Corn-derived dendrimer-like carbohydrate phytoglycogen nanoparticles as selective fluorescent sensor for silver ions

A dendrimer-like carbohydrate phytoglycogen (PG) extracted from corn was modified as a fluorescent nanocarrier via a simple method. Fluorescein was successfully linked to PG by covalent bonds through APTES as the bridge. NMR, XPS, UV, fluorescence and confocal microscopy validated the high feasibility and efficiency of the preparation of fluorescent phytoglycogen (F-PG). The morphology of F-PG was investigated by TEM and XRD analysis which showed amorphous nature and spherical or cauliflower-like shape with highly branched structures inside. The fluorescent carbohydrate nanoparticles inherited the high stability and excellent dispersibility in water, which was proved by DLS measurements. Furthermore, ratiometric response towards silver ions could be obtained from fluorescence spectroscopy in aqueous media without the need of adding organic solvents, with good linearity (R-2 = 0.993) and high selectivity, indicating a great potential of applying this renewable biopolymer as a sensor for silver ions in aqueous solution.