Nanoflowers (NFs) are flowered-shaped particles with overall sizes or features in the nanoscale. Beyond their pleasing aesthetics, NFs have found a number of applications ranging from catalysis, to sensing, to drug delivery. Compared to inorganic based NFs, their organic and hybrid counterparts are relatively underdeveloped mostly because of the lack of a reliable and versatile method for their construction. We report here a method for constructing NFs from a wide variety of biologically relevant molecules (guests), ranging from small molecules, like doxorubicin, to biomacromolecules, like various proteins and plasmid DNA. The method relies on the encapsulation of the guests within a hierarchically structured particle made from supramolecular G-quadruplexes. The size and overall flexibility of the guests dictate the broad morphological features of the resulting NFs, specifically, small and rigid guests favor the formation of NFs with spiky petals, while large and/or flexible guests promote NFs with wide petals. The results from experiments using confocal fluorescence microscopy, and scanning electron microscopy provides the basis for the proposed mechanism for the NF formation.
We describe precise supramolecules that enable the evaluation of the effective hydrophobicity of amphiphilic or “patchy” nanoglobular systems. These supramolecules exhibit the lower critical solution temperature phenomenon, which provides a quantitative measure of their effective hydrophobicity. Specifically, two isomeric 8-aryl-2′-deoxyguanosine derivatives with a transposed pair of methylene groups self-assemble into hexadecameric nanoglobular supramolecular G-quadruplexes (SGQs) that show large differences in their transition temperatures as determined by turbidity and differential scanning calorimetry studies. Molecular modeling studies suggested that differential clustering of the hydrophobic patches on the surface is responsible for the striking differences between the two isomeric supramolecules.