Rational design of ratiometric aggregation-induced emission luminogens for biosensing and bioimaging

Ratiometric fluorescence probes, with their inherent self-calibration capabilities, have become indispensable tools in the fields of biosensing and bioimaging. These probes can correct for factors that are independent of the target, making the development of innovative ratiometric fluorescent probes a highly sought-after endeavor. Aggregation-induced emission luminogens (AIEgens) do not emit when in solution but show strong emission when aggregated, thus opening up exciting avenues for designing and creating high-performance ratiometric fluorescence probes. This comprehensive review meticulously details the recent advancements in AIEgen-based ratiometric fluorescence probes. The discussion encompasses design principles, construction strategies, and sensing mechanisms. Subsequently, the review explores the diverse applications of ratiometric AIEgen probes, demonstrating their efficacy with seminal examples in biosensing and bioimaging. The concluding section addresses future prospects and current challenges. We believe that this review should inspire researchers to make further contributions to this intriguing field and aid in its progression.