Aptamers in Brucellosis: Diagnostic Advances, Current Challenges and Future Perspectives

Brucellosis, caused by Brucella species, is a major zoonosis with global health and economic burdens. Conventional diagnostics suffer from slow culture, biosafety risks, cross-reactivity, and equipment dependence. Aptamers, synthetic single-stranded oligonucleotides selected via Systematic Evolution of Ligands by Exponential Enrichment (SELEX), offer promising alternatives to antibodies. This review focuses primarily on recent advances in aptamer-based diagnostic technologies for brucellosis. The success of Brucella-specific aptamers is largely attributed to the development of whole-cell-based SELEX strategies and counter-selection against non-target bacteria, which help overcome the complexity of the Brucella outer membrane and improve target specificity. Brucella-specific aptamers such as B20 (KD = 40.179 pM), B21 (KD = 184.396 pM), and WS-6 (KD = 16.23 nM) exhibit high affinity and specificity. Integrated into biosensors, they enable detection limits as low as 1.5×10¹ CFU/mL (colorimetric) and 27 cells/mL (surface plasmon resonance). While aptamer-nanoparticle conjugates also show therapeutic potential against intracellular infections via immun4omodulation, this aspect remains secondary and requires further validation, and toxicity concerns remain. Despite progress, clinical validation, matrix interference, and regulatory hurdles persist. Future directions include multi-target aptamers, nanomaterial integration, and point-of-care translation. This review underscores the central role of aptamers in brucellosis diagnosis, with complementary therapeutic potential.