Protein Mimic Hydrophobicity Affects Intracellular Delivery but not Cargo Binding

Protein transduction domain mimics (PTDMs) enable cellular uptake of macromolecular cargo such as proteins and nucleic acids. The presence of hydrophobic domains in PTDMs has been shown to enhance cargo uptake, but the role of hydro-phobicity in PTDM-binding of the desired cargo is not fully understood. Herein, block copolymer PTDMs composed of varying hydrophobic monomers were synthesized via ring-opening metathesis polymerization (ROMP) to probe the effect that increasingly hydrophobic side chains had on binding enhanced green fluorescent protein (EGFP). PTDM-facilitated cellular uptake of EGFP into Jurkat T cells was performed to assess the correlation between binding, hydrophobicity, and delivery. Binding studies demonstrated that all PTDMs bound EGFP similarly despite a five log difference in monomer K-ow (octanol-water partition coefficient) and that intermediately hydrophobic PTDMs facilitated higher cellular uptake of EGFP. Taken as a whole, hydrophobicity of the PTDM is a better predictor of effective delivery in Jurkat T cells than cargo binding.