Enrichment of Aggregation-Induced Emission Aggregates Using Acoustic Streaming Tweezers in Microfluidics for Trace Human Serum Albumin Detection

Aggregation-dependent brightness (ADB) indirectly limits the in vitro performance of a pure aggregation-induced emission (AIE) probe in many ways; thus, controlling the aggregation state of the AIE probe is helpful for detecting an object of interest. Many studies are focused on the molecule design of the AIE probes, while less efforts have been made for the control of the aggregation of the AIEs. Here, an acoustic streaming tweezer (AST) generated using a gigahertz bulk acoustic wave resonator was applied to manipulate the aggregation status of the AIE probe and further enhance their performance for human serum albumin (HSA) detection. As the trapping size of the AST matches the working size of the AIE probe, the streaming can enrich and accumulate AIE nanoparticles, which then further trigger larger aggregates. Due to the ADB effect, the fluorescence intensity strongly increased, and thus, the detection limit of HSA was reduced to 0.5 mu g/mL, which is low enough for kidney disease detection. Such an AST-assisted ADB strategy is potentially applicable to other AIE probes and can work as a portable choice for the biomedical detection.

Automated summary

Aggregation-dependent brightness (ADB) indirectly hinders the performance of a pure aggregation-induced emission (AIE) probe in vitro, but controlling the aggregation state of AIE probe can improve its detection of objects of interest. This study applies an acoustic streaming tweezer (AST) to manipulate the aggregation status of AIE probes using gigahertz bulk acoustic wave resonator, thus enhancing their performance in human serum albumin (HSA) detection. The AST traps AIE nanoparticles, triggering larger aggregates and increasing fluorescence intensity through the ADB effect, effectively reducing the HSA detection limit to 0.5 µg/mL suitable for kidney disease detection. This AST-assisted ADB strategy shows potential for biomedical detection and can be used as a portable choice.