Efficient selection of vancomycin-specific aptamers via particle display and development of a high-sensitivity fluorescent apta-sensor for vancomycin detection

Vancomycin is a glycopeptide antibiotic medication employed in the treatment of various bacterial infections. In this work, we employed a novel single round high-throughput identification method based on particle display to acquire DNA aptamers specific to small molecules. Our method simplifies the traditional SELEX process for small molecule targets by enabling direct selection of affinity aptamers from the enriched library via fluorescence-activated cell sorting (FACS). Using this strategy, we obtained three aptamers for vancomycin. Notably, these aptamers were less prevalent in conventional screening library. Among them, the aptamer XN1 demonstrated a dissociation constant ( K d ) of 38.7   μM as determined by isothermal titration calorimetry. Additionally, a designed fluorescent aptamer-based biosensor (apta-sensor) exhibited a limit of detection (LOD) of 0.7   μM for vancomycin. This apta-sensor was successfully applied to quantify vancomycin in 90% wastewater samples and functioned effectively in 90% human serum.