4D Printed Non-Euclidean-Plate Jellyfish Inspired Soft Robot in Diverse Organic Solvents.

Soft robots have the potential to assist and complement human exploration of extreme and harsh environments (i.e., organic solvents). However, soft robots with stable performance in diverse organic solvents are not developed yet. In the current research, a non-Euclidean-plate under-liquid soft robot inspired by jellyfish based on phototropic liquid crystal elastomers is fabricated via a 4D-programmable strategy. Specifically, the robot employs a 3D-printed non-Euclidean-plate, designed with Archimedean orientation, which undergoes autonomous deformation to release internal stress when immersed in organic solvents. With the assistance of near-infrared light illumination, the organic solvent inside the robot vaporizes and generates propulsion in the form of bubble streams. The developed NEP-Jelly-inspired soft robot can swim with a high degree of freedom in various organic solvents, for example, N, N-dimethylformamide, N, N-dimethylacetamide, tetrahydrofuran, dichloromethane, and trichloromethane, which is not reported before. Besides bionic jellyfish, various aquatic invertebrate-inspired soft robots can potentially be prepared via a similar 4D-programmable strategy.

An Intrinsically Magnetic Epicardial Patch for Rapid Vascular Reconstruction and Drug Delivery.

Myocardial infarction (MI) is a major cause of mortality worldwide. The major limitation of regenerative therapy for MI is poor cardiac retention of therapeutics, which results from an inefficient vascular network and poor targeting ability. In this study, a two-layer intrinsically magnetic epicardial patch (MagPatch) prepared by 3D printing with biocompatible materials like poly (glycerol sebacate) (PGS) is designed, poly (ε-caprolactone) (PCL), and NdFeB. The two-layer structure ensured that the MagPatch multifariously utilized the magnetic force for rapid vascular reconstruction and targeted drug delivery. MagPatch accumulates superparamagnetic iron oxide (SPION)-labelled endothelial cells, instantly forming a ready-implanted organization, and rapidly reconstructs a vascular network anastomosed with the host. In addition, the prefabricated vascular network within the MagPatch allowed for the efficient accumulation of SPION-labelled therapeutics, amplifying the therapeutic effects of cardiac repair. This study defined an extendable therapeutic platform for vascularization-based targeted drug delivery that is expected to assist in the progress of regenerative therapies in clinical applications.

Light-Controlled Triple-Shape-Memory, High-Permittivity Dynamic Elastomer for Wearable Multifunctional Information Encoding Devices.

Self-powered information encoding devices (IEDs) have drawn considerable interest owing to their capability to process information without batteries. Next-generation IEDs should be reprogrammable, self-healing, and wearable to satisfy the emerging requirements for multifunctional IEDs; however, such devices have not been demonstrated. Herein, an integrated triboelectric nanogenerator-based IED with the aforementioned features was developed based on the designed light-responsive high-permittivity poly(sebacoyl diglyceride-co-4,4'-azodibenzoyl diglyceride) elastomer (PSeDAE) with a triple-shape-memory effect. The electrical memory feature was achieved through a microscale shape-memory property, enabling spatiotemporal information reprogramming for the IED. Macroscale shape-memory behavior afforded the IED shape-reprogramming ability, yielding wearable and detachable features. The dynamic transesterifications and light-heating groups in the PSeDAE afforded a remotely controlled rearrangement of its cross-linking network, producing the self-healing IED.

Peptidoglycan-inspired autonomous ultrafast self-healing bio-friendly elastomers for bio-integrated electronics.

Elastomers are essential for stretchable electronics, which have become more and more important in bio-integrated devices. To ensure high compliance with the application environment, elastomers are expected to resist, and even self-repair, mechanical damage, while being friendly to the human body. Herein, inspired by peptidoglycan, we designed the first room-temperature autonomous self-healing biodegradable and biocompatible elastomers, poly(sebacoyl 1,6-hexamethylenedicarbamate diglyceride) (PSeHCD) elastomers. The unique structure including alternating ester-urethane moieties and bionic hybrid crosslinking endowed PSeHCD elastomers superior properties including ultrafast self-healing, tunable biomimetic mechanical properties, facile reprocessability, as well as good biocompatibility and biodegradability. The potential of the PSeHCD elastomers was demonstrated as a super-fast self-healing stretchable conductor (21 s) and motion sensor (2 min). This work provides a new design and synthetic principle of elastomers for applications in bio-integrated electronics.

Mechanically and Electronically Robust Transparent Organohydrogel Fibers.

Stretchable conductive fibers are key elements for next-generation flexible electronics. Most existing conductive fibers are electron-based, opaque, relatively rigid, and show a significant increase in resistance during stretching. Accordingly, soft, stretchable, and transparent ion-conductive hydrogel fibers have attracted significant attention. However, hydrogel fibers are difficult to manufacture and easy to dry and freeze, which significantly hinders their wide range of applications. Herein, organohydrogel fibers are designed to address these challenges. First, a newly designed hybrid crosslinking strategy continuously wet-spins hydrogel fibers, which are transformed into organohydrogel fibers by simple solvent replacement. The organohydrogel fibers show excellent antifreezing (< -80 °C) capability, stability (>5 months), transparency, and stretchability. The predominantly covalently crosslinked network ensures the fibers have a high dynamic mechanical stability with negligible hysteresis and creep, from which previous conductive fibers usually suffer. Accordingly, strain sensors made from the organohydrogel fibers accurately capture high-frequency (4 Hz) and high-speed (24 cm s-1 ) motion and exhibit little drift for 1000 stretch-release cycles, and are powerful for detecting rapid cyclic motions such as engine valves and are difficult to reach by previously reported conductive fibers. The organohydrogel fibers also demonstrate potential as wearable anisotropic sensors, data gloves, soft electrodes, and optical fibers.

Biofunctionalized chondrogenic shape-memory ternary scaffolds for efficient cell-free cartilage regeneration.

Cartilage defect repair remains a great clinical challenge due to the limited self-regeneration capacity of cartilage tissue. Surgical treatment of injured cartilage is rather difficult due to the narrow space in the articular cavity and irregular defect area. Herein, we designed and fabricated chondrogenic and physiological-temperature-triggered shape-memory ternary scaffolds for cell-free cartilage repair, where the poly (glycerol sebacate) (PGS) networks ensured elasticity and shape recovery, crystallized poly (1,3-propylene sebacate) (PPS) acted as switchable phase, and immobilized bioactive kartogenin (KGN) endowed the scaffolds with chondrogenic capacity. The resultant scaffolds exhibited shape-memory properties with shape-memory fixed ratio of 98% and recovered ratio of 97% at 37°C for PPS/PGS/KGN-100, indicating a good potential for minimally invasive implantation. The scaffolds gradually degraded in Dulbecco's phosphate-buffered saline and released KGN up to 12 weeks in vitro. In addition, the scaffolds promoted chondrogenic differentiation while inhibiting osteogenic differentiation of bone marrow-derived mesenchymal stem cells in a concentration-dependent manner and cartilage regeneration in full-thickness defects of rat femoropatellar groove for 12 weeks. Consequently, the PPS/PGS/KGN-100 scaffolds stimulated the formation of an overlying layer of neocartilage mimicking the characteristic architecture of native articular cartilage even in the absence of exogenous growth factors and seeded cells. This study provides much inspiration for future research on cartilage tissue engineering. STATEMENT OF SIGNIFICANCE: There are two crucial challenges for cartilage defect repair: the lack of self-regeneration capacity of cartilage tissue and difficult scaffold implantation via traditional open surgery due to space-limited joints. Herein, bioactive body-temperature-responsive shape memory scaffolds are designed to simultaneously address the challenges. The scaffolds can be readily implanted by minimally invasive approach and recover by body-temperature of patient. The integration of kartogenin endows scaffolds the bioactivity, leading to the first example of bulk shape-memory scaffolds for cell-free cartilage repair. These characteristics make the scaffolds advantageous for clinical translation. Moreover, our developed material is easy to be functionalized due to the presence of extensive free hydroxyl groups and provides a versatile platform to design diverse functional shape memory biomaterials.