University of Basel’s Reusable Nanorobot Self-Assembles With DNA ‘Velcro’ and Killed 84% of Cancer Cells in Lab Test

Imagine a robot so small it can swim through your bloodstream, self-assemble on command, manufacture a drug on the spot, and then be retrieved, refueled, and reused. That is no longer science fiction. A team at the University of Basel has built exactly that — a modular, reusable nanorobot that clicks together using DNA-based "molecular Velcro" and has already demonstrated the ability to kill cancer cells in the lab [8, 9].

Led by Professor Dr. Cornelia Palivan, the researchers designed a nanorobot that resembles a miniature lunar rocket. It consists of two independent modules — a magnetic propulsion unit and a payload capsule — that autonomously assemble when complementary DNA strands on each module bind together . The DNA "Velcro" is programmable, allowing the modules to be paired, separated, and re-paired on demand .

How the Nanorobot Works

The system's architecture is deliberately simple and highly adaptable:

• Modular design: Two distinct, reconfigurable modules — a magnetic propulsion unit and a payload capsule .
• DNA-based 'molecular Velcro': Each module carries complementary DNA strands. When they meet, the strands bind, snapping the modules together into a functional nanorobot. The same bond can be undone, allowing module recovery .
• Magnetic propulsion: The propulsion module is magnetic, enabling external steering. A magnetic field can guide the robot to a target — such as a tumor — and later retrieve it for reuse .
• Payload capsule: The capsule houses four nanoscale polymer vesicles, each loaded with enzymes. Substrates enter through tiny pores, enzymes convert them into active products, and those products are released locally. The vesicles can also be selectively opened to release bioactive compounds .
• Docking capability: Additional biomolecules on the payload capsule allow the nanorobot to latch onto specific cell surfaces or materials .

HeLa Cell Test Results

The team put the nanorobot to the test against HeLa cancer cells, a widely used human cell line in cancer research:

• Nanorobots accumulated on the surface of HeLa cells, confirmed by fluorescent labeling .
• When equipped with enzymes that produce an anticancer drug, the nanorobots reduced HeLa cell viability to 16% within 72 hours — meaning 84% of cancer cells were killed .
• The effectiveness comes from concentrated local drug production, directly at the cell surface, rather than systemic delivery .

Broader Applications and Next Steps

The modular design means the platform is not limited to cancer therapy. By swapping the payload capsule, the same nanorobot can be repurposed for entirely different roles:

• Targeted medicine: Deliver therapeutic agents directly to tumors or diseased tissue, with the magnetic module enabling retrieval and reuse .
• Industrial catalysis: Refill the capsule with different enzymes for on-demand catalytic reactions in manufacturing .
• Environmental remediation: Potential uses include water purification and pollutant breakdown .
• Reusability: Modules can be separated, the payload capsule refilled, and the modules recombined — all while the magnetic propulsion unit is recovered and reused .
• Human use: Application in humans remains a long-term goal, but the platform is designed to be readily adapted simply by modifying the payload capsule .

The research was published in Advanced Functional Materials (DOI: 10.1002/adfm.202600079). It was conducted within the National Center of Competence in Research – Molecular Systems Engineering and the Swiss Nanoscience Institute, in collaboration with Heidelberg University [8, 12].