadruplex,H1N1 virus,Fluorescence method,DNA hybridization
更新于2025-09-19 17:15:36