Characterizing the Physical Properties and Cell Compatibility of Phytoglycogen Extracted from Different Sweet Corn Varieties.

Owing to its unique structure and properties, the glucose dendrimer phytoglycogen is gaining interest for medical and biotechnology applications. Although many maize variants are available from commercial and academic breeding programs, most applications rely on phytoglycogen extracted from the common maize variant, . Here we characterized the solubility, hydrodynamic diameter, water-binding properties, protein contaminant concentration, and cytotoxicity of phytoglycogens from different maize sources, A632, A619, Wesu7, and Ia453, harboring various mutants. A619-SW phytoglycogen was cytotoxic while A632-SW phytoglycogen was not. A632-Pu phytoglycogen promoted cell growth, whereas extracts from A632-NE, A632-NC, and A632-CM were cytotoxic. Phytoglycogen extracted from Wesu7-NE using ethanol precipitation was cytotoxic. Acid-treatment improved Wesu7 phytoglycogen cytocompatibility. Protease-treated Wesu7 extracts promoted cell growth. Phytoglycogen extracted from Ia453 21 days after pollination ("Ia435 21DAP") was cytotoxic, whereas phytoglycogen extracted at 40 days ("Ia435 40DAP") was not. In general, size and solubility had no correlation with cytocompatibility, whereas protein contaminant concentration and water-binding properties did. A632-CM had the highest protein contamination among A632 mutants, consistent with its higher cytotoxicity. Likewise, Ia435 21DAP phytoglycogen had higher protein contamination than Ia435 40DAP. Conversely, protease-treated Wesu7 extracts had lower protein contamination than the other Wesu7 extracts. A632-NE, A632-NC, and A632-CM had similar water-binding properties which differed from those of A632-Pu and A632-SW. Likewise, water binding differed between Ia435 21DAP and Ia435 40DAP. Collectively, these data demonstrate that maize phytoglycogen extracts are not uniformly cytocompatible. Rather, maize variant, plant genotype, protein contaminants, and water-binding properties are determinants of phytoglycogen cytotoxicity.