Studies of Carbohydrate-Conjugated Anthracenes in Self-Assembly, Bioimaging and Photosensitization

Abstract

Conjugation of a carbohydrate moiety to an aromatic core leads to glycostructures that possess a high propensity for self-assembly in aq. solutions, driven primarily by π-stacking of the aromatic ring, as well as, the hydrogen bonding interactions of the carbohydrate moieties and carbohydrate-carbohydrate interactions. The supramolecular glycostructures present a multivalent display of biologically relevant carbohydrates on its surface, enabling them to be used as multivalent ligands for carbohydrate-binding proteins such as lectins, for drug delivery, cell imaging and more. This chapter covers the self-assembly of carbohydrate-based aromatic amphiphiles and highlights the advantages of the self-assembly process in generating such multivalent glycostructures, namely, low molecular weight building blocks, tunable morphology and disruption of the structure by an external stimulus. In summary, the thesis establishes the following results: (i) 9-anthracenemethyl glycosides act as supramolecular synthons, undergoing self-assembly in aq. solutions and forming supramolecular structures, the chirality of which is determined by the configuration of the sugar moiety; (ii) the primary molecular structure affects the overall supramolecular, thus by varying the parameters such as the linker lengths between the carbohydrate and the anthracene segments, the morphology of the supramolecular structures formed are also varied; (iii) conjugation of carbohydrate to anthracene carboximides generates a new class of water-soluble fluorophores, that function as bioimaging agents. The ACI glycosides can also be used as fluorescent monovalent, as well as multivalent ligands for lectins, as a result of selfassembly in aq. solutions and (iv) anthracenemethyl glycosides form a new class of watersoluble, heavy atom-free photosensitizers, applicable to PDT studies, with carbohydrate moieties playing an important role in determining the light-induced cytotoxicity values.