The COVID‐19 pandemic, which began in 2019, has highlighted the importance of testing and tracking infected individuals as a means of mitigating the spread of the virus. In this context, the development of sensitive and rapid methods for the detection of SARS‐CoV‐2, the virus responsible for COVID‐19, is crucial. Herein, a biosensor based on oligonucleotide‐gated nanomaterials for the specific detection of SARS‐CoV‐2 spike protein is presented. The sensing system consists of a nanoporous anodic alumina disk loaded with the fluorescent indicator rhodamine B and capped with a DNA aptamer that selectively binds the SARS‐CoV‐2 spike protein. The system is initially evaluated using pseudotype virus systems based on vesicular stomatitis virus carrying different SARS‐CoV‐2 S‐proteins on their surface. When the pseudotype virus is present, the cap of the solid is selectively removed, triggering the release of the dye from the pore voids to the medium. The nanodevice demonstrated its ability to detect pseudotype virus concentrations as low as 7.5·10³ PFU mL. In addition, the nanodevice is tested on nasopharyngeal samples from individuals suspected of having COVID‐19.

Vibrio vulnificus , a marine pathogen and climate change biomarker, poses serious risks to human and animal health through seafood consumption and seawater exposure. Rapid detection methods are urgently needed for both vibriosis diagnosis and surveillance in warming coastal waters. We report a fluorogenic biosensor based on nanoporous anodic alumina loaded with rhodamine B and capped with an oligonucleotide probe targeting a unique sequence of the vvhA cytolysin gene, specific to V. vulnificus . In the presence of the target DNA, the probe is displaced, pores open, and the fluorophore is released, generating a measurable signal. The biosensor exhibited high sensitivity and selectivity across diverse matrices, including fish mucus and serum, human serum, sterilized brackish water, and—critically—unprocessed natural lake and seawater samples, without DNA extraction or amplification. Detection limits ranged between 10² and 5 × 10² CFU mL⁻¹, comparable in sensitivity to state‐of‐the‐art qPCR assays. The biosensor outperformed conventional approaches in speed, simplicity, and cost‐effectiveness, while maintaining accuracy. These findings underscore the potential of this platform for integrated One Health applications, bridging environmental monitoring with rapid diagnosis of vibriosis in humans and animals. Preliminary results from this study were previously made available as a preprint in SSRN (DOI: https://ssrn.com/abstract=5032822 ).

Desulfovibrio vulgaris is an anaerobic microorganism belonging to the group of sulphate-reducing bacteria (SRB). SRB form biofilms on metal surfaces in water supply networks, producing a microbiologically influenced corrosion (MIC). This process produces the deterioration of metal surfaces, leading to high economic costs and different environmental safety and health problems related to its chemical treatment. For that reason, rapid and accurate detection methods of SRB are needed. In this work, a new detection system for Desulfovibrio has been developed using gated nanoporous materials. The probe is based on hybrid nanoporous alumina films encapsulating a fluorescent molecule (rhodamine B), whose release is controlled by an oligonucleotide gate. Upon exposure to Desulfovibrio’s genomic material, a movement of the oligonucleotide gatekeeper happens, resulting in the selective delivery of the entrapped rhodamine B. The developed material shows high selectivity and sensitivity for detecting Desulfovibrio DNA in aqueous buffer and biological media. The implementation of this technology for the detection of Desulfovibrio as a tool for monitoring water supply networks is innovative and allows real-time in situ monitoring, making it possible to detect the growth of Desulfovibrio inside of pipes at an early stage and perform timely interventions to reverse it.