AIE-active bolaamphiphile assemblies: multifunctional biosensors for mitochondria-targeted cell imaging and fluorescence turn-on BSA sensing in living organisms

There is a persistent need for monitoring bovine serum albumin (BSA) at ultra-low levels, as it plays a significant role in identifying various health conditions and potential risks. Herein, we have developed three multifunctional nanoprobes based on bolaamphiphile assemblies for fluorescence “turn-on” BSA detection in living organisms and mitochondria-targeted cell imaging. The fluorescence intensities of as-prepared AIE-active bolaamphiphiles (TPE-C8-Br, TPE-C8-Ts and TPE-C8-HS) can be effectively enhanced by BSA based on the formation of bolaamphiphiles/BSA aggregates through electrostatic force of attraction between positive charges on the bolaamphiphile and negative charges on BSA. Moreover, the responses were linearly proportional to BSA concentration ranging from 0 to 2000 μg/mL, with low detection limits of 1.4, 0.7 and 1.2 μg/mL, respectively. Besides, three bolaamphiphiles can also be exploited as nanoscale optical biosensors for in vivo imaging based on their good water solubilities, low cytotoxicities and strong biorecognition ability. Bio-imaging studies demonstrated that bolaamphiphile assemblies could be targeted to mitochondrial organelles as specific and efficient mitochondrial tracers. Notably, they enabled BSA detection in live cells and even whole organisms like zebrafish. Thus, our study provides a promising approach for creating a novel class of multifunctional nanobiosensor for imaging of organelles and fluorescence turn-on biomacromolecules sensing in living organisms.