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In this work, SiO2/CNTs photonic crystal beads were constructed by doping CNTs into SiO2 photonic crystals, which have an angle-independent responsive structural color and can be used as bipolar electrodes due to their good electrical conductivity. In addition, the bipolar electrode-electrochemiluminescence (BPE-ECL) experiments and finite element simulation prove that the low driving voltage can trigger the bipolar electrode electrochemical reactions by confinement effect. Inspired by this, it is the first to combine the SiO2/CNTs structural color coding scheme with low-drive voltage induced wireless BPE-ECL imaging based on the confinement effect of microchannels to achieve simultaneous immune detection of ovarian cancer biomarkers (CA125, CEA, AFP). The detection limits of successfully constructed high-throughput BPE-ECL biosensor for AFP, CEA, and CA125 are 0.72 ng/mL, 0.95 ng/mL, and 1.03 U/mL, respectively, and have good stability and specificity, which expands the application of electrochemiluminescence and lays a foundation for the development of electrochemiluminescence coding technology.
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Baijiu, a traditional Chinese alcoholic beverage, carries China's rich historical and cultural heritage. Consumers experience varying levels of relaxation and pleasure after consuming different types of Baijiu, with the biological basis of delectation influenced by serotonin and dopamine. In this study, we prepared carbon fiber electrodes modified with surface decorated gold nanoparticles to directly measure the electrochemical response signals in the serum of mice before and after gavage with different types of Baijiu. It was observed that the serum signal change in mice after consuming Baijiu sample 1 (J1) was higher than that of the other two types of Baijiu. Consequently, trace flavor compounds in the Baijiu samples were detected using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), revealing the highest content of L-lactic acid in J1. Mice were intraperitoneally injected with 200 mg kg-1 of L-lactic acid. The changes in dopamine and serotonin in the serum of the injected mice were monitored using a biosensor, and the results were compared with the results of high performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-MS). The findings confirmed that L-lactic acid could indeed stimulate the secretion of both neurotransmitters in mice, suggesting that the trace components in J1 may even exhibit synergistic effects. This study contributes to a deeper understanding of the effects of Baijiu on the body and provides a scientific basis for the production and consumption of Baijiu.
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Constructing versatile metal nanoclusters (NCs) assemblies through noncovalent weak interactions between inter-ligands is a long-standing challenge in interfacial chemistry, while compelling interfacial hydrogen-bond-driven metal NCs assemblies remain unexplored so far. Here, the study reports an amination-ligand o-phenylenediamine-coordinated copper NCs (CuNCs), demonstrating the impact of interfacial hydrogen-bonds (IHBs) motifs on the luminescent behaviors of metal NCs as the alteration of protic solvent. Experimental results supported by theoretical calculation unveil that the flexibility of interfacial ligand and the distance of cuprophilic CuI···CuI interaction between intra-/inter-NCs can be tailored by manipulating the cooperation between the diverse IHBs motifs reconstruction, therewith the IHBs-modulated fundamental structure-property relationships are established. Importantly, by utilizing the IHBs-mediated optical polychromatism of aminated CuNCs, portable visualization of humidity sensing test-strips with fast response is successfully manufactured. This work not only provides further insights into exploring the interfacial chemistry of NCs based on inter-ligands hydrogen-bond interactions, but also offers a new opportunity to expand the practical application for optical sensing of metal NCs.
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Infection with drug-resistant bacteria poses a significant threat to human health. Judicious use of antibiotics could reduce the likelihood of bacterial resistance, which can be evaluated through antibiotic susceptibility testing (AST). This paper focuses on the application of a needle-like nanocapillary tip filled with chitosan (CS)/polyethylene pyrrolidone (PVP) hydrogel based on its specific pH-sensitive properties. The gel-filled nanocapillary has the potential to be used for electrical pH detection with a sensitivity of 3.06 nA/pH and a linear range from 7.3 to 4.3. Such sensitivity for pH measurement could be extended for monitoring of bacterial (such as Escherichia coli and Streptococcus salivarius) growth because of the relationship between pH and bacterial growth. Bacterial growth curves obtained using the hydrogel-filled nanocapillary showed good agreement with the OD600 method. Moreover, this device could be applied for rapid AST for tetracycline and norfloxacin on E. coli with minimum inhibitory concentrations of 2 and 0.125 µg/mL, respectively. This study expands the application of the hydrogel-based nanocapillary for bacterial research by monitoring changes in pH values.
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Antibacterianos , Quitosana , Escherichia coli , Hidrogéis , Testes de Sensibilidade Microbiana , Quitosana/química , Quitosana/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Hidrogéis/química , Hidrogéis/farmacologia , Concentração de Íons de Hidrogênio , Povidona/química , Povidona/farmacologiaRESUMO
Limited light absorption and rapid photo-generated carriers' recombination pose significant challenges to the practical applications of photocatalysts. In this study, we employed an efficient approach by combining the slow-photon effect with Z-scheme charge transfer to enhance the photo-degradation performance of antibiotics. Specifically, we incorporated 0D ZnIn2S4 quantum dots (QDs) into a 3D hierarchical inverse opal (IO) TiO2 structure through a facile one-step process. This combination enhanced the visible light absorption and provided abundant active surfaces for efficient photo-degradation. Moreover, the ZnIn2S4 QDs formed an artificial Z-scheme system with IO-TiO2, facilitating the separation and migration of charge carriers. To achieve a better band alignment with IO-TiO2, we doped Ag into the ZnIn2S4 QDs (Ag: ZIS QDs) to adjust their energy levels. Through an investigation of the different Ag contents in the ZnIn2S4 QDs, we found that the optimal photo-degradation performance was achieved with Ag (2.0): ZIS QDs/IO-TiO2, exhibiting degradation rates 19.5 and 14.8 times higher than those of ZnIn2S4 QDs and IO-TiO2, respectively. This study provides significant insights for elevating the photocatalytic capabilities of IO-TiO2 and broadening its prospective applications.
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Lower light absorption and faster carrier recombination are significant challenges in photocatalysis. This study introduces a novel approach to address these challenges by anchoring cadmium sulfide quantum dots (CdS QDs) on inverse opal (IO)-TiO2, which increases light absorption and promotes carriers' separation by coupling slow-photon effect with Z-scheme charge transfer. Specifically, the IO-TiO2 was created by etching a polystyrene opal template, which resulted in a periodic structure that enhances light absorption by reflecting light in the stop band. The size of CdS quantum dots (QDs) was regulated to achieve appropriate alignment of energy bands between CdS QDs and IO-TiO2, promoting carrier transfer through alterations in charge transfer modes and resulting in synergistic-amplified photocatalysis. Theoretical simulations and electrochemical investigations demonstrated the coexistence of slow-photon effects and Z-scheme transfer. The system's photodegradation performance was tested using rhodamine B as a model. This novel hierarchical structure of the Z-scheme heterojunction exhibits degradability 7.82 and 4.34 times greater than pristine CdS QDs and IO-TiO2, respectively. This study serves as a source of inspiration for enhancing the photocatalytic capabilities of IO-TiO2 and broadening its scope of potential applications.
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Recently, there has been an upsurge in the extent to which electrochemiluminescence (ECL) working in synergy with bipolar electrochemistry (BPE) is being applied in simple biosensing devices, especially in a clinical setup. The key objective of this particular write-up is to present a consolidated review of ECL-BPE, providing a three-dimensional perspective incorporating its strengths, weaknesses, limitations, and potential applications as a biosensing technique. The review encapsulates critical insights into the latest and novel developments in the field of ECL-BPE, including innovative electrode designs and newly developed, novel luminophores and co-reactants employed in ECL-BPE systems, along with challenges, such as optimization of the interelectrode distance, electrode miniaturization and electrode surface modification for enhancing sensitivity and selectivity. Moreover, this consolidated review will provide an overview of the latest, novel applications and advances made in this field with a bias toward multiplex biosensing based on the past five years of research. The studies reviewed herein, indicate that the technology is rapidly advancing at an outstanding purse and has an immense potential to revolutionize the general field of biosensing. This perspective aims to stimulate innovative ideas and inspire researchers alike to incorporate some elements of ECL-BPE into their studies, thereby steering this field into previously unexplored domains that may lead to unexpected, interesting discoveries. For instance, the application of ECL-BPE in other challenging and complex sample matrices such as hair for bioanalytical purposes is currently an unexplored area. Of great significance, a substantial fraction of the content in this review article is based on content from research articles published between the years 2018 and 2023.
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Técnicas Biossensoriais , Medições Luminescentes , Eletroquímica/métodos , Medições Luminescentes/métodos , Fotometria , Técnicas Biossensoriais/métodos , Eletrodos , Técnicas Eletroquímicas/métodosRESUMO
To combat the ongoing threat posed by severe fever with thrombocytopenia syndrome virus (SFTSV), especially in underserved areas, there is an urgent need for an affordable and reliable point-of-care diagnostic tool. This study presents a carbon black-based immunochromatographic test strip (CB-ICTS) for the detection of SFTSV, which is both quick and easy to operate. The study optimized the specific steps for carbon black-labeled antibodies, as well as the amount of carbon black and anti-SFTSV antibody used. Under optimal experimental conditions, the linear range and limit of detection of the CB-ICTS were evaluated using different concentrations of SFTSV standard samples. The detection range of the CB-ICTS for SFTSV was found to be 0.1-1000 ng mL-1, with a limit of detection of 100 pg mL-1. The precision and accuracy of the CB-ICTS were assessed by examining spiked healthy human serum samples, which displayed recoveries ranging from 91.58 to 105.4% with a coefficient of variation of less than 11%. This work evaluated the specificity of the CB-ICTS using various biomarkers (CA125, AFP, CA199, CEA, and HCG) and demonstrated that the CB-ICTS is highly specific for detecting SFTSV, suggesting its potential for the early diagnosis of SFTSV. In addition, the study evaluated the CB-ICTS in serum samples from patients with SFTSV, and the results were highly consistent with those detected by the polymerase chain reaction (PCR) method. Overall, this study demonstrates the feasibility and effectiveness of using the CB-ICTS as a reliable point-of-care diagnostic tool for the early detection of SFTSV.
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Colorimetria , Febre Grave com Síndrome de Trombocitopenia , Fuligem/química , Colorimetria/métodos , Febre Grave com Síndrome de Trombocitopenia/diagnóstico , Febre Grave com Síndrome de Trombocitopenia/virologia , Cromatografia de Afinidade/métodos , Anticorpos Monoclonais/imunologiaRESUMO
Magnetic quantum dot (QD) barcode holds great potential for automatic suspension array and rapid point-of-care detection since it enables simultaneous target encoding, enrichment and separation. However, a serious obstacle to enhancing the encoding capacity of magnetic QD microbeads (MBs) is the fluorescence quenching of magnetic nanoparticles (MNPs) to quantum dots (QDs) in the visible wavelength range due to the broad and strong optical absorption spectrum of MNPs. Here, we report Fe3O4/TiO2 core/shell MNPs and CdSe/ZnS QDs for the construction of dual-function magnetic QD barcodes. Fe3O4/TiO2 MNPs can significantly inhibit fluorescence quenching because the weak absorption of visible light by the TiO2. The two-dimension barcode library of 30 magnetic QD barcodes was constructed based on Fe3O4/TiO2 MNPs and CdSe/ZnS QDs. Moreover, the magnetic QD barcodes showed high sensitivity for the multiplex detection of four tumor markers, cancer antigen 125 (CA125), cancer antigen 199 (CA199), alpha-fetoprotein (AFP), and neuron specific enolase (NSE) with detection limits of 0.89 KU/L, 0.72 KU/L, 0.05 ng/mL, and 0.15 ng/mL, respectively. This bifunctional magnetic QD barcodes are promising for automatic high-sensitivity multiplex bioassay.
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Técnicas Biossensoriais , Pontos Quânticos , Biomarcadores Tumorais , Fenômenos MagnéticosRESUMO
In general, co-reactants are essential in highly efficient electrochemiluminescence (ECL) systems. Traditional co-reactants are usually toxic, so it is necessary to develop new environmentally friendly co-reactants. In this work, carbon dots (CDs) were assembled with dendritic silica nanospheres (CDs@dSiO2 NPs) to form a co-reactant of Ru(bpy)32+. Subsequently, a sandwich immunosensor for detecting human chorionic gonadotropin (HCG) was constructed based on CDs@dSiO2 NPs as co-reactants, the nanoprobe loaded with the secondary antibody, and Ru(bpy)32+ as a luminophore. In addition, compared to directly as a signal probe, the luminophore Ru (bpy)32+ as a part of the electrolyte solution is simpler in this work. The immunosensor has an extremely low limit of detection of 0.00019 mIU/mL. This work describes the synthesis of low-toxic, efficient, and environmentally friendly CDs, which have become ideal co-reactants of Ru(bpy)32+, and proposes an ECL immunosensor with excellent stability and selectivity, which has great potential in clinical applications.
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Técnicas Biossensoriais , Nanopartículas Metálicas , Humanos , Carbono , Imunoensaio , Medições Luminescentes , Técnicas Eletroquímicas , Limite de DetecçãoRESUMO
Fluorescent lateral flow immunoassay (FLFIA) is widely used mainly because of its low cost and instant detection. Its limit of detection (LOD) is closely related to fluorescence signals, and the development of fluorescence signals with fine performance remains a challenge. In this work, dendritic mesoporous silica nanoparticles (DMSNs) were used as fine carriers due to their large pore size and stable performance. We successfully synthesized carbon dots (CDs) with a 560 nm maximum emission wavelength (CD560) by the hydrothermal method. A new type of fluorescence signal for FLFIA was observed by loading CD560 on DMSNs through the Si-O bond which is denoted as DMSNs@CD560. Applying DMSNs@CD560 to the FLFIA can eliminate the influence of interfacial background blue fluorescence thus improving its detection sensitivity. The formed DMSNs@CD560-FLFIA achieved high sensitivity detection of ovarian cancer biomarkers carbohydrate antigen 125 (CA125) and human epididymal protein 4 (HE4). The LOD of CA125 is 0.5 U mL-1 and the correlation coefficient R2 = 0.985, and the LOD of HE4 reaches 0.05 ng mL-1 and the correlation coefficient R2 = 0.981. The DMSNs@CD560-FLFIA is sensitive and efficient providing a new method for the early diagnosis of ovarian cancer.
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Nanopartículas , Neoplasias Ovarianas , Feminino , Humanos , Biomarcadores Tumorais , Antígeno Ca-125 , Carbono/química , Imunoensaio/métodos , Neoplasias Ovarianas/diagnóstico , Sensibilidade e EspecificidadeRESUMO
The sensitivity of fluorescent lateral flow immunoassay (LFIA) test strips is compromised by the low fluorescence intensity of the signaling molecules. In this study, we synthesized novel phosphorus-doped carbon-dot-based dendritic mesoporous silica nanoparticles (DMSNs-BCDs) with a quantum yield as high as 93.7% to break this bottleneck. Meanwhile, the in situ growth method increased the loading capacity of carbon dots on dendritic mesoporous silica, effectively enhancing the fluorescence intensity of the composite nanospheres. Applied DMSNs-BCDs in LFIA can not only semi-quantitatively detect a single component in a short time frame (procalcitonin (PCT), within 15 min) but also detect the dual components with a low limit of detection (LOD) (carbohydrate antigen 199 (CA199) LOD: 1 U/mL; alpha-fetoprotein (AFP) LOD: 0.01 ng/mL). And the LOD of PCT detection (0.01 ng/mL) is lower by 1.7 orders of magnitude compared to conventional colloidal gold strips. For CA199, the LOD is reduced by a factor of four compared to LFIA using gold nanoparticles as substrates, and for AFP, the LOD is lowered by two orders of magnitude compared to colloidal gold LFIA. Furthermore, the coefficients of variation (CV) for intra-assay and inter-assay measurements are both less than 11%.
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Nanopartículas Metálicas , alfa-Fetoproteínas , Ouro , Corantes , Carbono , Coloide de Ouro , ImunoensaioRESUMO
The timelier and more accurate the diagnosis of the disease, the higher the patient's survival rate. Human epididymal protein 4 (HE4) has great significance as a biomarker of concern for reflecting ovarian cancer. Herein, we prepared a novel optical label that can be used in lateral-flow immuno-dipstick assay (LFIA) for sensitive visual detection of HE4 by implanting hydrophobic gold nanoparticles (Au NPs) at high density in Mg/Fe LDH nanoflowers (MF NFs). MF NFs with large specific surface area, high porosity, abundant active binding sites, and stable structure were employed for the first time as templates to directly anchor Au NPs in the organic phase. After simple modification with an optimized amount of branched polyethyleneimine, not only could MF@Au NFs be dispersed in the aqueous phase, but also amino functional groups were introduced on its surface to facilitate subsequent antibody coupling steps. The limit of detection reaches 50 pM with a detection range of 50 to 1000 pM. This work initially explored how MF NFs can be used to load signal labels with ideal stability and signal amplification capabilities, which greatly improves the practicability of LFIA and highlights its important role in the field of rapid diagnostics.
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Ouro , Nanopartículas Metálicas , Humanos , Ouro/química , Nanopartículas Metálicas/química , Polietilenoimina , Limite de Detecção , Íons , Eletrólitos , ImunoensaioRESUMO
Photonic crystals (PCs) have emerged as a promising electrochemiluminescence (ECL) matrix in the domain of immunoassay. Making maximum use of light manipulation properties of PCs is highly desired for improving the sensitivity. In this work, we proposed a band-edge effect-induced ECL enhancement strategy based on silica inverse opal PCs (SIOPCs). By fine-tuning the lattice constant and carefully calibrating the stopband position, we found that the band edge of the stopband exerted significant influences on the ECL intensity and spectral distribution. The high density of states at the blue edge of the photonic band gap increased the radiative transition probability of ECL emitters and enhanced the photon extraction during propagation, giving rise to â¼20-fold ECL signal amplification accompanied by a redistributed ECL spectrum for the Ru(bpy)32+-TPrA system. In combination with the intrinsic structural superiority, like large specific surface area and interconnected macropores, the developed SIOPC electrode was successfully applied in constructing a sandwich-type immunosensor. The fabricated immunosensor displayed a very low detection limit of 0.032 pg/mL and a wide linear range of 0.1 pg/mL-150 ng/mL for a carcinoembryonic antigen assay, showing its potential application in disease diagnosis.
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Técnicas Biossensoriais , Antígeno Carcinoembrionário , Técnicas Eletroquímicas , Imunoensaio , Limite de Detecção , Medições Luminescentes , Dióxido de Silício/químicaRESUMO
Direct synthesis of carbon dots on uniform mesoporous nanospheres is an ideal way to impart fluorescence properties to the nanomaterials and retain its original uniformity. Carbon dot-based nanospheres with high quantum yield (aqueous solution, 89.3%) were synthesized by the one-step hydrothermal treatment of sodium citrate and dendritic silica spheres grafted with N-ß-(aminoethyl)-γ-aminopropyltrimethoxysilane. Its excellent chemical properties such as fluorescence, stability, homogeneity and dispersion enable it to achieve a sensitive, specific, rapid and low-cost detection of anthrax protective antigen when used as a signal for immunochromatography.
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Nanosferas , Pontos Quânticos , Antígenos de Bactérias , Toxinas Bacterianas , Carbono , Nanosferas/química , Dióxido de Silício/químicaRESUMO
Early diagnosis of tumor markers is of great importance for the successful treatment of cancer. As a high-throughput and high-sensitivity detection technology, liquid suspension biochips based on quantum dot (QD) encoded microspheres have been widely used in the immunodetection of tumor markers. In this work, maleic anhydride grafted PLA (PLA-MA) microspheres based on quantum dot encoding were used as carriers for liquid phase suspension biochips for the immunoassay of tumor markers. PLA-MA fluorescent beads are prepared by embedding CdSe/ZnS quantum dots in PLA-MA using Shirasu porous glass (SPG) membrane emulsification technology, which has high fluorescence intensity, good stability, and good dispersion. Fluorescent immunoassays on dipsticks found that PLA-MA microspheres have high biological activity and good stability, which is conducive to immunoassays. Based on this, using the characteristics of CdSe/ZnS quantum dots and flow cytometry, monochromatic and two-color coding methods were developed, and 9 distinguishable coding beads were prepared. The results showed that PLA-MA fluorescent microspheres exhibited good biocompatibility, stable coding signals, low background noise, and low detection limits when performing quaternary immunoassays on tumor markers CA125, CA199, CA724, and CEA by CdSe/ZnS QD-encoded PLA-MA microsphere binding flow cytometry.
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Compostos de Cádmio , Pontos Quânticos , Compostos de Selênio , Biomarcadores Tumorais , Corantes , Imunoensaio/métodos , Anidridos Maleicos , Microesferas , Poliésteres , Sulfetos , Compostos de ZincoRESUMO
The combined detection of CA125, CEA and AFP is of great significance in the diagnosis of ovarian cancer. Photonic crystal (PhC) barcodes have apparent advantages in multiplex immunoassays of ovarian cancer markers. In this paper, a novel PhC barcode was assembled from dendritic silica nanoparticles (dSiO2) for multiplex detection of ovarian cancer biomarkers. The interconnected macroporous structure of the dSiO2 PhC beads and the open porous topography of dendritic silica particles could increase the surface area to volume ratio for antibody immobilization. We simultaneously detected multiple ovarian cancer markers in one test tube using the sandwich immunization method by utilizing dSiO2 PhC beads as a barcode and CdTe QDs as a detection signal. The detection limits of the three ovarian cancer markers, AFP, CEA and CA125, were 0.52 ng mL-1, 0.64 ng mL-1 and 0.79 U mL-1, respectively (the signal-to-noise ratio was 3). Compared with the classic silica colloidal crystal bead (SCCB) suspension array, the sensitivity of the dSiO2 PhC bead suspension array was increased. In addition, the results showed that this barcode suspension array had acceptable accuracy and good reproducibility.
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Compostos de Cádmio , Nanopartículas , Neoplasias Ovarianas , Pontos Quânticos , Biomarcadores Tumorais , Humanos , Imunoensaio/métodos , Neoplasias Ovarianas/diagnóstico , Reprodutibilidade dos Testes , Dióxido de Silício/química , TelúrioRESUMO
Quantum dot (QD)-encoded microbeads as optical barcode with high fluorescence intensity and fluorescence uniformity, excellent stability and dispersity are greatly important for suspension array (SA). However, the size distribution of the microbeads mass-produced by the membrane emulsification method usually shows polydispersity, which leads to obstacles, imposing labour-intensive experimental iterations for the application of fluorescence-encoded microbeads as a distinguishable barcode. Herein, a simple simulation strategy based on a multicolor fluorescence model (MFM) was used to predict the influence of the microbeads' size distribution on the barcode signals. The point L and S respectively represent the two end points of the barcode, and the line segment LS can be considered as a cluster of the QD-encoded microbeads (simulated barcode). Experimental clusters of fluorescent microbeads were found to be in good agreement with the simulated barcodes. This simple simulation strategy can effectively simplify the experimental iteration process because the fluorescence-encoded microbeads are not decoded by a flow cytometer. Moreover, when applied for the high-throughput ultrasensitive detection of three tumor markers (CEA, CA125 and CA199) in a single sample, these barcodes exhibit superior detection performance. Detection limits of 0.028 ± 0.001 ng mL-1 for CEA, 1.5 ± 0.02 KU L-1 for CA125 and 0.8 ± 0.1 KU L-1 for CA199 are achieved, which meet the sensitivity criteria of tumor marker analysis. Therefore, this simple simulation strategy helps to overcome technical and economic obstacles for the widespread application of SA.
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Pontos Quânticos , Corantes , Citometria de Fluxo , Microesferas , SuspensõesRESUMO
It is imminent to develop a new type of rapid COVID-19 detection method with high sensitivity. Here, we used novel red emission-enhanced carbon dot (CD)-based silica (RCS) spheres as the signals of lateral flow immunochromatography (LFI) to ultrasensitively detect novel severe acute respiratory syndrome coronavirus 2 nucleocapsid proteins (SARS-CoV-2 NPs). The red emission of CDs can be enhanced and enriched in silica spheres by a simple way. The amino ends of the N-ß-(aminoethyl)-γ-aminopropyltrimethoxy anchor carboxyl-rich CDs and enhance the red emission, while the other end is embedded in the silica carrier. Then, the composite silica spheres werecoated with 3-(triethylsilyl) propylamine to protect the CDs, promote bioconjugation and obtain RCS spheres. The optimal emission peaks of the aqueous solution and the solid state of RCS spheres were at 634 nm and 638 nm, respectively, with quantum yields (QYs) of 48.5% and 35.7%, respectively. Their red emission has a wide excitation range (from the ultraviolet region to the red region), and the best excitation wavelength is about 580 nm. Two fluorescence detection modes of the RCS-LFI technology for the SARS-CoV-2 NP assay are available: the simple mode of observation under ultraviolet light has a sensitivity of 100 pg mL-1; the advanced mode of detection under a fluorescence microscope has a sensitivity of 10 pg mL-1. This assay also exhibits the advantages of fast detection speed, high specificity, and simple operation. In addition, the feasibility of this method in actual sample detection was verified in human serum by the standard-addition method, and the results show that the method has excellent practicability. We believe that this method will be a valuable supplement for the diagnosis of COVID-19.
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COVID-19 , SARS-CoV-2 , Anticorpos Antivirais , Carbono , Humanos , Imunoensaio , Proteínas do Nucleocapsídeo , Sensibilidade e Especificidade , Dióxido de SilícioRESUMO
Enhanced electrochemiluminescence (ECL) signals of CdS quantum dots capped with 3-mercaptopropionic acid (MPA@CdS QDs) have been observed after using N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) to activate the carboxyl groups. The generated ECL signals are strong enough that their images can be captured using a Huawei mobile phone. A possible mechanism for the generation of enhanced ECL signals has been proposed. Then, a sandwich immunosensor platform for detecting Zika virus (ZIKV) was fabricated with silica microspheres as the carrier and MPA@CdS QDs as ECL signal labels. Due to the dual signal amplification of EDC activation and microsphere enrichment, good linearity from 1.0 fg mL-1 to 1.0 ng mL-1 was exhibited by the QD-based ECL immunosensor for ZIKV detection. The detection limit was 0.3 fg mL-1.