DendriPep Nanocoats: Substrate-Agnostic, Self-Assembling Constructs with Shear-Controlled Thickness and Permeability

This study investigates the self-assembly of hybrid poly(amidoamine)-peptide dendrimers (DendriPeps) into shear-responsive vesicle-like structures with nanometric thickness, called "Nanocoats", that are capable of encapsulating nano- and microscale particles. To assess the material-agnostic coating power of DendriPeps, we tested the formation of Nanocoats on a variety of synthetic and biological substrates, including polystyrene nanoparticles, poly(N-isopropylacrylamide) microgels, gallium-indium liquid metal nanodroplets, and bacteriophages and lentiviruses. Specifically, we utilized spectroscopic and microscopic techniques to monitor the reversible assembly of Nanocoats on the surface of the particles upon controlling the shear stress of the surrounding aqueous phase. Furthermore, we evaluated the use of Nanocoats as a glue mediating the formation of particle clusters, whose size, in terms of the number of particles and coating thickness, can be dynamically controlled by adjusting the shear stress. Finally, we harnessed the reconfigurability of DendriPep Nanocoats to develop vectors for the shear-controlled delivery of a bioactive payload. To that end, we achieved the controlled release of the antibacterial peptide polymyxin B from DendriPep-coated microgels by applying shear stresses of 0.5-1 Pa. These results demonstrate the potential of DendriPeps to develop reconfigurable systems for biomedical applications that leverage localized shear gradients.