Search Results (86)

Hydrocortisone is a typical glucocorticoid commonly used in livestock production; however, its overuse can result in hormone residues in milk. Long-term consumption of such milk may lead to a series of health issues. Therefore, the timely and rapid detection of hydrocortisone in milk is crucial for protecting human health. In this study, a magnetic particle-based direct chemiluminescence immunoassay (MP-DCLIA) incorporating a streptavidin–biotin signal amplification system was developed for the rapid and high-throughput detection of hydrocortisone in milk. Automated operations reduce human error and enhance the accuracy and repeatability of tests. The assay can be completed in 12 min with a linear detection range of 13.09–261.71 μg/L, a limit of detection (LOD) of 4.94 μg/L, a limit of quantification (LOQ) of 14.84 μg/L, and intra- and inter-batch variations of less than 5%. The method demonstrated stability and exhibited no cross-reactivity with structural analogues. Spiked recoveries of milk samples ranged from 85.85% to 100.30%, with results strongly correlating with those obtained from LC-MS/MS. The MP-DCLIA offers rapidity, high efficiency, stability, and precision, making it a promising tool for practical testing applications. Full article

As a type II ribosome-inactivating protein (RIP-II) toxin, Ricin has garnered widespread recognition due to its inherent qualities as an easily prepared and highly stable substance, posing serious implications as a potential chemical and biological terrorist threat. For the detection of ricin, traditional immunoassay technologies, including methods like peptide cleavage combined with liquid chromatography mass spectrometry (LC-MS) or the more commonly used enzyme-linked immunosorbent assay (ELISA), have offered reliable results. However, these techniques are unfortunately limited by the requirement of a complex sample pretreatment process, which can be time-consuming and labor-intensive. In an effort to overcome these limitations, a highly sensitive and selective method was introduced via metal element labeling combined with inductively coupled plasma mass spectrometry (ICP-MS) in this research. The method centered on designing and synthesizing a europium-labeled compound (DOTA-NHS-Eu) that specifically targets the amino groups (-NH₂) on ricin. The compound, coupled with the application of specific magnetic beads, achieved the specific enrichment and subsequent quantitative detection of ricin by ICP-MS, which is based on the amount of europium element present. The established method demonstrated high specificity for ricin recognition, with a signal response to bovine serum protein that was found to be less than 10% of that for ricin. Furthermore, the calibration curve created for the method (y = 81.543x + 674.02 (R² > 0.99)) for quantifying ricin in a concentration range of 1.0–100 μg/mL demonstrated good linearity. The method was further evidenced by the limit of detection and quantitation results of 0.1 and 1.89 μg/mL, respectively. Collectively, these findings suggested that the research has offered a highly sensitive and selective method for ricin detection, which was not only easy to operate but also provided efficient results. The scheme showed great potential for the verification of chemical weapons and the destruction of toxic chemicals, therefore representing a significant advancement in the field of biomolecular detection and analysis. Full article

The performance of heterophase immunoassays is often limited by the kinetics of analyte binding. This problem is partially solved by bead-based assays, which are characterized by rapid diffusion in the particle suspension. However, at low analyte concentrations, the binding rate is still low. Here, we demonstrate a further improvement of analyte binding kinetics in bead-based immunoassays by simultaneously concentrating both an analyte and magnetic beads in a compact spatial region where binding occurs. The analyte is electrophoretically concentrated in a flow cell where beads are magnetically retained and dragged along the channel by viscous force. The flow cell is integrated with a microarray-based signal detection module, where beads with bound analyte scan the microarray surface and are retained on it by single specific interactions, assuring ultra-high sensitivity of the method. Thus, a continuous flow assay system is formed. Its performance is demonstrated by simultaneous detection of model pathogen biomarkers, cholera toxin (CT) and staphylococcal enterotoxin B (SEB), with a detection limit of 0.1 fM and response time of under 10 min. The assay is capable of real-time online sample monitoring, as shown by a 12 h long continuous flow analysis of tap water for SEB and CT. Full article

Quantitative nucleic acid detection is widely used in molecular diagnostics for infectious diseases. Here, we demonstrate that the previously developed MLFIA (magnetically localized fluorescent immunoassay) has the potential to detect Polymerase Chain Reaction (PCR) and loop-mediated isothermal amplification (LAMP) products using biotinylated and fluorescent primers and streptavidin-coated magnetic nanoparticles. The functionalized nanoparticles separate amplified DNA from non-incorporated primers in situ, allowing the quantification of DNA products. We compare magnetically localized fluorescence detection to commercial technologies based on the DNA intercalation of fluorescent dyes. Our system allows the detection of PCR and LAMP products but is approximately 10 times less sensitive than standard commercial assays. Future optimizations, such as enhancing the signal-to-noise ratio and improving nanoparticle functionalization, could significantly increase sensitivity and bring it closer to current diagnostic standards. This work highlights the potential of magnetically localized fluorescence detection to detect DNA. Full article

Aflatoxin B1 (AFB1), a highly toxic secondary metabolite produced by Aspergillus species, represents a significant health hazard due to its widespread contamination of agricultural products. The urgent need for sensitive and sustainable detection methods has driven the development of diverse analytical approaches, most of which heavily rely on organic solvents, posing environmental challenges for routine food safety analysis. Here, we introduce a supramolecular platform leveraging acyclic cucurbit[n]uril (acCB) as a host molecule for environmentally sustainable AFB1 detection. Screening various acCB derivatives identified acCB6 as a superior host capable of forming a stable 1:1 complex with AFB1 in an aqueous solution, exhibiting a high binding affinity. Proton nuclear magnetic resonance (1H NMR) spectroscopy confirmed that AFB1 was deeply encapsulated within the host cavity, with isothermal titration calorimetry (ITC) experiments and molecular dynamics simulations further substantiating the stability of the interaction, driven by enthalpic and entropic contributions. This supramolecular host was incorporated into a scaffold-assembly-based bioluminescent enzyme immunoassay (SA-BLEIA), providing a green detection platform that rivals the performance of traditional organic solvent-based assays. Our findings highlight the potential of supramolecular chemistry as a foundation for eco-friendly mycotoxin detection and offer valuable insights into designing environmentally sustainable analytical methods. Full article

Background: Disruptions in epigenetic mechanisms regulating placentation, particularly imbalances in the levels of small non-coding RNAs, contribute to various pregnancy complications, including preeclampsia (PE) and placenta accreta spectrum (PAS). Given that abnormal trophoblast differentiation, invasiveness, and angiogenesis—reduced in PE and excessive in PAS—are central to the pathogenesis of these conditions, this study aimed to identify universal circulating piRNAs and their targets. Methods: Small RNA deep sequencing, quantitative reverse transcription combined with real-time polymerase chain reaction, magnetic bead-based multiplex immunoassay, ELISA, and Western blotting were employed to quantify circulating piRNAs and proteins in the blood serum of pregnant women during the 11th–14th weeks of gestation. Results: Statistically significant negative correlations were identified between PE- and PAS-associated piRNAs (hsa_piR_019122, hsa_piR_020497, hsa_piR_019949, and piR_019675) and several molecules, including Endoglin, IL-18, VEGF-A, VEGF-C, Angiopoietin-2, sFASL, HB-EGF, TGFα, and Clusterin. These molecules are involved in processes such as angiogenesis, inflammation, the epithelial–mesenchymal transition, cell proliferation, adhesion, and apoptosis. A first-trimester pregnancy screening algorithm was developed using logistic regression models based on Clusterin concentration and the levels of hsa_piR_020497, hsa_piR_019949, piR_019675, and hsa_piR_019122. Conclusions: The proposed screening tool for early pregnancy monitoring may enable the prediction of PE or PAS in the first trimester, allowing timely interventions to reduce maternal and perinatal morbidity and mortality. Full article

Detecting multiple tumor markers is of great importance. It helps in early cancer detection, accurate diagnosis, and monitoring treatment. In this work, gold nanoparticles–toluidine blue–graphene oxide (AuNPs-TB–GO) and gold nanoparticles–carboxyl ferrocene–tungsten disulfide (AuNPs–FMC–WS₂) nanocomposites were prepared for labeling Carcinoembryonic antigen (CEA) antibody and Carbohydrate antigen 72–4 (CA72-4) antibody, respectively, and used as two kinds of probes with different electrochemical signals. With the excellent magnetic performance of biotin immune magnetic beads (IMBs), the biofunctional IMBs were firmly deposited on the magnetic glassy carbon electrode (MGCE) surface by applying a constant magnetic field, and then the CEA and CA72-4 antibody were immobilized on the IMBs by the avidin–biotin conjugation. The assay was based on the change in the detection peak current. Under the optimum experimental conditions, the linear range of detection of CEA is of the two-component immunosensor is from 0.01 to 120 ng/mL, with a low detection limit of 0.003 ng/mL, and the linear range of detection of CA72-4 is from 0.05 to 35 U/mL, with a detection limit of 0.016 U/mL. The results showed that the proposed immunosensor enabled simultaneous monitoring of CEA and CA72-4 and exhibited good reproducibility, excellent high selectivity, and sensitivity. In particular, the proposed multiplexed immunoassay approach does not require sophisticated fabrication and is well-suited for high-throughput biosensing and application to other areas. Full article

β-parvalbumin (β-PV) is the primary fish allergen responsible for most allergic reactions in individuals sensitive to fish. To ensure food safety, a sandwich-based magnetic immunoassay was developed using maleimide-functionalized magnetic beads (NH-MBs). Specific anti-β-PV antibodies were immobilized on these MBs, and a screen-printed carbon electrode was employed as the electrochemical transducer. A linear concentration range from 10 to 1000 ng/mL, a limit of detection of 1.8 ng/mL, and a limit of quantification of 7.1 ng/mL were achieved. Nineteen commercial food samples were analyzed to assess the potential of the sensor for routine use in food quality control. Important factors such as protein source and food processing (e.g., boiling, grilling, and frying) and preservation (e.g., in oil, and vacuum) were evaluated. The validated results confer the usefulness of the assay for food quality control. Full article

Technologies based on digital microfluidics (DMF) have made significant advancements in the automated manipulation of microscale liquids and complex multistep processes. Due to their numerous benefits, such as automation, speed, cost-effectiveness, and minimal sample volume requirements, these systems are particularly well suited for immunoassays. In this review, an overview is provided of diverse DMF manipulation platforms and their applications in immunological analysis. Initially, droplet-driven DMF platforms based on electrowetting on dielectric (EWOD), magnetic manipulation, surface acoustic wave (SAW), and other related technologies are briefly introduced. The preparation of DMF is then described, including material selection, fabrication techniques and droplet generation. Subsequently, a comprehensive account of advancements in the integration of DMF with various immunoassay techniques is offered, encompassing colorimetric, direct chemiluminescence, enzymatic chemiluminescence, electrosensory, and other immunoassays. Ultimately, the potential challenges and future perspectives in this burgeoning field are delved into. Full article

This study evaluated the factors influencing IgG/IgM antibody levels in 120 patients with head and neck cancer (HNC) following vaccination with inactivated SARS-CoV-2 vaccines. Each patient’s demographic and clinical data were documented, and serum IgG and IgM antibodies were detected using a commercial magnetic chemiluminescence enzyme immunoassay kit. The results indicated that while all patients had received at least one vaccine dose, 95 tested positive for IgG and 25 were negative. A higher proportion of IgG-positive patients had received three vaccine doses. Comparatively, gamma-glutamyl transferase levels were elevated in IgM-negative patients. The study further differentiated patients based on their treatment status: 46 were treatment-naive and 74 had received chemotherapy combined with immune checkpoint inhibitors (ICT) at enrollment. Despite similar baseline characteristics and time from vaccination to antibody detection, IgM positivity was significantly lower in the ICT group, with no significant difference in IgG positivity between the treatment-naive and ICT groups. A multivariable analysis identified the number of vaccine doses as an independent factor of IgG positivity, while ICT emerged as an independent risk factor for IgM positivity. Additionally, IgG titers generally declined over time, although patients with higher baseline IgG levels maintained higher titers longer. In conclusion, ICT in patients with HNC does not significantly affect IgG levels post-vaccination. However, booster vaccinations have been shown to be associated with higher IgG positivity, although these levels gradually decrease over time. Full article

Our previous studies demonstrated the modulatory effects of new synthetic thio-chalcone derivatives in dishes on the Nrf2, NF-κB, and STAT3 signaling pathways in colon cancer cells. This study aimed to evaluate the effect of four selected active chalcone thio-derivatives on the NF-κB and STAT3 signaling pathways involved in inflammatory processes and cell proliferation in human liver cancer cells. Cell survival was assessed for cancer (HepG2) and normal (THLE-2) cell lines. Activation of NF-κB and STAT3 signaling pathways and the expression of proteins controlled by these pathways were estimated by Western blot, and qRT-PCR assessed the expression of NF-κB and STAT3 target genes. We also evaluated the impact on the selected kinases responsible for the phosphorylation of the studied transcription factors by MagneticBead-Based Multiplex Immunoassay. Among the thio-derivatives tested, especially derivatives 1 and 5, there was an impact on cell viability, cell cycle, apoptosis, and activation of NF-κB and STAT3 pathways in hepatocellular carcinoma (HCC), which confirms the possibilities of using them in combinatorial molecular targeted therapy of HCC. The tested synthetic thio-chalcones exhibit anticancer activity by initiating proapoptotic processes in HCC while showing low toxicity to non-cancerous cells. These findings confirm the possibility of using chalcone thio-derivatives in molecularly targeted combination therapy for HCC. Full article

The magnetic separation and cleaning module, as a core component of the fully automated chemiluminescence immunoassay (CLIA) analyzer, encounters issues including high magnetic bead loss rate, long cleaning time, and poor cleaning effect. Based on a simulation analysis using COMSOL, we proposed a novel magnetic separation and cleaning module applied to a fully automated CLIA analyzer. The module adopted a method of arranging spliced rectangular magnets on opposite sides, where the same polarity faced each other, as well as a three-stage magnetic bead collection method. With the proposed method, the total cleaning process can be accomplished within 225 s; the total magnetic bead loss rate over three rounds of cleaning is 6.03%, whereas that of traditional instruments is 25.85%; the coefficient of variation (CV) of the magnetic bead loss rate is less than 0.5%; effective cleaning of free markers is achieved under various sample conditions. Compared with traditional CLIA instruments, this method comprehensively improves key performance indicators of the magnetic separation and cleaning module, providing a reference for similar modules in fully automated CLIA analyzers and positively impacting the accuracy of CLIA for the detection of disease biomarkers. Full article

Antiretroviral therapy (ART) has reduced the mortality and morbidity associated with HIV. However, irrespective of treatment, people living with HIV remain at a higher risk of developing non-AIDS-associated diseases. In 2019, the World Health Organization recommended the transition from efavirenz (EFV)- to dolutegravir (DTG)-based ART. Data on the impact of this transition are still limited. The current study therefore investigated the metabolic profiles, cytokine inflammatory responses, and platelet activation before and after the treatment transition. Plasma samples from nine virally suppressed adults living with HIV and sixteen healthy, HIV-uninfected individuals residing in Gauteng, South Africa were compared. Metabolite and cytokine profiles, and markers associated with platelet activation, were investigated with untargeted proton magnetic resonance metabolomics, multiplex suspension bead array immunoassays, and sandwich enzyme-linked immunosorbent assays, respectively. In those individuals with normal C-reactive protein levels, the transition to a DTG-based ART regimen resulted in decreased concentrations of acetoacetic acid, creatinine, adenosine monophosphate, 1,7-dimethylxanthine, glycolic acid, 3-hydroxybutyric acid, urea, and lysine. Moreover, increased levels of formic acid, glucose, lactic acid, myo-inositol, valine, glycolic acid, and 3-hydroxybutyric acid were observed. Notably, levels of interleukin-6, platelet-derived growth factor-BB, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor–alpha, soluble cluster of differentiation 40 ligand, as well as regulated on activation, normal T-cell expressed and secreted (RANTES) reached levels close to those observed in the healthy control participants. The elevated concentration of macrophage inflammatory protein-1 alpha was the only marker indicative of elevated levels of inflammation associated with DTG-based treatment. The transition from EFV- to DTG-based regimens therefore appears to be of potential benefit with metabolic and inflammatory markers, as well as those associated with cardiovascular disease and other chronic non-AIDS-related diseases, reaching levels similar to those observed in individuals not living with HIV. Full article

Misusage of tetracycline (TC) antibiotics residue in animal food has posed a significant threat to human health. Therefore, there is an urgent need to develop highly sensitive and robust assays for detecting TC. In the current study, gold and platinum nanoparticles were deposited on carbon nanotubes (CNTs) through the superposition method (Au@Pt/CNTs-s) and one-pot method (Au@Pt/CNTs-o). Au@Pt/CNTs-s displayed higher enzyme-like activity than Au@Pt/CNTs-o, which were utilized for the development of sensitive magnetic immunoassays. Under the optimized conditions, the limits of detection (LODs) of magnetic immunoassays assisted by Au@Pt/CNTs-s and Au@Pt/CNTs-o against TCs could reach 0.74 ng/mL and 1.74 ng/m, respectively, which were improved 6-fold and 2.5-fold in comparison with conventional magnetic immunoassay. In addition, the measurement of TC-family antibiotics was implemented by this assay, and ascribed to the antibody used that could recognize TC, oxytetracycline, chlortetracycline, and doxycycline with high cross-reactivity. Furthermore, the method showed good accuracy (recoveries, 92.1–114.5% for milk; 88.6–92.4% for pork samples), which also were applied for determination of the targets in real samples. This study provides novel insights into the rapid detection of targets based on high-performance nanocatalysts. Full article

Lactoferrin (LF), an iron-binding glycoprotein with immunological properties and a high nutritional value, has emerged as a prominent research focus in the field of food nutrition. Lactoferrin is widely distributed in raw milk and milk that has undergone low-temperature heat treatment during pasteurization, making its rapid and accurate detection crucial for ensuring the quality control of dairy products. An enzyme-linked immunosorbent assay-based analytical protocol has often been referred to for the detection of LF in real samples. Signal amplification was accomplished using the streptavidin–biotin system. Here, an automated magnetic beads-based sandwich chemiluminescence enzyme immunoassay (MBs-sCLEIA) system was developed for the quantification of lactoferrin in pasteurized milk. The MBs-sCLEIA system consists of an automated chemiluminescence-based analyzer and a lactoferrin MBs-sCLEIA assay kit. Notably, our proposed method eliminates the need for pretreatment procedures and enables the direct addition of milk samples, allowing for the automatic quantitative detection of lactoferrin within a rapid 17 min timeframe for up to eight samples simultaneously. The MBs-sCLEIA was linear over the range of 7.24–800 ng/mL and displayed a limit of detection (LOD) of 2.85 ng/mL. As its good recovery and CV values indicate, the method exhibited high precision and accuracy. Furthermore, it was verified that it was selective towards five additional common milk proteins. A good correlation was observed between the results from the MBs-sCLEIA and heparin affinity column-HPLC (r² = 0.99042), which proves to be a useful and practicable way of conducting an accurate analysis of lactoferrin in dairy products. Full article