Drug-Loaded IRONSperm clusters: modeling, wireless actuation, and ultrasound imaging

Area of Science:

• Biohybrid microrobots
• Biomedical engineering
• Nanotechnology

Background:

• Individual microrobots show promise for in vivo tasks like drug delivery and minimally invasive surgery.
• Challenges remain in controlling and enhancing the functionality of individual microrobots for deep-tissue applications.

Purpose of the Study:

• To demonstrate the formation of biohybrid sperm-templated microrobot clusters.
• To enable wireless actuation, noninvasive localization, and drug delivery using these clusters.
• To investigate the collective behavior and enhanced functionalities of aggregated microrobots.

Main Methods:

• Ferromagnetic nanoparticles were electrostatically assembled around dead sperm cells.
• Nanoparticle-coated cells were magnetically assembled into 3D biohybrid clusters.
• A magneto-hydrodynamic model was used to analyze cluster rotational response and locomotion.

Main Results:

• Biohybrid clusters exhibited rolling locomotion on solid boundaries using rotating magnetic fields.
• Clusters were successfully localized using ultrasound imaging at a distance, indicating deep-tissue potential.
• Drug loading capacity scaled with cluster size and was retained for over 10 hours.

Conclusions:

• Biohybrid microrobot clusters offer enhanced ultrasound detectability and drug loading compared to individual units.
• Collective behavior of microrobots enables predictable rolling locomotion and improved functionality for in vivo applications.
• These findings highlight the potential of developing collective microrobots for advanced biomedical tasks.