Like a miniature lunar rocket: Researchers develop modular nanorobot

Nanorobots sound like science fiction: tiny machines for medicine, the environment, or industry. In fact, nanorobotics has become a rapidly growing field of research. It is considered a promising approach, for example, for delivering active substances to specific locations in the body. Unlike their larger-scale counterparts, they are not made of electronics, computer chips, and software, but rather of biomolecules and nanoparticles.

Researchers led by Prof. Dr. Cornelia Palivan from the University of Basel are now reporting on a sophisticated modular nanorobot with greater functional flexibility than many existing systems. “Previous nanorobots are often designed for a specific task only,” says Cornelia Palivan. “Our modular system, on the other hand, can be adapted to different applications.” The technology could be used not only in medicine but also in industry and environmental technology.

Propulsion module and payload capsule

The nanorobot, which the team describes in the journal Advanced Functional Materials, resembles a lunar rocket with multiple modules. A magnetic propulsion module moves the nanorobot, while a second module serves as a payload capsule, safely transporting therapeutic agents or enzymes to their target location.

The two modules are connected by a DNA-based “Velcro fastener”: complementary DNA strands on both modules ensure that the propulsion module and the payload capsule self-assemble in a programable manner and remain stably coupled.

To enable the nanorobot to dock onto specific cells or materials, the payload capsule is also equipped with additional biomolecules that facilitate docking. In the lab, the team tested this using a human cancer cell line known as HeLa cells. They loaded the nanorobots with fluorescent molecules and observed under the microscope that they accumulated on the surface of the cells.

Targeted attack on cancer cells and other applications

Equipped with the necessary enzymes, the nanorobots successfully produced an anticancer drug which reduced the viability of the HeLa cells to 16 percent within 72 hours. “The drug can have a concentrated local effect if we use our nanorobot to specifically target it to the cancer cells,” explains Dr. Voichita Mihali, the first author of the study.

For other applications outside the medical domain, for example catalysis, another feature might prove particularly valuable: Since the propulsion module is magnetic, the nanorobots can be retrieved and reused after their task is completed. The researchers were also able to separate the two modules, refill the payload capsules, and recombine them with the propulsion modules. 

The modular nanorobot represents an important step toward a multifunctional tool for a wide range of applications. Although its use in humans remains a long-term goal, the system can be readily adapted for other domains simply by modifying the payload capsule.

The work was conducted within the framework of the National Center of Competence in Research – Molecular Systems Engineering and the Swiss Nanoscience Institute. The University of Basel team collaborated with researchers from Heidelberg University.