Tiny gold nanorobots in a gel matrix help stem cells “work out” into bone cells. This could be a new method for growing custom tissues on demand.
Researchers at the Technical University of Munich (TUM) utilized nanorobots to precisely stimulate stem cells, leading to their consistent transformation into bone cells. The results were reported in Advanced Materials.
To do this, the robots apply external pressure to particular places in the cell wall. This approach could enable faster treatments in the future.
Professor Berna Özkale Edelmann’s nanorobots are made of little gold rods and plastic chains.
Several million of them are enclosed in a gel cushion of only 60 micrometers, together with a few human stem cells. Powered and controlled by laser light, the robots, which resemble small balls, mechanically stimulate stem cells by exerting pressure.
We heat the gel locally and use our system to precisely determine the forces with which the nanorobots press on the cell – thereby stimulating it.
Berna Özkale Edelmann, Professor, Technical University of Munich
This mechanical stimulation initiates biochemical activity within the cell. Ion channels alter cell characteristics, activating proteins, including one that is critical for bone formation.
Within three days, a stem cell can be consistently induced to grow into a bone cell if stimulated at the proper rhythm and with the appropriate (low) force. This procedure can be conducted within three weeks.
The corresponding stress pattern can also be found for cartilage and heart cells. It’s almost like at the gym: we train the cells for a particular area of application. Now we just have to find out which stress pattern suits each cell type
Berna Özkale Edelmann, Professor, Technical University of Munich
Mechanical Forces for Transformation into Bone Cells
The researchers use mesenchymal stem cells to generate bone cells. These are thought to be the body’s ‘repair cells.’ They range in size from 10 to 20 micrometers and can grow into bone, cartilage, or muscle cells.
The challenge is that, until now, distinguishing between cells in stem cell growth has been complicated and difficult to manage.
We have developed a technology that allows forces to be applied to the cell very precisely in a three-dimensional environment. This represents an unprecedented advance in the field.
Berna Özkale Edelmann, Professor, Technical University of Munich
The researchers believe that this technology could also be used to generate cartilage and heart cells from human stem cells.
Doctors may eventually require around one million differentiated cells for treatment.
That’s why the next step is to automate our production process so that we can produce more cells more quickly.
Berna Özkale Edelmann, Professor, Technical University of Munich
Journal References:
Wang, C., et al. (2025) Photothermally Powered 3D Microgels Mechanically Regulate Mesenchymal Stem Cells Under Anisotropic Force. Advanced Materials. DOI: 10.1002/adma.202506769.
Iyisan, N., et al. (2025). Hydrostatic Pressure Induces Osteogenic Differentiation of Single Stem Cells in 3D Viscoelastic Microgels. Small Science. DOI:10.1002/smsc.202500287.