A research team led by Professor Daniel Ahmed at the ETH Zurich has developed nanorobots that may prove to be invaluable to the development of therapeutics for cancer and blood clots. In studies, the team has demonstrated how the nano-sized robots can elegantly direct themselves to the disease site, allowing them to deliver drugs effectively and efficiently to otherwise hard-to-treat tumors.
Nanorobots could facilitate the treatment of blood clots and stroke with targeted drug delivery. Image Credit: sdecoret/Shutterstock.com
The robots may also facilitate targeted drug delivery in stroke, allowing patients to be treated more effectively, reducing mortality rates and the severity of damage caused when ischemic strokes cut off blood flow in the brain.
Guiding Nanoswimmers using Ultrasound
Nanoparticles are smaller than red blood cells by a factor of 10, giving them great potential for use in biomedical applications. Usually, however, they are passive, meaning there is no way to control them. To get around this problem, Ahmed and his team working in the SONOBOTS project in Switzerland used ultrasound to guide the nanodevices constructed to safely encapsulate cancer-killing pharmaceuticals.
In medicine, ultrasound is commonly used to create real-time images of structures within the body. The work undertaken in the SONOBOTS project, however, has demonstrated that they can also be used to guide air bubbles trapped within a polymer shell alongside an imaging chemical, allowing the journey to be visualized by the high-frequency waves. These innovative vehicles were coined “nanoswimmers” due to their efficacy in moving through liquid. Tests have shown that ultrasound can accurately guide these nanoswimmers, moving them towards the walls of the blood vessels Fortunately, this force is not strong enough to impact the red blood cells and influence their movement.
The inspiration for the method came, according to Prof. Ahmed, from understanding how sperm travel along the vaginal walls, sticking to them and using them to guide themselves forward. Similarly, the nanoswimmers use the blood vessel’s walls to guide them, stirring them in the correct direction through the vessel.
Using Nanoswimmers to Treat Cancer
So far, the results have been promising, showing the potential of the nanoswimmers to precisely deliver pharmaceuticals to disease sites. However, the technology needs more research and development before it can reach its full potential. At this stage, scientists have successfully guided and tracked nanoswimmers in zebrafish embryos, but planned studies with mice may help to develop the technology further.
Glioblastomas are notoriously difficult to treat. Rather than being self-contained tumors within clearly defined borders, glioblastomas spread in thread-like tendrils through the brain. Ahmed’s team aims to develop its nanoswimmer technology that can effectively deliver drugs to these difficult-to-treat tumors. To obtain this goal, the scientists will need to fine-tune the technology so that the nanoswimmers can navigate the leaky blood vessels that typically surround cancer cells. Once this technology is firmly established, the unloading of the drugs from the vesicles is a simpler task, the team at ETH are confident that they can shake the nanoswimmers with acoustic waves, forcing them to release their pharmaceutical load.
Using Nanoswimmers to Treat Stroke
Other common, deadly illnesses could also potentially be tackled with nanoswimmer technology. Targeted drug delivery could offer a more effective form of treatment for stroke patients. Affecting more than 1.1 people in Europe each year, strokes present a leading cause of death. Blood clots in the brain prevent blood flow and lead to strokes. The longer the clot remains, the more damage the lack of blood and subsequent deprivation of oxygen to the brain cells can cause. In treating strokes, rapid and effective treatment is vital to reducing the severity of symptoms suffered post-stroke and to reducing mortality rates.
Currently, the leading treatment option for patients diagnosed with stroke is clot-busting drugs. However, the delivery of these drugs lacks precision. They delivered intravenously and travel around the body before reaching the affected site within the brain. Additionally, these drugs are associated with many side effects, including nausea, low blood pressure, and even brain bleeds. Because of these serious side effects, not all patients are suitable candidates to take them.
The team at ETH sees the opportunity to create a new and more effective treatment for stroke via the development of its nanoswimmers. The team could potentially create a system that directly delivers the drugs to the location of the clot, clearing it more quickly and effectively. This theoretical nanoswimmer method may be free of the more severe side effects associated with traditional blood clot drugs and may be suitable for a wider range of people.
Overall, the development of these nanoswimmers will likely make a great impact on drug delivery treatments and could possibly revolutionize treatment for several diseases.
References and Further Reading
Acousto-Magnetic Micro/Nanorobots for Biomedical Applications. European Commission. Available at: https://cordis.europa.eu/project/id/853309
Ahmed, D., Lu, M., Nourhani, A., Lammert, P., Stratton, Z., Muddana, H., Crespi, V. and Huang, T., 2015. Selectively manipulable acoustic-powered microswimmers. Scientific Reports, 5(1). https://www.nature.com/articles/srep09744
Nanorobots could target cancers and clear blood clots. Sarah Wild. Phys.org. Available at: https://phys.org/news/2021-05-nanorobots-cancers-blood-clots.html
Wafa, H., Wolfe, C., Emmett, E., Roth, G., Johnson, C. and Wang, Y., 2020. Burden of Stroke in Europe. Stroke, 51(8), pp.2418-2427. https://www.ahajournals.org/doi/10.1161/STROKEAHA.120.029606
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