The formation of supramolecular bottle-brush polymers consisting of a non covalent backbone assembled through directional hydrogen bonds and of poly(isobutylene) (PIB) side-chains was investigated in cyclohexane by light scattering. Two limiting cases were observed depending on the balance between the favorable formation of hydrogen bonds and the unfavorable stretching of the PIB chains within the supramolecular bottle-brushes, in agreement with a theoretical model developed by Wang et al. On one hand, a bisurea self-assembling unit able to form four cooperative

Functional drug carrier systems have potential for increasing solubility and potency of drugs while reducing side effects. Complex polymeric materials, particularly anisotropic structures, are especially attractive due to their long circulation times. Here, we have conjugated cyclic peptides to the biocompatible polymer poly(2-hydroxypropyl methacrylamide) (pHPMA). The resulting conjugates were functionalized with organoiridium anticancer complexes. Small angle neutron scattering and static light scattering confirmed their self-assembly and elongated cylindrical shape. Drug-loaded nanotubes exhibited more potent antiproliferative activity toward human cancer cells than either free drug or the drug-loaded polymers, while the nanotubes themselves were nontoxic. Cellular accumulation studies revealed that the increased potency of the conjugate appears to be related to a more efficient mode of action rather than a higher cellular accumulation of iridium.

Self-assembling cyclic peptides (CP) consisting of amino acids with alternating d- and l-chirality form nanotubes by hydrogen bonding, hydrophobic interactions, and π-π stacking in solution. These highly dynamic materials are emerging as promising supramolecular systems for a wide range of biomedical applications. Herein, we discuss how varying the polymer conformation (linear vs. brush), as well as the number of polymer arms per peptide unimer affects the self-assembly of PEGylated cyclic peptides in different solvents, using small angle neutron scattering. Using the derived information, strong correlations were drawn between the size of the aggregates, solvent polarity, and its ability to compete for hydrogen bonding interactions between the peptide unimers. Using these data, it could be possible to engineer cyclic peptide nanotubes of a controlled length.