Oleic Acid Constructed Supramolecular Hyperbranched Polysiloxane with Enhanced Fluorescence and Excellent Drug Delivery Ability

Hyperbranched polysiloxane (HBPSi) as a novel unconventional fluorescent polymer has attached great attention due to its stable fluorescence, facile preparation, and good biocompatibility. Study shows that the fluorescence of unconventional fluorescent polymer is closely related to the aggregate state. To promote the aggregate of HBPSi and endow it with drug delivery ability, in this work, different contents of renewable oleic acid are grafted onto a water-soluble HBPSi. Results show that oleic acid constructs compact supramolecular HBPSi, leading to the enhancement of electronic communication among hydroxyl, amine, ether, and ─Si(O)₃ groups in the supramolecular, which inhibits the movement of molecular chains and subsequently enhances the fluorescence. The novel compact supramolecular HBPSi has a high drug loading capacity (470 mg g^–1) due to its typical structure, which is much higher than the reported β-cyclodextrin modified HBPSi (180 mg g^–1), and the drug release is also pH-controlled. Moreover, the fluorescence of HBPSi-OA is sensitive to Fe³⁺. Therefore, the supramolecular HBPSi can be applied in drug delivery and Fe³⁺ sensing.