Selectivity and bio-compatibility of self-assembled chiral flower-like and helical nanostructures

Abstract

The molecular building block NDI-LCA was synthesized by substitution of NDA at di-imide position with two lithocholic acid moieties. It was found that the NDI-LCA conjugate exhibits good thermal stability. The photophysical such as UV-vis and fluorescence spectral measurements and theoretical calculations reveal that NDI-LCA possesses stronger absorption and fluorescence emission properties. Furthermore, NDI-LCA derivative self-assembled into chiral flower-like structures in THF/MCH solvent mixture, whereas, NDI-LCA in THF/water produces chiral fibril nanostructures. The formation of supramolecular self-assembly in solution was characterization by UV-vis, fluorescence spectroscopy, and dynamic light scattering (DLS). Circular dichroism is used to study chiral induction in supramolecular structures. Scanning Electron Microscopy (SEM) confirms the formed structure on the silicon wafer. X-ray diffraction (XRD) clearly shows the formation of the crystalline nature of morphology. In addition, NDI-LCA's supramolecular structures in THF exhibit remarkable bio-compatibility and increased cellular uptake in cancer cells. From cell morphology and uptake studies, it can be assumed that NDI-LCA in THF supramolecular structures can act effectively as a platform for both cell markers and as a delivery agent for further studies.