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Illumination conditions in microsphere-assisted microscopy
摘要： White-light microsphere-assisted microscopy is a full-field and label-free imaging promising technique making it possible to achieve a sub-diffraction lateral resolution. However, performance of this technique depends not only on the geometrical parameters but also on the illumination conditions of the optical system. In the present work, experimental measurements and computer simulations have been performed in air in order to determine the influence of the two diaphragm apertures of the K?hler arrangement and the spectral width of the light source on both the depth-of-focus of the microsphere and the optimisation of the imaging contrast. Furthermore, the super-resolution phenomenon is demonstrated and the cumulated optical aberrations are shown through the measurement of the optical transfer function for the different arrangements of the illumination part.
关键词： Super-resolution microscopy,Illumination,Microsphere,Optical transfer function,Imaging depth
更新于2025-10-24 16:39:32
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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
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Preparation and evaluation of fluorescent poly(p-phenyleneethylene) covalently coated microspheres with reactive sites for bioconjugation
摘要： Fluorescent microspheres with reactive sites for interacting with biomolecules are greatly demanded in flow cytometry based suspension array. Aiming to develop new method for preparing fluorescent microspheres, two poly(p-phenyleneethylene) (PPE) conjugated polymers (CPs) with pedant carboxylic groups were synthesized via Sonogarshira coupling and followed with hydrolysis of ester groups; then the conjugated polymers were immobilized onto monodispersed amino-modified porous poly(glycidylmethacrylate) (APGMA) microspheres via coupling reaction between carboxylic and amino groups to give APGMA-CP fluorescent microspheres. The fluorescent microspheres were found to have good photo- and thermal stability as well as negligible influence from rigorous washing. The emission was uniform all across the inner and surface of the spheres. To evaluate the effectiveness of bioconjugation on the fluorescent microspheres, fluorescein isothiocyanate isomer I (FITC) labeled bovine serum albumin (BSA) (BSA-FITC) was chosen as the representative biomolecule to react with the fluorescent microspheres to give APGMA-CP-BSA-FITC. In the flow cytometry study, fluorescence compensation between the V500 and FITC detectors (receiving signals from fluorophores excited by 405 nm and 488 nm, respectively), to remove the interference between the emission of FITC and CPs, was realized using singly-stained microspheres. Finally, APGMA-CP-BSA-FITC microspheres were found to be double positive for CP and FITC with very high percentage (>95%), suggesting the bioconjugation is very effective. This study provides a facile method for simultaneous introduction of fluorescence and reactive sites onto the microspheres, which is very promising to be used as general strategy for fabricating fluorescence microspheres for application in high-throughput technology.
关键词： Fluorescence,Bioconjugation,Flow Cytometry,Microsphere,Conjugated Polymer
更新于2025-09-23 15:22:29
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Large field-of-view super-resolution image obtained by manipulating submerged microsphere
摘要： Images with super-resolution can be obtained by dielectric microspheres with appropriate refractive index. However, in practical applications, the microsphere must be moved to the desired position and can scan the large specific area. Here we present a simple method of positioning a microsphere by using a four-dimensional precision translation stage. The simulations have been performed to confirm that 16 μmφ barium titanate glass (BTG) microsphere submerged in alcohol can obtain high quality images and the influence of the probe and the flowing liquid on imaging can be ignored. Therefore, by driving the translation stage, the submerged microsphere can scan the sample surface along the X and Y axis at the speed of 10 μm/s and the large field-of-view image can be achieved by stitching the pictures of different positions. This work has provided a new technique in super-resolution imaging and can be widely applied in field of scientific research.
关键词： photonic nanojet,scanning,super-resolution imaging,large field-of-view,microsphere
更新于2025-09-23 15:21:21
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Laser Sources Based on Rare-Earth Ion Doped Tellurite Glass Fibers and Microspheres
摘要： In recent years, huge progress has been made in the development of rare-earth ion doped tellurite glass laser sources, ranging from watt- and multiwatt-level fiber lasers to nanowatt level microsphere lasers. Significant success has been achieved in extending the spectral range of tellurite fiber lasers generating at wavelengths beyond 2 μm as well as in theoretical understanding. This review is aimed at discussing the state of the art of neodymium-, erbium-, thulium-, and holmium-doped tellurite glass fiber and microsphere lasers.
关键词： microsphere laser,tellurite glass fiber,microlaser,rare-earth ions,tellurite fiber laser
更新于2025-09-23 15:21:01
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Rapid Self-Assembly of Au Nanoparticles on Rigid Mesoporous Yeast-Based Microspheres for Sensitive Immunoassay
摘要： A simple, rapid, inexpensive, ecofriendly, and high-throughput biological strategy for the preparation of functional microspheres on a yeast-cell platform was introduced. Microspheres prepared through the treatment of yeast cells with formaldehyde and decoating buffer exhibited excellent characteristics, such as superior mechanical strength, high sulfhydryl group content, and mesoporous structure. Au nanoparticles (NPs) easily and rapidly self-assembled onto the surfaces of the yeast-based microspheres within 5 min to form rigid yeast@Au microspheres with high monodispersity and uniformity. The rapid formation of yeast@Au microspheres mainly involved the enhancement of sulfhydryl groups and mesoporosity. The yeast@Au microspheres were successfully used in a flow cytometry immunoassay to detect Pseudorabies viral infection events. Signal-to-noise ratio was enhanced by approximately 49.4-fold. The presence of Au NPs on the yeast-based microspheres greatly improved sensitivity by decreasing noise through reducing nonspecific adsorption, highly enhancing the fluorescence signal caused by the surface plasmon resonance effect, and increasing the coupling efficiency of the capture protein. The presented method was used to analyze 81 clinical swine serum specimens. The results obtained by this developed method were compared with those of commercial diagnostic kits. The sensitivity, specificity, and efficiency of the developed method were 92.31%, 88.24%, and 88.89%, respectively. The excellent characteristics of the yeast@Au microspheres illustrate its great potential for high-throughput immunoassay applications in the fields of disease diagnosis, environmental analysis, and food safety.
关键词： immunoassay,self-assembly,yeast,Au NPs,microsphere
更新于2025-09-23 15:21:01
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai, China (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - A stretchable translucent conductive film based on polymer microspheres lithography technology
摘要： Transparent and translucent conductor has played an important role in various of photoelectric device electrodes, including photovoltaics (PVs), light-emitting diodes (LEDs), liquid-crystal displays (LCDs), touch-screen panels (TSPs), and radiofrequency identification (RFID) and so on [1, 2]. Some conductive oxides are transparent but do not stretchable. We have confirmed a method based on polystyrene (PS) microspheres to obtain a stretchable transparent conductive film. The homogeneous mono-layer PS microstructure arrays were self-assembled on surface of modified polydimethylsiloxane (PDMS) film, and then the size and spacing distance of the microspheres were adjusted by plasma etching technology to obtain non-closed PS arrays, and the magnetron sputtering technology was used to deposit a layer of conductive metal on the etched microsphere arrays. The stretchable translucent conductive films show relatively high transmittance (53% at 550 nm), and good electrical stability under stretching conditions. They also posses better conformability and conformal on complex curve surfaces than conventional bendable transparent conductive films, and present excellent potential application in flexible electronic and biomedicine fields.
关键词： Stretchable,Polymer microsphere lithography,Self-assembly,Flexible optoelectronics,translucent conductors
更新于2025-09-23 15:21:01
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Reduced graphene oxide@ceria nanocomposite-coated polymer microspheres as a highly active photocatalyst
摘要： Herein we report a facile two-step synthetic strategy for fabricating the ternary polystyrene/reduced graphene oxide/ceria (PS/RGO@CeO2) nanocomposite particles for the first time through the self-assembly of the RGO on the surface of PS microsphere (PS/RGO) and then the attachment of CeO2 nanoparticles (NPs) onto the as-prepared PS/RGO nanocomposite particles. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis have been employed to characterize the morphology and composition of the as-prepared samples. The size and mass loading of resulting CeO2 NPs on the PS/RGO nanocomposite particles are easily tunable. Furthermore, the photocatalytic performance of as-prepared ternary nanocomposite particles towards the degradation of methylene blue is investigated. Notably, the PS/RGO@CeO2 nanocomposite particles have high photocatalytic activity due to the synergistic effect between the CeO2 NPs and RGO in such a unique structure, and moreover, they also exhibit high stability in a recyclable manner. Therefore, it can be expected that our ternary nanocomposite particles are an attractive photocatalyst candidate for various photocatalytic applications.
关键词： polystyrene microsphere,ceria nanoparticle,reduced graphene oxide,nanocomposite particle,catalysis
更新于2025-09-19 17:15:36
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[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) - A fiber etched cavity for microsphere whispering-gallery-mode excitation
摘要： In this paper, we demonstrate a fiber etched cavity for excitation of WGM in a microsphere resonator. The device consists of a section of NCF fusion spliced with multimode fiber (MMF) and single mode fiber (SMF) at its two ends, an etched cavity created at the end face of the MMF by use of hydrofluoric (HF) acid, and a microsphere glued at the bottom of the etched cavity. When the microsphere is located at the bottom of the etched cavity, its surface is tangent with the arc of the etched cavity at their contacting point. Thus when the light propagation path is tangential to the arc of the etched cavity (or the microsphere surface), the circulating light is excited. The etched cavity-microsphere device does no need to be accurately aligned, and hence is easy to implement in practical applications.
关键词： whispering gallery mode,microsphere resonator
更新于2025-09-16 10:30:52
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MgO/ZnO microsphere bilayer structure towards enhancing the stability of the self-powered MAPbI3 perovskite photodetectors with high detectivity
摘要： In recent years, organic-inorganic hybrid perovskite photodetectors (PDs) have been regarded as promising next-generation PDs. However, the commercialization of the perovskite PDs still faces signi?cant challenges, one of which is the poor stability. Herein, we demonstrate MgO/ZnO microsphere (MS) bilayer structure for improving the device stability with high detectivity. In this MgO/ZnO MS bilayer, ZnO MS array sca?old can facilitate the penetration of perovskite into nano-arrays and bene?ts the light harvest e?ciency due to the special micro-sphere array structure, which behaves a big gap between aligned nanostructures. MgO passivates the interface between ZnO and perovskite, enhancing the device stability and promoting the carrier transport. Finally, our PDs with the bilayer structure exhibit high performance with the on/o? ratio of up to more than 7.0 × 104, the linear dynamic range of 87.7 dB, and the detectivity of 1.5 × 1012 Jones, all of which are better than those of the device without MgO. More importantly, the device with the bilayer structure shows better stability compared with the device without MgO. Under illumination with the optical power of 314 mW/cm2, the photocurrent of the device with MgO shows almost no attenuation after continuous illumination for 30 min. In addition, after storing in air for 15 days, the performance of the device with MgO exhibits slight attenuation and the on/o? ratio is still as high as 2.3 × 104, indicating that the device has good storage stability.
关键词： MgO passivation,Perovskite photodetector,Self-powered,ZnO microsphere
更新于2025-09-16 10:30:52