Terminal Group‐Determined and Dendrimer‐Encapsulated Perovskite Probes for High‐Contrast Biomedical Imaging

Abstract Dendrimers with multiple passivation sites are demonstrated as a feasible interface protection strategy to solve the poor stability of perovskite nanomaterials and devices. However, the interaction mechanism is still unclear in achieving the optimal choice among thousands of dendrimers. Here, a terminal‐group determined strategy is demonstrated to investigate the passivation effect between the interface of perovskite nanocrystals and poly(amidoamine) (PAMAM) dendrimers. Combining the molecular dynamics simulation and experiment results, PAMAM with the terminal carboxyl groups promotes the formation of strong coordination bonds, which are used to prepare water and oxygen‐resistant inorganic perovskite (CsPbBr 3 ) nanocrystals. After being conjugated with the Epsin 3 (EPN3) antibodies, the CsPbBr 3 nanocrystal‐based probes display a high tumor‐to‐normal (T/N) ratio (≈9.3) in imaging breast cancers, achieving 5.2 times higher than that of traditional fluorescent probes. Benefiting from the high tumor targetability of EPN3 and 95% luminescence efficiency, the perovskite probe can successfully differentiate lymph node metastasis of breast cancer in 10 mins, with an area under the curve (AUC) of up to 93%. The perovskite probes shed new light on the rapid and accurate recognition of breast cancer patients with lymph node metastasis, which gives sufficient evidence for making individualized treatment.