Search Results (736)

Multiplexed detection of arboviruses using a 4 × 4 Si-based electrolyte-gated transistor (EGT) array functionalized with specific aptamers has been investigated. The Si-based EGTs were fabricated using conventional Si microfabrication processes. The EGTs showed excellent intrinsic electrical characteristics, including a low threshold voltage of 0.8 V, a sub-threshold swing of 75 mV/dec, and a gate leakage of <10 pA, ensuring uniform device performance with low device-to-device variation. Aptamers specific to the yellow fever virus nonstructural protein 1 (YF), dengue virus nonstructural protein 1 (DN), and chikungunya virus envelope protein 2 (CHK) were functionalized on EGT arrays to evaluate individual and multiplexed detection. In individual-target detections, concentration-dependent negative shifts in threshold voltage were observed, and relevant limits of detection (LOD) as low as 38.6 pg/mL, 95.2 pg/mL, and 1.6 ng/mL were extracted for YF, DN, and CHK, respectively. In multiplexed detections, sensitivities decreased and variations increased relative to the individual responses, resulting in higher LODs. The extracted LODs were 0.2 ng/mL, 0.6 ng/mL, and 2.8 ng/mL for YF, DN, and CHK, respectively, which are lower than those reported for other methods. These results suggest that Si-based EGT arrays are promising as a scalable, low-cost, and highly sensitive biosensing platform for multiplexed arbovirus detection and point-of-care diagnostics. Full article

1,2,4-Triazoles, as heterocyclic compounds, represent an attractive class of ligands in the design of metal–organic frameworks (MOFs) due to their donor–acceptor character, thermal and chemical stability, and ability to form extended coordination networks. This review summarizes the literature published between 2019 and 2025 on luminescent MOFs incorporating 1,2,4-triazole scaffold. The analysis covers synthetic conditions and provides a detailed discussion of the luminescent properties of these materials. Particular emphasis is placed on their applicability as luminescent probes for environmental monitoring and medical diagnostics, as well as on their potential use in light-emitting diode construction. The collected data highlight promising results, including strong correlations between analyte concentration and luminescent response, enabling sensitive detection with low limits of detection (LOD) for selected analytes. This article may serve as a valuable resource for chemists, physicists, and engineers involved in the design of functional materials and the development of detection and optoelectronic technologies. Full article

Rapid blood type detection in point-of-care testing (POCT) scenarios is crucial for various clinical treatments. In this study, we present a sensitive, cost-effective, and straightforward biosensing approach for visual blood typing that notably simplifies the procedure by eliminating any need for blood sample pretreatment. Our technique achieves this by directly trapping and accumulating red blood cell (RBC) clusters within a photolithography-based microfluidic chip, thereby bypassing complex preprocessing. By employing an antigen–antibody assay involving isoagglutinins A, B, and/or D on the RBC surface and their corresponding antibodies, we effectively determine blood types. When antibodies are present, the corresponding RBCs bind to the antibody-conjugated RBC clusters, which are subsequently trapped within the microfluidic accumulation chip, resulting in the formation of a visible bar. The blood group can then be readily identified by observing this visual bar with the naked eye or under microscopy. Notably, we integrate two continuous mixing units (Z and S) at the entrance of the biochip to improve mixing efficiency and accelerate the antigen–antibody interaction. This method demonstrates high selectivity, accuracy, and stability across various clinical blood samples. Moreover, the sensor operates with minimal sample volume (as low as 10 μL) and delivers results within 5 min. The fabrication cost of the PDMS-based biochip is approximately $0.2 per chip, and the limit of detection (LOD) is determined to be 3 × 10⁶ cells/mL, indicating excellent sensitivity and affordability for practical use. Overall, this biochip provides a fast, low-cost, and reliable solution for emergency blood typing, particularly in resource-limited settings. Full article

People are exposed to mixtures of metals, per- and polyfluoroalkyl substances (PFAS), phthalates, and polycyclic aromatic hydrocarbons (PAH) rather than single chemicals, yet mixture inference is hampered by high dimensionality, correlation, missingness, and left-censoring below limits of detection (LOD). We analyzed 2013–2014 National Health and Nutrition Examination Survey (NHANES) biomarkers (n = 4367) to (i) recover latent, interpretable co-exposure structures and (ii) quantify how these mixtures relate to liver health. To denoise and handle censoring, we applied Principal Component Pursuit with LOD adjustment (PCP-LOD), decomposing the exposure matrix into a non-negative low-rank component (population co-exposure profiles) and a sparse component (individual spikes), and then used Bayesian Kernel Machine Regression (BKMR) to estimate nonlinear and interactive associations with AST, ALT, GGT, ALP, total bilirubin, and the Fatty Liver Index (FLI), retaining analytes with ≥50% detection. PCP-LOD revealed coherent clusters (e.g., long-chain PFAS grouping; shared metal loadings), while the sparse layer highlighted episodic phthalate elevations. BKMR indicated outcome-specific mixture effects: PAHs and selected phthalates showed consistently positive associations with ALP, GGT, and FLI; PFAS (PFOS, PFNA, PFOA) exhibited modest associations with ALP and bilirubin; metals displayed mixed directions. A joint increase in the overall mixture from the 25th to 75th percentile corresponded to an upward shift in FLI and a smaller rise in ALT. This censoring-aware low-rank-plus-sparse framework coupled with flexible mixture modeling recovers actionable exposure architecture and reveals clinically relevant links to liver injury and steatosis, motivating longitudinal and mechanistic studies to strengthen causal interpretation. Full article

Mosquito-borne viruses like West Nile virus (WNV) and Usutu virus (USUV) present growing public health concerns, especially with climate change and expanding vector ranges. This study describes the development and validation of a duplex Real-Time RT-PCR assay targeting β-actin (ACTB) mRNA as an endogenous control and a conserved 92 bp region shared by WNV and USUV genomes. Degenerate primers for ACTB ensure RNA extraction quality and PCR performance while enabling simultaneous detection of both viruses. A total of 1002 mosquito pools collected in Piedmont, Italy, during the 2024 vector season under the National Surveillance Plan for Arboviruses (PNA), were tested. The assay showed 100% accuracy—ACTB mRNA was detected in all pools, and six pools tested positive for WNV or USUV (three each). Diagnostic specificity was confirmed on 40 horse and bovine serum samples. Sanger sequencing confirmed ACTB identity across multiple mosquito species. The assay also demonstrated reproducibility across different operators and thermocyclers. The limit of detection (LOD) evaluation showed that the assay is capable of detecting viral RNA at very low concentrations, confirming its high analytical sensitivity. The duplex RT-PCR here developed is a reliable, sensitive, and specific tool for arbovirus surveillance, combining pathogen detection with internal quality control of RNA extraction and amplification, thus improving early warning and rapid response to mosquito-borne disease threats. Full article

Hepatitis B virus (HBV) represents a significant global health challenge, affecting over 254 million individuals and contributing to 1.1 million deaths from liver-related complications in 2022. The World Health Organization has set ambitious targets to reduce HBV infections and mortality by 2030. However, only a small proportion (13%) of infected individuals receives timely diagnosis and treatment. HBV elimination efforts necessitate substantial improvements in HBV diagnosis, particularly in identifying early-stage infections, occult HBV infections (OBI), and breakthrough cases. The hepatitis B surface antigen (HBsAg) is a key biomarker in HBV diagnosis, serving as a reliable indicator of infection status and treatment response. Conventional HBsAg assays, with a lower limit of detection (LoD) between 0.03 and 250 IU/mL, often fail to detect OBI and HBV reactivation. In contrast, ultrasensitive HBsAg assays, with an LoD as low as 0.005 IU/mL, can improve the identification of low concentration levels of HBsAg, facilitating earlier diagnosis, monitoring of therapeutic response, and assessment for functional cure. Research confirms the superiority of ultrasensitive assays in detecting HBV in cases missed by conventional assays, detecting NAT-yield samples, and enabling earlier detection of HBV reactivation. This review examines the challenges in HBV diagnostics and the clinical utility of ultrasensitive HBsAg assays in improving progress toward global HBV elimination. Full article

Albendazole (ABZ) is a broad-spectrum anthelmintic drug whose residual presence in food and the environment raises public health concerns, requiring rapid and sensitive methods of detection. In this work, a sensitive Fabry–Pérot interferometer (FPI) probe was fabricated by realizing a cavity located at the tip of a single-mode optical fiber core with a molecularly imprinted polymer (MIP) for ABZ detection. The fabrication process involved the development of a photoresist-based micro-hole filled by the specific MIP via thermal polymerization. Interferometric measurements obtained using the proposed sensor system have demonstrated a limit of detection (LOD) of 27 nM, a dynamic concentration range spanning from 27 nM (LOD) to 250 nM, and a linear response at the nanomolar level (27 nM–100 nM). The selectivity test demonstrated no signal when interfering molecules were present, and the application of the sensor for ABZ quantification in a commercial pharmaceutical sample provided good recovery, in accordance with bioanalytical validation standard methods. These results demonstrate the capability of a MIP layer-based FPI probe to provide low-cost and selective optical-sensing strategies, proposing a competitive approach to traditional analytical techniques for ABZ monitoring. Full article

Electrochemical aptasensors have been successfully applied in a number of fields, including food safety, environmental monitoring, and the health sector. They offer a robust and environmentally friendly alternative to antibody-based detection, with the added benefits of flexible design, high chemical and thermal stability, and low immunogenicity. In this work, we present an electrochemical aptasensor based on a semiconducting mesoporous TiO₂:Mn working electrode (WE) for the sensitive detection of tetracycline (TET). The TiO₂:Mn electrodes were fabricated using a scalable screen-printing process, providing a cost-efficient and reproducible platform for sensor development. Specifically, a 5 μM solution of the DNA aptamer with the sequence 5′-CCC CCG GCA GGC CAC GGC TTG GGTTGG TCC CAC TGC GCG-3′ was utilized for the detection of tetracycline (TET) in spiked aqueous samples, across a concentration range of 0.3 to 25.0 ng/mL. Detection was performed via differential pulse voltammetry (DPV) using a Pt wire cathode. The buffer used in the experiment was Tris–HCl (20 mM, pH 7.6), 100 mM of NaCl, MgCl₂ (2 mM), KCl (5 mM), and CaCl₂ (1 mM). The limit of detection (LOD) was calculated to be approximately 1 ng/mL. Full article

Synthetic food colourings are widely used because they are stable, inexpensive, reliable, and effective in shaping consumer perception and behaviour, even though some are under scrutiny for adverse health effects. In this work, we present a new sensitive voltammetric method for the determination of brilliant blue FCF (BB) using a cyclic renewable silver-based mercury film electrode (Hg(Ag)FE). The experimental parameters, including pulse height, step potential, preconcentration potential and duration, and the composition of the supporting electrolyte, were systematically optimised. Under these conditions, the calibration curve exhibited linearity within the range of 0.7 up to 250 µg L⁻¹. For an Hg(Ag)FE with a surface area of 10.9 mm², with a short preconcentration step of 15 s, the limits of detection (LOD) and quantification (LOQ) of BB were 0.24 µg L⁻¹ and 0.72 µg L⁻¹, respectively. The repeatability of the method at a concentration level of the analyte as low as 2.0 µg L⁻¹, expressed as RSD, was 2.39% (n = 6). The proposed method was successfully applied in the analysis of brilliant blue FCF in popular beverages and artificial juices. The obtained results not only verify that BB levels are within acceptable limits, but also enrich the limited data on the quantitative compositions of ‘popular’ beverages. Full article

Fluorescence anisotropy (FA) has been widely used for analyzing biomolecules due to its high throughput, homogeneous detection, and strong resistance to photobleaching. However, the traditional FA method suffers from low sensitivity when the target molecules are small and rotate rapidly, often producing insignificant changes in the FA value. In this study, by combining double signal amplification through the trans-cleavage of CRISPR-Cas12a and DNA tetrahedron assemblies with a large molecular size, a new, fast, simple and highly sensitive FA method was constructed to achieve the quantitative detection of hepatitis B virus DNA (HBV-DNA). The experimental results showed that the linear range of this method was 0.5–9 nmol/L, and the detection limit (LOD = 3σ/k) was 48 pmol/L. In addition, the method demonstrated excellent selectivity and anti-interference, and it was successfully applied to detect HBV-DNA in human serum, indicating that this method has the potential for clinical diagnosis. Full article

Electrochemical detection is widely used in environmental, health, and food analysis due to its portability, low cost, and high sensitivity. However, when analytes with similar redox potentials coexist, overlapping voltammetric signals often occur, which compromises detection accuracy and sensitivity. In this study, a simple second-derivative image sharpening (IS) algorithm is applied to the electrochemical detection of chlorophenol (CP) isomers with similar redox behaviors. Specifically, a graphene-modified electrode was employed for the electrochemical detection of two chlorophenol isomers: ortho-CP (o-CP) and meta-chlorophenol (m-CP) in the range from 1.0 to 10.0 μmol/L. After image-sharpening, the peak potential difference between o- and m-CP increased from 0.08 V to 0.12 V. The limits of detection (LOD) for o-CP and m-CP decreased from 0.6 to 0.9 μmol/L to 0.12 and 0.31 μmol/L, respectively. The corresponding sensitivities also improved from 0.92 to 1.35 A/(mol L⁻¹) to 4.11 and 3.71 A/(mol L⁻¹), respectively. Moreover, the sharpened voltammograms showed enhanced peak resolution, facilitating visual discrimination of the two isomers. These results demonstrate that image sharpening can significantly improve peak shape, peak separation, sensitivity, and detection limit in electrochemical analysis. The obtained algorithm is computationally efficient (<30 lines of C++ (Version 6.0)/OpenCV, executable in <1 ms on an ARM-M0 microcontroller) and easily adaptable to various programming environments, offering a promising approach for data processing in portable electrochemical sensing systems. Full article

YKL-40 is a glycoprotein that may be present at elevated levels in many cancers and neurodegenerative diseases. It has been investigated in numerous studies as a potential biomarker for several conditions, including Alzheimer’s Disease (AD). In this study, a biosensor with Surface Plasmon Resonance imaging (SPRi) detection, sensitive to YKL-40, was constructed for the detection of this analyte in the blood plasma of AD patients. Extensive validation of the biosensor was performed. This included the determination of analytical parameters such as the biosensor’s response characteristics, detection and quantification limits, precision, accuracy, repeatability, selectivity, stability, and performance in natural samples. Validation parameters were primarily tested using standard solutions, while natural samples were employed to evaluate repeatability, stability, and assay accuracy in three groups of samples from different patients. A YKL-40-specific antibody was used as the receptor layer, immobilized on a gold plate using the EDC/NHS protocol on thiol 11-MUA. The biosensor exhibited a wide operating range (1–200 ng/mL), a low detection limit (LOD) of 2 pg/mL, and a quantification limit (LOQ) of 7 pg/mL. High precision and accuracy were confirmed by the calculated standard deviations (SD) and coefficients of variation (CV), which ranged from 0.0009 to 7.02 ng/mL and from 0.12% to 9.24%, respectively. The sensor also demonstrated good repeatability (CV = 4.995%) and was capable of detecting the analyte of interest in complex biological matrices. Its applicability was confirmed in a study using plasma from AD patients and two selected control groups: plasma from smokers and patients with prostatitis. This allowed the assessment of YKL-40 levels across different groups. The results were consistent with literature values, and statistical analysis confirmed the significance of concentration differences between groups. Furthermore, ROC curve analysis confirmed the diagnostic usefulness of the constructed YKL-40 test in the context of Alzheimer’s disease. Full article

Water is a critical resource for both environmental integrity and human health. This study assessed the concentrations of potentially toxic elements (PTEs)—Pb, Cd and Hg—in surface waters adjacent to six urban settlements within the Barranca de Metztitlán Biosphere Reserve (MBR), Mexico. Ecological and health risks were evaluated for vulnerable groups, including children, adolescents, and the elderly. Cd and Hg water concentrations surpassed the national and international water quality criteria at three locations. Ecological and health risk analysis of Pb was not conducted as Pb concentrations were below LOD (0.02 ppm). Ecological risk analysis revealed a low potential risk for Cd exposure but a high risk for Hg at its highest concentration in the reserve. Health risk assessment revealed that Cd and Hg pose a non-carcinogenic risk, particularly to children under three years old. Hazard quotients (HQ) and cumulative risk indices (HI) exceeded safe thresholds at multiple sites. Infants (0–11 months) were the most susceptible, even at contaminant levels near detection limits. These findings emphasize the importance of routine monitoring and early intervention strategies to mitigate exposure risks, especially in vulnerable populations within the MBR. Full article

Foodborne pathogenic bacteria in meat pose a serious threat to human health. Traditional detection methods for these bacteria are often time-consuming and labor-intensive. In this study, we applied surface-enhanced Raman scattering (SERS) combined with portable Raman spectroscopy as a rapid and convenient detection technique. SERS is a sensitive and fast method that enhances light scattering on rough metal surfaces. Silver nanoparticles (AgNPs) were used as SERS substrates to identify and analyze four pathogenic bacteria, including Escherichia coli (E. coli) O157:H7, Salmonella typhimurium (S. typhimurium), Staphylococcus aureus (S. aureus), and Listeria monocytogenes (L. monocytogenes), in beef. We optimized the detection conditions of AgNPs and established the limit of detection (LOD) for these four pathogenic bacteria in both pure culture and beef samples. The LODs were as low as 4–23 CFU/mL in beef samples, indicating high detection sensitivity. Linear discriminant analysis (LDA) was used to analyze the SERS spectra, yielding an accuracy of 91.7–97.3%. This study not only provides a rapid and portable detection method for pathogenic bacteria in beef but also overcomes the limitations of traditional methods that are often time-consuming and not suitable for on-site detection. However, the current study is limited to the detection of the four specific pathogenic bacteria, and further research is needed to expand the range of detectable pathogens and to improve the robustness of the detection models for more complex meat samples. Overall, this research demonstrates the potential of SERS combined with portable Raman spectroscopy as a powerful tool for the rapid detection of pathogenic bacteria in meat products, which could significantly enhance food safety monitoring and control. Full article

Clusterin plays an important role in carcinogenesis and serves as an important diagnostic biomarker of various clinical conditions. This work describes an application of a surface-enhanced Raman scattering (SERS)-based immunoassay using Al foil substrate that has the potential for the detection of clusterin. We first optimized the parameters of the assay using anti-human IgG/human IgG (hIgG) as a model antibody/antigen system using various substrates based on Au film, Si, Al tape and Al foil. Among the tested substrates, Al foil exhibited better performance, when assay of human IgG on Al foil demonstrated a detection limit of 2 pM and a semi logarithmic trend range from 10 pM to 1000 pM. Afterwards, the same SERS immunoassay method was implemented for detection of clusterin and resulted in a good semi-logarithmic calibration line with a high R² value of 0.99, which was obtained in the range from 1 ng/mL to 1000 ng/mL. The low detection limit for clusterin antigen was found to be 3 ng/mL, which is better than most LODs for clusterin reported in the literature and also nearly 4 orders of magnitude lower than possible concentrations of clusterin in human blood. Moreover, the assay requires a relatively low volume of sample (10 μL). Overall, the assay performance demonstrates the significant potential of SERS on Al foil as a low-cost/high-availability substrate for sensing and biosensing, including detection of cancer biomarkers. Full article