AlgaeSperm: Microalgae-Based Soft Magnetic Microrobots for Targeted Tumor Treatment

Area of Science:

• Biomedical Engineering
• Materials Science
• Nanotechnology

Background:

• Sperm-inspired magnetic microrobots show promise for targeted drug delivery due to flexible undulation.
• Challenges remain in mass production and achieving high-speed propulsion for these microrobots.
• Novel structure design and facile fabrication methods are crucial for advancing this technology.

Purpose of the Study:

• To develop a novel strategy for large-scale preparation of microalgae-based soft magnetic microrobots.
• To create microrobots with a fully magnetic head-to-tail structure, named AlgaeSperm.
• To enhance propulsion, maneuverability, and chemo-photothermal performance for targeted drug delivery.

Main Methods:

• Utilized microalgae (Chlorella) as a base for microrobot fabrication.
• Deposited Palladium-Aurum (Pd@Au) nanoparticles (NPs) within cells, coated with Iron(III) oxide (Fe3O4) NPs and polydopamine for magnetic heads.
• Constructed flexible flagella using magnetic assembly of Fe3O4@Polyvinylpyrrolidone (PVP) NPs.

Main Results:

• Achieved large-scale preparation of AlgaeSperm with a robust head-to-tail magnetic structure.
• Demonstrated high-speed forward propulsion up to 2.3 body lengths/second, the highest reported for sperm-like magnetic microrobots.
• Verified flexible maneuverability in swarms and successful in vitro anti-cancer experiments with doxorubicin (DOX) loading.

Conclusions:

• The proposed strategy offers a significant paradigm for constructing sperm-like soft magnetic microrobots.
• AlgaeSperm exhibit excellent propulsion, maneuverability, and chemo-photothermal performance.
• These microrobots hold great potential for targeted tumor treatment applications.