Affiliation:
1. Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging School of Biomedical Engineering Shenzhen University Medical School Shenzhen University Shenzhen Guangdong 518055 China
2. College of Physics and Optoelectronic Engineering Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province Shenzhen University Shenzhen 518060 China
3. Guangdong and Hong Kong Joint Research Centre for Optical Fiber Sensors College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen 518060 China
Abstract
AbstractLuminogens with aggregation‐induced emission characteristics (AIEgens) are considered good options for two‐photon (2P) probes, owing to their flexibility of design, heavy‐metal‐free composition, and resistance to photobleaching. However, the design principles for large 2P absorption cross‐section (δ) generally require high coplanarity, strong donor–acceptor (D‐A) interactions, and long conjugation, which can severely weaken the brightness of AIEgens at the aggregated state and undermine their potential in 2P fluorescence imaging (2PFI). Exploration of a feasible approach to overcome the “Buckets Effect” of AIEgen‐based 2P probes is thus a fascinating yet challenging task. Herein, an AIEgen, namely (Z)‐2‐(4‐aminophenyl)‐3‐(5‐(4‐(bis(4‐methoxyphenyl)amino)phenyl)thiophen‐2‐yl)acrylonitrile (MTAA) is designed to have a big δ according to the calculation result and a low fluorescence quantum yield (QY) of 2.2% in dimethyl sulfoxide (DMSO). Impressively, upon integrating into bovine serum albumin (BSA), the protein‐sized MTAA@BSA dots exhibit a 25‐fold higher fluorescence QY compared to MTAA molecules, contributing to an imaging depth of 818 µm in the brain vasculature. The retention and clearance of MTAA@BSA dots in the liver and kidney are also studied using 2PFI. Overall, this work provides a facile approach to overcome the “Buckets Effect” of AIEgen to generate highly efficient, reliable, and biocompatible 2P probes.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Guangdong Province
Subject
Pharmaceutical Science,Biomedical Engineering,Biomaterials