Recently artificial micro/nanorobots has gained an immense interest in medical applications, like, targeted drug deliver, nano sensing, therapeutics, nano surgery and so on. These tiny nanorobots have the potential ability to move into deep tissue inside our body and release a particular type of drug by sensing the requirement of the surroundings. Hence, scientists are trying to use this approach for cancer therapeutics where it is extremely useful because of its ability to target a pre-determined tissue and release the drug accordingly.
Prof. Richard Feynman envisioned various kind of interesting possibilities of manipulation in very small scale. His visionary lecture, named “There’s plenty of room at the bottom” at an American physical society meeting at Caltech on December 29th, 1959, inspired scientists to explore the immense possibilities nanotechnology. Seven years later, Richard Fleischer made a science fiction film, Fantastic Voyage, on similar concept where a submarine crew shrink to microscopic size using a technology that can miniaturize matter and then venture into the body of a scientist to repair the damage due to blood clot in his brain. But these ideas remained a fantasy till very recently scientists fabricated tiny nanorobots.
Scientists, from various part of the globe, are trying to make various types of nanorobots for different purposes. Recent development in nanotechnology has enabled them to achieve this goal which leads to a tremendous development in the field of micro/nanorobots. Though most of these results are still in laboratory, we hope very soon they can be used in clinical environment where the patient would be able to swallow, inhale and inject these nanorobots and using proper guidance from outside, we would be able to move them into the diseased site in a non-invasive manner and then perform tasks like sensing or therapy at the particular site without affecting the functionality of adjacent cells.
A new study reported recently in Advanced materials (“Maneuverability of Magnetic Nanomotors inside Living Cell”) shows that helical shaped magnetic nanorobots can be manipulated inside a living cell, the basic unit of our body. Intracellular environment is a highly heterogeneous environment. Scientist had tried to manipulate gold nanorods inside biological cell, but they never managed to move them in a controlled fashion. That is why this group of scientists used a different class of nanorobots to achieve this target. They have engineered a strategy to controllably maneuver these nanorobots inside a cell. Hence, using this technique, it will be possible to position payload at a desired site inside in cell itself which has a great importance in cell biology and biophysics. In simple term, these nanorobots open up new possibilities in understanding the intracellular environment better which was not possible before.
Nanorobots are helical shaped magnetic nanostructures which are fabricated using a technique called GLancing angle deposition (GLAD). In thise particular project, the team has used nanorobots of two different dimensions, smaller one is 250 nm thick and 2.4 microns long while the bigger one is 400 nm thick and 2.8 microns long. Maneuverability of the smaller nanorobot is better inside the cell than that of the bigger ones which is because of natural porosity of intracellular environment. These tiny structures are actuated remotely using a rotating magnetic field from a triaxial Helmholtz coil.
This work has been done by a group of scientists, which includes both physicists and biologists, at Indian Institute of Science, Bangalore. Due to the diverse nature of the work, scientists from Centre for Nano Science and Engineering, Department of Molecular Reproduction and Department of Biochemistry had a close collaboration for this project. The ‘Optics, Nanostructures & Quantum Fluids Laboratory’ of Prof. Ambarish Ghosh, is one of the pioneer in the field of helical magnetic nanorobots, which is currently being pursued by several research groups worldwide because of its useful future applications.
One great importance of these nanorobots is that they can sense viscosity of surrounding medium. An earlier work from Prof. Ghosh’s lab reported how one can measure viscosity of the medium by analyzing the dynamics of these nanorobots. This is an important aspect because without any modification to the nanorobots, we can measure viscosity which is a very important parameter for many biological processes. Hence, it can serve the purpose of sensing.
Apart from sensing, the nanorobots are also capable of delivering payload with great speed and precision. Another work from Prof. Ghosh’s group showed that it is possible to capture a payload by coupling the nanorobots with plasmonic, a special kind of light matter interaction. This technique allows selective pickup, transport, release, and positioning of submicrometer objects. Hence, it serves the purpose of targeted drug delivery. In short, these tiny nanorobots have all the potential to be a unique tool in future medical application.
This group of scientists, form IISc, sees the present work as significant step towards next generation therapeutics. Manipulation of artificial magnetic nanorobots in a heterogeneous intracellular environment in a controlled manner along with the ability of these tiny motors to sense the environment and the capability in payload transport makes it a promising candidate for medical interventions of the future.
Though these are very interesting achievements, there are few more challenges for future autonomous and non-invasive therapeutics. The main challenge is to image these nanorobots while they are moving deep inside a tissue. Prof. Ghosh’s group has already started to find the possible solution for this particular problem. They are trying to track these tiny nanorobots inside live organs. Once this is sorted out, it will be possible to navigation through the desired paths in a tissue using external magnetic forces and release drug in diseased site, even inside the cell, which would be triggered by sensing the environment.
“Manoeuverability of Magnetic Nanomotors Inside Living Cells” – Pal M., et al., Advanced Materials, 2018, 1800429. https://doi.org/10.1002/adma.201800429