Forscher haben blasenartige Mikroroboter aus Hydrogel und magnetischen Nanopartikeln entwickelt, die mithilfe eines externen Magnetfelds therapeutische Medikamente genau dort abgeben können, wo sie benötigt werden, und dann vom Körper absorbiert werden können

>Greer’s group has expertise in two-photon polymerization (TPP) lithography, a technique that uses extremely fast pulses of infrared laser light to selectively cross-link photosensitive polymers according to a particular pattern in a very precise manner. The technique allows a structure to be built up layer by layer, in a way reminiscent of 3D printers, but in this case, with much greater precision and form complexity.
>
>Greer’s group managed to “write,” or print out, microstructures that are roughly 30 microns in diameter—about the diameter of a human hair.

>In their final form, the microrobots incorporate magnetic nanoparticles and the therapeutic drug within the outer structure of the spheres. The magnetic nanoparticles allow the scientists to direct the robots to a desired location using an external magnetic field. When the robots reach their target, they remain in that spot, and the drug passively diffuses out.

>The presence of trapped bubbles is also crucial for moving the robots and for keeping track of them with real-time imaging. For example, to enable propulsion, the team designed the microrobot sphere to have two cylinder-like openings—one at the top and another to one side. When the robots are exposed to an ultrasound field, the bubbles vibrate, causing the surrounding fluid to stream away from the robots through the opening, propelling the robots through the fluid. Gao’s team found that the use of two openings gave the robots the ability to move not only in various viscous biofluids, but also at greater speeds than can be achieved with a single opening

Paper: [Imaging-guided bioresorbable acoustic hydrogel microrobots | Science Robotics](https://www.science.org/doi/10.1126/scirobotics.adp3593)