Opportunity
The development of microrobots for biomedical applications, such as minimally invasive surgery, targeted drug delivery, and in vivo sensing, has been hindered by several limitations in existing technologies. Traditional soft-bodied microrobots, while flexible, often suffer from weak structural integrity, making them prone to failure in harsh environments or under significant motion resistance. Additionally, their fabrication processes are typically complex and costly, involving sophisticated materials and techniques. Another critical challenge is achieving precise control over microrobot movement in low Reynolds number (Re) regimes, such as in bodily fluids, where viscous forces dominate inertial forces. Existing solutions, like fluid-driven actuators, lack the robustness and simplicity needed for widespread clinical or research use. This patent addresses these gaps by introducing a magnetically controllable robotic device that combines rigidity, ease of fabrication, and precise external control via magnetic fields.
Technology
The patent describes a magnetically controllable robotic device composed of rigid body parts movably connected through pivot-type joints. The key innovation lies in the device's design and fabrication:
1. Rigid Body Structure: The device is made of rigid, photo-curable materials (e.g., polymers like IP-L 780) using 3D laser lithography, ensuring structural integrity and resistance to deformation.
2. Selective Magnetization: Only the first body part (the "head") is coated with a magnetically responsive material (e.g., nickel, iron, or neodymium) via sputtering or electron beam deposition, enabling external magnetic control while keeping other parts non-magnetic.
3. Motion Transmission: The device features arm-like protrusions on each body part that interact with adjacent parts, converting the head's oscillation into undulatory propulsion. This design breaks time-reversal symmetry, allowing net forward motion in low Re environments.
4. Tetherless Operation: The device is entirely externally controlled by oscillating magnetic fields, eliminating the need for internal power sources or tethers.
The magnetic control system uses diametrically opposed magnets to generate uniform fields, with adjustable frequency and amplitude to steer the device. This combination of rigid-body mechanics and magnetic actuation solves the trade-off between flexibility and robustness in microrobotics.
Advantages
- Structural Robustness: Rigid body parts resist deformation in harsh environments.
- Simplified Fabrication: 3D laser lithography and selective magnetization reduce production complexity.
- Precise Control: External magnetic fields enable tunable speed and direction.
- Low Re Compatibility: Undulatory motion is effective in viscous fluids (e.g., blood, lymph).
- Scalability: Suitable for micron-scale biomedical applications.
Applications
- Targeted Drug Delivery: Navigate to specific tissues or tumors.
- Minimally Invasive Surgery: Perform precise operations in confined spaces.
- In Vivo Sensing: Monitor biochemical parameters in real time.
- Tissue Engineering: Manipulate cellular structures or scaffolds.
- Lab-on-a-Chip Systems: Transport samples in microfluidic devices.
