Ionic tactile sensors (ITS) represent a new class of deformable sensory platforms that mimic not only the tactile functions and topological structures but also the mechanotransduction mechanism across the biological ion channels in human skin, which can demonstrate a more advanced biological interface for targeting emerging human-interactive technologies compared to conventional e-skin devices. Recently, flexible and even stretchable ITS have been developed using novel structural designs and strategies in materials and devices. These skin-like tactile sensors can effectively sense pressure, strain, shear, torsion, and other external stimuli with high sensitivity, high reliability, and rapid response beyond those of human perception. In this review, the recent developments of the ITS based on the novel concepts, structural designs, and strategies in materials innovation are entirely highlighted. In particular, biomimetic approaches have led to the development of the ITS that extend beyond the tactile sensory capabilities of human skin such as sensitivity, pressure detection range, and multimodality. Furthermore, the recent progress in self-powered and self-healable ITS, which should be strongly required to allow human-interactive artificial sensory platforms is reviewed. The applications of ITS in human-interactive technologies including artificial skin, wearable medical devices, and user-interactive interfaces are highlighted. Last, perspectives on the current challenges and the future directions of this field are presented.

Biological cellular structures have inspired many scientific disciplines to design synthetic structures that can mimic their functions. Here, we closely emulate biological cellular structures in a rationally designed synthetic multicellular hybrid ion pump, composed of hydrogen-bonded [EMIM + ][TFSI − ] ion pairs on the surface of silica microstructures (artificial mechanoreceptor cells) embedded into thermoplastic polyurethane elastomeric matrix (artificial extracellular matrix), to fabricate ionic mechanoreceptor skins. Ionic mechanoreceptors engage in hydrogen bond-triggered reversible pumping of ions under external stimulus. Our ionic mechanoreceptor skin is ultrasensitive (48.1–5.77 kPa −1 ) over a wide spectrum of pressures (0–135 kPa) at an ultra-low voltage (1 mV) and demonstrates the ability to surpass pressure-sensing capabilities of various natural skin mechanoreceptors (i.e., Merkel cells, Meissner’s corpuscles, Pacinian corpuscles). We demonstrate a wearable drone microcontroller by integrating our ionic skin sensor array and flexible printed circuit board, which can control directions and speed simultaneously and selectively in aerial drone flight.

Artificial smart designs inspired by structural and functional features of biological organisms have opened new avenues to develop high-performance flexible tactile sensors and advanced artificial sensory systems.