TSPBNTM · Tubular Supramolecular Polymer Brushes as Novel Therapeutic Materials

Tubular Supramolecular Polymer Brushes as Novel Therapeutic Materials

The morphology of self-assembled nanostructures play a very important role in their functionalities, for instance, cylindrical micelles have been reported to show increased in vivo circulation times and different cellular internalisation pathways compared to spherical nanoparticles, thus making them a promising platform for biomedical applications. Here we report that introducing highly directional and robust supramolecular interactions enables to transform the self-assembly of block copolymers from spherical into rigid cylindrical micelles (tubisomes). In our system, cyclic peptides (CPs), flat ring-like peptides consisting of an even number of alternating D- and L-amino acids, were synthesized and employed as a joint linker between the hydrophilic and hydrophobic segments of amphiphilic block copolymers. The multiple hydrogen bonding interactions between the CPs can drive the formation of tubular nanostructures. As a result, the amphiphilic CP-polymer conjugates self-assemble into tubisomes independent of the ratio of the hydrophilic and hydrophobic domains, thereby providing an efficient approach for cylindrical polymeric micelles. Moreover, accessible modifications of either cyclic peptides or conjugated polymers could endow the tubisomes with a host of functionalities, which can make them versatile candidates for various applications especially as drug delivery vehicles. To this end, we further exploit the potential of tubisomes as controlled drug delivery systems. Photo-responsive tubisome was fabricated to realise the controlled release of anticancer drug Doxorubicin, and the anticancer efficacy was evaluated. Furthermore, to get better understanding of tubisomes based drug delivery vehicles, fluorescent labelling which can track their intracellular distribution during drug delivery is our concern. By synergetic combination of aggregation induced emission effects and cyclic peptide shaped tubular self-assembly, we reported the construction of a type of multi-functional tubisome in water, which shows unique topological structure and excellent fluorescent property. In-situ monitoring of drug release was realised. This work provides an efficient method to prepare cylindrical polymeric micelles and an intriguing drug delivery mode which can determine the intracellular location of the delivery vehicles and the drug releasing position, showing promising potentials in cancer therapy.

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