Magnetically actuated hydrogel-based capsule microrobots for intravascular targeted drug delivery

Area of Science:

• Biomedical Engineering
• Materials Science
• Robotics

Background:

• Targeted drug delivery in blood vessels is crucial for effective treatment.
• Hydrogel-based microrobots offer a promising platform for in vivo applications.
• Controlling microrobot size and motion is essential for navigating complex vascular networks.

Purpose of the Study:

• To design and fabricate hydrogel capsule microrobots for drug delivery.
• To investigate the formation mechanism and size control of microrobots using a microfluidic chip.
• To develop and analyze a magnetic drive system for precise microrobot navigation in blood vessels.

Main Methods:

• Fabrication of capsule microrobots using a triaxial microfluidic chip.
• Analysis of flow phases (plug, bullet, droplet) for size control via flow rate ratios.
• Development and simulation of a three-degree-of-freedom magnetic drive system.
• Simulation of microrobot motion in vascular microchannels under magnetic fields.

Main Results:

• Microrobot size is controllable by adjusting the flow rate ratio in the microfluidic chip.
• Irregular multicore microrobots can be prepared with a 20:1 outer-to-inner phase flow rate ratio.
• The magnetic drive system enables microrobot speeds up to 800 μm/s at 0.4 Hz.
• Microrobots achieved peak speeds of 3077 μm/s and climbed 1000 μm obstacles under specific magnetic fields.

Conclusions:

• Hydrogel capsule microrobots can be precisely fabricated and controlled for targeted drug delivery.
• The developed magnetic drive system is effective for navigating complex vascular environments.
• These microrobots demonstrate significant potential for overcoming obstacles and delivering drugs in simulated vascular channels.