Magnetic Micromachine Using Nickel Nanoparticles for Propelling and Releasing in Indirect Assembly of Cell-Laden Micromodules

A Novel Electromagnetic Driving System for 5-DOF Manipulation in Intraocular Microsurgery

This work presents a novel electromagnetic driving system that consists of eight optimized electromagnets arranged in an optimal configuration and employs a control framework based on an active disturbance rejection controller (ADRC) and virtual boundary. The optimal system configuration enhances the system's compatibility with other ophthalmic surgical instruments, while also improving its capacity to generate magnetic force in the vertical direction. Besides, the optimal electromagnet parameters provide a superior comprehensive performance on magnetic field generation capacity and thermal power. Hence, the presented design achieves a stronger capacity for sustained work. Furthermore, the ADRC controller effectively monitors and further compensates the total disturbance as well as gravity to enhance the system's robustness. Meanwhile, the implementation of virtual boundaries substantially enhances interactive security via collision avoidance. The magnetic and thermal performance tests have been performed on the electromagnet to verify the design optimization. The proposed electromagnet can generate a superior magnetic field of 2.071 mT at a distance of 65 mm with an applied current of 1 A. Moreover, it demonstrates minimal temperature elevation from room temperature (25 °C) to 46 °C through natural heat dissipation in 3 h, thereby effectively supporting prolonged magnetic manipulation of intraocular microsurgery. Furthermore, trajectory tracking experiments with disturbances have been performed in a liquid environment similar to the practical ophthalmic surgery scenarios, to verify the robustness and security of the presented control framework. The maximum root mean square (RMS) error of performance tests in different operation modes remains 35.8 μm, providing stable support for intraocular microsurgery.

Magnetic Soft Materials and Robots

In conventional classification, soft robots feature mechanical compliance as the main distinguishing factor from traditional robots made of rigid materials. Recent advances in functional soft materials have facilitated the emergence of a new class of soft robots capable of tether-free actuation in response to external stimuli such as heat, light, solvent, or electric or magnetic field. Among the various types of stimuli-responsive materials, magnetic soft materials have shown remarkable progress in their design and fabrication, leading to the development of magnetic soft robots with unique advantages and potential for many important applications. However, the field of magnetic soft robots is still in its infancy and requires further advancements in terms of design principles, fabrication methods, control mechanisms, and sensing modalities. Successful future development of magnetic soft robots would require a comprehensive understanding of the fundamental principle of magnetic actuation, as well as the physical properties and behavior of magnetic soft materials. In this review, we discuss recent progress in the design and fabrication, modeling and simulation, and actuation and control of magnetic soft materials and robots. We then give a set of design guidelines for optimal actuation performance of magnetic soft materials. Lastly, we summarize potential biomedical applications of magnetic soft robots and provide our perspectives on next-generation magnetic soft robots.

Bioinspired soft microrobots actuated by magnetic field

In contrast to traditional large-scale robots, which require complicated mechanical joints and material rigidity, microrobots made of soft materials have exhibited amazing features and great potential for extensive applications, such as minimally invasive surgery. However, microrobots are faced with energy supply and control issues due to the miniaturization. Magnetic field actuation emerges as an appropriate approach to tackle with these issues. This review summarizes the latest progress of biomimetic soft microrobots actuated by magnetic field. Starting with an overview of the soft material and magnetic material adopted in the magnetic field actuated soft microrobots, the various fabrication methods and design structures of soft microrobots are summarized. Subsequently, practical and potential applications, such as targeted therapy, surgical operation, and the transportation of microscopic objects, in the fields of biomedicine and environmental remediation are presented. In the end, some current challenges, and the future development trends of magnetic soft microrobots are briefly discussed. This review is expected to offer a helpful guidance for the new researchers of biomimetic soft microrobots actuated by magnetic field.

Micro/nanoscale magnetic robots for biomedical applications

Magnetic small-scale robots are devices of great potential for the biomedical field because of the several benefits of this method of actuation. Recent work on the development of these devices has seen tremendous innovation and refinement toward ​improved performance for potential clinical applications. This review briefly details recent advancements in small-scale robots used for biomedical applications, covering their design, fabrication, applications, and demonstration of ability, and identifies the gap in studies and the difficulties that have persisted in the optimization of the use of these devices. In addition, alternative biomedical applications are also suggested for some of the technologies that show potential for other functions. This study concludes that although the field of small-scale robot research is highly innovative ​there is need for more concerted efforts to improve functionality and reliability of these devices particularly in clinical applications. Finally, further suggestions are made toward ​the achievement of commercialization for these devices.

Perspective: Ferromagnetic Liquids

Mechanical jamming of nanoparticles at liquid-liquid interfaces has evolved into a versatile approach to structure liquids with solid-state properties. Ferromagnetic liquids obtain their physical and magnetic properties, including a remanent magnetization that distinguishes them from ferrofluids, from the jamming of magnetic nanoparticles assembled at the interface between two distinct liquids to minimize surface tension. This perspective provides an overview of recent progress and discusses future directions, challenges and potential applications of jamming magnetic nanoparticles with regard to 3D nano-magnetism. We address the formation and characterization of curved magnetic geometries, and spin frustration between dipole-coupled nanostructures, and advance our understanding of particle jamming at liquid-liquid interfaces.

Tissue Engineering and Regenerative Medicine 2019: The Role of Biofabrication-A Year in Review

Despite its relative youth, biofabrication is unceasingly expanding by assimilating the contributions from various disciplinary areas and their technological advances. Those developments have spawned the range of available options to produce structures with complex geometries while accurately manipulating and controlling cell behavior. As it evolves, biofabrication impacts other research fields, allowing the fabrication of tissue models of increased complexity that more closely resemble the dynamics of living tissue. The recent blooming and evolutions in biofabrication have opened new windows and perspectives that could aid the translational struggle in tissue engineering and regenerative medicine (TERM) applications. Based on similar methodologies applied in past years' reviews, we identified the most high-impact publications and reviewed the major concepts, findings, and research outcomes in the context of advancement beyond the state-of-the-art in the field. We first aim to clarify the confusion in terminology and concepts in biofabrication to therefore introduce the striking evolutions in three-dimensional and four-dimensional bioprinting of tissues. We conclude with a short discussion on the future outlooks for innovation that biofabrication could bring to TERM research.