researchers have developed a way of transporting chemotherapy drugs directly to cancer cells via microrobots. at present, most patients undergoing chemotherapy treatment receive the cancer-killing drugs either intravenously or orally, both of which cause a range of unpleasant side effects. this new technology, tested by jiawen li, li zhang, dong wu and colleagues, could revolutionize cancer treatment by delivering drugs only where they’re needed. 

shape-changing microrobots deliver chemo drugs directly to cancer cells
the fish microrobot had an adjustable mouth that opened and closed





in a proof-of-concept study, the scientists tested three microrobots shaped as different tiny animals: a fish, a crab, and a butterfly. the microrobots were 4D printed from pH-responsive hydrogel using a femtosecond laser. using the same principles as 3D printing, 4D printing creates a three-dimensional object that can morph its shape. in this case, the microscopic ‘animals’ changed their form when exposed to a change in pH level—cancer cells are generally more acidic than normal cells.


the researchers also needed a method of guiding the little robots. to achieve this, they submerged the microrobots in a suspension of iron oxide nanoparticles, making them magnetic. guided by a magnet, the ‘fish’ was steered through a petri dish filled with artificial blood vessels. when the fish came to a more acidic part of the solution, it reacted by opening its mouth to release a chemo drug, which killed the cells closest to it.

shape-changing microrobots deliver chemo drugs directly to cancer cells
the team also got the ‘crab’ to grab a microparticle, transport it, and release it



before the microrobots make it to an actual patient, they need to be made even smaller to navigate real blood vessels, and a suitable imaging method must be identified to track their movements in the body.


the research was published in a paper titled ‘environmentally adaptive shape-morphing microrobots for localized cancer cell treatment’ in journal ACS nano.