Controlling supramolecular organization and chiral assembly of functional molecules using heparin

Abstract

The controlled assembly of π-conjugated molecules in water represents a key strategy in the development of functional supramolecular materials. This work presents the synthesis of a series of positively charged achiral molecules and explores their ability to self-assemble with negatively charged biomolecules, particularly heparin, in aqueous medium. The aim was to investigate how the binding of a biomolecule like heparin, along with other non-covalent interactions, drive the formation of functional supramolecular nanomaterials and how the chiral nature of heparin induces supramolecular chirality in the assembly of achiral molecular systems. The resulting supramolecular assemblies were characterized using ultraviolet-visible (UV-Vis) absorption, fluorescence, circular dichroism (CD) spectroscopies as well as transmission electron microscopy (TEM). We demonstrated that the binding of heparin resulted in the formation of helical nanostructures with distinct absorption and fluorescence properties and chiroptical activity. These findings demonstrate that the interaction between cationic achiral molecules and chiral polyanions not only enables the formation of well-defined nanostructures but also activates functional optical responses. It can be concluded that this strategy provides a promising platform for a) controlling supramolecular assembly of functional molecules; b) the design of responsive materials for the optical detection of biologically and biomedically relevant molecules