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Polyelectrolytes, macromolecules with ionizable groups, play a critical role in applications ranging from energy storage and drug delivery to adhesives, owing to their strong interactions with ionic solutes and water. Despite their widespread utility, an atomistic understanding of how polyelectrolytes interact with ions remains incomplete, limiting the ability to precisely control their conformation and functional properties. To bridge this knowledge gap, we conducted molecular dynamics simulations of two representative polyelectrolytes, poly(vinylbenzyl trimethylammonium chloride) (PVBTACl) and sodium polystyrene sulfonate (NaPSS), across varying salt concentrations. We observed distinct salt-responsive behaviors: as the salt (NaCl) concentration increases from 0 to 2 M, the radius of gyration (Rg) of NaPSS decreases, indicating polymer compaction, while PVBTACl remains relatively unaffected. When the salt concentration is further increased to 6 M, PVBTACl undergoes significant collapse, whereas NaPSS remains in a compact state with minimal further conformational change. The difference in the salt-responsive behavior results from the local counterion structures, where the counterions of PVBTACl are less ordered than those of NaPSS. We further examined the PVBTACl/NaPSS complex to assess deviations from the behavior of isolated polymers, revealing enhanced association in contrast to the conventionally observed dissociation at the high salt concentration. Experimental transmittance measurements of equimolar PVBTACl/NaPSS mixtures across increasing salt concentrations confirmed stable complexation behavior under high-salt conditions, supporting the simulation-based observations of persistent association between PVBTACl and NaPSS. This study offers a mechanistic understanding of salt-induced conformational changes, providing design principles for tuning polyelectrolyte properties in functional materials. 

A dual-drug loaded nanoparticle demonstrates superior inhibition of NLRP3 inflammasome activation and improves the survival rate in a mouse model of septic peritonitis. 

Abstract Microrobots have the potential for diverse applications, including targeted drug delivery and minimally invasive surgery. Despite advancements in microrobot design and actuation strategies, achieving precise control over their motion remains challenging due to the dominance of viscous drag, system disturbances, physicochemical heterogeneities, and stochastic Brownian forces. Here, a precise control over the interfacial motion of model microellipsoids is demonstrated using time‐varying rotating magnetic fields. The impacts of microellipsoid aspect ratio, field characteristics, and magnetic properties of the medium and the particle on the motion are investigated. The role of mobile micro‐vortices generated is highlighted by rotating microellipsoids in capturing, transporting, and releasing cargo objects. Furthermore, an approach is presented for controlled navigation through mazes based on real‐time particle and obstacle sensing, path planning, and magnetic field actuation without human intervention. The study introduces a mechanism of directing motion of microparticles using rotating magnetic fields, and a control scheme for precise navigation and delivery of micron‐sized cargo using simple microellipsoids as microbots.