Alkyl chain length-dependent protein nonadsorption and adsorption properties of crystalline alkyl β-celluloside assemblies

Cellulose-based crystalline assemblies artificially constructed in a bottom-up manner are attracting increasing attention as chemically stable and functionally designable nano- to macroscale materials. However, basic knowledge of how such crystalline assemblies interact with biomolecules and how to control them via molecular design is still limited. In this study, we investigated the protein adsorption properties of crystalline lamella assemblies composed of alkyl β-cellulosides (namely, ethyl, n-butyl, and n-hexyl β-cellulosides) or plain cellulose, which all have an antiparallel molecular arrangement. It was found that the adsorption of proteins was observed only for the n-hexyl β-celluloside assembly, while it was hardly observed for other assemblies. The n-hexyl groups appeared to be ordinarily embedded in the assembly surface in an aqueous phase, while, when in contact with proteins, n-hexyl groups appeared to be tethered to promote protein adsorption. All-atom molecular dynamics simulations supported the contradictory protein adsorption properties. The basic knowledge obtained herein is highly valuable for controlling the interactions of cellulose-based synthetic assemblies with proteins for designing new biological applications.