Figure 1.

Schematic diagram illustrating the state-of-the-art and aims of this article. (A) Current method of delivering proteins by conjugating cyclic CPPs. (B) Developed “CPP-additive technology” employs an excess amount of free CPP with an electrophilic thiol-reactive moiety, which facilitates the cellular uptake of protein cargo. (C) Proposed improvement of CPP-additives through the addition of a hydrophobic “anchor” moiety, aiming to enhance intracellular uptake and delivery efficiency of protein-CPP cargoes.