Amphiphilic BODIPY-based fluorophores: synthesis, photophysical characterization and bio-relevant aggregation studies

Fluorescent nanostructures are becoming key components of next-generation smart materials, particularly in the fields of bioimaging, biosensing, and biomimetic systems [1]. In this study, we present the rational design and synthesis of three novel amphiphilic BODIPY-based fluorophores. These molecules are functionalized with a pyrene moiety and bearing either mono- or bis-sulfonic acid groups on styryl arms. They combine water solubility, membrane permeability, and strong π–π stacking capabilities, enabling their self-assembly into nanostructures in aqueous media. Synthetic strategies include selective Knoevenagel-type condensation reactions, which afford mono- or distyryl derivatives by modulating solvent polarity and aldehyde stoichiometry, thus toluene favoring mono-substitution and acetonitrile enabling efficient bis-substitution. Subsequent sulfonation with 1,3-propane sultone under optimized basic conditions yields the target amphiphilic sulfonates in good to excellent yields (Scheme 1). The successful derivatization has been demonstrated by spectroscopic characterization, which has revealed solvent and conjugation- dependent optical properties. Cellular uptake studies and preliminary self-assembly assessments highlight their potential for bioimaging applications. Beyond their biological relevance, the presence of pyrene units suggests opportunities for integration with graphenic materials, expanding their application to hybrid optoelectronic systems [2]. Overall, this work emphasizes the structural versatility and functional tunability of BODIPY scaffolds for the development of next-generation fluorescent probes. References [1] X. Cai, B. Liu, Angew. Chem. Int. Ed., 2020, 59, 9868-9886. [2] M. Cordaro, G. Neri, A. Piperno, A. M. Cancelliere, A. Santoro, S. Serroni, F. Nastasi, A. Arrigo, Sustain. Energy Fuels, 2024, 8, 2235-2244.