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How timely identification and determination of pathogen species in pathogen-contaminated foods are responsible for rapid and accurate treatments for food safety accidents. Herein, we synthesize four aggregation-induced emissive nanosilicons with different surface potentials and hydrophobicities by encapsulating four tetraphenylethylene derivatives differing in functional groups. The prepared nanosilicons are utilized as receptors to develop a nanosensor array according to their distinctive interactions with pathogens for the rapid and simultaneous discrimination of pathogens. By coupling with machine-learning algorithms, the proposed nanosensor array achieves high performance in identifying eight pathogens within 1 h with high overall accuracy (93.75-100%). Meanwhile, Cronobacter sakazakii and Listeria monocytogenes are taken as model bacteria for the quantitative evaluation of the developed nanosensor array, which can successfully distinguish the concentration of C. sakazakii and L. monocytogenes at more than 103 and 102 CFU mL-1, respectively, and their mixed samples at 105 CFU mL-1 through the artificial neural network. Moreover, eight pathogens at 1 × 104 CFU mL-1 in milk can be successfully identified by the developed nanosensor array, indicating its feasibility in monitoring food hazards.
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Microbiologia de Alimentos , Listeria monocytogenes , Aprendizado de Máquina , Listeria monocytogenes/isolamento & purificação , Cronobacter sakazakii/isolamento & purificação , Dióxido de Silício/química , Sistemas Automatizados de Assistência Junto ao Leito , Animais , Leite/microbiologia , Leite/química , Técnicas Biossensoriais , Redes Neurais de ComputaçãoRESUMO
Bimodal-type multiplexed immunoassays with complementary mode-based correlation analysis are gaining increasing attention for enhancing the practicability of the lateral flow immunoassay (LFIA). Nonetheless, the restriction in visually indistinguishable multitargets induced by a single fluorescent color and difficulty in single acceptor ineffectual fluorescence quenching due to the various spectra of multiple different donors impede the further execution of colorimetric-fluorescence bimodal-type multiplexed LFIAs. Herein, the precise spectral overlap-based donor-acceptor pair construction strategy is proposed by regulating the size of the nanocore, coating it with an appropriate nanoshell, and selecting a suitable fluorescence donor with distinct colors. By in situ coating Prussian blue nanoparticles (PBNPs) on AuNPs with a tunable size and absorption spectrum, the resultant APNPs demonstrate efficient fluorescence quenching ability, higher colloidal stability, remarkable colorimetric intensity, and an enhanced antibody coupling efficiency, all of which facilitate highly sensitive bimodal-type LFIA analysis. Following integration with competitive-type immunoreaction, this precise spectral overlap-supported spatial separation traffic light-typed colorimetric-fluorescence dual-response assay (coined as the STCFD assay) with the limits of detection of 0.013 and 0.152 ng mL-1 for ractopamine and clenbuterol, respectively, was proposed. This work illustrates the superiority of the rational design of a precise spectral overlap-based donor-acceptor pair, hinting at the enormous potential of the STCFD assay in the point-of-care field.
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Clembuterol , Nanopartículas Metálicas , Ouro , Imunoensaio , Fenômenos Químicos , Limite de DetecçãoRESUMO
The authors describe a fluorometric method for the quantification of tannic acid (TA). MoO3-x quantum dots (QDs) can selectively capture TA via the formation of an organic molybdate complex. This causes an electron transfer effect and an inner filter effect to result in synergistic quenching of the fluorescence of the QDs. TA can be detected via this effect with a linear response in the of 0.1-10 µM concentration range and a lower detection limit of 30 nM within 1 min. The use of such QDs as a quenchable fluorescent probe warrants good selectivity even in the presence of relatively high concentration of potentially interferents and makes the method suitable for real sample analysis. Graphical abstract Tannic acid can be rapidly and selectively detected in food using a MoO3-x quantum dots based fluorometric assay.
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MiR-615 and epidermal growth factor receptor (EGFR) are associated with a number of disease processes and pathogenesis. However, little is known about the mechanisms of miR-615 and EGFR in human glioblastoma multiforme (GBM). Here, we found that down-regulation of miR-615 expression occurred in GBM tissues and cells, and was inversely correlated with overall survival, relapse-free survival, WHO grade as well as EGFR expression. We further determined that miR-615 functions as a tumor suppressor by inhibiting GBM cell proliferation, cell cycle, migration and invasion, and promoting cell apoptosis. In-vivo assay validated the inhibition effect of miR-615 on tumor growth and EGFR expression. Luciferase reporter assays demonstrated that miR-615 targeted the 3'-untranslated region (3'-UTR) of EGFR. Besides, over-expression of EGFR reversed the inhibition effects of miR-615, while silencing of EGFR aggravated these inhibition effects. In conclusions, we identified that miR-615 plays a tumor suppressor role in GBM cell proliferation, migration and invasion by targeting EGFR expression, and miR-615 may act as a novel biomarker for early diagnosis or therapeutic targets of GBM.
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Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Movimento Celular/genética , Receptores ErbB/metabolismo , Glioblastoma/genética , Glioblastoma/patologia , MicroRNAs/metabolismo , Sequência de Bases , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação para Baixo/genética , Receptores ErbB/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Análise Multivariada , Invasividade Neoplásica , Modelos de Riscos ProporcionaisRESUMO
An immunochromatographic strip (ICS) using urchin-like gold nanoparticles (UGNs) for sensitive detection of fumonisin B1 (FB1) was developed to meet the requirement for rapidly monitoring FB1 in grain samples. The sensitivity of the ICS was 5.0 ng/mL, which represents a fourfold increase in sensitivity over conventional strip preparation using colloidal gold as the antibody-labeled probe. Analysis of FB1 in grain samples showed that data obtained from the strip tests were in a good agreement with those obtained from HPLC and enzyme-linked immunosorbent assays (ELISAs). This qualitative test did not require any specialized equipment, and the detection time was less than 5 min, which is suitable for on-site testing of FB1 in grain samples. Overall, to our knowledge, this is the first report of using a UGN as the antibody-labeled probe for sensitive detection of FB1 in grains using an ICS. Graphical Abstract Preparation of ICS using conventional colloidal gold and urchin-like gold nanoparticle, respectively.
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Cromatografia de Afinidade/métodos , Grão Comestível/química , Fumonisinas/análise , Ouro/química , Nanopartículas Metálicas/química , Anticorpos Monoclonais/imunologia , Fumonisinas/imunologia , Limite de DetecçãoRESUMO
BACKGROUND: Liver cancer (LC) is a prevalent malignancy and a leading cause of cancer-related mortality worldwide. Extensive research has been conducted to enhance patient outcomes and develop effective prevention strategies, ranging from molecular mechanisms to clinical interventions. Single-cell sequencing, as a novel bioanalysis technology, has significantly contributed to the understanding of the global cognition and dynamic changes in liver cancer. However, there is a lack of bibliometric analysis in this specific research area. Therefore, the objective of this study is to provide a comprehensive overview of the knowledge structure and research hotspots in the field of single-cell sequencing in liver cancer research through the use of bibliometrics. METHOD: Publications related to the application of single-cell sequencing technology to liver cancer research as of December 31, 2023, were searched on the web of science core collection (WoSCC) database. VOSviewers, CiteSpace, and R package "bibliometrix" were used to conduct this bibliometric analysis. RESULTS: A total of 331 publications from 34 countries, primarily led by China and the United States, were included in this study. The research focuses on the application of single cell sequencing technology to liver cancer, and the number of related publications has been increasing year by year. The main research institutions involved in this field are Fudan University, Sun Yat-Sen University, and the Chinese Academy of Sciences. Frontiers in Immunology and Nature Communications is the most popular journal in this field, while Cell is the most frequently co-cited journal. These publications are authored by 2799 individuals, with Fan Jia and Zhou Jian having the most published papers, and Llovet Jm being the most frequently co-cited author. The use of single cell sequencing to explore the immune microenvironment of liver cancer, as well as its implications in immunotherapy and chemotherapy, remains the central focus of this field. The emerging research hotspots are characterized by keywords such as 'Gene-Expression', 'Prognosis', 'Tumor Heterogeneity', 'Immunoregulation', and 'Tumor Immune Microenvironment'. CONCLUSION: This is the first bibliometric study that comprehensively summarizes the research trends and developments on the application of single cell sequencing in liver cancer. The study identifies recent research frontiers and hot directions, providing a valuable reference for researchers exploring the landscape of liver cancer, understanding the composition of the immune microenvironment, and utilizing single-cell sequencing technology to guide and enhance the prognosis of liver cancer patients.
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Bibliometria , Neoplasias Hepáticas , Análise de Célula Única , Humanos , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/genética , Análise de Célula Única/métodosRESUMO
Immunochromatography (ICA) remains untapped toward enhanced sensitivity and applicability for fulfilling the nuts and bolts of on-site food safety surveillance. Herein, we report a fortified dual-spectral overlap with enhanced colorimetric/fluorescence dual-response ICA for on-site bimodal-type gentamicin (Gen) monitoring by employing polydopamine (PDA)-coated AuNPs (APDA) simultaneously serving as a colorimetric reporter and a fluorescence quencher. Availing of the enhanced colorimetric response that originated from the PDA layer, the resultant APDA exhibits less required antibody and immunoprobes in a single immunoassay, which facilitates improved antibody utilization efficiency and immuno-recognition in APDA-ICA. Further integrated with the advantageous features of fortified excitation and emission dual-spectral overlap for the Arg/ATT-AuNCs, this APDA-ICA with a "turn on/off" pattern achieves the visual limits of detection of 1.0 and 0.5 ng mL-1 for colorimetric and fluorescence patterns (25- and 50-fold lower than standard AuNPs-ICA). Moreover, the excellent self-calibration and satisfactory recovery of 79.03-118.04% were shown in the on-site visual colorimetric-fluorescence analysis for Gen in real environmental media (including real river water, an urban aquaculture water body, an aquatic product, and an animal byproduct). This work provides the feasibility of exploiting fortified dual-spectral overlap with an enhanced colorimetric/fluorescence dual response for safeguarding food safety and public health.
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With the global limited food resources receiving grievous damage from frequent climate changes and ascending global food demand resulting from increasing population growth, perovskite nanocrystals with distinctive photoelectric properties have emerged as attractive and prospective luminogens for the exploitation of rapid, easy operation, low cost, highly accurate, excellently sensitive, and good selective biosensors to detect foodborne hazards in food practices. Perovskite nanocrystals have demonstrated supreme advantages in luminescent biosensing for food products due to their high photoluminescence (PL) quantum yield, narrow full width at half-maximum PL, tunable PL in the entire visible spectrum, easy preparation, and various modification strategies compared with conventional semiconductors. Herein, we have carried out a comprehensive discussion concerning perovskite nanocrystals as luminogens in the application of high-performance biosensing of foodborne hazards for food products, including a brief introduction of perovskite nanocrystals, perovskite nanocrystal-based biosensors, and their application in different categories of food products. Finally, the challenges and opportunities faced by perovskite nanocrystals as superior luminogens were proposed to promote their practicality in the future food supply.
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Compostos de Cálcio , Análise de Alimentos , Nanopartículas , Óxidos , Titânio , Estudos Prospectivos , Qualidade dos AlimentosRESUMO
The conventional lateral flow immunoassay (LFIA) based on gold nanoparticles (Au NPs) is limited by low sensitivity due to the insufficient brightness of Au NPs. To address this problem, noble metal nanomaterials with localized surface plasmon resonance (LSPR) and synthetic tunability are potential signal outputs for LFIA, which can achieve better optical properties by adjusting the preparation conditions. Herein, this study prepared the hollow silver/gold nano-stars (HAg/Au NSts) as LFIA signal output via the galvanic replacement method. HAg/Au NSts with anisotropic hollow alloy nanostructures exhibit a wide visible light absorption band and great NIR thermal conversion efficiency (η = 37.32 %), which endows them with enhanced colorimetric and photothermal signals. Further, we constructed a colorimetric-photothermal (CM-PT) dual-signal HAg/Au NSts-LFIA and chose staphylococcal enterotoxin B as the target analyte. The linear range of HAg/Au NSts-LFIA is 0.19-100 ng mL-1, and the limit of detection (LOD) is up to 0.29 ng mL-1 and 0.09 ng mL-1 in the colorimetric and photothermal modes respectively. Compared with the conventional Au NPs-LFIA, HAg/Au NSts-CM/PT-LFIA effectively improved the detection performance of LFIA. In addition, HAg/Au NSts-LFIA also showed satisfactory sensitivity (vLOD = 0.78 ng mL-1) and recovery (89.06-114.74 %) in milk and pork samples. Therefore, this work provides a new shape design idea for noble metal nanomaterials in biosensor applications.
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The development of a rapid, sensitive, and accurate screening method for staphylococcal enterotoxin B (SEB) in food is urgently needed because trace amounts of SEB can pose a serious threat to human health. Here, we developed a ultrasensitive triple-modal immunochromatographic assay (ICA) for SEB detection. The AuNFs@Ir nanoflowers exhibited enhanced colorimetric, photothermal, and catalytic performance by modulating the sharp branching structure of the gold nanoflowers and depositing high-density Ir atoms. Subsequently, the combination of AuNFs@Ir and ICA promoted colorimetric, catalytic amplified colorimetric, and photothermal-assisted quantitative detection. The results showed detection limits of 0.175, 0.0188, and 0.043 ng mL-1 in the colorimetric/photothermal/catalytic mode, which increased the sensitivity by 16.5-fold, 153.7-fold, and 67.2-fold, respectively, compared with the AuNPs-ICA. Furthermore, the proposed strategy was verified in milk, milk powder, pork, and beef successfully. This strategy improves significantly the sensitivity, accuracy, flexibility and offers an effective insight for foodborne bacterial toxin monitoring.
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We report a method to construct ordered hierarchical porous structures in carbon nanofiber membranes using poly(ethylene oxide)-block-polydimethylsiloxane bottlebrush block copolymers (BBCPs) as templates. The BBCPs self-assemble into a spherical morphology driven by small-molecule hydrogen bond donors which act as bridges between carbon precursors and templates to promote uniform dispersion of the templates. We successfully obtained flexible, self-supporting, and porous carbon nanofiber membranes (PCNFs) with high porosity. Then, a supercapacitor electrode was independently prepared using PCNFs as an active substance without infiltrating any conductive agents or binders. The PCNFs exhibit excellent performance with a capacitance of 234.1 F g-1 at a current density of 1 A g-1 owing to the abundant hierarchical porous structures and high content of nitrogen and oxygen elements internally. The aqueous symmetric supercapacitor prepared using PCNFs electrodes maintains more than 95% capacitance retention after 55,000 charge-discharge cycles. Furthermore, the capacitance retention reaches up to 67.72% at a current density of 50 A g-1 (compared to 1 A g-1), exhibiting excellent cycling stability and rate capability. Based on the excellent electrochemical performance and flexible self-supporting ability of PCNFs, this work is expected to facilitate the development of flexible displays, flexible sensors, wearable devices, and electrocatalysis.
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Diabetes mellitus is a metabolic disease with a high prevalence worldwide, and cardiovascular complications are the leading cause of mortality in patients with diabetes. Diabetic cardiomyopathy (DCM), which is prone to heart failure with preserved ejection fraction, is defined as a cardiac dysfunction without conventional cardiac risk factors such as coronary heart disease and hypertension. Mitochondria are the centers of energy metabolism that are very important for maintaining the function of the heart. They are highly dynamic in response to environmental changes through mitochondrial dynamics. The disruption of mitochondrial dynamics is closely related to the occurrence and development of DCM. Mitochondrial dynamics are controlled by circadian clock and show oscillation rhythm. This rhythm enables mitochondria to respond to changing energy demands in different environments, but it is disordered in diabetes. In this review, we summarize the significant role of circadian clock-controlled mitochondrial dynamics in the etiology of DCM and hope to play a certain enlightening role in the treatment of DCM.
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Relógios Circadianos , Cardiomiopatias Diabéticas , Dinâmica Mitocondrial , Humanos , Mitocôndrias/patologia , Diabetes Mellitus , Cardiomiopatias Diabéticas/patologia , AnimaisRESUMO
Salmonella are major pathogens that cause foodborne diseases. In this work, a broad-spectrum Salmonella nanobody-01 (Nb-01) was isolated and applied in the development of a streptavidin-bridged sandwich ELISA (SAB-ELISA) for simultaneously identifying five Salmonella serovars, including Salmonella Enteritidis (S. Enteritidis), Salmonella Typhimurium (S. Typhimurium), Salmonella London (S. London), Salmonella Paratyphi B (S. Paratyphi B) and Salmonella Hadar (S. Hadar). In this work, streptavidin (SA) was utilized as a scaffold to directionally immobilize biotinylated nanobody (BiNb) and Salmonella was detected by phage-displayed nanobodies. The SAB-ELISA can be accomplished within 180 min with a limit of detection (LOD) of 6.31 × 103 colony forming units (CFU) mL-1, 9.15 × 103 CFU mL-1, 4.23 × 103 CFU mL-1, 7.31 × 103 CFU mL-1 and 7.25 × 103 CFU mL-1 towards S. Typhimurium, S. Enteritidis, S. London, S. Paratyphi B and S. Hadar, respectively. In comparison of sandwich ELISA by passive immobilization of Nb-01 on polystyrene plate, the sensitivity was increased by around 6-fold, which confirmed the enhanced immobilization efficacy of SAB-ELISA. Furthermore, the feasibility of the assay for S. Typhimurium determination in actual samples was evaluated, showing excellent recovery, inter-day and intra-day precision.
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Anticorpos de Domínio Único , Ensaio de Imunoadsorção Enzimática , Salmonella enteritidis , Sorogrupo , EstreptavidinaRESUMO
Although lateral flow immunoassay (LFIA) as a point-of-care (POC) diagnostic tool has been widely used because of numerous merits, it remains challenging to realize higher sensitivity, easier labeling, and fewer antibodies consumption. Herein, a bioresource-derived tannic acid (TA)-supported immuno-network based LFIA for clenbuterol (CLE) monitoring was proposed by employing poly TA nanospheres (PTAN) as the new tracer. Attributing to the effective protein-enrichment ability of TA, plenty of goat anti-mouse immunoglobulins (GAMI) were first absorbed on the surface of PTAN and then monoclonal antibodies (AbCLE) were added to form immuno-network. Compared with directly coupling antibodies, the utilization efficiency of AbCLE was significantly improved. Thus, the detection sensitivity (take the cut-off value as an example) was enhanced 5-fold and 10-fold at least compared with PTAN-AbCLE and colloidal gold-based LFIA, respectively. Additionally, the proposed method was successfully verified in beef and pork liver and provided an effective strategy for food safety monitoring.
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Clembuterol , Nanopartículas Metálicas , Nanosferas , Animais , Bovinos , Coloide de Ouro , Imunoensaio/métodos , Limite de Detecção , Camundongos , TaninosRESUMO
Staphylococcal enterotoxins (SEs) represent the leading reason for staphylococcal food poisoning (SFP) and various other diseases. Reports often indicate Staphylococcal enterotoxin C (SEC) as the most frequently found enterotoxin in dairy products. To minimize consumer exposure to SEC, this paper aimed to create a sandwich enzyme-linked immunosorbent assay (ELISA) based on nanobodies (sandwich Nbs-ELISA) to accurately detect SEC in dairy products without the influence of staphylococcal protein A (SpA). Therefore, after inoculating a Bactrian camel with SEC, a phage display Nb library was created. Eleven Nbs against SEC were identified in three biopanning steps. Based on their affinity and pairing level, a sandwich Nbs-ELISA was developed using the C6 anti-SEC Nb as the capture antibody, while the detection antibody was represented by the C11 phage display anti-SEC Nb. In optimal conditions, the quantitative range of the present sandwich ELISA was 4-250 ng/mL with a detection limit (LOD) of 2.47 ng/mL, obtained according to the blank value plus three standard deviations. The developed technique was subjected to specific measurements, revealing minimal cross-reactivity with Staphylococcus aureus (S. aureus), Staphylococcal enterotoxin A (SEA), Staphylococcal enterotoxin B (SEB), and SpA. The proposed method exhibited high specificity and an excellent recovery rate of 84.52~108.06% in dairy products. Therefore, the sandwich Nbs-ELISA showed significant potential for developing a specific, sensitive technique for SEC detection in dairy products.
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As one of the leading causes of food poisoning, staphylococcal enterotoxins (SEs) secreted by Staphylococcus aureus pose a serious threat to human health. The immunoassay has become the dominant tool used for the rapid detection of harmful bacteria and toxins as a result of its excellent specificity. However, with regard to SEs, staphylococcal protein A (SpA) is likely to bind with the fragment crystallizable (Fc) terminal of the traditional antibody and result in a false positive, limiting the practical application of this method. Therefore, to eliminate the bottleneck problem, the sandwich immunoassay was development by replacing the traditional antibody with a nanobody (Nb) that lacked a Fc terminal. Using 0.5 × 107 colony-forming units, the Nb library was constructed using Bactrian camels immunized with staphylococcal enterotoxin B (SEB) to obtain a paired Nb against SEB with good affinity. A sandwich enzyme-linked immunosorbent assay (ELISA) was developed using one Nb as the capture antibody and a phage-displayed Nb with signal-amplifying properties as the detection antibody. In optimal conditions, the current immunoassay displayed a broad quantitative range from 1 to 512 ng/mL and a 0.3 ng/mL limit of detection. The recovery of spiked milk, milk powder, cheese, and beef ranged from 87.66 to 114.2%. The Nbs-ELISA was not influenced by SpA during the detection of SEB in S. aureus food poisoning. Therefore, the Nb developed here presented the perfect candidates for immunoassay application during SE determination as a result of the complete absence of SpA interference.
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Enterotoxinas/análise , Ensaio de Imunoadsorção Enzimática/métodos , Proteína Estafilocócica A/química , Animais , Camelus , Queijo/análise , Queijo/microbiologia , Ensaio de Imunoadsorção Enzimática/instrumentação , Contaminação de Alimentos/análise , Leite/química , Leite/microbiologia , Ligação Proteica , Anticorpos de Domínio Único/química , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/metabolismoRESUMO
The variable domain of heavy chain only antibody (VHH), also named as nanobody obtained from camelid antibody libraries, has shown great potential in immunochemistry, with many advantages over conventional antibodies. Here, nanobodies towards Salmonella enteritidis (S. enteritidis) were isolated for the first time after biopanning of an immune camelid nanobody library. Those nanobodies showed high thermostability and good specificity. A sandwich-ELISA was developed with nanobody Nb 13, which exhibited a detection limit of 1.4 × 105 CFU/mL. The proposed assay was also applied to detect S. enteritidis in milk samples, which could detect 6 CFU/mL of S. enteritidis in milk after 10 h of enrichment. This study demonstrated an alternative strategy for S. enteritidis determination, and further proved the utility and practicality of nanobody-based reagents in bioanalytical chemistry.
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Microbiologia de Alimentos/métodos , Leite/microbiologia , Salmonella enteritidis/imunologia , Anticorpos de Domínio Único/imunologia , Animais , Camelus/imunologia , Ensaio de Imunoadsorção Enzimática , Limite de Detecção , Sensibilidade e Especificidade , Anticorpos de Domínio Único/genéticaRESUMO
To overcome the drawbacks of antibody labeling dependence and single-readout system in the conventional lateral flow immunoassays (LFIAs) as well as the non-targeted combination of new capture agents reported recently for pathogen detection, in this work, a multi-readout and label-free LFIA was proposed for rapid detection of Escherichia coli O157:H7 (E. coli O157:H7) based on a nanozyme-bacteria-antibody sandwich pattern. A type of functional nanozyme-mannose modified Prussian blue (man-PB), was introduced as the recognition agent as well as signal indicator. Apart from original signal intensity on the T-line, the peroxidase-like catalytic activity-driven generation of colorimetric signal could be used as another format of quantitation. Importantly, such LFIA could exhibit excellent performance for target pathogens detection separately with a quantitative range of 102-108 cfu·mL-1 and a low detection limit of 102 cfu·mL-1 based on different readout formats, indicating the application potential of the proposed LFIA in real samples.
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Escherichia coli O157/isolamento & purificação , Imunoensaio , Nanopartículas/química , Anticorpos Antibacterianos/química , Anticorpos Antibacterianos/imunologia , Catálise , Colorimetria , Escherichia coli O157/imunologia , Ferrocianetos/química , Microbiologia de Alimentos , Limite de Detecção , Manose/química , Nanopartículas/metabolismoRESUMO
Currently, the low sensitivity and poor binding stability of detection probe prepared via electrostatic adsorption have become the dilemmas of colloidal gold-based lateral flow immunoassays (Au-LFIAs). In this connection, polydopamine nanospheres (PDA NPs) with an eminent covalent connectivity property were introduced as a promising substitute to improve the stability of probe and sensitivity of LFIA. Whereafter, the PDA NPs-based LFIA was applied for the monitoring of furazolidone (FZD) in food samples because of the potential carcinogenic/mutagenic effects to human of its metabolite (3-amino-2-oxazolidinone, AOZ). Compared with electrostatic adsorption, the binding stability of PDA NPs-based probes was superior. And, as expected, the PDA NPs-based LFIA biosensor exhibited higher sensitivity than that of the Au-LFIA with a detection limit of 3.5 ng mL-1 for AOZ by naked-eye readout. Based on the significant enhanced binding stability and sensitivity, the PDA NPs-based LFIA is of certain spreading value for detecting other analytes.
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Furazolidona/análise , Imunoensaio , Indóis/química , Nanosferas/química , Polímeros/química , Técnicas Biossensoriais , Humanos , Limite de DetecçãoRESUMO
Lateral flow immunoassay (LFIA) is a class and widespread applied point-of-care biosensor in the rapid monitoring field. To address the matched antibodies and antibody labeling dependence in the conventional LFIAs, in this work, an innovative label-free LFIA was proposed for the sensitive detection of Salmonella enteritidis (S. enteritidis) by introducing a new nanoparticles-bacteria-antibody sandwich strategy in the sensor. Surface positively charged nitrogen-rich carbon (pNC) nanoparticles, synthesized via calcination and etching reactions, were used as adsorbent to capture bacteria as well as for generating signals. In the presence of target pathogens, bacterial cells could combine with pNC through electrostatic interaction and hydrogen bonding, then the complex would be captured specifically by the anti-bacteria monoclonal antibody (McAb) coated on the test line (T-line). With the accumulation of nanoparticles-bacteria, the color on T-line would be gradually deepened from nearly colorless to deep black. Importantly, the pNC-based immunoassay could exhibit high sensitivity for target pathogens detection with a linear range of 102-108 cfuâ¯mL-1 and a low detection limit of 102 cfuâ¯mL-1. Furthermore, this system was validated preliminarily to screen S. enteritidis in different food samples with recoveries ranging from 85% to 110%. Taking advantages of simplicity, label-free, convenience, and sensitivity, the pNC-based LFIA has the application potential for pathogenic microorganisms monitoring in food safety and early clinical diagnosis fields.