Infertility is a significant global health issue, affecting an estimated 186 million people worldwide. Among the various causes of infertility, fallopian tube obstruction is one of the leading factors, contributing to 11%–67% of female infertility cases. Conditions like fibroids, endometriosis, and pelvic inflammatory disease can all result in fallopian tube blockages, which complicate natural conception. Traditional surgical approaches—typically involving hysterosalpingography combined with catheters and guidewires—are commonly employed to clear such blockages. However, these methods face serious limitations, particularly when addressing distal tubal obstructions due to the large size of catheters and the poor steerability of guidewires.
In a groundbreaking study, researchers from the SIAT Magnetic Soft Microrobots Lab have proposed a novel solution in the form of a magnetically-driven robotic microscrew. This innovative microrobot represents a major step forward in treating tubal blockages, offering potential as a minimally invasive alternative to traditional surgical methods.
The Challenge of Tubal Recanalization: Traditional Methods and Their Limitations
As highlighted by the researchers in the study, “The current mainstream surgical approach to removing the blockage is represented by hysterosalpingography combined with conventional tubal catheters and guidewires“. These methods, while useful in some cases, are ineffective when it comes to distal tubal obstructions. The fallopian tubes are narrow, with diameters often less than 1 mm, making it challenging for traditional catheters to navigate and treat blockages effectively. “The traditional catheter can only reach the proximal fallopian tube, and the guidewire has poor steerability in the fallopian tube,” the authors note, pointing out the critical need for a more refined approach to addressing distal blockages in the fallopian tubes.
The study emphasizes the limitations of current techniques, particularly in terms of their inability to effectively clear obstructions that are far from the opening of the fallopian tube. The new magnetically-driven microscrew addresses these challenges head-on.
The Microrobots: Magnetically-Driven Robotic Microscrews
The authors of the study introduce a novel solution to the problem: a magnetically driven robotic microscrew. This study was published in AIP Advances. This microrobot is fabricated with precision using 3D microfabrication technology and designed to clear fallopian tube blockages with remarkable efficiency. Unlike traditional methods that rely on bulky devices, the microscrew is small, maneuverable, and capable of navigating the narrow, delicate passages of the fallopian tube.
As Haifeng Xu, one of the lead authors, explains: “This new technology offers a potentially less invasive alternative to the traditional surgical methods currently used to clear tubal obstructions.” The unique design of the microscrew includes a helical body, a cylindrical central tube, and a disk-shaped tail, all of which are critical to its functionality. The helical structure generates the propulsion force needed for movement, while the disk-shaped tail stabilizes the robot’s motion.
The key advantage of this microrobot is its ability to clear blockages through a process of mechanical drilling. The robot’s screw-like motion allows it to generate friction against the blockage, breaking it apart and clearing the path for fertility restoration. The debris is then carried to the back of the microrobot via the vortex field generated by its movement. Hence, it makes the process more efficient.
Advanced Design: Fabrication and Propulsion Mechanisms
The design and fabrication of the microscrew are central to its effectiveness. As the researchers describe, the robotic microscrew consists of a helical body, a cylindrical central tube, and a disk-shaped tail. The microrobot is constructed using high-resolution 3D microfabrication techniques and the application of an ultra-thin iron layer through magnetron sputtering. So that it gives the microrobot its magnetic properties. A titanium layer is also added to enhance the robot’s stability and biocompatibility.
The propulsion of the microrobot is based on its helical shape, which allows for a unique form of motion known as helical propulsion. The authors conducted several simulations to test the robot’s performance. They found that the helical structure produced the required propulsion force to move the robot efficiently, while the additional tail enhanced its stability and drilling effectiveness. “The helical structure is designed to generate the propulsion force, and the needle structure and the triangular blade are designed to facilitate the penetration of the blockage,” they explain.
This propulsion system, combined with the robot’s small scale and ability to navigate in confined spaces, makes it a promising tool for treating obstructions in the fallopian tube.
Magnetic Actuation and Controlled Navigation
A critical aspect of the robot’s functionality is; controlling its ability remotely via an external magnetic field. This allows the user to precisely navigate the microrobot through the fallopian tube, overcoming the challenges of poor steerability associated with traditional catheters and guidewires. The microrobot’s motion is governed by a combination of static and rotating magnetic fields. The direction, strength, and frequency of its motion can be adjusted.
In the study, the authors used a magnetic microrobot control platform to accurately control the robot’s movements. The system consists of a microscope and the MagnebotiX MFG-100 magnetic field generator, allowing for real-time control of the magnetic fields. This setup ensures that the microrobot can be steered with high precision as it moves through the fallopian tube, and breaks tube blockages as it goes.
“The robot is coated by magnetron sputtering with an extremely thin layer of iron. The ultrathin iron layer can be regarded as a superparamagnetic material. Therefore, the magnetization of the magnetic microrobots is zero without the external magnetic field,” the authors explain. The ability to control the microrobot’s orientation and movement through the magnetic field adds another layer of precision to the procedure, making it an ideal tool for delicate surgeries.
Demonstrating Effectiveness: Recanalization in Fallopian Tube-Mimicking Phantoms
The study includes impressive experimental results that demonstrate the microrobot’s ability to clear blockages in a fallopian tube-mimicking phantom. Using a glass channel with a diameter of 1.7 mm to simulate the fallopian tube, the researchers showed how the microrobot could navigate the narrow passage and break up cell clusters that mimicked blockages in the fallopian tube.
The effectiveness of the microrobot was clear as it successfully drilled through the cell clusters in just 18 seconds, reducing the size of the blockage significantly. This rapid recanalization is a key advantage over traditional methods, which may struggle to achieve the same level of precision and speed. The vortex flow generated by the robot helped carry the fragmented debris to the tail. To make sure that blockage was cleared efficiently.
Conclusion: A Future of Precision and Efficiency in Tubal Recanalization
In conclusion, the development of the magnetically driven robotic microscrew marks a significant breakthrough in the field of infertility treatment. This innovative microrobot offers a highly effective, minimally invasive solution to the challenge of fallopian tube blockages, which have long been difficult to treat with traditional surgical methods.
“The present microrobot shows great potential in blockage recanalization in the small lumen with microscale dimension,” the authors assert. With its precise control, ability to navigate narrow passages, and capacity to clear blockages efficiently, this technology could revolutionize the way we approach fertility treatments in the future. By providing a less invasive, more effective method of recanalization, the magnetic microscrew represents a promising tool in the quest to combat infertility caused by fallopian tube obstructions.
As the study progresses toward clinical applications, this innovative approach could help millions of women who face infertility due to tubal obstructions, offering new hope and possibilities in reproductive health.