Microfish act as proof-of-concept for sensing toxins

Nanoengineers from the nanoengineering department at the University of California, San Diego  (UC San Diego) have created 3D printed micro robots in the form of a small fish, called micro fish, as a proof-of-concept for detoxing and sensing toxins

The nanoengineers hope the micro fish are the first step in a new generation of smart micro robots which can be applied to health application like directed drug delivery and micro robot-assisted surgery.

The swimming synthetic micro fish, measuring around 120 microns long and 30 microns thick were 3D printed with a new method called microscale continuous optical printing (μCOP) which was developed in the lab at the UC San Diego.

The 3D-printed micro fish are self-propelled, chemically powered and steered magnetically thanks to functional nanoparticles.

In the tails researchers applied platinum nanoparticles which propel the microfish forwards when their tails come into contact with hydrogen peroxide. Magnetic iron oxide nanoparticles were also placed in the heads of the microfish for steering.

Co-first author Wei Zhu, a nanoengineering PhD student at the Jacobs School of Engineering, UC San Diego, said: “We have developed an entirely new method to engineer nature-inspired microscopic swimmers that have complex geometric structures and are smaller than the width of a human hair.

“With this method, we can easily integrate different functions inside these tiny robotic swimmers for a broad spectrum of applications.”

To prove the micro fish could be both detoxification systems and toxin sensors, the researchers added a type of polymer nanoparticle (polydiacetylene) to capture pore-forming toxins, like toxins found in the venoms of honeybees, some spiders and sea anemones.

According to the researchers, when the polydiacetylene nanoparticles bound with toxin molecules, they became fluorescent and emitted red-coloured light.

The intensity of the red glow of the micro fish allowed the researchers to monitor their detoxification abilities.

The research on the micro fish was published in the August 12 issue of the journal, Advanced Materials.