Chapter 5: Glyconanotechnology and Disease: Gold Nanoparticles Coated with Glycosides as Multivalent Systems for Potential Applications in Diagnostics and Therapy

Gold nanoparticles functionalised with glycosides (gold glyconanoparticles, GNP) allow nanotechnology-oriented research in biological processes where carbohydrates are involved. One important characteristic of these hybrid nanomaterials is related to glycan valency (number of glycan copies per nanoparticle). Multimerisation of glycosides onto nanoscaffolds usually results in increasing the affinity of the monovalent carbohydrate for the biological counterpart (carbohydrate-binding proteins, such as lectins), with implications for the design of multivalent inhibitors. Another key issue is related to functionality and modality, due to the opportunity to tailor different types of molecules (not limited to glycosides) on the same GNP and to vary its nucleus composition, size and shape. Multimodal imaging probes (luminescent components for optical imaging, magnetic elements for MRI, plasmonic properties for ultrasensitive and real-time detection techniques), targeted drug delivery systems and/or bionanomaterials for photothermal therapy can be potentially generated. In the field of diagnostics, nanobiosensors for in vitro detection of pathologies are the most promising device to reach the clinic, while the administration of GNP in vivo is appealing but still has to fully overcome toxicity concerns. In addition to functional properties, the presence of carbohydrates in the organic shell can radically improve the biocompatibility, stability and water dispersibility of gold nanostructures.