Tetraphenylethylene (TPE)-Based AIE Luminogens: Recent Advances in Bioimaging Applications

Aggregation-induced emission (AIE) luminogens are materials that exhibit enhanced light emission in the aggregated state, primarily due to the restriction of intramolecular motions, which reduces energy loss through non-radiative pathways. Tetraphenylethylene (TPE) and its derivatives are prominent examples of AIE-active materials, owing to their ease of synthesis, tuneable photophysical properties, and strong aggregation tendencies. This review provides an overview of the fundamental AIE mechanisms in TPE-based systems, with a focus on the role of restricted intramolecular rotation (RIR) and π-twisting in governing their emission behaviour. It explores the influence of molecular structure, electronic configuration, and intermolecular interactions on fluorescence properties. Furthermore, recent advances in practical applications of TPE-based AIE luminogens are highlighted across a spectrum of biological imaging domains, including cellular imaging, tissue and in vivo imaging, and organelle-targeted imaging. Additionally, their integration into multifunctional and theranostic platforms, along with the development of stimuli-responsive and self-assembled systems, underscores their versatility and expanding potential in biomedical research and diagnostics. This review aims to offer valuable insights into the design principles and functional potential of TPE-based AIE luminogens, guiding the development of next-generation materials for advanced bioimaging technologies.