The Need

Manipulatable miniaturized robots have a variety of applications in biomedical sciences, specifically microrobots capable of navigating in vivo blood vessels have the potential to revolutionize non-invasive surgery and targeted drug delivery for cancer and other disease treatment. Drug discovery can be assisted by legions of microrobots designed to manipulate biological cells in vitro. For these applications to be feasible, however, one needs to be able to manipulate more than one miniature microrobot simultaneously. This is challenging for several reasons. Extremely small robots do not allow for on-board computation and navigation, and complex propulsion mechanisms. Robots can be designed such that they are controllable remotely. However, they need to be independently controllable from a remote source.

The Technology

Dr. Hiran Wijesinghe has developed a method for controlling multiple heterogenous magnetic bacteria at a solid-liquid interface using a uniform magnetic fields. Artificial, bio-hybrid, and biological magnetic microswimmers have been proposed for remote-controlled applications using external magnetic fields. Among them, magnetotactic bacteria (MTB) such as AMB-1 (strain) can be guided using external fields. In order to gain simultaneous control over the positions of many MTB relative to an underlying surface, the method seeks to exploit variability in certain properties among individual MTB in a population.

When a magnetic field is applied to a motile MTB, its swimming axis aligns with the magnetic field. However, the trajectory of an MTB swimming near a surface is also dependent on the hydrodynamic interactions with the wall. As a result of the inhomogeneity of various properties of the swimming bacteria in a population, a distribution of swimming velocities can be observed in the population when swimming near a surface subjected to an external magnetic field. The proposed method maps certain properties of MTB onto a mathematical space, and seeks a basis system that sufficiently spans a target configuration of the bacteria, solving for a magnetic field sequence that can the be remotely applied.

Commercial Applications

• Healthcare professionals' diagnostic tool
• Non-invasive surgical procedures
• Hospitals and healthcare professionals

Benefits/Advantages

• Bacteria are easier to culture in large quantities compared to fabricating remote controllable microrobots capable of swimming.
• Exploits a combination of heterogeneities rather than relying on a single property.
• Can be designed as a "lab-on-a-chip" microfluidic device in a small form factor.

Research Interests

Dr. Wijesinghe has a Ph.D in Physics from Ohio State. His research focused on new approaches for cell manipulation, nano/micro-scale magnetism, fluid dynamics and biophysics.