A flexible polyimide ionogel was prepared as a strain sensor which can not only be used as a conformal soft material for body motions but also provides an opportunity for controlling AI robots in extreme environments (−60 to 180 °C).

Characterization of the elasticity of biological cells is growing as a new way to gain insight into cell biology. Cell mechanics are related to most aspects of cellular behavior, and applications in research and medicine are broad. Current methods are often limited since they require physical contact or lack resolution. From the methods available for the characterization of elasticity, those relying on high frequency ultrasound (phonons) are the most promising because they offer label-free, high (even super-optical) resolution and compatibility with conventional optical microscopes. In this Perspective contribution, we review the state of the art of picosecond ultrasonics for cell imaging and characterization, particularly for Brillouin scattering-based methods, offering an opinion for the challenges faced by the technology. The challenges are separated into biocompatibility, acquisition speed, resolution, and data interpretation and are discussed in detail along with new results.

Cell sheet engineering represents a new era of precise and efficient regenerative medicine, but its efficacy is limited by the elaborative preparation and the weak mechanics. Herein, a near-infrared (NIR)-triggered dynamic wrinkling biointerface was designed for rapid acquisition of practical cell sheets. The biocompatible NIR can initiate the photothermal-mechanical linkage cascade to efficiently dissolve the collagen supporting layer and release the high-quality cell sheets. The interfacial shear force generates with the dynamic wrinkling, playing an active role in accelerating the cell sheet release. High-quality and self-supporting cell sheets can be harvested within a few minutes, demonstrating a new paradigm of photothermal-mechanical manipulation. The transplantable cell sheets with outstanding physiological and mechanical performances were proven to promote wound healing in skin regeneration. This method may open a completely new front in thermal and mechanical responsive cascade to harvest cell sheets, facilitating their wide applications in regenerative medicine.

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When compared to random cell organization, cell sheets with well-organized cell orientation are similar to natural tissues exhibiting better mechanical strength. Furthermore, as living materials, the mechanical strength of cell...