Electromagnetic-based actuation is receiving increasing attention for driving microparticles, particularly for in vivo biomedical applications. This study presents a core shape design for electromagnetic coils to develop a magnetic gradient field-based actuation system that can enable microrobotic manipulation. Based on mathematical model using the finite element method, the shape of the iron core and the size of the probe are optimized aiming to increase the gradient at the focused area. A thin disc is also attached to the end of the iron core for reducing the waste of magnetic field energy. Through this design, the magnetic field generated by the electromagnetic actuation system can be considerably enhanced to propel microrobots in the in vivo environments. The designed system is tested in different in vitro environments, including pure water, artificial cerebrospinal fluid, mouse blood, and a special environment with an extremely high viscosity coefficient. The system is also tested for driving microrobots in an in vivo environment, namely, zebrafish yolk. Experimental results effectively demonstrate the capacity of the designed platform in manipulating microrobots for in vitro and in vivo applications.

Soft robots, inspired by the flexibility and versatility of biological organisms, have potential in a variety of applications. Recent advancements in magneto-soft robots have demonstrated their abilities to achieve precise remote control through magnetic fields, enabling multi-modal locomotion and complex manipulation tasks. Nonetheless, two main hurdles must be overcome to advance the field: developing a multi-component substrate with embedded magnetic particles to ensure the requisite flexibility and responsiveness, and devising a cost-effective, straightforward method to program three-dimensional distributed magnetic domains without complex processing and expensive machinery. Here, we introduce a cost-effective and simple heat-assisted in-situ integrated molding fabrication method for creating magnetically driven soft robots with three-dimensional programmable magnetic domains. By synthesizing a composite material with neodymium-iron-boron (NdFeB) particles embedded in a polydimethylsiloxane (PDMS) and Ecoflex matrix (PDMS:Ecoflex = 1:2 mass ratio, 50% magnetic particle concentration), we achieved an optimized balance of flexibility, strength, and magnetic responsiveness. The proposed heat-assisted in-situ magnetic domains programming technique, performed at an experimentally optimized temperature of 120 °C, resulted in a 2 times magnetization strength (9.5 mT) compared to that at 20 °C (4.8 mT), reaching a saturation level comparable to a commercial magnetizer. We demonstrated the versatility of our approach through the fabrication of six kinds of robots, including two kinds of two-dimensional patterned soft robots (2D-PSR), a circular six-pole domain distribution magnetic robot (2D-CSPDMR), a quadrupedal walking magnetic soft robot (QWMSR), an object manipulation robot (OMR), and a hollow thin-walled spherical magneto-soft robot (HTWSMSR). The proposed method provides a practical solution to create highly responsive and adaptable magneto-soft robots.

Wireless capsule endoscopy (WCE) has the potential to fully replace conventional wired counterparts for its low invasiveness. Recent studies have attempted

Exosomes are essential early biomarkers for health monitoring and cancer diagnosis. A prerequisite for further investigation of exosomes is the isolation, which is technically challenging due to the complexity of body fluids. This paper presents the development of an integrated microfluidic chip for exosomes isolation, which combines the traditional immunomagnetic bead-based protocol and the recently emerging microfluidic approach, resulting in benefits from both the high-purity of the former and the automated continuous superiority of the latter. The chip was designed based on an S-shaped micromixer with embedded baffle. The excellent mixing efficiency of this micromixer compared with Y-shaped and S-shaped micromixers was verified by simulation and experiments. The photolithography technique was employed to fabricate the integrated microfluidic chip, and the manufacturing process was elucidated. We finally established an experimental platform for exosomes isolation with the fabricated microfluidic chip built in. Exosomes isolation experiments were conducted using this platform. The distribution and morphology of the isolated exosomes were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Quantitative size analyses based on transmission electron micrographs indicated that most of the obtained particles were between 30 and 150 nm. Western blot analyses of the isolated exosomes and the serum were conducted to verify the platform’s capability of isolating a certain subpopulation of exosomes corresponding to specified protein markers (CD63). The complete time for isolation of 150 μL serum samples was approximately 50 min, which was highly competitive with the reported existing protocols. Experimental results proved the capacity of the established integrated microfluidic chip for exosomes isolation with high purity, high integrity, and excellent efficiency. The platform can be further developed to make it possible for practical use in clinical applications as a universal exosomes isolation and characterization tool.

This article addresses the challenge of state observer design for sliding mode security control in Markov jump cyber-physical systems subjected to stochastic injection attacks. To enhance network efficiency, a dynamic event-triggered algorithm is introduced in the communication channel. First, the design begins with a Luenberger state observer featuring an adaptive compensator. This configuration aims to effectively counteract malicious attacks. Second, an integral sliding hyperplane is formulated within the estimation space, which serves as the foundation for deriving the sliding mode dynamics, ensuring robustness against disturbances. Recognizing the diversity of transition rates (TRs), an elastic sliding mode controller is designed to accommodate three distinct types of TRs, which is also strategically designed to guarantee reachability and maintain sliding motion. Third, stochastic stability with an $H_{\infty }$ attenuation level is conducted separately for each type of TR. Correspondingly, the development of an algorithm for determining threshold parameters in triggered conditions is presented. Simultaneously, a proof of the nonexistence of Zeno behavior is provided, ensuring the stability and efficiency of the proposed system. Finally, a simulation study using a practical model is included to empirically demonstrate the validity of the proposed method in a real-world context.