Such nanorobots, say the researchers, could offer a safe and efficient way to detoxify and decontaminate biological fluids. For example, in tests using the nanorobots to treat blood samples contaminated with MRSA - an antibiotic-resistant strain of Staphylococcus aureus - and their toxins, after five minutes the blood samples had three times less bacteria and toxins than untreated samples.
The nanorobots were built by coating gold nanowires with a hybrid of platelet and red blood cell membranes. The hybrid cell membrane coating enables the nanorobots to perform the tasks of two different cells at once - platelets, which bind pathogens like MRSA bacteria, 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.
"By integrating natural cell coatings onto synthetic nanomachines, we can impart new capabilities on tiny robots such as removal of pathogens and toxins from the body and from other matrices," says Joseph Wang, a professor in the Department of NanoEngineering at the UC San Diego Jacobs School of Engineering. "This is a proof-of-concept platform for diverse therapeutic and biodetoxification applications."
"The idea is to create multifunctional nanorobots that can perform as many different tasks at once," says co-first author of a paper on the research, Berta Esteban-Fernández de Ávila, a postdoctoral scholar in Wang’s research group at UC San Diego. "Combining platelet and red blood cell membranes into each nanorobot coating is synergistic - platelets target bacteria, while red blood cells target and neutralize the toxins those bacteria produce."
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.
Researchers say that