Rapid Antigen Biosensor Detects Active Tuberculosis in One Hour

The World Health Organization’s 2024 global report cites it as the leading cause of death from a single infectious agent. Rapid and reliable diagnosis is critical to interrupt transmission and initiate appropriate therapy. A new study shows a sensor-based approach that detects active disease within 60 minutes.

At the Inter-University Institute for Molecular Recognition and Technological Development (IDM) at the Universitat Politècnica de València (Valencia, Spain), investigators developed an antibody-coated nanoporous anodic alumina biosensor that targets the MPT64 antigen, a marker of active tuberculosis. The platform incorporates a nanoporous matrix loaded with a fluorescent reporter and capped with an antibody specific to MPT64. When the antigen is present, displacement of the antibody opens the pores and releases the fluorescent molecule, generating a detectable light signal.

According to the research team, trials demonstrated a very low detection limit and high selectivity against proteins from other respiratory pathogens, including influenza viruses, SARS-CoV-2, respiratory syncytial virus, and non-tuberculous mycobacteria. The device was further assessed using cultured clinical samples obtained from patients. Results were delivered in approximately one hour, markedly shorter than microbiological culture, which can require several weeks.

In a final validation using 20 cultures of respiratory samples from patients with tuberculosis, the system achieved a sensitivity of 80% and a specificity of 90%, with favorable predictive values. The authors note that the biosensor is designed to discriminate active infection by detecting a secreted bacterial protein rather than nucleic acid fragments. The researchers point to its simplicity and selective detection as key attributes.

The study was published in Talanta. It was led by IDM at the Universitat Politècnica de València and the Universitat de València, with participation from the UPV–IIS La Fe Joint Research Unit on Nanomedicine and Sensors, the CIBER Center for Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), the UPV–CIPF Joint Research Unit for Disease Mechanisms and Nanomedicine, and the Microbiology Department and Severe Infection Group at Hospital Universitari i Politècnic La Fe. The team highlights potential utility in resource-poor settings where advanced techniques are less accessible.

"One of the main innovations of the biosensor is that it detects active disease, which is particularly significant because other molecular techniques, such as PCR, can identify fragments of bacterial DNA without distinguishing whether the infection is active, past or latent. In contrast, this system recognizes a protein secreted by the bacterium during active infection, providing more accurate information from a clinical perspective," said Ramón Martínez Máñez, head of the NANOSENS group at IDM-UPV and the Joint Unit for Nanomedicine and Sensors at IIS La Fe.

"In the final validation we conducted with 20 cultures of respiratory samples from tuberculosis patients, the system achieved a sensitivity of 80% and a specificity of 90%, with good predictive values, confirming its potential as a diagnostic tool," said Dr. Ana Gil, from the Microbiology Department at the Hospital Universitari i Politècnic La Fe in Valencia.

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