Detecting live bacteria instantly utilizing AIE strategies.

A new class of biosensor molecules evoking fluorescent emission by rotation-restricted binding with bacteria was examined for its applicability in detecting live bacteria instantly. The fluorogens possessed multiple tetraphenylethene (TPE)-cored boronic acids to oligomerize through complexation with cis-diols on bacterial surfaces, resulting in aggregation-induced emission (AIE). The fluorogen having two boronic acid units discriminated between live and dead bacteria by showing AIE activity only with the latter. Live bacteria were instantly detected by consequent treatment with reagents of three and four di-boronates (which showed AIE activity with both live and dead bacteria). This phenomenon may lead to a practical method for live bacteria detection.