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The purpose of this study was to measure organ blood flow (OBF) in yellow catfish (YC, Pelteobagrus fulvidraco), largemouth bass (LB, Micropterus salmoides), and grass carp (GC, Ctenopharyngodon idella) using the method of fluorescent microspheres. Yellow–green microspheres were injected into the fish via cardiac catheterization using a syringe pump at a rate of 0.8 mL/min. Reference blood samples were collected from the dorsal aorta, and fish tissues were harvested after 5 min and processed for fluorescence spectrophotometric analysis. The results showed that the OBF of the heart increased significantly with the increase in temperature from 20 to 30 °C, while there was no significant difference in the OBF of other organs/tissues in YC. The OBFs of different species of LB and GC were also determined at 25 °C. In GC, the blood flow rates of the heart, spleen, kidney, liver, others, gills, swim bladder, intestines, muscles, and skin were 9.55, 1.00, 10.3, 6.92, 6.70, 6.04, 2.06, 2.81, 1.78, and 3.72 (mL/min/g), respectively. In LB, the blood flow rates of the same organs were 8.80, 2.33, 1.01, 0.71, 4.11, 2.72, 1.22, 0.54, 9.47, and 0.40 (mL/min/g), respectively. Compared to the OBFs of YC at 25 °C, the OBFs in GC were the highest, followed by LB. These results reflect that OBF in fish has significant species differences. These studies provide fundamental physiological data on OBFs in YC, GC, and LB, which has practical implications for improving the development of disciplines associated with fish physiology. [ABSTRACT FROM AUTHOR]

Traditional single nucleic acid assays can only detect one target while multiple nucleic acid assays can detect multiple targets simultaneously, providing comprehensive and accurate information. Fluorescent microspheres in multiplexed nucleic acid detection offer high sensitivity, specificity, multiplexing, flexibility, and scalability advantages, enabling precise, real-time results and supporting clinical diagnosis and research. However, multiplexed assays face challenges like complexity, costs, and sample handling issues. The review explores the recent advancements and applications of fluorescent microspheres in multiple nucleic acid detection. It discusses the versatility of fluorescent microspheres in various fields, such as disease diagnosis, drug screening, and personalized medicine. The review highlights the possibility of adjusting the performance of fluorescent microspheres by modifying concentrations and carrier forms, allowing for tailored applications. It emphasizes the potential of fluorescent microsphere technology in revolutionizing nucleic acid detection and advancing health, disease treatment, and medical research. [ABSTRACT FROM AUTHOR]

In this study, to investigate the feasibility of applying pectin as an adsorbent to prevent pollinosis, we focused on the two types, low- and high‑methoxy pectin, and investigated its properties for application in nasal mucosa-protective preparations. A film adhesion test was performed, and the number of fluorescent microspheres (FMs) adsorbed to the pectin layer was prepared using a hydrophilic polyvinylidene fluoride filter, and mucin was quantified by fluorescence. High‑methoxy pectin (HMP) caught more FMs than low‑methoxy pectin (LMP)(p < 0.05). The quartz crystal microbalance with dissipation monitoring revealed that HMP adhered more to mucin than LMP. The concentration of HMP did not affect adhesiveness. Furthermore, from evaluating the adsorbency of FMs on pectin and mucin, HMP shows higher adsorbency than LMP (p < 0.05). From these results, it could be concluded that pectin with an HMP had stronger interactions with mucin than LMP and could be applied to the nasal formulation to prevent pollinosis.

Based on the new hapten of fipronil, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and time-resolved fluorescent immunochromatographic assay (TRFICA) for the determination of fipronil were developed. The sensitivity (IC50) of the ic-ELISA method was 2.33 ± 0.14 ng mL−1 (n = 3), and the limit of detection (LOD) (IC20) was 0.27 ± 0.02 ng mL−1 (n = 3). The cross-reaction rates of the three fipronil metabolites were all higher than 66.7%, and those of the three analogs were no more than 0.05%. The TRFICA was optimized with a handheld reader. The LOD was 0.862 ng mL−1 (n = 3). In this study, the pretreatment methods of samples such as Chinese cabbage, spinach, apple and egg, were explored. Methanol and acetonitrile were used to extract different food samples and the diluents were optimized. Three concentration levels in the spiked food samples were detected by the two methods. The range of recovery was 88.65–116.32% for ic-ELISA and 95.48–112.61% for TRFICA. In this study, the accuracy of the two methods was also judged by testing commercial quality control samples. The results showed that the accuracy was 83.75%–113.33% for ic-ELISA and 98.33–107.13% for TRFICA. [ABSTRACT FROM AUTHOR]

Objective By endowing polymer microspheres with a fluorescent characteristic that enables them to have tracer performance, the actual situation of adsorption, retention, and migration of polymer microspheres in the formation can be clearly understood based on the detection of the produced liquid. However, a difficult problem that needs to be solved urgently is how to maximize the displacement ability of keeping the original microspheres with the effective integration of fluorescent materials and polymer microspheres. Methods The preparation of fluorescent microspheres was achieved through copolymerization reaction using ordinary core-shell microspheres with cationic functional monomers, acrylamide, and other main components as carriers and carbon quantum dots as fluorescent materials. The fluorescence intensity was measured and a comparative experiment of Zeta potential, hydration expansion, and sealing performance was carried out. Results The fluorescence yield rate of carbon quantum dots was high, with a minimum detection limit of 0.05%; The Zeta potential data demonstrated that the fluorescent monomer was successfully fixed to the core layer of the microspheres, ensuring effective fusion of the fluorescent material with the prototype microspheres; The difference in sealing efficiency between fluorescent microspheres and ordinary core-shell microspheres was within 3%, and the hydration expansion and sealing performance of them were basically same. Conclusions The introduction of the carbon quantum dot fluorescent material into the core layer has not changed the characteristics of the polymer microspheres, and the detection limit value is low, which is expected to be used in subsequent field applications. [ABSTRACT FROM AUTHOR]

The purpose of this study was to measure organ blood flow (OBF) in yellow catfish (YC, Pelteobagrus fulvidraco), largemouth bass (LB, Micropterus salmoides), and grass carp (GC, Ctenopharyngodon idella) using the method of fluorescent microspheres. Yellow–green microspheres were injected into the fish via cardiac catheterization using a syringe pump at a rate of 0.8 mL/min. Reference blood samples were collected from the dorsal aorta, and fish tissues were harvested after 5 min and processed for fluorescence spectrophotometric analysis. The results showed that the OBF of the heart increased significantly with the increase in temperature from 20 to 30 °C, while there was no significant difference in the OBF of other organs/tissues in YC. The OBFs of different species of LB and GC were also determined at 25 °C. In GC, the blood flow rates of the heart, spleen, kidney, liver, others, gills, swim bladder, intestines, muscles, and skin were 9.55, 1.00, 10.3, 6.92, 6.70, 6.04, 2.06, 2.81, 1.78, and 3.72 (mL/min/g), respectively. In LB, the blood flow rates of the same organs were 8.80, 2.33, 1.01, 0.71, 4.11, 2.72, 1.22, 0.54, 9.47, and 0.40 (mL/min/g), respectively. Compared to the OBFs of YC at 25 °C, the OBFs in GC were the highest, followed by LB. These results reflect that OBF in fish has significant species differences. These studies provide fundamental physiological data on OBFs in YC, GC, and LB, which has practical implications for improving the development of disciplines associated with fish physiology.

Photo‐responsive porous materials have demonstrated their versatility in various areas. However, photoactivation in the fluorescent conjugated microporous polymer (CMP) microspheres is barely reported. Herein, a facile synthesis of benzosilole‐based CMPs with uniform microspheric morphology and their unprecedented photoactivated fluorescence enhancement as converse‐photobleaching behavior are reported. By simple ultraviolet irradiation, the fluorescence of the CMP microspheres as the dispersion in various solvents is enhanced up to 60‐fold. More importantly, the photoactivation‐induced emission enhancement is carefully revealed to originate from the renovation of the ubiquitous defects by solvent molecule adsorption, photo‐dissociating, photo‐interparticle coupling, and photochemical reactions, supported by control experiments, theoretical calculations, and molecular dynamics simulations. The systematic elucidation of the CMP defects can open a new door to developing photo‐responsive polymers for various applications. [ABSTRACT FROM AUTHOR]

Traditional single nucleic acid assays can only detect one target while multiple nucleic acid assays can detect multiple targets simultaneously, providing comprehensive and accurate information. Fluorescent microspheres in multiplexed nucleic acid detection offer high sensitivity, specificity, multiplexing, flexibility, and scalability advantages, enabling precise, real-time results and supporting clinical diagnosis and research. However, multiplexed assays face challenges like complexity, costs, and sample handling issues. The review explores the recent advancements and applications of fluorescent microspheres in multiple nucleic acid detection. It discusses the versatility of fluorescent microspheres in various fields, such as disease diagnosis, drug screening, and personalized medicine. The review highlights the possibility of adjusting the performance of fluorescent microspheres by modifying concentrations and carrier forms, allowing for tailored applications. It emphasizes the potential of fluorescent microsphere technology in revolutionizing nucleic acid detection and advancing health, disease treatment, and medical research.

Although studies on microplastics are increasing every year, still very little is known about their toxicity. Especially for plant species, even studies of uptake of microplastics are only few, not to mention phytotoxicity of microplastics. Therefore, we conducted a pilot study on the phytotoxicity of 1-μm-sized fluorescent microplastics (FMPs) on the free-floating aquatic plants Spirodela polyrhiza and Salvinia natans and the emergent aquatic plant Phragmites australis using 0.1% and 0.01% FMP treatment. Furthermore, uptake of FMPs by plants was verified by detecting fluorescence of FMPs by laser. A free-floating aquatic plant S. polyrhiza and emergent aquatic plant P. australis showed significantly decreased harvested biomass after 3 weeks indicating phytotoxicity of FMPs, but S. natans did not show any differences of harvested biomass or chlorophyll contents among treatments. Detection of fluorescence from plant leaves provided evidence of active FMPs uptake by plants. The emission spectra of plant leaves in 0.1% FMP treatment showed similar peaks to those of free fluorescent microplastics, providing a firm evidence of FMPs uptake by plants. This study is one of the pioneering studies to explore fluorescent microplastic uptake and toxicity in aquatic plants and therefore provides a baseline for further studies. [ABSTRACT FROM AUTHOR]

A simple and cost‐efficient method for fluorescent microsphere synthesis, which does not require any fluorescent monomers or modification steps to incorporate fluorescent moieties into the polymer particles, is reported. Using rhodamine B and benzophenone as bimolecular initiation system in type II photoinitiated precipitation polymerization, the method enables the preparation of fluorescent microspheres in one step, at room temperature and without the need for a stabilizer or surfactant of any type. [ABSTRACT FROM AUTHOR]

Performed gels are widely used in fields to support profile modification and Enhance Oil Recovery. Previous studies of profile modification of performed gels mainly used the index of pressure, resistance factor, or residual resistance factor to represent their ability. However, there is a lack of methods available to directly study their modification ability. In this article, the preformed gels with fluorescence properties, CQDs@PPG, would provide a new way to explore the profile modification of preformed gels. This paper uses poly (acrylamide, sodium p-styrene sulfonate), carbon quantum dots, and N,N-methylenebisacrylamide to prepare the CQDs@PPG via inverse emulsion polymerization. The morphology, size distribution, structure, fluorescence characteristics, surface potential thermal stability, viscosity changes, and viscoelastic properties of CQDs@PPG were analyzed. Moreover, the fluorescence properties of CQDs@PPG under different temperature, salinity, and pH were examined. Results indicate that the CQDs@PPG have excellent stability and that pH and salinity have little influence on their fluorescence properties. Further, only the temperature would affect the fluorescence properties of CQDs@PPG, but that effect is reversible after the temperature drops. By examining the fluorescence intensity, it would be more direct for researchers to study the profile modification in further experiments. [ABSTRACT FROM AUTHOR]

In contrast to small fluorescent molecules, fluorescent microspheres are easier to be modified and more stable. In this work, a novel fluorescent microsphere was obtained by ternary copolymerisation of maleic anhydride (MAn), vinyl acetate (VAc) and fluorescent monomer containing Rhodamine B group (FM-Rh B). The morphology, structure, composition and fluorescent performances of the fluorescent microspheres were characterised by scanning electron microscope, Fourier transform infrared spectrometer, UV–vis spectrophotometer, and fluorescence spectroscope. The results show that the surface of the fluorescent microspheres was smooth and free of impurities, which are conducive to its application in the fields of biology and medicine. The microspheres display good fluorescence properties under both blue and green light, which expands the application of these microspheres. It can emit strong fluorescence at 566 nm even in polar solvents. The size of the fluorescent microspheres is in the range of 184–1022 nm and can be controlled by changing polymerisation conditions. [ABSTRACT FROM AUTHOR]

Virulent Newcastle disease virus (NDV) as well as highly pathogenic avian influenza (HPAIV) subtypes H5 and H7 induce contagious and lethal systemic disease in poultry. In contrast, low pathogenic AIV H5 and H7 may circulate clinically unnoticed in poultry but eventually generate HPAIV. Low pathogenic NDV strains are widely used as live-attenuated vaccines against ND. Serological tools are essential to conduct active surveillance for infections with notifiable AIV-H5, -H7 and to control vaccination against NDV and HPAIV in poultry populations. Here, recombinant nucleocapsid proteins (NP) of AIV and NDV, and haemagglutinin protein fragment-1 (HA1) of AIV subtypes H5 and H7 were expressed in E. coli. Purification and refolding were required before coating fluorescent microspheres via streptavidin-biotin linkage. The tetraplexed inhibition fluorescent microsphere immunoassay (iFMIA) was then assembled for analysis on a Luminex®-like platform (Bioplex®) using murine monoclonal antibodies specific for each of the four targets. The assay was evaluated by testing galliform poultry sera derived from experimental infections (n = 257) and from farms (n = 250), respectively. The tetraplex iFMIA compared favorably with commercially available ELISAs and the "gold standard" hemagglutination inhibition assay. Tetraplexed iFMIA provided a specific and sensitive tool to detect and discriminate AIV- and NDV-specific antibodies in the sera of galliform poultry. [ABSTRACT FROM AUTHOR]

Microglia, the resident immune cells in the central nervous system, canmonitor the microenvironment and actively respond to ischemic stroke and other brain injuries. In this procedure, microglia and neurons can cross-talk via transmembrane chemokine, Fractalkine (CX3CL1), to impact one another. We used a rat model of multifocal microinfarcts induced by the injection of fluorescent microspheres into the right common carotid artery and examined the morphological alteration of blood vessels, microglia, astrocytes, and neurons at 6 h, 1, 7, and 14 days after modeling, along with neurobehavioral tests and the staining of CX3CL1 in this study. Our results demonstrated that in the infarcted regions, astrocytes and microglia activated in response to neuronal degeneration and upregulation of cleaved caspase-3, which occurred concurrently with vascular alteration and higher expression of CX3CL1. We provided sequential histological data to shed light on the morphological changes after modeling, which would help in the identification of new targets and the choice of the ideal time window for therapeutic intervention in ischemic stroke. [ABSTRACT FROM AUTHOR]

Copyright of Journal of East China University of Science & Technology is the property of Journal of East China University of Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pandemic of new coronary pneumonia caused by the COVID-19 virus continues to ravage the world. Large-scale population testing is the key to controlling infection and related mortality worldwide. Lateral flow immunochromatographic assay (LFIA) is fast, inexpensive, simple to operate, and easy to carry, very suitable for detection sites. This study developed a COVID-19 N protein detect strip based on p-toluenesulfonyl modified rare earth fluorescent microspheres. The p-toluenesulfonyl-activated nanomaterials provide reactive sulfonyl esters to covalently attach antibodies or other ligands containing primary amino or sulfhydryl groups to the nanomaterial surface. Antibodies are immobilized on these nanomaterials through the Fc region, which ensures optimal orientation of the antibody, thereby increasing the capture rate of the target analyte. The use of buffers with high ionic strength can promote hydrophobic binding; in addition, higher pH could promote the reactivity of the tosyl group. The detection limit of the prepared COVID-19 N protein strips can reach 0.01 ng/mL, so it has great application potential in large-scale population screening. [ABSTRACT FROM AUTHOR]

• We successfully developed and employed a novel approach for NGAL detection, utilizing NGAL monoclonal antibody (NGAL-McAb) conjugates with fluorescent microspheres. • The developed test strip demonstrated high accuracy in detecting low concentrations of NGAL proteins present in serum samples. • The test strip exhibited excellent linearity within a NGAL concentration range of 0–160 ng/mL, as evidenced by a strong R2 value of 0.9943. Neutrophil gelatinase-associated lipocalin (NGAL) has been identified by the International Nephrology Association (INA) as a promising biomarker for the early evaluation of renal injury. This study aimed to develop and evaluate NGAL test strips as a rapid, simple, and economical method for the early diagnosis of acute kidney injury (AKI). Recombinant prokaryotic expression vectors, purified NGAL protein, and anti-NGAL monoclonal antibodies were prepared. NGAL test strips were developed, and serum samples were collected from healthy individuals and patients with early-stage kidney injury at the Third Affiliated Hospital of Sun Yat-sen University between January 2023 and May 2024. Samples were tested using both the self-made strips and commercially available reagents. The NGAL test strip comprised a conjugate pad containing 0.2 μL of fluorescent microspheres conjugated with anti-NGAL monoclonal antibody (McAb7#), a test line containing 1 mg/mL of a different anti-NGAL monoclonal antibody (McAb3#), and a control line containing 0.5 mg/mL of goat anti-mouse IgG. The test utilized 60 μL of sample (30 μL serum diluted with 30 μL of sample diluent) and was completed within 15 min at 25 °C and 35 %-85 % relative humidity. The developed strip accurately detected NGAL, demonstrating good linearity within the range of 0–160 ng/mL (R2 = 0.9943). The sensitivity and specificity of the NGAL strip for AKI diagnosis were 86.1 % and 78.8 %, respectively, comparable to the performance of commercially available testing reagents. The developed test strip, utilizing anti-NGAL antibodies coupled with fluorescent microspheres, effectively detected trace amounts of NGAL protein in serum samples. [ABSTRACT FROM AUTHOR]

The novel polymer fluorescent microspheres (PS-TPY) based on styrene and terpyridine units were successfully synthesized via radical precipitation polymerization using ethanol and water as mixing dispersion medium. The structures and properties of the polymer microspheres were systematically investigated by NMR, IR, UV–vis absorption and fluorescence emission spectra. The average diameter of 380–630 nm for the resulted polymer microspheres was verified by dynamic light scattering (DLS) and scanning electron microscopy (SEM), and could be regulated effectively through changing the ratio of the monomers and the composition of the dispersion medium. The introducing of the conjugated terpyridine unit into the microspheres resulted into a distinct blue emission at about 360–430 nm wavelength. Based on the interaction between the transition metal ions and the terpyridine structure, these fluorescent polymer microspheres displayed high selectivity and sensitivity for probing Fe3+. [Display omitted] [ABSTRACT FROM AUTHOR]

Performed gels are widely used in fields to support profile modification and Enhance Oil Recovery. Previous studies of profile modification of performed gels mainly used the index of pressure, resistance factor, or residual resistance factor to represent their ability. However, there is a lack of methods available to directly study their modification ability. In this article, the preformed gels with fluorescence properties, CQDs@PPG, would provide a new way to explore the profile modification of preformed gels. This paper uses poly (acrylamide, sodium p-styrene sulfonate), carbon quantum dots, and N,N-methylenebisacrylamide to prepare the CQDs@PPG via inverse emulsion polymerization. The morphology, size distribution, structure, fluorescence characteristics, surface potential thermal stability, viscosity changes, and viscoelastic properties of CQDs@PPG were analyzed. Moreover, the fluorescence properties of CQDs@PPG under different temperature, salinity, and pH were examined. Results indicate that the CQDs@PPG have excellent stability and that pH and salinity have little influence on their fluorescence properties. Further, only the temperature would affect the fluorescence properties of CQDs@PPG, but that effect is reversible after the temperature drops. By examining the fluorescence intensity, it would be more direct for researchers to study the profile modification in further experiments.

Virulent Newcastle disease virus (NDV) as well as highly pathogenic avian influenza (HPAIV) subtypes H5 and H7 induce contagious and lethal systemic disease in poultry. In contrast, low pathogenic AIV H5 and H7 may circulate clinically unnoticed in poultry but eventually generate HPAIV. Low pathogenic NDV strains are widely used as live-attenuated vaccines against ND. Serological tools are essential to conduct active surveillance for infections with notifiable AIV-H5, -H7 and to control vaccination against NDV and HPAIV in poultry populations. Here, recombinant nucleocapsid proteins (NP) of AIV and NDV, and haemagglutinin protein fragment-1 (HA1) of AIV subtypes H5 and H7 were expressed in E. coli. Purification and refolding were required before coating fluorescent microspheres via streptavidin-biotin linkage. The tetraplexed inhibition fluorescent microsphere immunoassay (iFMIA) was then assembled for analysis on a Luminex®-like platform (Bioplex®) using murine monoclonal antibodies specific for each of the four targets. The assay was evaluated by testing galliform poultry sera derived from experimental infections (n = 257) and from farms (n = 250), respectively. The tetraplex iFMIA compared favorably with commercially available ELISAs and the “gold standard” hemagglutination inhibition assay. Tetraplexed iFMIA provided a specific and sensitive tool to detect and discriminate AIV- and NDV-specific antibodies in the sera of galliform poultry.

Abstract Background Influenza A and B viruses mainly cause respiratory infectious disease. Till now, few tests are able to simultaneously detect both, especially in primary medical establishments. Methods This study was designed to compare the performance of two different one-step-combined test strips for the detection of influenza A and B: one strip with fluorescent microspheres for tracers (FMT); and the other strip with colored microspheres for tracers (CMT). To test the strips, cultures of influenza A, B, and other pathogenic viruses were used, in addition to 1085 clinical specimens from symptomatic patients with respiratory infections. Real-time RT-PCR was also considered as a reference method used to detect the different results of FMT and CTM. Results Detection thresholds for influenza A and B cultures using serial dilutions revealed that the sensitivity of FMT was higher than that of CMT (both P

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract Background Rotavirus (RV) and enteric adenovirus (AdV) mainly cause infantile infectious gastroenteritis. Several separate test methods for the detection of RV or AdV are currently available, but few tests are able to simultaneously detect both RV and AdV viruses, especially in primary medical institutions. Methods The present study was mainly designed to compare the performance of two combined test strips for the detection of RV and AdV: a rotavirus–adenovirus strip with fluorescent microspheres for tracers (FMT); and the CerTest rotavirus–adenovirus blister strip with colored microspheres for tracers (CMT). To test the strips cultures of RV, AdV and from other enteric pathogens were used, in addition to 350 stool specimens from 45 symptomatic patients with gastrointestinal infections. Results Detection thresholds for RV and AdV cultures using serial dilutions showed that the sensitivity of FMT was significantly higher than that of CMT (both P

Fluorescent microspheres (FMs) are widely employed in diagnostics and life sciences research; here, we investigated the effect of capillary coating, polymer concentration, electric field strength, and sample concentration on the separation performance of 1.0 μm FMs in hydroxyethyl cellulose (HEC) by capillary electrophoresis (CE). Results showed that (1) capillary coating could enhance the fluorescence signal. (2) For HEC with the same molecular weight, the higher HEC concentration is, the later the first peak appears in the electropherogram. (3) When FMs are diluted, increasing the electric field strength can enhance the migration speed and reduce the aggregation of FMs. (4) The number of FMs calculated is close to the theoretical value when it is diluted 10,000 times. The optimum conditions for CE were as follows: 6 cm/8 cm of effective length and total length of the coated capillary, 0.3% HEC (1300 k), and 300 V/cm of electric field strength. Such a study is helpful for the development of a FM counting system. [ABSTRACT FROM AUTHOR]

[Display omitted] • A CFMs-based RFP was proposed for ultrasensitive sensing of AO. • Dual-emissive CFMs were prepared by loading CDs into MF microspheres. • A smartphone-integrated paper device were prepared for AO visualization. A paper-based assay for visualization of auramine O (AO) was for the first time established by using CFMs as a ratiometric fluorescent probe (RFP). The CFMs were melamine formaldehyde microspheres (MFMs) incorporated with carbon dots (CDs), where the CDs species as sensing units and MFMs as a signal amplification carrier. The proposed RFP can quantitatively measure AO content from 0.0 to 10.0 μM and exhibited an ultralow limit of detection (LOD, 15.7 nM). In particular, obvious luminescence color change of CFMs from blue to green was perceived with naked-eyes and therefore, a solution-based and a paper-based visualization platform were respectively proposed for on-site visual detection of AO with LODs of 1.15 μM and 0.83 μM, separately. Finally, those fluorescence methods were adopted in sensitively quantitative measurement of AO within various food and drug samples, providing new prospects for analysts and technical support in food quality monitoring. [ABSTRACT FROM AUTHOR]

Aflatoxin B1 (AFB1) is a toxic compound naturally produced by the genera Aspergillus. Distillers’ grains can be used as animal feed since they have high content of crude protein and other nutrients. However, they are easily contaminated by mycotoxins, and currently there are no rapid detection methods for AFB1 in distillers’ grains. In this study, a lateral flow immunoassay (LFIA) based on red fluorescent microsphere (FM), is developed for quantitative detection of AFB1 in distillers’ grains. The whole test can be completed within 15 min, with the cut-off value being 25.0 μg/kg, and the quantitative limit of detection (qLOD) being 3.4 μg/kg. This method represents satisfactory recoveries of 95.2–113.0%, and the coefficients of variation (CVs) are less than 7.0%. Furthermore, this technique is successfully used to analyze AFB1 in real samples, and the results indicates good consistency with that of high-performance liquid chromatography (HPLC). The correlation coefficient is found to be greater than 0.99. The proposed test strip facilitates on-site, cost-effective, and sensitive monitoring of AFB1 in distillers’ grains.

Abstract Multiple miRNA detection is often limited by sample, time-consuming, and complicated procedures. To address such challenges, we present a relatively simple and amplification-free fluorescent strategy based on hybridization-initiated exonuclease resistance for simultaneous detection of multiple miRNAs in a single tube. Single-stranded linear DNA probes were designed with dual roles of capture and reporter DNA, i.e. each DNA probe was labeled with biotin at the 3′-end for signal readout and amino at the 5′-end for probe immobilization. After target miRNAs specifically hybridized with the corresponding probes, the formation of double-stranded probe-target duplex protected the biotin on the probe from Exonuclease I digestion, thus resulting in high fluorescent intensities through the reaction between biotin and streptavidin-phycoerythrin. Coupling with the 3-plex fluorescent microsphere-based assay system, herein we successfully demonstrated the simultaneous and quantitative measurement of three sequence-specific miRNAs at concentration range of 2.5 pM to 1.25 nM and detection limits of 2 pM. To meet high throughput and rapid turnaround time requirements, we have also exemplified that, even shortening the total reaction time within 1 h, wider linear response range and lower detection limit were guaranteed. We further applied this assay to detect endogenous target miRNA levels from five kinds of cancer cell line and one normal cell line HEK 293T. This simple and rapid strategy will hold great potential for monitoring of multiple miRNAs biomarkers in biomedical research and early clinical diagnosis. Graphical abstract fx1 Highlights • A multiple miRNAs detection assay based on the hybridization-initiated exonuclease resistance strategy and xMAP array. • One single-stranded linear probe with dual roles of capture and reporter DNA. • Simultaneous detection of miR-21, miR-155 and miR-141 in cell lysates. [ABSTRACT FROM AUTHOR]

Abstract: With water-soluble CdTe quantum Dots (QDs) as fluorescent labels and TEMPO-oxidized cellulose nanofibrils (CNF) as matrix, dual-color QD-encoded microspheres were prepared by mechanical spraying, freeze-molding and subsequent electrostatic cross-linking by calcium ion. The entire preparation process was accomplished in aqueous phase without any chemical treatment. The nanocellulose microspheres possessed porous structure and were able to be dispersed stably in water in the form of hydrogels. CdTe QDs were efficiently fixed in the network of intertwined nanofibrils via hydrogen bonding with CNF, making the microspheres to obtain high photoluminescence (PL) intensity and identifiable encoding signals consisting of seven kinds of microsphere arrays. The crystalline structure and chemical composition of both CdTe QDs and CNF were not affected during the preparation process. The comparision of PL behaviors of CdTe QDs and QD-encoded microspheres in different media indicate that CNF matrix provided good protection of QDs and improved the PL intensity and photostability.Graphical Abstract: Dual-color CdTe-encoded nanocellulose microspheres were prepared via pure physical process in aqueous phase. The fluorescent microspheres possessed high photoluminescence intensity and identifiable seven kinds of encoding signals. The nanocellulose matrix provided good protection of CdTe QDs and improved the photoluminescence intensity and photostability. [ABSTRACT FROM AUTHOR]

Two different fluorescent block copolymers of poly(lactic acid) (PLA) and polyethylene glycol (PEG) containing fluorescein grafted to the polymer chain were synthesized by Ugi four-component condensation (UFCC). The structure of these PEG-PLA copolymers was confirmed by 1H-NMR and fluorescence spectroscopy. Paclitaxel-loaded fluorescent microspheres (PCT-FMS1 and PCT-FMS2) were prepared from them by the single-emulsion solvent evaporation method. A kinetic study of drug release in vitro using high-performance liquid chromatography showed a prolonged and controlled release of paclitaxel. Anticancer activity of release medium against colorectal cancer cell line (Caco-2) was determined using the cell viability assay. Paclitaxel-loaded microspheres were able to inhibit cancer cell growth and colony formation. The main contribution of this work is to propose a new application for UFCC in the preparation of biomasked fluorescent drug delivery systems able to improve cancer treatment. [ABSTRACT FROM AUTHOR]

As the popularity of marine aquaria grows, the potential exists for increased harvest of marine ornamental fishes and invertebrates from the oceans around the world. Aquaculture may be an alternative source to wild capture fisheries if commercial production protocols can be developed for species of interest, however numerous impediments must be overcome. Experiments were conducted on the reef butterflyfish ( Chaetodon sedentarius ), Pacific blue tang ( Paracanthurus hepatus ), African moony ( Monodactylus sebae ) and golden trevally ( Gnathanodon speciosus ) to evaluate and define prey preferences at first feeding among the rotifer, Brachionus plicatiilis , the copepod, Parvocalanus crassirostris , and the ciliate Euplotes sp., by marking each prey with a different colored fluorescent microsphere. Prey preferences observed at the larval first feeding stage were species specific. Pacific blue tang larvae preferred rotifers above ciliates, and ciliates above copepod nauplii. African moony larvae preferred ciliates and nauplii equally over rotifers. Reef butterflyfish larvae preferred ciliates over rotifers and rotifers over nauplii. Golden trevally larvae preferred nauplii over ciliates, and ciliates over rotifers. Take together these data provide critical information which may aid in development of feeding protocols for marine ornamental species. [ABSTRACT FROM AUTHOR]

Nicotinamide has been shown to affect blood flow in both tumor and normal tissues, including skeletal muscle. Intraperitoneal injection of nicotinamide was used as a simple intervention to test the sensitivity of noninvasive diffuse correlation spectroscopy (DCS) to changes in blood flow in the murine left quadriceps femoris skeletal muscle. DCS was then compared with the gold-standard fluorescent microsphere (FM) technique for validation. The nicotinamide dose-response experiment showed that relative blood flow measured by DCS increased following treatment with 500 and 1000-mg&/kg nicotinamide. The DCS and FM technique comparison showed that blood flow index measured by DCS was correlated with FM counts quantified by image analysis. The results of this study show that DCS is sensitive to nicotinamide-induced blood flow elevation in the murine left quadriceps femoris. Additionally, the results of the comparison were consistent with similar studies in higher-order animal models, suggesting that mouse models can be effectively employed to investigate the utility of DCS for various blood flow measurement applications. [ABSTRACT FROM AUTHOR]

Abstract: g‐C3N4 has been found to be highly functional in many fields, such as photocatalysis, electrocatalysis, and chemical analysis. Pickering emulsion polymerization is a fascinating strategy to fabricate a range of nanomaterials, in which the emulsion is stabilized by solid particles, rather than molecular surfactants. Herein, we demonstrate that g‐C3N4 can act as a remarkable stabilizer for Pickering emulsion polymerization. Contrary to normal Pickering systems, monodisperse polystyrene microspheres with tunable size, surface charge, and morphology were achieved using this approach. Importantly, the g‐C3N4 hybridized latex is highly processable and has exhibited multiple functions: manufacture of photonic crystals via self‐organization, stabilizing Pickering emulsion owing to proper wettability, and acting as bioimaging agents with enriched fluorescent colors. Considering the easy synthesis and low cost of g‐C3N4, our approach has a high potential for scale‐up synthesis and practical translation. [ABSTRACT FROM AUTHOR]

Nucleic acid-based tests have a profound impact in every medical discipline. Because multigene tests offer higher diagnostic accuracy and lower overall cost than single assays, they are especially useful for diseases, like prostate cancer, that present variability at the molecular level and diversity of available therapeutic interventions. We have developed a quantitative competitive PCR for an eight-gene panel, related to prostate cancer, that includes five genes of the human tissue kallikrein family ( KLKs), prostate-specific membrane antigen (PSMA), prostate cancer antigen 3 ( PCA3), and HPRT1 as a reference gene. Using PCR as a synthetic tool, a competitor was prepared for each target sequence containing the same primer binding sites as the target but differing in a short segment to enable discrimination by hybridization. The assay involves multiplex amplification of targets and competitors followed by a multiplex hybridization assay for the 16 amplification products. The assay was performed on optically encoded microspheres with oligonucleotide probes attached to their surface. The microspheres were analyzed rapidly (1 min) by flow cytometry. The signal ratio of the target and cognate competitor is a function of the target copy number in the sample prior to amplification. The multiplexing potential of the proposed method is much higher than real-time PCR and other end-point methods since there are 100 sets of commercially available microspheres. [ABSTRACT FROM AUTHOR]

Conjugating the EDC activated fluorescent microspheres with antibody to prepare the fluorescence chromatographic strip for simultaneous detection of tPSA and fPSA. The performance analysis and methodological comparison for the test strip were further performed. The results showed that the sensitivity for PSA and fPSA detection by the test strip were 0.08 ng/mL and 0.06 ng/mL, respectively. The coefficient of variation within and between groups was less than 10% and 15%, respectively. The recovery rates ranged from 95% to 105%. The specificity of the test strip was well. The results revealed a good correlation between self-prepared test strip and electrochemiluminescence detection, which could satisfy the needs of aided diagnosis of small- scale hospitals. [ABSTRACT FROM AUTHOR]

We use many types of equipment and technologies to make our measurements but give little thought to how they developed. Evolution was once described as a series of recoils from blind alleys, and this is exemplified by the gradual development of the microsphere method of measuring blood flows. The microsphere method is one of the most frequently used methods for measuring blood flow to organs and portions of organs. The method can measure myocardial blood flow with reasonable accuracy (within 10%) down to samples weighing >50 mg but probably will not do so for samples weighing 1-10 mg. Microspheres with diameters from 10 to 15 μm provide the best compromise between accurate flow measurement and retention in tissue. Radioactive labels have been almst entirely replaced by fluorescent labels, but colored microspheres and neutron-activated labels are also used. [ABSTRACT FROM AUTHOR]

Background: In vivo determination of regional pulmonary blood flow (PBF) is a valuable tool for the evaluation of many lung diseases. In this study, the use of Ga-DOTA PET for the in vivo quantitative determination of regional PBF is proposed. This methodology was implemented and tested in healthy pigs and validated using fluorescent microspheres. The study was performed on young large white pigs ( n = 4). To assess the reproducibility and consistency of the method, three PET scans were obtained for each animal. Each radiotracer injection was performed simultaneously to the injection of fluorescent microspheres. PBF images were generated applying a two-compartment exchange model over the dynamic PET images. PET and microspheres values were compared by regression analysis and Bland-Altman plot. Results: The capability of the proposed technique to produce 3D regional PBF images was demonstrated. The correlation evaluation between Ga-DOTA PET and microspheres showed a good and significant correlation ( r = 0.74, P < 0.001). Conclusions: Assessment of PBF with the proposed technique allows combining the high quantitative accuracy of PET imaging with the use of Ga/Ge generators. Thus, Ga-DOTA PET emerges as a potential inexpensive method for measuring PBF in clinical settings with an extended use. [ABSTRACT FROM AUTHOR]

Digital analysis is an effective single-molecule detection method and has attracted extensive attention in the field of bioassays. However, most digital assays require microchambers for signal compartmentalization. Herein, we developed a microchamber-free and enzyme-free digital assay by labeling paramagnetic beads directly with ultrabright fluorescent microspheres. In this assay, a DNA sandwich analysis was firstly performed on the bead to label a fluorescent microsphere. Then, the beads were loaded on the glass slide to form a monolayer film for signal readout. The whole analysis process does not require the participation of enzymes and the preparation of microchambers, which greatly simplifies the experimental steps and saves the costs. Furthermore, by introducing non-enzymatic hybridization chain reaction (HCR) and biotinylated DNA-conjugated gold nanoparticles (Au NPs-Bio), the capture efficiency and analytical sensitivity were improved. As a proof of concept, single-stranded DNA (ssDNA) of SARS-CoV-2 fragment was chosen as a model, and a detection limit of 1.5 fM was achieved. Spiked and recovery experiments on human serum and saliva samples validated the good performance of the proposed digital assay in real biological samples. The proposed assay provides a facile way of signal generation and readout for digital analysis. • A microchamber-free digital assay was developed. • A digital assay that does not require the involvement of enzymes was achieved. • The discrimination between positive and negative beads in digital assay was improved. • A facile way of signal generation and readout for digital analysis was proposed. [ABSTRACT FROM AUTHOR]

Tilmicosin has been widely used in the dairy industry, but this compound is hazardous to human health. Therefore, it is urgent to develop a rapid, convenient, sensitive, cost-effective, and user-friendly method to determine tilmicosin. A fluorescent microsphere-based immunochromatographic assay was developed for this analyte. A 200-nm red fluorescent microspheres were selected to be the label, and the mass of the labeled antibody was 4.48 µg/mL. 1-Ethyl-3- (3-dimethylaminopropyl)-carbodiimide was used to catalyze carboxyl groups on the surface of the microspheres. The optimum reaction time between the antibodies and fluorescent microspheres was 30 min, and under these conditions, high coupling ratios and stable conjugations were obtained. The linear dynamic range of the developed protocol was from 0.02 to 2.10 µg/L. The half maximal inhibitory concentration was 0.19 µg/L. The recoveries were from 87 to 98% with a coefficient of variation less than 7.14%. In comparison with a colloidal gold immunochromatographic assay, the developed method offered a higher coupling rate, lower amounts of antibodies, and higher sensitivity. This approach is simple, sensitive, and suitable for on-site applications on farms for rapid screening. [ABSTRACT FROM AUTHOR]