The medical nanorobots of decades to come will be a close fusion between natural and artificial molecular machinery. They will exist because it is possible to build worker devices that are more effective and efficient at a given task that evolved cells and cellular structures. Today, however, the state of the art involves melding simple cell structures with nanoparticles or other molecular machines. A great deal of innovation and experimentation is taking place, but it isn't always clear which of these many projects will make the leap into commercial development, versus serving as an inspiration or bridge to later efforts in the lab. In many ways this is still the barnstorming era of biotechnology, in which we should expect many strange feats, works of art, and dead ends along the way to the standard tools of the 2040s and beyond.
Scientists have developed tiny ultrasound-powered robots that can swim through blood, removing harmful bacteria along with the toxins they produce. These proof-of-concept nanorobots could one day offer a safe and efficient way to detoxify and decontaminate biological fluids. Researchers built the nanorobots by coating gold nanowires with a hybrid of platelet and red blood cell membranes.
This hybrid cell membrane coating allows the nanorobots to perform the tasks of two different cells at once - platelets, which bind pathogens like MRSA bacteria (an antibiotic-resistant strain of Staphylococcus aureus), and red blood cells, which absorb and neutralize the toxins produced by these bacteria. The gold body of the nanorobots responds to ultrasound, which gives them the ability to swim around rapidly without chemical fuel. This mobility helps the nanorobots efficiently mix with their targets (bacteria and toxins) in blood and speed up detoxification.
Researchers created the hybrid coating by first separating entire membranes from platelets and red blood cells. They then applied high-frequency sound waves to fuse the membranes together. Since the membranes were taken from actual cells, they contain all their original cell surface protein functions. To make the nanorobots, researchers coated the hybrid membranes onto gold nanowires using specific surface chemistry. The nanorobots are about 25 times smaller than the width of a human hair. They can travel up to 35 micrometers per second in blood when powered by ultrasound. In tests, researchers used the nanorobots to treat blood samples contaminated with MRSA and their toxins. After five minutes, these blood samples had three times less bacteria and toxins than untreated samples.