Recent Advances in NIR-II Molecular Aggregates and Applications in the Biomedical Field

Near-infrared (NIR) light is a promising tool for biomedical imaging and therapy, offering excellent tissue penetration, low scattering, and minimal biological fluorescence interference. An NIR-II optical range of 900–1880 nm with reduced background interference is particularly useful for disease diagnosis and treatment. Probes based on organic molecules are gaining attention for their structural flexibility and stable performance. Organic molecular aggregates, such as J-aggregates, H-aggregates, and aggregation-induced emission (AIE)-aggregates, exhibit unique optical properties like tunable spectral shifts, improved photostability, and higher absorption and fluorescence quantum yields. This mini review briefly discusses the advancements in NIR-II optical imaging and therapy technologies, focusing on the classification, formation mechanisms, and applications of organic molecular aggregates in disease diagnosis and treatment, offering a theoretical foundation and practical guidance for future research.