Caseins, proteins in the milk of mammalian species, have been used as wood adhesives since the early 1900's. Caseins' ability to bind certain materials has been exploited in a variety of products over the years. However, the nature of the binding interaction remains unknown, and studies performed involve the collective casein system, or some of the isolated fractions, but not all of the individual or combinations of various casein subunits. The proposed research includes the separation and purification of the four casein subunits: alphas1-, alphas2-, beta, and kappa, by a simplified reverse phase high performance liquid chromatography (RP-HPLC) method. The binding affinity of the collective casein system, as well as the purified subunits, for various forms of cellulose is examined. Preliminary data suggests that whole bovine casein binds preferentially to highly crystalline nanodimensional cellulose purified from cotton. The hypothesis behind the nature of the binding interaction reflects the basic chemistry of the individual casein proteins. With improved understanding of the functionality of the casein protein system, new opportunities for high value products for the dairy and associated industries can be presented.