4D-Printed Biomimetic Snake-like Soft Robot

Academic Background

With advancements in medical technology, the ability of wireless microrobots to navigate complex vascular networks within living organisms has garnered significant attention. These robots can perform precise medical tasks in confined spaces, such as targeted drug delivery, endoscopic examinations, and minimally invasive surgeries. However, traditional microrobots, due to their bulky size and complex connections, struggle to move flexibly in narrow vascular environments. To address this issue, researchers have begun exploring biomimetic designs, particularly inspired by the locomotion of snakes. Snakes, with their high aspect ratio bodies and undulating swimming patterns, exhibit exceptional maneuverability in liquid environments, providing inspiration for designing microrobots capable of navigating narrow blood vessels.

Source of the Paper

This paper was co-authored by researchers from Sun Yat-sen University, including Xingcheng Ou, Jiaqi Huang, and Dantong Huang, among others. It was published in the journal Bio-design and Manufacturing and made available online on January 10, 2025. The paper, titled “4D-printed snake-like biomimetic soft robots”, aims to design a biomimetic snake-like soft robot using 4D printing technology and magnetic-responsive intelligent ink for drug delivery in narrow blood vessels.

Research Process and Results

1. Preparation and Optimization of Magnetic-Responsive Ink

The researchers first prepared a magnetic-responsive intelligent ink by mixing neodymium-iron-boron (NdFeB) magnetic particles with an uncured polymer (Ecoflex 00-10) at a mass ratio of 3:1. The magnetic particles were uniformly dispersed using a planetary centrifugal mixer, and air bubbles were removed. The rheological properties of the ink were measured using a rotational rheometer to ensure good flowability at high shear rates and shape stability at low shear rates. By adjusting printing pressure and speed, the researchers optimized the ink’s printing parameters to ensure the printing of continuous filaments with controllable diameters.

2. Fabrication of the Snake-like Robot

The researchers used a self-built direct ink writing (DIW) 3D printer to fabricate the snake-like robot through layer-by-layer deposition. The robot model was designed using Unigraphics NX software, and G-code was generated through slicing software to control the printing path. After printing, the robot was magnetized using a strong pulsed magnetic field, enabling it to perform undulatory motion under the control of an external magnetic field.

3. Motion Control and Experimental Analysis

The researchers developed a sophisticated motion control strategy, utilizing a 3D Helmholtz coil system to generate dynamic magnetic fields, enabling the snake-like robot to perform various movements, such as straight swimming, precise turns, circular motions, and collective movements. The robot’s motion was monitored in real-time using a high-speed camera, and motion data were analyzed using open-source software, Tracker. Experimental results showed that the snake-like robot could achieve efficient undulatory swimming under different magnetic field intensities and frequencies, with a maximum speed of 51.159 mm/s.

4. Drug Delivery Experiment

To validate the potential application of the snake-like robot in drug delivery, the researchers encapsulated a drug mimic (Rhodamine B) in the robot’s head and conducted navigation and drug release experiments in a simulated coronary vascular model. The results demonstrated that the snake-like robot could quickly navigate to the target area in warm water at 32°C and complete drug release within 7 minutes.

Conclusions and Significance

This study successfully designed and fabricated a biomimetic snake-like soft robot using 4D printing technology and magnetic-responsive intelligent ink, achieving high-precision manufacturing and flexible motion control. The robot can efficiently navigate narrow vascular environments and perform precise drug delivery. This innovative design provides a new tool for future minimally invasive medical surgeries and targeted drug delivery, holding significant scientific and application value.

Research Highlights

1. Biomimetic Design: Mimicking the undulatory swimming patterns of snakes, the robot features a high aspect ratio, enabling flexible movement in narrow blood vessels.
2. 4D Printing Technology: Utilizing 4D printing technology, the robot was fabricated with magnetic-responsive properties, achieving high precision and customizable manufacturing.
3. Magnetic Motion Control: Through dynamic magnetic field control, the robot can perform various complex movements, such as straight swimming, turning, and collective motion.
4. Drug Delivery Application: Experiments validated the robot’s drug delivery capability in a simulated vascular environment, demonstrating its potential in medical applications.

Additional Valuable Information

The researchers also developed a finite element analysis (FEA) model to simulate the behavior of the snake-like robot in a magnetic field. By programming magnetic anisotropy, the researchers could predict the robot’s deformation patterns under different magnetic field conditions, providing theoretical support for the robot’s design and optimization.

This study not only advances the development of biomimetic soft robotics but also opens new possibilities for future medical applications.