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Inspired by the human skin, electronic skins (e-skins) composed of various flexible sensors, such as strain sensor, pressure sensor, shear force sensor, temperature sensor, and humility sensor, and delicate circuits, are emerged to mimic the sensing functions of human skins. In this review, the strategies to realize the versatile functionalities of natural skin-like e-skins, including strain-, pressure-, shear force-, temperature-and humility-sensing abilities, as well as self-healing ability and other functions are summarized. Some representative examples of high-performance e-skins and their applications are outlined and discussed. Finally, the outlook of the future of e-skins is presented.

Understanding allostery may serve to both elucidate mechanisms of protein regulation and provide a basis for engineering active mutants. Herein we describe directed evolution applied to the integrin ␣L inserted domain for studying allostery by using a yeast surface display system. Many hot spots for activation are identified, and some single mutants exhibit remarkable increases of 10,000-fold in affinity for a physiological ligand, intercellular adhesion molecule-1. The location of activating mutations traces out an allosteric interface in the interior of the inserted domain that connects the ligand binding site to the ␣7-helix, which communicates allostery to neighboring domains in intact integrins. The combination of two activating mutations (F265S͞F292G) leads to an increase of 200,000-fold in affinity to intercellular adhesion molecule-1. The F265S͞F292G mutant is potent in antagonizing lymphocyte function-associated antigen 1-dependent lymphocyte adhesion, aggregation, and transmigration.

Within the Ig superfamily (IgSF), intercellular adhesion molecules (ICAMs) form a subfamily that binds the leukocyte integrin ␣L␤2. We report a 1.65-Å-resolution crystal structure of the ICAM-3 N-terminal domain (D1) in complex with the inserted domain, the ligand-binding domain of ␣L␤2. This high-resolution structure and comparisons among ICAM subfamily members establish that the binding of ICAM-3 D1 onto the inserted domain represents a common docking mode for ICAM subfamily members. The markedly different off-rates of ICAM-1, -2, and -3 appear to be determined by the hydrophobicity of residues that surround a metal coordination bond in the ␣L␤2-binding interfaces. Variation in composition of glycans on the periphery of the interfaces influences on-rate. structure ͉ protein recognition ͉ cell adhesion ͉ LFA-1

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