Editorial for the Special Issue on Fundamentals and Applications of Micro/Nanorobotics.

In recent years, microrobots have drawn extensive attention due to their promising potential in biomedical applications [...

One-step formation of polymorphous sperm-like microswimmers by vortex turbulence-assisted microfluidics.

Microswimmers are considered promising candidates for active cargo delivery to benefit a wide spectrum of biomedical applications. Yet, big challenges still remain in designing the microswimmers with effective propelling, desirable loading and adaptive releasing abilities all in one. Inspired by the morphology and biofunction of spermatozoa, we report a one-step formation strategy of polymorphous sperm-like magnetic microswimmers (PSMs) by developing a vortex turbulence-assisted microfluidics (VTAM) platform.

Larvae-Inspired Soft Crawling Robot with Multimodal Locomotion and Versatile Applications.

Soft crawling robots have been widely studied and applied because of their excellent environmental adaptability and flexible movement. However, most existing soft crawling robots typically exhibit a single-motion mode and lack diverse capabilities. Inspired by larvae, this paper proposes a compact soft crawling robot (weight, 13 g; length, 165 mm; diameter, 35 mm) with multimodal locomotion (forward, turning, rolling, and twisting).

A Review of Intelligent Walking Support Robots: Aiding Sit-to-Stand Transition and Walking.

Nowadays, numerous countries are facing the challenge of aging population. Additionally, the number of people with reduced mobility due to physical illness is increasing. In response to this issue, robots used for walking assistance and sit-to-stand (STS) transition have been introduced in nursing to assist these individuals with walking.

Insect-Scale Biped Robots Based on Asymmetrical Friction Effect Induced by Magnetic Torque.

Multimodal and controllable locomotion in complex terrain is of great importance for practical applications of insect-scale robots. Robust locomotion plays a particularly critical role. In this study, a locomotion mechanism for magnetic robots based on asymmetrical friction effect induced by magnetic torque is revealed and defined.

AI co-pilot bronchoscope robot.

The unequal distribution of medical resources and scarcity of experienced practitioners confine access to bronchoscopy primarily to well-equipped hospitals in developed regions, contributing to the unavailability of bronchoscopic services in underdeveloped areas. Here, we present an artificial intelligence (AI) co-pilot bronchoscope robot that empowers novice doctors to conduct lung examinations as safely and adeptly as experienced colleagues. The system features a user-friendly, plug-and-play catheter, devised for robot-assisted steering, facilitating access to bronchi beyond the fifth generation in average adult patients.

Learning a simulation-based visual policy for real-world peg in unseen holes.

This paper proposes a learning-based visual peg-in-hole that enables training with several shapes in simulation and adapting to arbitrary unseen shapes in the real world with minimal sim-to-real cost. The core idea is to decouple the generalization of the sensory-motor policy from the design of a fast-adaptable perception module and a simulated generic policy module. The framework consists of a segmentation network (SN), a virtual sensor network (VSN), and a controller network (CN).

DPCN++: Differentiable Phase Correlation Network for Versatile Pose Registration.

Pose registration is critical in vision and robotics. This article focuses on the challenging task of initialization-free pose registration up to 7DoF for homogeneous and heterogeneous measurements. While recent learning-based methods show promise using differentiable solvers, they either rely on heuristically defined correspondences or require initialization.

Weakly-Interactive-Mixed Learning: Less Labelling Cost for Better Medical Image Segmentation.

Common medical image segmentation tasks require large training datasets with pixel-level annotations which are very expensive and time-consuming to prepare. To overcome such limitation and achieve the desired segmentation accuracy, a novel Weakly-Interactive-Mixed Learning (WIML) framework is proposed by efficiently using weak labels. On one hand, utilize weak labels to reduce annotation time for high-quality strong labels by designing a Weakly-Interactive Annotation (WIA) part of the WIML which prudently introduces interactive learning into the weakly-supervised segmentation strategy.

Unmanned Aerial Vehicle Mediated Drug Delivery for First Aid.

Timely administration of key medications toward patients with sudden diseases is critical to saving lives. However, slow transport of first-aid therapeutics and the potential absence of trained people for drug usage can lead to severe injuries or even death. Herein, an unmanned aerial vehicle (UAV)-mediated first-aid system for targeted delivery (uFAST) is developed.

Artificial Intelligence-Assisted Bioinformatics, Microneedle, and Diabetic Wound Healing: A "New Deal" of an Old Drug.

Diabetic wounds severely influence life, facing grand challenges in clinical treatments. The demand for better treatment is growing dramatically. Diabetic wound healing is challenging because of inflammation, angiogenesis disruptions, and tissue remodeling.

A Survey on Design, Actuation, Modeling, and Control of Continuum Robot.

In this paper, we describe the advances in the design, actuation, modeling, and control field of continuum robots. After decades of pioneering research, many innovative structural design and actuation methods have arisen. Untethered magnetic robots are a good example; its external actuation characteristic allows for miniaturization, and they have gotten a lot of interest from academics.

Milli-scale cellular robots that can reconfigure morphologies and behaviors simultaneously.

Modular robot that can reconfigure architectures and functions has advantages in unpredicted environment and task. However, the construction of modular robot at small-scale remains a challenge since the lack of reliable docking and detaching strategies. Here we report the concept of milli-scale cellular robot (mCEBOT) achieved by the heterogeneous assembly of two types of units (short and long units).

A Proprioceptive Soft Robot Module Based on Supercoiled Polymer Artificial Muscle Strings.

In this paper, a multi-functional soft robot module that can be used to constitute a variety of soft robots is proposed. The body of the soft robot module made of rubber is in the shape of a long strip, with cylindrical chambers at both the top end and bottom end of the module for the function of actuators and sensors. The soft robot module is driven by supercoiled polymer artificial muscle (SCPAM) strings, which are made from conductive nylon sewing threads.

Swarm of micro flying robots in the wild.

Aerial robots are widely deployed, but highly cluttered environments such as dense forests remain inaccessible to drones and even more so to swarms of drones. In these scenarios, previously unknown surroundings and narrow corridors combined with requirements of swarm coordination can create challenges. To enable swarm navigation in the wild, we develop miniature but fully autonomous drones with a trajectory planner that can function in a timely and accurate manner based on limited information from onboard sensors.

A 3D-Printed Fin Ray Effect Inspired Soft Robotic Gripper with Force Feedback.

Soft robotic grippers are able to carry out many tasks that traditional rigid-bodied grippers cannot perform but often have many limitations in terms of control and feedback. In this study, a Fin Ray effect inspired soft robotic gripper is proposed with its whole body directly 3D printed using soft material without the need of assembly. As a result, the soft gripper has a light weight, simple structure, is enabled with high compliance and conformability, and is able to grasp objects with arbitrary geometry.

Robot-aided fN∙m torque sensing within an ultrawide dynamic range.

In situ scanning electron microscope (SEM) characterization have enabled the stretching, compression, and bending of micro/nanomaterials and have greatly expanded our understanding of small-scale phenomena. However, as one of the fundamental approaches for material analytics, torsion tests at a small scale remain a major challenge due to the lack of an ultrahigh precise torque sensor and the delicate sample assembly strategy. Herein, we present a microelectromechanical resonant torque sensor with an ultrahigh resolution of up to 4.

Robust Orthogonal-View 2-D/3-D Rigid Registration for Minimally Invasive Surgery.

Intra-operative target pose estimation is fundamental in minimally invasive surgery (MIS) to guiding surgical robots. This task can be fulfilled by the 2-D/3-D rigid registration, which aligns the anatomical structures between intra-operative 2-D fluoroscopy and the pre-operative 3-D computed tomography (CT) with annotated target information. Although this technique has been researched for decades, it is still challenging to achieve accuracy, robustness and efficiency simultaneously.

Millimeter-Scale Soft Continuum Robots for Large-Angle and High-Precision Manipulation by Hybrid Actuation.

Developing small-scale soft continuum robots with large-angle steering capacity and high-precision manipulation offers broad opportunities in various biomedical settings. However, existing continuum robots reach the bottleneck in actuation on account of the contradiction among small size, compliance actuation, large tender range, high precision, and small dynamic error. Herein, a 3D-printed millimeter-scale soft continuum robot with an ultrathin hollow skeleton wall (300 μm) and a large inner-to-outer ratio (0.

An agglutinate magnetic spray transforms inanimate objects into millirobots for biomedical applications.

Millirobots that can adapt to unstructured environments, operate in confined spaces, and interact with a diverse range of objects would be desirable for exploration and biomedical applications. The continued development of millirobots, however, requires simple and scalable fabrication techniques. Here, we propose a minimalist approach to construct millirobots by coating inanimate objects with a composited agglutinate magnetic spray.

Battery-Less Soft Millirobot That Can Move, Sense, and Communicate Remotely by Coupling the Magnetic and Piezoelectric Effects.

The soft millirobot is a promising candidate for emerging applications in various in-vivo/vitro biomedical settings. Despite recent success in its design and actuation, the absence of sensing ability makes it still far from being a reality. Here, a radio frequency identification (RFID) based battery-less soft millirobot that can move, sense, and communicate remotely by coupling the magnetic and piezoelectric effects is reported.

Low-Invasive Cell Injection based on Rotational Microrobot.

The advancement of cell injections has created a need for accurate, efficient, and low-invasive injections. However, the conventional approaches to reduce cell damage during penetration, mainly optimization of micropipette tips and vision-based automatic injections, have almost reached the limit. Here, described are the design and implementation of a robotic-aided rotatory microinjection system to reduce cell deformation and penetration force during the injection.

Magnetically Actuated Heterogeneous Microcapsule-Robot for the Construction of 3D Bioartificial Architectures.

Core-shell microcapsules as one type of the most attractive carriers and reactors have been widely applied in the fields of drug screening and tissue engineering owing to their excellent biocompatibility and semi-permeability. Yet, the spatial organization of microcapsules with specific shapes into three-dimensional (3D) ordered architectures still remains a big challenge. Here, we present a method to assemble shape-controllable core-shell microcapsules using an untethered magnetic microcapsule-robot.

Automatic 3D reconstruction of SEM images based on Nano-robotic manipulation and epipolar plane images.

This paper reports a new and general 3D reconstruction algorithm by using the light field reconstruction theory to effectively construct 3D SEM images in a large range. Firstly, a nano-robotic system was employed to automatically capture a group of SEM images along a linear path with a fixed step size, which allowed the 3D SEM images to be reconstructed beyond the field of view (FOV) of SEM. Then, the epipolar-plane images (EPI) were generated, and the depth image was reconstructed based on the specific linear structures emerging in EPI and the automatic depth estimation algorithm.

Programmable higher-order biofabrication of self-locking microencapsulation.

Three-dimensional (3D) hydrogel microcapsules offer great potential in a wide variety of biomedical and tissue engineering applications for their promising biodegradability and customizable geometry. Although recent advances in microfluidics and electrospray techniques have achieved high-throughput production of droplet microcapsules, they are still faced with the intractable challenge of obtaining programmable shape-engineered microcapsules with complex spatial architecture. Herein, a programmable light-induced biofabrication strategy is proposed to construct higher-order microcapsule architectures by developing a microencapsulation microchip.