Application of Polysaccharide Metal Nanoconjugates in Cancer Detection and Therapy

Cancer is a genetically rooted disease that is characterized by uncontrolled growth and the spread of undifferentiated cells. It is a heterogeneous disease condition that accounts for the second leading cause of mortality, a highly complex disease to understand, as it involves numerous cellular physiological systems. The causes and treatment regimes of cancer are described briefly in figure 1.1. Current mainstream treatment includes surgery, chemotherapy, and radiotherapy that concomitant with certain side effects in patients during and post-treatment regime(DeVita et al.,2008). The application of nanotechnology in cancer biology has provided optimism to scientists in developing novel cancer therapeutic strategies and has made incredible progress. Many nano constructs have been developed from natural sources through physical or chemical methods which have revolutionized the cancer-drug delivery system with relevance to the biomedical application(Liu et al.,2016). Numerous natural compounds including polyphenols, polypeptides, metallic complexes, and polysaccharides have been investigated for their potential as an anti-cancer agent. Among these, polysaccharides are an extremely versatile class of biopolymers with superior structural properties and supreme biological activities. 1.2. Polysaccharides Polysaccharides belong to a class of bio-macromolecules enriched with hydroxyl groups with the occurrence of versatile monosaccharide units covalently jointed with O-glycosidic bonds(Aspinall,2014). Special enzymes bind to these monomers and catalyze polymerization reactions to form polysaccharides or glycans. Polysaccharides are homo-polysaccharides or hetero-polysaccharides depending on the monomer units present in them. In homo-polysaccharides, all the monomer units are the same whereas in the hetero-polysaccharides different monomer units are present. Structural variations and complexities are the main hallmarks of polysaccharides that describe the biological activities of these compounds(Mizumoto et al.,1988). Polysaccharides generally do not have definite molecular weights and there is no template for the polysaccharide synthesis.