Nonconventional Luminescent Polymers with Efficient Emission in Dilute Solutions for Lysosome Targeting and Al³⁺ Detection

Nonconventional luminescent polymer materials (NLMs) hold great promise for advancing bioimaging due to their unique optical properties and biocompatibility. However, their practical applications are hindered by limitations such as nonemissive behavior in dilute solutions and difficulties in organelle-specific imaging. The cooperative effects of hydrogen bonding and n → π* interactions between amide groups could facilitate molecular clustering, thereby increasing the emission efficiency of NLMs in dilute solutions. To confirm this method, two water-soluble NLMs, P1 and P2, based on aspartic acid, were synthesized. These polymers exhibit remarkable photoluminescence quantum yields (5.42% and 3.11%) at a low concentration of 0.1 mg/mL, accompanied by concentration- and excitation wavelength-dependent emsission, and aggregation-induced emission (AIE) properties. Furthermore, both polymers demonstrate temperature-sensitive emission, excellent photostability, and low cytotoxicity, making them ideal candidates for various bioapplications. Importantly, P1 exhibits selective recognition of Al3+ ions with a low detection limit of 0.92 μM, significantly below the World Health Organization guideline of 7.4 μM. Additionally, both P1 and P2 demonstrate lysosomal targeting ability, suggesting their potential for diverse applications in cellular imaging and ion sensing.