Dual model fluorescent probe for BSA and tetracycline derivatives based on dipyridinyltriphenylamine and indole-fused-naphthalimide

Abstract

A fluorescent probe (DPTPA5) was designed and synthesized by conjugating the dipyridinyltriphenylamine and indole-fused naphthalimine moities. DPTPA5 outputs the ratiometric response towards bovine serum protein (BSA) and “turn off” response towards the tetracycline (TC), respectively. With the intrinsic emission around 515 nm and 710 nm, DPTPA5 can provide ratiometric detection for BSA. With addition of BSA, the ratiometric signal (I515/I710) changes from 0.23 ± 0.01 to 1.98 ± 0.03, gradually. The limit of detection (LOD) of the probe is calculated at 2 μg/mL (0.18 nM) for BSA. On the other hand, DPTPA5 outputs a quenching signal in the NIR channel at the presence of TC. The fluorescent intensity at 710 nm decreased to 46.43 ± 2.7% of the original intensity when 60 μM TC was added in the solution. The LOD value is calculated at 12 μM for TC. It is valuable that this work provides a method for integrating the dual sensing modes in one molecule that achieves the individual detection of different analytes.