An aptamer beacon responsive to botulinum toxins

► Two related aptamer beacons are described which detect botulinum holotoxins A, B, and E to low ng/mL levels. ► The best beacon does not work in 50% human serum, but could still detect low levels of botulinum toxins in a dilute soil suspension indicating that it could function for a rapid (15-20 min) environmental field test using a commercially available portable fluorometer. ► Similarities to other published botulinum aptamer sequences are discussed.