Search Results (65)

Mycotoxins are responsible for a multitude of diseases in both humans and animals, resulting in significant medical and economic burdens worldwide. Conventional detection methods, such as enzyme-linked immunosorbent assay (ELISA), high-performance liquid chromatography (HPLC), and liquid chromatography-tandem mass spectrometry (LC-MS/MS), are highly effective, but they are generally confined to laboratory settings. Consequently, there is a growing demand for point-of-care testing (POCT) solutions that are rapid, sensitive, portable, and cost-effective. Lateral flow assays (LFAs) are a pivotal technology in POCT due to their simplicity, rapidity, and ease of use. This review synthesizes data from 78 peer-reviewed studies published between 2015 and 2024, evaluating advances in nanoparticle-based LFAs for detection of singular or multiplex mycotoxin types. Gold nanoparticles (AuNPs) remain the most widely used, due to their favorable optical and surface chemistry; however, significant progress has also been made with silver nanoparticles (AgNPs), magnetic nanoparticles, quantum dots (QDs), nanozymes, and hybrid nanostructures. The integration of multifunctional nanomaterials has enhanced assay sensitivity, specificity, and operational usability, with innovations including smartphone-based readers, signal amplification strategies, and supplementary technologies such as surface-enhanced Raman spectroscopy (SERS). While most singular LFAs achieved moderate sensitivity (0.001–1 ng/mL), only 6% reached ultra-sensitive detection (<0.001 ng/mL), and no significant improvement was evident over time (ρ = −0.162, p = 0.261). In contrast, multiplex assays demonstrated clear performance gains post-2022 (ρ = −0.357, p = 0.0008), largely driven by system-level optimization and advanced nanomaterials. Importantly, the type of sample matrix (e.g., cereals, dairy, feed) did not significantly influence the analytical sensitivity of singular or multiplex lateral LFAs (Kruskal–Wallis p > 0.05), confirming the matrix-independence of these optimized platforms. While analytical challenges remain for complex targets like fumonisins and deoxynivalenol (DON), ongoing innovations in signal amplification, biorecognition chemistry, and assay standardization are driving LFAs toward becoming reliable, ultra-sensitive, and field-deployable platforms for high-throughput mycotoxin screening in global food safety surveillance. Full article

This paper presents a sensitive and stable fluorescence rapid test sensing system for the quantitative analysis of influenza rapid test results, integrating a detection reader to minimize errors from conventional visual interpretation. The hardware includes a control board, touchscreen, camera module, UV LED illumination, and a dark chamber, while the software handles camera and light source control, as well as image processing. Validation shows strong linearity, high precision, and reproducibility. For influenza A (H1N1), the system achieved a coefficient of determination (R²) of 0.9782 (25–200 ng/mL) and 0.9865 (1–10 ng/mL); for influenza B (Yamagata), the coefficient of determination (R²) was 0.9762 (2–10 ng/mL). The coefficient of variation ranged from 1–5% for influenza A and 4–9% for influenza B. Detection limits were 4 ng/mL for influenza A and 6 ng/mL for influenza B. These results confirm the system’s capability for accurate quantitative analysis while reducing reliance on subjective interpretation. Its compact, portable design supports on-site rapid testing and allows for potential expansion to detect other targets, such as COVID-19, RSV, and myocardial enzymes. The system’s scalability makes it a promising tool for clinical diagnostics, point-of-care testing (POCT), and infectious disease monitoring. Full article

Ciprofloxacin has been extensively utilized in aquaculture due to its remarkable efficacy in preventing and treating bacterial infections in fish animals. However, the widespread application of ciprofloxacin has led to significant residue accumulation, necessitating the development of rapid, sensitive and specific detection methods. In this study, we developed a novel dual-mode quantitative immunochromatographic assay based on a portable reader and a photothermal instrument, enabling on-site ciprofloxacin detection. Under optimized conditions, the portable reader mode (Mode 1) achieved a detection range of 0.1–100.0 ng/L with a limit of detection (LOD) of 0.1 ng/mL. The photothermal instrument mode (Mode 2) achieved a detection range of 0.1–500.0 ng/mL with an LOD of 0.1 ng/mL. The sensitivity and accuracy of the method were validated using an Enzyme-Linked Immunosorbent Assay. This developed method successfully detected ciprofloxacin residues in samples of Parabramis pekinensis, Larimichthys crocea, Channa argus, Carassius auratus and Micropterus salmoides, with satisfactory recovery rates. The results demonstrated excellent specificity and applicability across various fish product matrices, offering a reliable and efficient solution for the on-site monitoring of ciprofloxacin residues in fish products. Full article

Heavy and transition metal (HTM) ions have significant harmful effects on the physical environment and play crucial roles in biological systems; hence, it is crucial to accurately identify and quantify any trace pollution. Molecular sensors which are based on organic molecules employed as optical probes play a crucial role in sensing and detecting toxic metal ions in water, food, air, and biological environments. When appropriate combinations of conduction and selective recognition are combined, fluorescent and colorimetric chemosensors are appealing instruments that enable the selective, sensitive, affordable, portable, and real-time investigation of the possible presence of heavy and transition metal ions. This feature article aims to provide readers with a more thorough understanding of the different methods of synthesis and how they work. As noted in the literature, we will highlight colorimetric and fluorometric sensors based on their receptors into multiple categories for heavy metal ion detection, such as Hg²⁺, Ag²⁺, Cd^2+, Pb²⁺, and In³⁺, and simultaneous multiple-ion detection. Full article

Copper ions (Cu²⁺) are the third most essential transition metal ions critical to human health. Rapid detection of Cu²⁺ in water and biological fluids is of significant importance. In this study, we develop a sensitive multi-channel paper microfluidic device integrated with a 3D-printed smartphone-based colorimetric reader for the rapid detection of Cu²⁺. A novel rhodamine derivative, 1-(N,N-dichloromethine) amino-4-rhodamine B hydrazine-benzimide (RBCl), exhibiting high selectivity and sensitivity to Cu²⁺, was synthesized and applied as the detection reagent. The interaction mechanism between RBCl and Cu²⁺ was investigated, revealing a structural transition from a colorless spirolactam (closed-ring) to an open-ring amide structure, resulting in a pink color upon Cu²⁺ binding. A multi-channel paper microfluidic device with eight detection zones was fabricated, enabling the simultaneous analysis of eight samples. To enhance portability and quantification, a 3D-printed smartphone colorimetric reader was integrated, providing a rapid and efficient detection platform. The system achieved highly specific Cu²⁺ detection within 2 min, with a detection limit as low as 1.51 ng/mL, meeting water monitoring standards in most countries. Excellent recoveries were demonstrated in real samples, including tap water, river water, blood serum, and urine diluent. This integrated paper microfluidic system is highly sensitive and specific, offering a promising solution for water quality monitoring and health assessment through its rapid sample-to-answer capability. Full article

Point-of-care (POC) testing has revolutionized diagnostics by providing rapid, accessible solutions outside traditional laboratory settings. However, many POC systems lack the sensitivity or multiplexing capability required for complex diseases. This study introduces an LED-based fluorescence reader designed for POC applications, enabling multiplex detection of lupus nephritis (LN) biomarkers using a biomarker microarray (BMA) slide. The reader integrates an LED excitation source, neutral density (ND) filters for precise intensity control, and onboard image processing with Gaussian smoothing and centroid thresholding to enhance signal detection and localization. Five LN biomarkers (VSIG4, OPN, VCAM1, ALCAM, and TNFRSF1B) were assessed, and performance was validated against a Genepix laser-based scanner. The LED reader demonstrated strong correlation coefficients (r = 0.96–0.98) with the Genepix system for both standard curves and patient samples, achieving robust signal-to-noise ratios and reproducibility across all biomarkers. The multiplex format reduced sample volume and allowed simultaneous analysis of multiple biomarkers. These results highlight the reader’s potential to bridge the gap between laboratory-grade precision and POC accessibility. By combining portability, cost-effectiveness, and high analytical performance, this fluorescence reader provides a practical solution for POC diagnostics, particularly in resource-limited settings, improving the feasibility of routine monitoring and early intervention for diseases requiring comprehensive biomarker analysis. Full article

We present a lateral flow aptasensor for the visual detection of alpha-fetoprotein (AFP) in human serum. Leveraging the precise molecular recognition capabilities of aptamers and the distinct optical features of gold nanoparticles, a model system utilizing AFP as the target analyte, along with a pair of aptamer probes, is implemented to establish proof-of-concept on standard lateral flow test strips. It is the first report of an antibody-free lateral flow assay using aptamers as recognition probes for the detection of AFP. The analysis circumvents the numerous incubation and washing steps that are typically involved in most current aptamer-based protein assays. Qualitative analysis involves observing color changes in the test area, while quantitative data are obtained by measuring the optical response in the test zone using a portable strip reader. The biosensor exhibits a linear detection range for AFP concentrations between 10 and 100 ng/mL, with a minimum detection limit of 10 ng/mL. Additionally, it has been successfully applied to detect AFP in human serum samples. The use of aptamer-functionalized gold nanoparticle probes in a lateral flow assay offers great promise for point-of-care applications and fast, on-site detection. Full article

There is a growing field that is devoted to developing inexpensive microscopes and measurement devices by leveraging low-cost commercial parts that can be controlled using smartphones or embedded devices, such as Arduino and Raspbery Pi. Examples include the use of Blu-ray optical heads like the PHR-803T to perform cytometry, spinning disc microscopy, and lensless holographic microscopy. The modular or disposable nature of these devices means that they can also be used in contaminating and degrading environments, including radioactive environments, where replacement of device elements can be expensive. This paper presents the development and operation of a confocal microscope that uses the PHR-803T optical device in a Blu-ray reader for both imaging and detection of temperature variations with between 1.5 and 15 µm resolution. The benefits of using a PHR-803T confocal system include its relatively inexpensive design and the accessibility of the components that are used in its construction. The design of this scanning confocal thermal microscope (SCoT) was optimized based on cost, modularity, portability, spatial resolution, and ease of manufacturability using common tools (e.g., drill press, 3D printer). This paper demonstrated the ability to resolve microscale features such as synthetic spider silk and measure thermal waves in stainless steel using a system requiring <USD 1000 in material costs. Full article

We report a low-cost, portable biosensor composed of an aptamer-functionalized nanoporous anodic aluminum oxide (NAAO) membrane and a commercial microcontroller chip-based impedance reader suitable for electrochemical impedance spectroscopy (EIS)-based sensing. The biosensor consists of two chambers separated by an aptamer-functionalized NAAO membrane, and the impedance reader is utilized to monitor transmembrane impedance changes. The biosensor is utilized to detect amodiaquine molecules using an amodiaquine-binding aptamer (OR7)-functionalized membrane. The aptamer-functionalized membrane is exposed to different concentrations of amodiaquine molecules to characterize the sensitivity of the sensor response. The specificity of the sensor response is characterized by exposure to varying concentrations of chloroquine, which is similar in structure to amodiaquine but does not bind to the OR7 aptamer. A commercial potentiostat is also used to measure the sensor response for amodiaquine and chloroquine. The sensing response measured using both the portable impedance reader and the commercial potentiostat showed a similar dynamic response and detection threshold. The specific and sensitive sensing results for amodiaquine demonstrate the efficacy of the low-cost and portable biosensor. Full article

Novel low-cost portable spectrophotometers could be an alternative to traditional spectrophotometers and calibrated RGB cameras by offering lower prices and convenient measurements but retaining high colorimetric accuracy. This study evaluated the colorimetric accuracy of low-cost, portable spectrophotometers on the established color calibration target—RAL Design System Plus (RAL+). Four spectrophotometers with a listed price between USD 100–1200 (Nix Spectro 2, Spectro 1 Pro, ColorReader, and Pico) and a smartphone RGB camera were tested on a representative subset of 183 RAL+ colors. Key performance metrics included the devices’ ability to match and measure RAL+ colors in the CIELAB color space using the color difference CIEDE2000 ΔE. The results showed that Nix Spectro 2 had the best performance, matching 99% of RAL+ colors with an estimated ΔE of 0.5–1.05. Spectro 1 Pro and ColorReader matched approximately 85% of colors with ΔE values between 1.07 and 1.39, while Pico and the Asus 8 smartphone matched 54–77% of colors, with ΔE of around 1.85. Our findings showed that low-cost, portable spectrophotometers offered excellent colorimetric measurements. They mostly outperformed existing RGB camera-based colorimetric systems, making them valuable tools in science and industry. Full article

Malaria poses a serious global health problem, with half the world population being at risk. Regular screening is crucial for breaking the transmission cycle and combatting the disease spreading. However, current diagnostic tools relying on blood samples face challenges in many malaria-epidemic areas. In the present study, we demonstrate the detection of the malaria-causing Plasmodium parasite in non-invasive saliva samples (N = 61) from infected individuals by combining a DNA-based Rolling-circle-Enhanced-Enzyme-Activity-Detection (REEAD) sensor system with a chemiluminescence readout that could be detected with an in-house-developed affordable and battery-powered portable reader. We successfully transferred the technology to sub-Saharan Africa, where the malaria burden is high, and demonstrated a proof of concept in a small study (N = 40) showing significant differences (p < 0.00001) between malaria-positive individuals (N = 33) and presumed asymptomatic negative individuals (N = 7) all collected in Gabon. This is the first successful application of the REEAD sensor system for the detection of malaria in saliva in a high-epidemic area and holds promise for the potential future use of REEAD for malaria diagnosis or surveillance based on non-invasive specimens in sub-Saharan Africa. Full article

Herein, we present a novel approach to quantify ferritin based on the integration of an Enzyme-Linked Immunosorbent Assay (ELISA) protocol on a Graphene Field-Effect Transistor (gFET) for bioelectronic immunosensing. The G-ELISA strategy takes advantage of the gFET inherent capability of detecting pH changes for the amplification of ferritin detection using urease as a reporter enzyme, which catalyzes the hydrolysis of urea generating a local pH increment. A portable field-effect transistor reader and electrolyte-gated gFET arrangement are employed, enabling their operation in aqueous conditions at low potentials, which is crucial for effective biological sample detection. The graphene surface is functionalized with monoclonal anti-ferritin antibodies, along with an antifouling agent, to enhance the assay specificity and sensitivity. Markedly, G-ELISA exhibits outstanding sensing performance, reaching a lower limit of detection (LOD) and higher sensitivity in ferritin quantification than unamplified gFETs. Additionally, they offer rapid detection, capable of measuring ferritin concentrations in approximately 50 min. Because of the capacity of transistor miniaturization, our innovative G-ELISA approach holds promise for the portable bioelectronic detection of multiple biomarkers using a small amount of the sample, which would be a great advancement in point–of–care testing. Full article

With the steady increase in allergy prevalence worldwide, there is a strong need for novel diagnostic tools for precise, fast, and less invasive testing methods. Herein, a miniatured fluorescence-based biosensing system is developed for the rapid and quantitative detection of allergen-specific immunoglobulin-E. An antibody-based fluorescence assay in a microfluidic-patterned slide, combined with a custom-made portable fluorescence reader for image acquisition and user-friendly software for the data analysis, enables obtaining results for multiple allergens in just ~1 h with only 80 μL of blood serum. The multiplexed detection of common birch, timothy grass, cat epithelia, house dust mite, and dog epithelia shows quantitative IgE-mediated allergic responses to specific allergens in control serum samples with known total IgE concentration. The responses are verified with different control tests and measurements with a commercial fluorescence reader. These results open the door to point-of-care allergy screening for early diagnosis and broader access and for large-scale research in allergies. Full article

A miniaturized multi-array system is being developed for immune-signature testing. The presented system includes microfluidic chips functionalized with allergens for IgE detection and a custom-made portable reader for fast (~1 s), quantitative, and sensitive (500 dye molecules/μm²) detection, with a high spatial resolution (~50–100 μm). The developed solution enables the rapid sensing of allergic reactions at the point of care with a low-cost portable device. Full article

To improve the efficiency and patient coverage of the current healthcare system, user-friendly novel homecare devices are urgently needed. In this work, we developed a smartphone-based analyzing and reporting system (SBARS) for biomarker detection in lupus nephritis (LN). This system offers a cost-effective alternative to traditional, expensive large equipment in signal detection and quantification. This innovative approach involves using a portable and affordable microscopic reader to capture biomarker signals. Through smartphone-based image processing techniques, the intensity of each biomarker signal is analyzed. This system exhibited comparable performance to a commercial Genepix scanner in the detection of two potential novel biomarkers of LN, VISG4 and TNFRSF1b. Importantly, this smartphone-based analyzing and reporting system allows for discriminating LN patients with active renal disease from healthy controls with the area-under-the-curve (AUC) value = 0.9 for TNFRSF1b and 1.0 for VSIG4, respectively, indicating high predictive accuracy. Full article