UC Berkeley

Due to the widespread use of surfactants, there have been renewed efforts to develop bio-derived and bio-degradable alternatives. However, the large-scale production of designer bio-surfactants for medical or environmental purposes remains a challenge regarding economic viability compared to their synthetic counterparts. This work shows that the previously studied and characterized intrinsically disordered protein (IDP) that was genetically modified to self-assemble into micelles (IDP-2Yx2A) has promise to be used as a vehicle for traditionally unusable hydrophobic drugs for\textit{ in vivo }delivery to mice. Additionally, this work created a scalable and versatile production method for these amphiphilic proteins and has allowed for the development of different iterations and mutant sequences that were easily attained. The protein sequence was separated and explored by its two opposing hydrophilic and hydrophobic domains. Variants with increased overall charges and systematically decreased hydrophilic domain lengths were produced and examined for their sizes, morphologies, and critical micelle concentrations (CMCs). Additionally, to explore the role of the hydrophobic domain on self-assembly properties, we developed a bioconjugation method to attach N-terminal cysteine peptides of varying hydrophobicities to the C-terminal tyrosine residue of the hydrophilic domain. This represents a facile method for creating a large number of hydrophobic library members to be screened as IDP-based bio-surfactants.