Rapid detection of Bacillus cereus spores is essential for preventing food contamination and spoilage. Many existing methods detect B. cereus vegetative cells rather than spores and cannot be applied directly to foods. Here, we present a combination of aptamers targeting different moieties on the surface of B. cereus spores with rapid electrochemical detection. When DNA aptamers, previously selected for B. cereus spores, were immobilized on screen-printed gold electrodes, they exhibited higher binding capacity than individual aptamers, suggesting a synergistic effect. Additionally, the mixture of rhodamine-labelled aptamers enabled spatial fluorescent visualization of the B. cereus endospore structure, confirming the increased binding efficiency. The electrochemical aptasensor based on three aptamers exhibited a wide dynamic range (10²-10⁷ CFU/mL) and low limit of detection (∼1 CFU/mL) using just 15 μL of sample. Validation in spiked salad, using direct spore sensing in rinse water and comparison with the culturing method, confirmed its sensitivity and specificity. These combined aptamer approaches, achieving rapid (15 min) and single-step detection may also be suitable for detecting other foodborne pathogens.

The rapid and sensitive detection of regulatory elements within transgenic constructs of genetically modified organisms (GMOs) is essential for effective monitoring and control of their distribution. In this study, we present several innovative electrochemical biosensing platforms for the detection of regulatory sequences in genetically modified (GM) plants, combining the loop-mediated isothermal amplification (LAMP) method with electrodes functionalized by two-dimensional (2D) nanomaterials. The sensor design exploits the high surface area and excellent conductivity of reduced graphene oxide, Ti₃C₂T_x, and molybdenum disulfide (MoS₂) to enhance signal transduction. Furthermore, we used a “green synthesis” method for Ti₃C₂T_x preparation that eliminates the use of hazardous hydrofluoric acid (HF) and hydrochloric acid (HCl), providing a safer and more sustainable approach for nanomaterial production. Within this framework, the performance of various custom-fabricated electrodes, including laser-patterned gold leaf films, physical vapor deposition (PVD)-deposited gold electrodes, and screen-printed gold electrodes, is evaluated and compared with commercial screen-printed gold electrodes. Additionally, gold and carbon electrodes were electrochemically covered by gold nanoparticles (AuNPs), and their properties were compared. Several electrochemical methods were used during the DNA detection, and their importance and differences in excitation signal were highlighted. Electrochemical properties, sensitivity, selectivity, and reproducibility are characterized for each electrode type to assess the influence of fabrication methods and material composition on sensor performance. The developed biosensing systems exhibit high sensitivity, specificity, and rapid response, highlighting their potential as practical tools for on-site GMO screening and regulatory compliance monitoring. This work advances electrochemical nucleic acid detection by integrating environmentally-friendly nanomaterial synthesis with robust biosensing technology.

Advances in isothermal amplification, combined with microfluidics and diverse readouts, enable rapid, sensitive, and portable bacterial detection.

This review critically highlights recent breakthroughs in eco-friendly biosensors utilizing natural pigments, exploring their structural mechanisms and diverse applications in monitoring environmental pollutants, pH variations, and pathogen genes.