Scientists invent micro-robots to probe human cells

This microbot has the adeptness to navigate precisely within clusters of cells.
Mrigakshi Dixit
Representational image of microbes inside human body.
Representational image of microbes inside human body.


In recent years, introducing tiny robots into biological studies and therapeutic delivery has generated significant excitement and is poised to revolutionize the medical field.

These mini robotic systems, often measuring just a few millimeters or even smaller, bring various capabilities and advantages, transforming multiple aspects of medicine, including targeting precise tumor sites to deliver drugs, cellular simulation, and even performing microsurgery.

Now, researchers at the Technical University of Munich (TUM) have invented a microrobot, which they say is the first of its kind. 

This microbot has the adeptness to navigate precisely within clusters of cells.

“In a worldwide first, we have developed a system that not only enables microbots to navigate through groups of cells. It can even stimulate individual cells through temperature changes,” said Özkale Edelmann in an official release.

The team believes it could be used for the study of cellular processes as well as for the development of new precision-based treatments to treat various diseases, including skin wounds and cancer

The main components of the robot 

The newly designed micro-robotic system is referred to as TACSI, which stands for Thermally Activated Cell-Signal Imaging. Simply put, it is an image-based technology capable of heating cells to “activate” them.

The robot is circular, boasting a thickness of just half that of human hair. The microbots are made of gold nanorods and fluorescent luminous dye encased in an algae-derived biomaterial. 

The fluorescent dye chosen for this robot is known as orange rhodamine B dye. Notably, it has the remarkable property of diminishing its color intensity as the temperature rises.

The gold nanorods used in this robot are incredibly small, measuring between 25 and 90 nanometers (nm) in length. What distinguishes them is their extraordinary ability to heat up and cool down when subjected to laser rapidly.

It takes only a mere few microseconds to elevate the robot's temperature by 5°C using these nanorods. These nanorods may also be heated to temperatures as high as 60°C.

When exposed to laser light, the microbots can be propelled to move between cells. 

“The entire system requires a microscope to enlarge the small-scale worlds, a computer and a laser to drive the 30-micrometer (µm), human-controlled microbots,” mentioned the release.  

According to the developers, these components allow them to "make up to 10,000 microbots in a single production run." 

Currently, they are employed for in vitro applications, which means usage outside the human body.

Scientists invent micro-robots to probe human cells
PhD student Philipp Harder produces thousands of new microrobots in the lab.

The testing of this microbot in cells

Slight fluctuations in temperature can wield remarkable influence over cellular processes. These subtle changes can trigger a cascade of reactions within cells, impacting their behavior, metabolism, and even their ability to function optimally.

The team tested the robot in kidney cells to showcase its ability to influence cellular ion channels. For this purpose, they directed the TACSI microbots towards the cells with the help of lasers. 

“We used the infrared laser to raise the temperature. To measure the increase, we measured the intensity of the rhodamine B dye color,” explains Philipp Harder. 

The researchers discovered that the ion channels within the cells opened at specific temperatures. For instance, this opening allowed calcium to enter the cell.

“Using this concrete example, we showed that heat causes changes in the cell, even with slight temperature increases,” said Edelmann.

Edelmann is especially interested in whether "thermal stimulation" may be utilized to heal wounds

The developers hope that this microbot could be used one day to develop innovative treatments, such as the potential to direct drugs into specific individual cells.

The results were published in the journal Advanced Healthcare Materials. 

Study abstract:

Here, the study presents a thermally activated cell-signal imaging (TACSI) microrobot, capable of photothermal actuation, sensing, and light-driven locomotion. The plasmonic soft microrobot is specifically designed for thermal stimulation of mammalian cells to investigate cell behavior under heat active conditions. Due to the integrated thermosensitive fluorescence probe, Rhodamine B, the system allows dynamic measurement of induced temperature changes. TACSI microrobots show excellent biocompatibility over 72 h in vitro, and they are capable of thermally activating single cells to cell clusters

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