When Dr. Mariana Medina Snchez was 21 years old, her mother died of cervical cancer.
She was just 38 years old when it happened, Medina Snchez told The Daily Beast. And the therapies were very invasive. She had chemotherapy and radiation and many secondary effects in other organs in the body.
Cervical cancer is caused by the human papillomavirus, or HPV, a sexually transmitted virus. The World Health Organization calls it the most common viral infection of the reproductive tract. And while a vaccine exists for the two strands of HPV that cause cervical cancer, there are nearly half a million affected with the disease every year, 270,000 of whom will die from it, according to the WHO.
Medina Snchez, a group leader of the micro- and nanobiomedical engineering group at Leibniz Institute for Solid State and Materials Research Dresden in Germany, has been researching a new technique that could help decrease these numbers or at least help patients with cervical cancer feel better as theyre going through treatment: drug-loaded sperm robots that can swim through the female reproductive tract directly to a tumor.
Xu explained that the team loaded bovine (or bull) sperm, which swim similarly to how human sperm swim, with doxorubicin hydrochloride, a wide-spectrum anti-cancer drug. Then, they coupled the sperm with a tetrapod, a microdevice with four arms thats covered in iron and can thus be controlled by a magnetic field, to direct the sperm exactly toward the tumor.
Sperm was a natural choice for this application, Xu told The Daily Beast, because they can swim by themselves. However, they need external guidance to get directly to a tumor, which is where the magnetic field comes in. Xu said that the magnetic field can change the direction of the spermbot in six different ways, directing the drug carrier exactly where it needs to go and with the exact amount of medication it needs to kill a tumor.
With conventional drug delivery, its in contact with other fluids in the body and the drug is less effective, Medina Snchez said. With this, once the sperm reaches the tumor and the cancer cell, they have the ability to fuse with the cell and the drug is delivered inside the cancer cell because both cells are fused.
This technique could one day be applied to cancer patients with the same techniques used for artificial insemination; it can also be extended to treat other gynecological cancers, as sperm is a natural fit for the reproductive tract.
However, both Medina Snchez and Xu admit this research is far from ready for human research or a clinical setting, as it has a number of issues to be worked out.
First of all, the micromotors are coated with an iron that could potentially be toxic to the body.
We have to analyze the toxicity effects of what wed finally use, Medina Snchez said. [The iron is] not biodegradable, but in principle it should be possible to replace the material.
And then theres the big problem of pregnancy. There could be the possibility that youd get pregnant, Medina Snchez said. But itd be possible to control if we applied the therapy when youre not ovulating. Of course its something you cannot control completely, and thats why we have the structures to guide them to effective tissue.
For now, the team is working on improving the technology by increasing the drug dose and loading more doxorubicin hydrochloride into each spermbot to kill more cancerous cells in humans. We are trying to collaborate with some doctors and we actually have some preliminary results but its not published yet, Xu said.
Medina Snchez added that a clinical application is about a decade away and acknowledged its still very unclear how the technology will transfer to humans. We cannot say that this is better than existing technologies because we have done it in vitro, so we dont know how effective it is in people, she said.
The team said theres also the possibility that the technology could be used beyond cervical cancer by guiding sperm for fertilization. But for now, the goal is to improve the quality of life in patients suffering from cervical or gynecological cancers.
Medina Snchez, for one, is driven by her family history. Although this happened a long time ago, I am still affected by that and thats why I am trying to apply my knowledge on engineering and material science to the biomedicine, she said. The spermbot might help ensure what happened to her mother wont happen to someone else.