Four-dimensional (4D) printed magnetoactive soft material (MASM) with a three-dimensional (3D) patterned magnetization profile possesses programmable shape transformation and controllable locomotion ability, showing promising applications in actuators and soft robotics. However, typical 4D printing strategies for MASM always introduced a printing magnetic field to orient the magneto-sensitive particles in polymers. Such strategies not only increase the cooperative control complexity of a 3D printer but may also induce local agglomeration of magneto-sensitive particles, which disturbs the magnetization of the already-printed structure. Herein, we proposed a novel 4D printing strategy that coupled the traditional 3D injection printing with the origami-based magnetization technique for easy fabrication of MASM objects with a 3D patterned magnetization profile. The 3D injection printing that can rapidly create complex 3D structures and the origami-based magnetization technique that can generate the spatial magnetization profile are combined for fabrication of 3D MASM objects to yield programmable transformation and controllable locomotion. A physics-based finite element model was also developed for the design guidance of origami-based magnetization and magnetic actuation transformation of MASM. We further demonstrated the diverse functions derived from the complex shape deformation of MASM-based robots, including a bionic human hand that played “rock-paper-scissors” game, a bionic butterfly that swung the wings on the flower, and a bionic turtle that crawled on the land and swam in the water.

Achieving effective dropwise capture and ultrafast water transport is essential for fog harvesting. In nature, cactus uses the conical spine with microbarbs to effectively capture fog, while Sarracenia utilizes the trichome with hierarchical microchannels to quickly transport water. Herein, we combined their advantages to present a novel configuration, a spine with barbs and hierarchical channels (SBHC), for simultaneous ultrafast water transport and high-efficient fog harvesting. This bioinspired SBHC exhibited the fastest water transport ability and the highest fog harvesting efficiency in comparison with the spine with hierarchical channels (SHCs), the spine with barbs and grooves (SBG), and the spine with barbs (SB). Based on the fundamental SBHC unit, we further designed and fabricated a twodimensional (2D) spider-web-like fog collector and a three-dimensional (3D) cactus-like fog collector using direct laser structuring and origami techniques. The 2D spider-web and 3D cactus-like fog collectors showed high-efficient fog collection capacity. We envision that this fundamental understanding and rational design strategy can be applied in fog harvesting, heat transfer, liquid manipulation, and microfluidics.

and joints can efficiently transport and collect water from moisture. [4] The tenebrionid beetle with hydrophilic/hydrophobic patterned structures can collect drinking water from foggy air. [5] Many Cactaceae species living in highly arid deserts are extremely drought-tolerant owing to their excellent fog harvesting ability and minimal water loss. [6] Cacti uses conical spines with oriented microbarbs and hydrophilic trichomes as a continuous and effective fog harvesting system that relies on the cooperation effect of the Laplace pressure gradient and wettability difference. [6a,7] The Laplace pressure gradient generated from the conical shape of spines produces a unidirectional transport of water drops. Oriented microbarbs on spines have an asymmetrical morphology, which aids the unidirectional transport of drops. The wettability difference between spines and trichomes facilitates the rapid absorption and preservation of water drops. This multi structural and multifunctional integrated fog collection system can achieve spontaneous and continuous fog collection, transport, and preservation.Inspired by this superior fog collection system of cacti, several artificial spine-based fog collectors have been developed. [1b,8] However, these spine-based fog collectors are rarely integrated with oriented microbarbs for the fog harvesting owing to the fabrication limitation of microbarbs on the curved spine surface. Heng et al. [7] fabricated a branched ZnO wire structure using a two-step vapor-phase approach for the fog harvesting. The stem wire and branched wires were used to imitate the conical spine and microbarbs, respectively. This artificial branched wire structure collected more water compared with the cactus structure owing to relatively larger surface areas of the branched wires. However, the orientation of branched wires on the stem wire was random. Thus, it is still a challenge to construct oriented microbarbs on curved surfaces, and the effect of oriented microbarbs on the fog harvesting process lacks a systematical investigation.Herein, we propose the magnetorheological drawing lithography (MRDL) method to fabricate cactus-inspired conical spines with/without oriented microbarbs on the superhydrophilic porous substrate for efficient fog harvesting. MRDL is an effective additive manufacturing technique that can easily form 3D conical spines with/without oriented microbarbs on a porous substrate with the assistance of an external magnetic field. [9] The water collection behavior and the underlying In nature, cacti use conical spines with oriented microbarbs and hydrophilic trichomes as an effective fog harvesting system. However, the fabrication dilemma of complex cactus-inspired conical spines with oriented microbarbs limits their applications. Here, a magnetorheological drawing lithography (MRDL) method is developed to additively manufacture 3D cactus-inspired conical spines with/without oriented microbarbs on a superhydrophilic porous substrate for efficient fog harvesting. Cactus-inspired conical spin...

Theranostic system combined diagnostic and therapeutic modalities is critical for the real-time monitoring of disease-related biomarkers and personalized therapy. Microneedles, as a multifunctional platform, are promising for transdermal diagnostics and drug delivery. They have shown attractive properties including painless skin penetration, easy self-administration, prominent therapeutic effects, and good biosafety. Herein, an overview of the microneedles-based diagnosis, therapies, and theranostic systems is given. Four microneedles-based detection methods are concluded based on the sensing mechanism: i) electrochemistry, ii) fluorometric, iii) colorimetric, and iv) Raman methods. Additionally, robust microneedles are suitable for implantable drug delivery. Microneedles-assisted transdermal drug delivery can be primarily classified as passive, active, and responsive drug release, based on the release mechanisms. Microneedles-assisted oral and implantable drug delivery mechanisms are also presented in this review. Furthermore, the key frontier developments in microneedles-mediated theranostic systems as the major selling points are emphasized in this review. These systems are classified into open-loop and closed-loop theranostic systems based on the indirectness and directness of feedback between the transdermal diagnosis and therapy, respectively. Finally, conclusions and future perspectives for next-generation microneedles-mediated theranostic systems are also discussed. Taken together, microneedle-based systems are promising as the new avenue for diagnosis, therapy, and disease-specific closed-loop theranostic applications.

Soft magneto-active machines capable of magnetically controllable shape-morphing and locomotion have diverse promising applications such as untethered biomedical robots. However, existing soft magneto-active machines often have simple structures with limited functionalities and do not grant high-throughput production due to the convoluted fabrication technology. Here, we propose a facile fabrication strategy that transforms 2D magnetic sheets into 3D soft magneto-active machines with customized geometries by incorporating origami folding. Based on automated roll-to-roll processing, this approach allows for the high-throughput fabrication of soft magneto-origami machines with a variety of characteristics, including large-magnitude deploying, sequential folding into predesigned shapes, and multivariant actuation modes (e.g., contraction, bending, rotation, and rolling locomotion). We leverage these abilities to demonstrate a few potential applications: an electronic robot capable of on-demand deploying and wireless charging, a mechanical 8-3 encoder, a quadruped robot for cargo-release tasks, and a magneto-origami arts/craft. Our work contributes for the high-throughput fabrication of soft magneto-active machines with multi-functionalities.