Injectable ultrasonic sensor for wireless monitoring of intracranial signals.

Direct and precise monitoring of intracranial physiology holds immense importance in delineating injuries, prognostication and averting disease. Wired clinical instruments that use percutaneous leads are accurate but are susceptible to infection, patient mobility constraints and potential surgical complications during removal. Wireless implantable devices provide greater operational freedom but include issues such as limited detection range, poor degradation and difficulty in size reduction in the human body.

Calcium Peroxide-Based Hydrogel Patch with Sustainable Oxygenation for Diabetic Wound Healing.

Nonhealing diabetic wounds are predominantly attributed to the inhibition of angiogenesis, re-epithelialization, and extracellular matrix (ECM) synthesis caused by hypoxia. Although oxygen therapy has demonstrated efficacy in promoting healing, its therapeutic impact remains suboptimal due to unsustainable oxygenation. Here, this work proposes an oxygen-releasing hydrogel patch embedded with polyethylene glycol-modified calcium peroxide microparticles, which sustainably releases oxygen for 7 days without requiring any supplementary conditions.

Magnetic soft microfiberbots for robotic embolization.

Cerebral aneurysms and brain tumors are leading life-threatening diseases worldwide. By deliberately occluding the target lesion to reduce the blood supply, embolization has been widely used clinically to treat cerebral aneurysms and brain tumors. Conventional embolization is usually performed by threading a catheter through blood vessels to the target lesion, which is often limited by the poor steerability of the catheter in complex neurovascular networks, especially in submillimeter regions.

A Laparoscopically Compatible Rapid-Adhesion Bioadhesive for Asymmetric Adhesion, Non-Pressing Hemostasis, and Seamless Seal.

Bioadhesive hydrogels offer unprecedented opportunities in hemostatic agents and tissue sealing; however, the application of existing bioadhesive hydrogels through narrow spaces to achieve strong adhesion in fluid-rich physiological environments is challenged either by undesired indiscriminate adhesion or weak wet tissue adhesion. Here, a laparoscopically compatible asymmetric adhesive hydrogel (aAH) composed of sprayable adhesive hydrogel powders and injectable anti-adhesive glue is proposed for hemostasis and to seal the bloody tissues in a non-pressing way, allowing for preventing postoperative adhesion. The powders can seed on the irregular bloody wound to rapidly absorb interfacial fluid, crosslink, and form an adhesive hydrogel to hemostatic seal (blood clotting time and tissue sealing in 10 s, ≈200 mm Hg of burst pressure in sealed porcine tissues).

Learning-based intelligent trajectory planning for auto navigation of magnetic robots.

Electromagnetically controlled small-scale robots show great potential in precise diagnosis, targeted delivery, and minimally invasive surgery. The automatic navigation of such robots could reduce human intervention, as well as the risk and difficulty of surgery. However, it is challenging to build a precise kinematics model for automatic robotic control because the controlling process is affected by various delays and complex environments.

Bioinspired Soft Elastic Metamaterials for Reconstruction of Natural Hearing.

Natural hearing which means hearing naturally like normal people is critical for patients with hearing loss to participate in life. Cochlear implants have enabled numerous severe hearing loss patients to hear voice functionally, while cochlear implant users can hardly distinguish different tones or appreciate music subject to the absence of rate coding and insufficient frequency channels. Here a bioinspired soft elastic metamaterial that reproduces the shape and key functions of the human cochlea is reported.

Minimally invasive bioprinting for liver regeneration.

bioprinting is promising for developing scaffolds directly on defect models in operating rooms, which provides a new strategy for tissue regeneration. However, due to the limitation of existing biofabrication technologies including printing depth and suitable bioinks, bioprinting scaffolds in deep dermal or extremity injuries remains a grand challenge. Here, we present an scaffold fabrication approach by minimally invasive bioprinting electroactive hydrogel scaffolds to promote tissue regeneration.

Robust Neural Interfaces with Photopatternable, Bioadhesive, and Highly Conductive Hydrogels for Stable Chronic Neuromodulation.

A robust neural interface with intimate electrical coupling between neural electrodes and neural tissues is critical for stable chronic neuromodulation. The development of bioadhesive hydrogel neural electrodes is a potential approach for tightly fixing the neural electrodes on the epineurium surface to construct a robust neural interface. Herein, we construct a photopatternable, antifouling, conductive (∼6 S cm), bioadhesive (interfacial toughness ∼100 J m), soft, and elastic (∼290% strain, Young's modulus of 7.

Fabrication of ZnO dual electron transport layer via atomic layer deposition for highly stable and efficient CsPbBrperovskite nanocrystals light-emitting diodes.

Electron transport layers (ETLs) are important components of high-performance all-inorganic perovskite nanocrystals light-emitting diodes (PNCs-LED). Herein, atomic layer deposition (ALD) of inorganic ZnO layer is combined to the organic 1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBi) to form dual ETLs to enhance both the efficiency and stability of PNCs-LED simultaneously. Optimization of ZnO thickness suggested that 10 cycles ALD yields the best performance of the devices.

The Shape Memory Properties and Actuation Performances of 4D Printing Poly (Ether-Ether-Ketone).

Shape-memory polymers (SMPs) have gradually emerged in the mechanism and biomedical fields and facilitate the upgrading of industrial mechanisms and the breakthrough of technical bottlenecks. However, most of the SMPs are infeasible in harsh environments, such as aerospace, due to the low glass transition temperature. There are still some works that remain in creating truly portable or non-contacting actuators that can match the performances and functions of traditional metal structures.

Magnetic soft robotic bladder for assisted urination.

The poor contractility of the detrusor muscle in underactive bladders (UABs) fails to increase the pressure inside the UAB, leading to strenuous and incomplete urination. However, existing therapeutic strategies by modulating/repairing detrusor muscles, e.g.

Inverse-Designed Aid Lenses for Precise Correction of Color Vision Deficiency.

Color vision deficiency (CVD) is a common ocular disorder affecting more than 300 million people on the earth. Although no clinical cure for the disorder currently exists, some specialized color filtering glasses/lenses based on dyes, metasurfaces, or nanocomposites have been employed for CVD management. However, as CVD patients usually diversify in their classification and severity, none of the current lenses provides a customized correction for various CVD patients, resulting in undesirable correction effects.

Soft and disordered hyperuniform elastic metamaterials for highly efficient vibration concentration.

Vibrations, which widely exist throughout the world, could be a nearly endless and locally obtained green energy source. It has been a long-standing challenge to efficiently utilize dispersed vibration energy, especially within the high-frequency range, since the amplitudes of high-frequency vibrations in local parts of objects are relatively weak. Here, for the first time, we propose a soft and disordered hyperuniform elastic metamaterial (DHEM), achieving a remarkable concentration of vibrations in broad frequency bands by a maximum enhancement factor of ∼4000 at 1930 Hz.

Ferromagnetic soft catheter robots for minimally invasive bioprinting.

In vivo bioprinting has recently emerged as a direct fabrication technique to create artificial tissues and medical devices on target sites within the body, enabling advanced clinical strategies. However, existing in vivo bioprinting methods are often limited to applications near the skin or require open surgery for printing on internal organs. Here, we report a ferromagnetic soft catheter robot (FSCR) system capable of in situ computer-controlled bioprinting in a minimally invasive manner based on magnetic actuation.

Cu-Doped CsPbI Nanocrystals with Enhanced Stability for Light-Emitting Diodes.

Black phase CsPbI perovskites have emerged as one of the most promising materials for use in optoelectronic devices due to their remarkable properties. However, black phase CsPbI usually possesses poor stability and involves a phase change process, resulting in an undesired orthorhombic (δ) yellow phase. Here, the enhanced stability of CsPbI nanocrystals is achieved by incorporating the Cu ion into the CsPbI lattice under mild conditions.

All-Dielectric Silicon Nanoring Metasurface for Full-Color Printing.

Structural color has been particularly attractive as it provides a highly promising approach for next-generation color printing. Plasmonic nanostructures have been intensively investigated for color printing, while suffering from intrinsic loss that degrades the quality of the coloration. Dielectric materials have emerged as an alternative because of their high refractive index that enables highly confined optical modes within the nanostructure at the diffraction limit.

Fatigue-resistant adhesion of hydrogels.

The adhesion of soft connective tissues (tendons, ligaments, and cartilages) on bones in many animals can maintain high toughness (∽800 J m) over millions of cycles of mechanical loads. Such fatigue-resistant adhesion has not been achieved between synthetic hydrogels and engineering materials, but is highly desirable for diverse applications such as artificial cartilages and tendons, robust antifouling coatings, and hydrogel robots. Inspired by the nanostructured interfaces between tendons/ligaments/cartilages and bones, we report that bonding ordered nanocrystalline domains of synthetic hydrogels on engineering materials can give a fatigue-resistant adhesion with an interfacial fatigue threshold of 800 J m, because the fatigue-crack propagation at the interface requires a higher energy to fracture the ordered nanostructures than amorphous polymer chains.

Nonintrusive Monitoring of Mental Fatigue Status Using Epidermal Electronic Systems and Machine-Learning Algorithms.

Mental fatigue, characterized by subjective feelings of "tiredness" and "lack of energy", can degrade individual performance in a variety of situations, for example, in motor vehicle driving or while performing surgery. Thus, a method for nonintrusive monitoring of mental fatigue status is urgently needed. Recent research shows that physiological signal-based fatigue-classification methods using wearable electronics can be sufficiently accurate; by contrast, rigid, bulky devices constrain the behavior of those wearing them, potentially interfering with test signals.

The inverse design of structural color using machine learning.

Efficiently identifying optical structures with desired functionalities, referred to as inverse design, can dramatically accelerate the invention of new photonic devices, and this is especially useful in the design of large scale integrated photonic chips. Structural color with high-resolution, high-saturation, and low-loss holds great promise in image display, data storage and information security. However, the inverse design of structural color remains an open challenge, and this impedes practical application.

Synthesis and Characterization of the Conducting Polymer Micro-Helix Based on the Template.

As one of the most interesting naturally-occurring geometries, micro-helical structures have attracted attention due to their potential applications in fabricating biomedical and microelectronic devices. Conventional processing techniques for manufacturing micro-helices are likely to be limited in cost and mass-productivity, while , which shows natural fine micro-helical forms, can be easily mass-reproduced at an extremely low cost. Furthermore, considering the extensive utility of conducting polymers, it is intriguing to synthesize conducting polymer micro-helices.

Multifunctional "Hydrogel Skins" on Diverse Polymers with Arbitrary Shapes.

Slippery and hydrophilic surfaces find critical applications in areas as diverse as biomedical devices, microfluidics, antifouling, and underwater robots. Existing methods to achieve such surfaces rely mostly on grafting hydrophilic polymer brushes or coating hydrogel layers, but these methods suffer from several limitations. Grafted polymer brushes are prone to damage and do not provide sufficient mechanical compliance due to their nanometer-scale thickness.

Fully Stretchable and Humidity-Resistant Quantum Dot Gas Sensors.

Stretchable gas sensors that accommodate the shape and motion characteristics of human body are indispensable to a wearable or attachable smart sensing system. However, these gas sensors usually have poor response and recovery kinetics when operated at room temperature, and especially suffer from humidity interference and mechanical robustness issues. Here, we demonstrate the first fully stretchable gas sensors which are operated at room temperature with enhanced stability against humidity.

Observation of elastic topological states in soft materials.

Topological elastic metamaterials offer insight into classic motion law and open up opportunities in quantum and classic information processing. Theoretical modeling and numerical simulation of elastic topological states have been reported, whereas the experimental observation remains relatively unexplored. Here we present an experimental observation and numerical simulation of tunable topological states in soft elastic metamaterials.

Dynamically tunable interface states in 1D graphene-embedded photonic crystal heterostructure.

Optical interface states exhibit promising applications in nonlinear photonics, low-threshold lasing, and surface-wave assisted sensing. However, the further application of interface states in configurable optics is hindered by their limited tunability. Here, we demonstrate a new approach to generate dynamically tunable and angle-resolved interface states using graphene-embedded photonic crystal (GPC) heterostructure device.

Out-of-Plane Designed Soft Metasurface for Tunable Surface Plasmon Polariton.

Reliable and repeatable tunability gives functional diversity for reconfigurable plasmonics devices, while reversible and large mechanical deformation enabled by soft materials provides a new way for the global or partial regulation of metadevices. Here, we demonstrate a soft metasurface with an out-of-plane design for tuning the energy of surface plasmon polaritons (SPPs) bloch wave using theory, simulation, and experiments. Our metasurface is composed of two-layered gold nanoribbon arrays (2GNRs) on a soft substrate.