Synthesis of C3-symmetric star shaped amphiphiles for drug delivery applications

Abstract

C ₃-symmetric star-shaped aromatic compounds are known to possess unique characteristics which facilitate their industrial and biomedical applications. Herein, we report the design, synthesis, self-assembly and drug/dye delivery capabilities of C₃-symmetric, hexa-substituted benzene-based amphiphiles. The synthesis of the hexa-substituted C₃-symmetric core involves C-acetylation of phloroglucinol to yield the corresponding tri-acetyl derivative. This was further subjected to O-propargylation, followed by the carbonyl reduction of acetyl groups to yield the central core. Various hydrophilic (mPEG) and lipophilic units were then incorporated into this core via click and esterification reactions, respectively, to produce a new type of star shaped amphiphiles. So the obtained amphiphilic architectures have a tendency to aggregate in an aqueous medium forming nanosized assemblies with an inner hydrophobic core, allowing the substituents to control the tension-active properties. The critical aggregation concentration of the amphiphiles was evaluated by fluorescence measurement using the dye Nile red as a fluorescent probe. The hydrodynamic diameter of self-assembled aggregates in aqueous solution was studied by dynamic light scattering, while the actual size and morphology were determined by cryo-transmission electron microscopy (cryo-TEM) analysis. The physicochemical properties of the amphiphiles suggested their suitability for exploring their drug delivery applications. In this endeavor, the amphiphiles were utilized for the encapsulation of model hydrophobic entities and studying their subsequent release from their hydrophobic core in a controlled manner. The transport potential of the synthesised amphiphiles was explored for transdermal drug delivery. Furthermore, cytotoxicity studies were conducted using MCF7 and HeLa cells, which indicated that the nanocarriers had no toxic effect on the cells.