Jafar Soleymani

Ochratoxin A (OTA) is a potent mycotoxin produced by Aspergillus and Penicillium species, frequently contaminating a variety of food commodities, including cereals, coffee, grapes, and processed food products. Its high stability and strong nephrotoxic, immunosuppressive, teratogenic, and carcinogenic properties make OTA one of the most significant mycotoxins of concern for both the food industry and public health. Conventional analytical methods offer high sensitivity and accuracy; however, their application is often limited due to high costs, lengthy preparation times, the need for expensive instrumentation, and the requirement for skilled operators. Therefore, there is a growing demand for alternative detection strategies that are cost-effective, portable, selective, and suitable for rapid on-site analysis. In the present study, a copper oxide (CuO) cluster like nanoparticles (CuO c-NPs)/reduced-graphene oxide (rGO)/molecularly imprinted polymer (MIP)-based electrochemical sensor was fabricated onto a gold electrode surface for the selective recognition and detection of OTA in coffee, almond, and pistachio samples. The CuO c-NPs/rGO sensing layer was prepared through electro-polymerization of pyrrole monomers in the presence of OTA as a template molecule, resulting in highly specific binding sites complementary in shape, size, and functional groups to the target analyte. After template removal, the MIP-modified gold electrode was characterized using different spectroscopic and electrochemical techniques. The developed sensor showed a linear relationship between peak current intensity and OTA concentration in the range of 0.1 to 1000 ng/mL, with a limit of detection (LOD) of 35 pg/mL. Moreover, the sensor showed excellent reproducibility (i.e. <5.0%) and stability (i.e. ~28 days), making it suitable for accurate detection of OTA. Validation studies confirmed high recovery rates and accuracy, highlighting its potential for real-sample applications.

Early cancer diagnosis is vital for improving patient survival. The present work uses a novel and label-free baseline calibrated electrochemical immunosensor for the sensitive detection of carcinoembryonic antigen (CEA). The sensor platform was constructed on a glassy carbon electrode (GCE) modified with electro-synthesized silver nanoparticles (e-AgNPs) and carboxyl-functionalized NiFe₂O₄ nanoparticles (cit-NFO-COOH). This nanocomposite enhanced the electrode surface area, conductivity, and antibody immobilization stability. Comprehensive material characterization was performed using Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX), X-Ray diffraction analysis (XRD), and dynamic light scattering (DLS), and zeta potential analysis, while electrochemical performance was evaluated via cyclic and differential pulse voltammetry. Optimization studies disclosed that the optimal concentrations for AgNO₃, cit-NFO-COOH, and antibody were 0.05 mM, 1000 mg/L, and 20 µg/mL, respectively. The fabricated immunosensor exhibited a wide linear detection range (0.1 pg/mL to 10 ng/mL) with a linear regression equation of y = 0.2306ln [CEA] + 3.0227 (R² = 0.999) and an exceptionally low detection limit of 0.09 pg/mL. The precision and accuracy of the probe for intraday and interday tests were assessed as mean relative standard deviation (RSD%) and relative error (RE%) with values of 4.1%, 3.0%, 10.2%, and 10.9%, respectively. Also, specificity was tested in the presence of various biologically available biomarkers and biomolecules with absolute mean change of 8.2%. The validation results were confirmed following the Food and Drug Administration (FDA) guidelines for developing sensing platforms in biological media. The high sensitivity and stability of this biosensor highlight its significant potential as a powerful tool for clinical application in cancer biomarker monitoring. Graphical Abstract

The analysis of recognized biomarkers associated with certain diseases typically occurs in centralized laboratories, leading to considerable delays and elevated expenses. This is particularly concerning for cancer, which continues to be a major global public health issue with high mortality rates. In response, oncological biomarker screening assays have garnered considerable interest as a cost-effective tool for real-time diagnosis, particularly for early detection applications. To address these challenges, the miniaturization of sensor devices has facilitated improved integration with monitoring systems. Label-free biosensors have recently gained popularity as an alternative for quantifying biomolecules owing to their notable advantages, including high sensitivity, rapid analysis, ease of use, minimal handling, simple pretreatment, and low cost. This study provides a thorough assessment of label-free biosensing platforms for cancer biomarkers based on the promising results reported in scientific literature. It emphasizes the application of various materials for each sensor and contrasts existing challenges, providing insights for future investigations into label-free sensing.

The overexpression of folate receptors (FR) on the surface Michigan Cancer Foundation 7 (MCF-7) cancer cells offers a strategic target for enhancing cancer imaging and diagnostic accuracy due to their high affinity toward folic acid (FA). Graphene quantum dots (GQDs) were synthesized via thermal pyrolysis and chelated with terbium (Tb) ions. These Tb-GQDs were then coated with a silica layer and functionalized with FA, resulting in a fluorescent nanoprobe specifically designed for targeted bioimaging of FR-positive cells. The synthesized Tb-GQDs-SiO₂-APTES-NH₂-FA nanoprobe demonstrated intense fluorescence emission at 425 nm upon excitation at 310 nm. Characterization of the nanoprobe revealed a high quantum yield (QY) of 29%, along with excellent photostability and favourable optical properties, establishing its efficacy as a tool for specifically targeting FR on MCF-7 cancer cells. Qualitative analysis via fluorescence microscopy confirmed the successful and specific uptake of Tb-GQDs-SiO₂-APTES-NH₂-FA by MCF-7 cells, which was evaluated across varying incubation times and concentrations. Cytotoxicity assays further confirmed the biocompatibility of the nanoprobe at concentrations up to 1000 µg/mL, with cell viability remaining above 90%. These findings collectively suggest that Tb-GQDs-SiO₂-APTES-NH₂-FA holds significant potential for future in vivo cancer cell imaging applications. In conclusion, the Tb-GQDs-SiO₂-APTES-NH₂-FA nanoprobe represents a promising and biocompatible platform for the targeted bioimaging of cancer cells, with strong implications for improving diagnostic precision in breast cancer.

MicroRNAs (miRNAs) are stable and accessible biomarkers for disease diagnosis. Elevated levels of human cytomegalovirus (HCMV)-encoded miRNA-UL22A-5p (miR-

Doxorubicin (DOX), a potent anticancer drug, requires sensitive and precise detection due to its narrow therapeutic window. In this study, a novel electrochemical sensor was developed by electrodepositing silver nanoprisms (AgNPrs), Fe₃O₄ nanoparticles, and reduced graphene oxide aerogel (rGOA) on a glassy carbon electrode (GCE). The cyclic voltammetry technique was utilized for electrodeposition of Fe₃O₄@rGOA/AgNPrs nanocomposite within a potential range of − 1.0 to + 1.0 V. The Fe₃O₄@rGOA/AgNPrs–modified GCE probe was optimized for the detection and quantification of DOX in human plasma samples. At an optimized pH of 6, DOX exhibited distinct redox behavior on the modified electrode. Differential pulse voltammetry was employed for the quantification of DOX and showed a wide linear dynamic range (0.075 to 5.0 µg/mL) with a low limit of quantification (LLOQ) of 0.075 µg/mL and limit of detection (LOD) of 0.028 µg/mL in blood plasma. The developed sensor demonstrated excellent sensitivity, selectivity, and reproducibility, enabling direct quantification of DOX in plasma samples. These findings underscore the potential of the proposed sensor as a reliable, efficient, and cost-effective platform for therapeutic drug monitoring and clinical diagnostics.

Salmonella Typhimurium (S. Typhimurium) is one of the most common food-borne diseases, highlighted as the top food-borne bacterial pathogen in the world with a low infectious dose (1 CFU) and high mortality rate. It is commonly associated with numerous foods such as dairy products, protein sources (multiple types of meat, poultry, and eggs), and bakery products. Therefore, an accurate and rapid detection method for this bacterium is always needed. This study used a fluorescent platform based on extraction and detection of the S. Typhimurium in eggs. Specifically, S. Typhimurium was isolated using aptamer-functionalized magnetic nanoparticles and then detected using a fluorescent method by aptamer-functionalized metal–organic frameworks. Under optimal conditions, this study achieved a linear detection range of 7.5 to 7.5 × 10⁶ CFU/mL, a detection limit of 4.61 CFU/mL, and a total detection time of 90 min. The recovery range for egg samples was 97.0–101.0%, proposing high accuracy of the developed probe in real samples. Also, the specificity study results confirmed excellent selectivity of the probe in the presence of non-target bacteria, arising from the stable interactions between the S. Typhimurium and aptamer-functionalized probes. This platform serves as an effective in situ probe for fast and reliable control of eggs and may also be validated for other food samples. Graphical Abstract