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Extracellular matrix (ECM) proteins containing cell‐attachable Arg‐Gly‐Asp (RGD) sequences exhibit variable bridging and non‐bridging in fibronectin‐collagen and laminin‐collagen complexes that can regulate inflammation, tissue repair, and wound healing. In this study, linking molecule‐mediated conjugation of 1D magnetic nanocylinders (MNCs) to material surfaces pre‐decorated with gold nanospheres (GNSs) is performed, thereby yielding RGD‐coated MNCs (RGD‐MNCs) over RGD‐coated GNSs (RGD‐GNSs) in a non‐bridging state. The RGD‐MNCs are drawn closer to the RGD‐GNSs via magnetic field‐mediated compression of the linking molecules to establish the bridging between them. Relative proportion of the RGD‐MNCs to the RGD‐GNSs is optimized to yield effective remote stimulation of integrin binding to variably bridged RGDs similar to that of invariably bridged RGDs used as a control group. Remote manipulation of the RGD bridging facilitates the attachment structure assembly of macrophages that leads to pro‐healing/anti‐inflammatory phenotype acquisition. In contrast, the non‐bridged RGDs inhibited macrophage attachment that acquired pro‐inflammatory phenotypes. The use of various nanomaterials in constructing heterogeneous RGD‐coated materials can further offer various modes in remote switching of RGD bridging and non‐bridging to understand dynamic integrin‐mediated modulation of macrophages that regulate immunomodulatory responses, such as foreign body responses, tissue repair, and wound healing. [ABSTRACT FROM AUTHOR]

Developing materials with the capability of changing their innate features can help to unravel direct interactions between cells and ligand‐displaying features. This study demonstrates the grafting of magnetic nanohelices displaying cell‐adhesive Arg‐Gly‐Asp (RGD) ligand partly to a material surface. These enable nanoscale control of rapid winding ("W") and unwinding ("UW") of their nongrafted portion, such as directional changes in nanohelix unwinding (lower, middle, and upper directions) by changing the position of a permanent magnet while keeping the ligand‐conjugated nanohelix surface area constant. The unwinding ("UW") setting cytocompatibility facilitates direct integrin recruitment onto the ligand‐conjugated nanohelix to mediate the development of paxillin adhesion assemblies of macrophages that stimulate M2 polarization using glass and silicon substrates for in vitro and in vivo settings, respectively, at a single cell level. Real time and in vivo imaging are demonstrated that nanohelices exhibit reversible unwinding, winding, and unwinding settings, which modulate time‐resolved adhesion and polarization of macrophages. It is envisaged that this remote, reversible, and cytocompatible control can help to elucidate molecular‐level cell–material interactions that modulate regenerative/anti‐inflammatory immune responses to implants. [ABSTRACT FROM AUTHOR]

Design of materials with remote switchability of the movement of decorated nanostructures presenting cell‐adhesive Arg‐Gly‐Asp ligand can decipher dynamic cell‐material interactions in decorated ligand nanostructures. In this study, the decoration of ligand‐bearing gold nanoparticles (ligand‐AuNPs) on the magnetic nanoparticle (MNP) with varying ligand‐AuNP densities is demonstrated, which are flexibly coupled to substrate in various MNP densities to maintain constant macroscopic ligand density. Magnetic switching of upward ("Upper Mag") or downward ("Lower Mag") movement of varying ligand‐AuNPs is shown via stretching and compression of the elastic linker, respectively. High ligand‐AuNP densities promote macrophage adhesion‐regulated M2 polarization that inhibits M1 polarization. Remote switching of downward movement ("Lower Mag") of ligand‐AuNPs facilitates macrophage adhesion‐regulated M2 polarization, which is conversely suppressed by their upward movement ("Upper Mag"), both in vitro and in vivo. These findings are consistent with human primary macrophages. These results provide fundamental understanding into designing materials with decorated nanostructures in both high ligand‐AuNP density and downward movement of the ligand‐AuNPs toward the substrate to stimulate adhesion‐regulated M2 polarization of macrophages while suppressing pro‐inflammatory M1 polarization, thereby facilitating tissue‐healing responses. [ABSTRACT FROM AUTHOR]

Macrophage Polarization: Remote Switching of Elastic Movement of Decorated Ligand Nanostructures Controls the Adhesion-Regulated Polarization of Host Macrophages (Adv. Funct. Keywords: elastic ligand movement; macrophage adhesion; macrophage polarization; magnetic switching; nanoparticle decoration EN elastic ligand movement macrophage adhesion macrophage polarization magnetic switching nanoparticle decoration 1 1 1 05/26/21 20210521 NES 210521 In article number 2008698, Young Keun Kim, Heemin Kang, and co-workers report magnetic switching of the movement of decorated ligand-presenting nanostructures that regulates the adhesion-mediated polarization of macrophages in vivo. Elastic ligand movement, macrophage adhesion, macrophage polarization, magnetic switching, nanoparticle decoration. [Extracted from the article]