Preparation of high-efficiency near-infrared aggregation-induced emission nanoparticles based on FRET and their use in bio-imaging.

Recently, the development of fluorescent probes has contributed to significant advances in cell biology and medical diagnostic imaging. In this work, we use biocompatible bovine hemoglobin (BHb) molecules to co-coat aggregation-induced emission (AIE) molecules amino tetraphenylethylene (TPE-NH) and near-infrared emission molecules 2-(4-aminophenyl)-3-(4-(4-(diphenylamino)styryl)phenyl) fumaronitrile (TPAADFN), to get TPE-NH/TPAADFN@BHb nanoparticles. Due to the fluorescence resonance energy transfer (FRET) between the two fluorescent molecules, the prepared fluorescent nanoparticles have high fluorescence quantum efficiency. The prepared TPE-NH/TPAADFN@BHb nanoparticles also have large Stokes shift, which helps to avoid the cross-talk between the absorption and emission of the particles themselves. This is beneficial to avoid the self-absorption of biological tissues and obtain very high detection sensitivity. Furthermore, due to the good biocompatibility of BHb, TPE-NH/TPAADFN@BHb nanoparticles have good mono-dispersity, low toxicity and high brightness, which is very propitious in the application of bio-imaging.