Design and control of soft biohybrid microrobots and synthetic analogues for magnetically enhanced drug delivery

Simone Schürle, PhD
Assistant Professor
ETH Zürich, Switzerland
Research Interests
Micro-and nanorobots, biosensing, tissue probing, drug delivery

Microrobots have experienced a tremendous surge in development due to their wide range of biomedical applications, including surgical procedures, sensing, and drug delivery. Particularly noteworthy are soft microrobots made of flexible biocompatible materials that have emerged as a promising solution for navigation and control in physiological environments like the human body, owing to their deformability. Magnetic fields, with their excellent biocompatibility and tissue penetration, provide a suitable energy source to power and control these soft microrobots. Among the different types of magnetic stimuli, rotational magnetic fields (RMF) are especially compelling as they can effectively apply strong torques to generate motion and are more readily scalable to patients, unlike gradient-based magnetic approaches.

In this talk, we will delve into the design and control of two types of soft microrobots that are driven by external RMF. The first one is a living, bacteria-based biohybrid microrobot based on a magnetically responsive bacteria strain that can be controlled using a hybrid control scheme. This approach leverages the innate sensing and taxis of the microorganism and its effective ferrohydrodynamic coupling, as it encapsulates a string of biomineralized magnetic nanoparticles within its comparatively large, soft body. Supported by in silico, in vitro, and in vivo data, we demonstrate that this approach significantly enhances extravasation and tissue penetration in tumor models, ultimately enhancing drug delivery efficiency. The second microrobot is inspired by this bacterium and mimics its advantageous ferrohydrodynamic properties. It is composed of a soft photopolymerizable hydrogel containing magnetic nanoparticles and is synthesized using high throughput droplet-based microfluidics under external magnetic fields. This microrobot can be programmed for tailored magnetic interaction, depending on the resulting magnetic subdomains. We demonstrate swarm control of heterogenous clusters and showcase potential applications in targeting microvascular obstructions.

Simone Schuerle is Assistant Professor (tenure track) at ETH Zurich, Switzerland, where she heads the Responsive Biomedical System Lab. With her team, she develops diagnostic and therapeutic systems at the nano-and microscale with the aim of tackling a range of challenging problems in medicine.  Prior to taking this position, she researched as postdoctoral scientist at the Koch Institute for Integrative Cancer Research at MIT on nanosensors for in vivo tumor profiling as well methods to wirelessly enhance drug transport (2014-2017). She is recipient of several awards, such as the Ernst Th. Jucker price for Cancer Research, the Prix Zonta for Women in Science, and fellowships from the SNSF, DAAD, Branco Weiss foundation and more. She was one of the “Top 10 winners” of the Falling Walls Breakthrough Award in Engineering and Technologies and was honored with the distinction of “Young Scientist” by the World Economic Forum (WEF) in 2017 and by the World Laureate Forum in 2020 and 2021. In 2014, she co-founded the spin-off MagnebotiX that offers electromagnetic control systems for wireless micromanipulation. She is co-inventor of two patents and sets a strong focus on clinical translation of her research. Simone earned her PhD degree with specialization in microrobotics in 2013 at ETHZ, for which she was awarded with the ETH medal, and a master’s degree in industrial engineering with specialization on microsystems and nanotechnology at the Karlsruhe Institute of Technology in Germany.