PHYTOGLYCOGEN (PG), A NATURAL WATER-SOLUBLE POLYSACCHARIDE PRODUCED IN SWEET CORN SEEDS HAS BEEN GETTING A LOT OF ATTENTION FOR ITS CHARACTERISTICS AND POTENTIAL APPLICATIONS IN NANOTECHNOLOGY. PHYTOGLYCOGEN IS A SMALL PARTICLE (~80NM), MONODISPERSE, HAS HIGH STABILITY IN WATER, LOW VISCOSITY AND EXCEPTIONAL WATER RETENTION. PHYTOGLYCOGEN IS ALSO EXTRACTED FROM A COMMON FOOD SOURCE AND BIODEGRADES INTO SIMPLE SUGARS THAT ARE READILY METABOLIZED. WHILE THE LIST OF RECENT PUBLICATIONS AND PATENTS ABOUT PG IS IMPRESSIVE, IT IS IMPORTANT TO NOTE THAT ALL THE REPORTED APPLICATIONS HAVE EVALUATED ONE PARTICULAR FORM OF PG ISOLATED FROM ONE MUTANT ALLELE OF SWEET CORN. OUR PRELIMINARY FINDINGS INDICATE THAT DIFFERENT VARIETIES OF SWEET CORN AND DIFFERENT MUTANT ALLELES WITHIN GENES OF THE STARCH BIOSYNTHESIS PATHWAY RESULT IN DIFFERENT WATER-SOLUBLE POLYSACCHARIDES - ALL ARE TERMED PHYTOGLYCOGEN. THESE VARIETIES FORM PGS WITH DIFFERENT MAMMALIAN BIOCOMPATIBILITY LEVELS AND PARTICLE SIZES. ELUCIDATING THE PARAMETERS THAT DEFINE THE BIOCOMPATIBILITY AND BIOMATERIAL PROPERTIES OF PG MOLECULES, COUPLED WITH UNDERSTANDING THE MECHANISM CONTROLLING THE BIOSYNTHESIS OF PHYTOGLYCOGEN IN SWEET CORN, WILL ENABLE BREEDERS TO SELECT VARIETIES THAT PRODUCE MORE PG AND/OR PROVIDE VARIANTS WITH IMPROVED PROPERTIES FOR BIOMEDICAL, NUTRACEUTICAL AND COSMETIC APPLICATIONS. IN THIS PROJECT, WE WILL PERFORM A BIOCHEMICAL CHARACTERIZATION OF PG-PRODUCING ALLELES (AIM 1), IDENTIFY NOVEL GENES REGULATING THE AMOUNT OF PG PRODUCTION (AIM 2) AND TRANSLATE OUR FINDINGS TO PROVIDE AN INITIAL ASSESSMENT OF BIOMEDICAL APPLICATION OF DIFFERENT FORMS OF PG, AND TO IDENTIFY THE PHYSICAL FACTORS AND CORRESPONDING MOLECULAR MECHANISM ASSOCIATED WITH HIGH CELL BIOCOMPATIBILITY (AIM 3).