A team of scientists created specially coated nanometer-sized vehicles that can be used to move through dense tissue of the eye. Until now, scientists have successfully transported nanobots or nano-vehicles in model systems or through biological fluids. This is the first time nanobots could drill into a real tissue of eyeball. These nanobots are just 500 nm wide and they can easily roam through the tight molecular matrix of an eye.
To go further, a clear idea about nanobots is essential.
What are nanobots or nanorobots or nano-vehicles?
Nanobots are the robots of size close to the microscopic scale of a nanometer (10−9 meters). So far, nanorobotics considered as hypothetical nanotechnology engineering discipline of designing and building nanorobots.
When nanobots in medicine are considered, the most popular idea is self-propelled nanomotors and other biodegradable nanodevices made of bio-nano components. They are used to carry cargo to the target sites. It means they deliver drugs to diseased cells.
Such drug delivery approach promises an effective and improved transport of drugs compared to conventional methods. For instance, scientists can program nanorobots to transport essential drugs to remove blood blockages, which can cure the tumors.
A team of international scientists of the Micro, Nano and Molecular Systems Lab at the Max Planck Institute for Intelligent Systems in Stuttgart performed comprehensive research on these eyeball-drilling nanobots.
The research is named as “A swarm of slippery micro-propellers penetrates the vitreous body of the eye”, by Zhiguang Wu, Jonas Troll, Hyeon-Ho Jeong, Qiang Wei, Marius Stang, Focke Ziemssen, Zegao Wang, Mingdong Dong, Sven Schnichels, Tian Qiu, Peer Fischer, published in Science Advances (2018).
Based on the above research, this article covers some aspects of these novel nanobots and their role in curing eye diseases. Here are some of their key features:
A size which can easily roam inside an eye
Covered in a non-stick coating, these nano-drills are 500nm wide size approximately matches the mesh size of the network in the vitreous. They are helical in shape and 200 times smaller than the diameter of a human hair. This size is even smaller than a bacterium’s width. Researchers call it slippery micro-propellers.
Slippery surface coating inspired by nature
Most tissues including the vitreous have a tight macromolecular matrix that acts as a barrier and prevents its penetration. Surprisingly, the slippery coating on these nanobots removed this barrier of penetrations. This enables the nanobots to move in the vitreous seamlessly.
The slippery exterior allows them to be actively propelled through the vitreous humor to reach the retina. Primarily, all this happens without damaging the sensitive biological tissues around them.
One of the authors of the study, Zhiguang Wu explains, “For the coating, we look to nature for inspiration”. Further, he added, “In the second step, we applied a liquid layer found on the carnivorous pitcher plant, which has a slippery surface on the peristome to catch insects. It is like the Teflon coating of a frying pan.”
The first film of slippery coating on these nanorobots consists of molecules bound to the surface, while the second is a coating with liquid fluorocarbon. This clever combination enables the nanorobots to go through the tight mesh of the eyeballs dense tissue.
This slippery coating is crucial for the efficient propulsion of robots inside the eye, as it minimizes the adhesion between the biological protein network in the vitreous and the surface of nanorobots.
Traditional delivery methods rely on the random, passive diffusion of molecules. These methods do not allow for the rapid delivery of a concentrated cargo to a defined region of the eye. The use of particles promises targeted delivery but faces the challenge of macromolecular resistance.
Further, improvements in the precision of the delivery are possible with a controlled injection system. In addition, real-time feedback navigation during the propulsion in the vitreous will also help in precise delivery.
Moreover, targeted delivery assures lower side effects and higher efficiency. Next, the experimental results suggest that the particles can move from the center of the vitreous to the retina in a short span of 30 min.
Real-time testing and results
To test their nano-propellers, the researchers injected them through a small needle into a dissected pig’s eye. The needle comprised tens of thousands of nanobots. Scientists used the surrounding magnetic field that rotates the nanopropellers.
Additionally, they utilized optical coherence tomography. It is a non-invasive imaging technique widely used in the diagnostics of eye diseases field. Using these technologies, they were able to direct and observe the swarm to the retina at the back of the pig’s eye.
Ultimately, scientists believe that this technique has the potential to be used as a tool for precisely delivering drugs directly to the complex parts of the human body.
Treatment of multifaceted eye diseases
Over the last decade, nanobots have already shown their ability to move through fluids like blood to reach drug delivery sites. However, these eyeball-drilling nanobots can dig in tight eye tissues and supply essential drugs.
They have solved the biggest challenge of targeted drug delivery. Therefore, it has extended the possibilities to cure hard-to-treat eye diseases. Glaucoma, retinitis, and diabetic retinopathy are one of the numerous retinal diseases that are difficult to cure.
Eye’s vitreous humor is the major obstacle that prevents drugs from reaching the target site at the bottom of the retina. Conjoined with non-stick slippery coating these nano-size nanobots can be transported through the eye’s vitreous humor.
Currently, scientists have successfully tested these nanobots on a pig’s eye. If they work successfully on the human eye, then these nanorobots could revolutionize the conventional eye treatments.
They will also speed up the recovery process, as they do not harm any tissue during operations. The future possibilities are endless and the human race is on the verge of making hypothetical concepts into reality. With extraordinary imagination, approach, and drive towards making human lives easier, researchers are exceeding these possibilities.
One can expect that, in coming years, nanobots will live inside a human body, unremittingly maintaining it and repairing it. The future is near and we all need to be prepared to upgrade!
By Mayur Shewale (Assistant Writer)