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.

This study presents dual-responsive colloidal microgels to repair nonwoven fiber mats (NWFs) and recover their native morphological and functional properties. The formulation comprises poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAm-co-AA) microgels loaded with iron oxide nanoparticles acting as magneto-responsive "bricks" and poly(N-isopropylacrylamide-co-N-4-benzoylphenyl acrylamide) (PNIPAm-co-BPAm) serving as photo-cross-linkable "mortar". The formulation is employed to repair small tears in meltblown polypropylene (PP) and polybutylene terephthalate (PBT) NWFs and recover the functional properties of the native membranes. Specifically, magnetically directed and UV-light-triggered repair recovers (i) the topological integrity, as shown by optical microscopy and image analysis of PP and PBT NWFs, (ii) the mechanical properties, as demonstrated by the values of tensile modulus of native, damaged, and repaired PP NWFs, and (iii) the permeability to sodium chloride of both PP and PBT NWFs. A comparative study of repair using magneto-responsive and photo-cross-linkable vs photo-cross-linkable-only formulations demonstrate that magnetic localization is vital to ensure rapid, spatially accurate, and effective recovery of the morphological and functional properties of damaged NWFs.

The past three decades have witnessed an exponential increase in the structural diversity and applications of dendrimers, spanning across drug delivery and diagnostics, protein, and enzyme mimicry, solubility enhancement, coatings, light harvesting, and catalysis. The dendrimer community has recently focused on internally functionalized dendrimers (IFDs) owing to their advanced design and functionality. The synthesis of IFDs relies on advanced orthogonal chemistries and/or (de)protection schemes, as well as careful purification to minimize polydispersity of composition and molecular weight. The studies published on IFDs, however, lay scattered across the chemical literature, and a comprehensive presentation of structural rationale, synthetic procedures, and technologically relevant applications is missing. To address this need, this review presents a comprehensive collection and discussion of all available studies on IFDs, detailing their methods of synthesis and their structure-function correlations. The wide variety of internal functionalities, including hydroxyl, amine, carboxylic acid, allyl, alkyne, and imidazole groups, enables myriad applications in biochemistry, chemical and biomedical engineering, and material science. Particular focus is given to IFDs that are amenable to modular synthetic strategies, which promote higher synthetic yield and scalability, and therefore possess stronger translational and commercial potential. As such, this review guides research groups pursuing the difficult task of IFD rational design and synthesis providing them a concise roadmap to their mission.

This article presents an integrated experimental and computational study of DendriPeps, a novel class of dendrimers featuring a polyamidoamine (PAMAM) backbone hybridized with peptide segments. Hydroxyl-terminated Generation 2 (G.2) DendriPeps, comprising either four lysines (Lys) or four glutamic acids (Glu), and G.3 DendriPeps, comprising 8 Lys or 8 Glu, were first characterized in terms of hydrodynamic radius (R-h) and zeta-potential in aqueous solution. Unlike PAMAM dendrimers, DendriPeps form aggregates with Rh between 60 and 980 nm and zeta-potential between -130 and 80 mV despite their strong net charge. Upon application of shear, all aggregates disassemble into monomeric DendriPeps (R-h similar to 1-3 nm), but reform rapidly as shear is removed. Rheological characterization confirmed that DendriPep aggregates are disrupted by mild shear, but reform reversibly. Molecular dynamics simulations, informed by titrimetry, suggest that DendriPep aggregation derives from their multipolar structure and ability to rearrange the intermolecular/intramolecular pairing of titratable moieties at different pH values.

In this work, the first synthesis of poly(amidoamine) (PAMAM) dendrimers whose branches are hybridized with peptide segments (DendriPeps) is reported. The intercalation of amino acids within the branches of PAMAMs provides supplementary internal functionalities to the coronal groups. Four DendriPep prototypes are synthesized with lysine or glutamic acid as "guest" amino acids, displaying, respectively, a primary amine or a carboxyl group, on generation (G)2 and G3 PAMAMs as host scaffolds. The precise control over the number, type, and topological placement of functional groups expands the functional behavior of DendriPeps beyond current PAMAM dendrimers toward new frontiers or colloids, drug delivery vectors, and catalysis.