A couple of years ago, we told you about how German researchers had devised an ingenious way to boost male fertility — "spermbots," which basically are tiny remote-controlled vehicles designed to propel weak-swimming sperm far enough into a woman's body that they can reach and fertilize eggs. As a paper published Dec. 21, 2015 in the journal Nano Letters details, the vehicles, whose movements are controlled by a magnetic field, fasten themselves around the heads and tails of the sperm, and then are magnetically guided to move toward their destination. Sounds like a pretty nifty trick, right?
But as it turns out, reproduction may not be the only use for this fascinating technology. A team that includes some of the same researchers has published another paper, which appeared Dec. 4, 2017 in ACS Nano, showing how spermbots also can be used to deliver chemotherapy drugs to fight cancers in the female reproductive system.
In the experiment, bovine sperm cells were washed with doxorubicin, a chemotherapy drug used to treat a variety of different cancers, then equipped with magnetic-guided motors, and released into a culture dish containing HeLa cells cultured from a cervical tumor. The spermbots swam toward the cancer cells, and over a three-day period killed 87 percent of their targets. That's a significantly higher kill rate than the 55 percent that the same dose of the drug can achieve when delivered conventionally in a solution.
As the researchers noted in their article, spermbots can deliver higher concentrations of anticancer drugs and protect them from dilution by bodily fluids. They're also able to release proteins and protosomes that neutralize the host's immune system, allowing them to avoid the rejection that would stop a totally artificial device. And their ability to fuse with other cells enables them to deliver the drugs through membranes.
While there are still some issues to be worked out before this protocol can be applied in actual human patients — questions about such things as dosing, negative immune system reactions and imaging issues, among others — implementation of this technology is expected in the near future.