Spatio-temporal heterogeneities in nanosegregated single-molecule polymeric nanoparticles

Trifaceted Mickey Mouse Amphiphiles for Programmable Self-Assembly, DNA Complexation and Organ-Selective Gene Delivery

Instilling segregated cationic and lipophilic domains with an angular disposition in a trehalose-based trifaceted macrocyclic scaffold allows engineering patchy molecular nanoparticles leveraging directional interactions that emulate those controlling self-assembling processes in viral capsids. The resulting trilobular amphiphilic derivatives, featuring a Mickey Mouse architecture, can electrostatically interact with plasmid DNA (pDNA) and further engage in hydrophobic contacts to promote condensation into transfectious nanocomplexes. Notably, the topology and internal structure of the cyclooligosaccharide/pDNA co-assemblies can be molded by fine-tuning the valency and characteristics of the cationic and lipophilic patches, which strongly impacts the transfection efficacy in vitro and in vivo. Outstanding organ selectivities can then be programmed with no need of incorporating a biorecognizable motif in the formulation. The results provide a versatile strategy for the construction of fully synthetic and perfectly monodisperse nonviral gene delivery systems uniquely suited for optimization schemes by making cyclooligosaccharide patchiness the focus.

Mikto-Arm Stars as Soft-Patchy Particles: From Building Blocks to Mesoscopic Structures

We present an atomistic molecular dynamics study of self-assembled mikto-arm stars, which resemble patchy-like particles. By increasing the number of stars in the system, we propose a systematic way of examining the mutual orientation of these fully penetrable patchy-like objects. The individual stars maintain their patchy-like morphology when creating a mesoscopic (macromolecular) self-assembled object of more than three stars. The self-assembly of mikto-arm stars does not lead to a deformation of the stars, and their shape remains spherical. We identified characteristic sub-units in the self-assembled structure, differing by the mutual orientation of the nearest neighbor stars. The current work aims to elucidate the possible arrangements of the realistic, fully penetrable patchy particles in polymer matrix and to serve as a model system for further studies of nanostructured materials or all-polymer nanocomposites using the mikto-arm stars as building blocks.

How Does the Number of Arms Affect the Properties of Mikto-Arm Stars in a Selective Oligomeric Matrix? Insights from Atomistic Simulations

We present a simulation study of amphiphilic mikto-arm star copolymers in a selective polymer host. By means of atomistic molecular dynamics simulations, we examine the structural and dynamical properties of mikto-arm stars with varying number, n, of poly(ethylene oxide) (PEO) and polystyrene (PS) arms, (PEO) n (PS) n in a 33% wt blend with an oligomeric PEO host (o-PEO). As the number of arms increases, the stars resemble more spherical particles with less separated PEO and PS intramolecular domains. As a result of their internal morphology and associated geometrical constraints, the mikto-arm stars self-assemble either into cylindrical-like objects or a percolated network with increasing n, within the o-PEO matrix. The segmental dynamics is mostly governed by the star architecture and the heterogeneous local environment, formed by the intra- and intermolecular nanosegregation. We discuss the role of each factor and compare the results with previously published studies on mikto-arm stars.