DNA Robot as a Promising Future of Nanomedicine

The human body is like a battle zone. The soldiers of our immune system fight viral spies, cancerous saboteurs, bacterial terrorists, and parasitic war machines all the time. However, sometimes our soldiers are weaker than the enemies so this condition makes us sick. Modern science allows for a good bit of outside interference. For example, we ship in our pharmaceutical weapons, high-tech surveillance equipment, and the occasional blast of radioactive power to our body. However, these weapons are insufficient and ineffective. It’s just like if we drop a bomb on a city block and wipe out enemy insurgents, we will also kill innocent civilians and destroy important infrastructure. We damage the very thing we aim to protect. Because of that, we urgently need something which is capable of making deadly accurate strikes at a cellular level, a military drone to patrol our inner body. In the nanotech era, scientists try to solve these problems by creating such type DNA origami “DNA robots” which are a useful and promising nano-vehicle for nanomedicine in the future.

The DNA nanorobots are machines which can transport “molecular weapon” such as drugs or other molecular payloads to cells, sense signals from cell surfaces for trigger activation, and reconfigure their structure for payload delivery. The DNA nanorobots are built by using DNA origami. DNA origami is a method to build a nanoscale shape which is atomically precise by utilizing DNA as building blocks. The technique involves the folding of long single strands of DNA and DNA templates combined with hundreds of short “staple” DNA. When the long and short DNA strands are mixed and incubated, they will self-assembly to form a shape which is deserved by the designer. The shape of the DNA robot is like an open barrel / clamps shell. The 2 half shells of the DNA robot links together with a flexible lock DNA double helix. The diameter of the clamp is about 35 nm. It contains 12 sites on the inside for attaching payload molecules and has two linkers on the outside for attaching aptamers, short nucleotide strands

with special sequences, for recognizing protein signals on the target cell.

The DNA robots recognize very specific cells and deliver the payload of molecular weapons onto the cells. First, the aptamers which are attached on the surface of the DNA robot recognize and bind to the protein on the surface of the cells. Then, the lock will change the formation from a double helix to a single strand; it is like opening a zip. While the zip opens, the entire structure will open too. Finally, all the molecular weapons inside the DNA robots will be released on to the target cell. One of the most important properties of the DNA nanorobots is that it is able to recognize small populations of target cells within large healthy cells. Therefore, the DNA nanorobot will only drop a drug bomb on the target cells and wipe out enemy insurgents and give zero damage to the infrastructure and civilians in the healthy eclls. You can imagine it is like a combination lock, only when both markers are in place, the entire robot can

open.

The Application of DNA nanorobots are in diagnosis and medical treatment. For example, DNA nanorobots might be used as well to seek and break kidney stones. DNA nanorobots also can be used to cure skin diseases; a cream containing nanorobots may be used. They can remove the right amount of dead skin, remove excess oils, add missing oils, apply the right amounts of natural moisturizing compounds, and even achieve the elusive goal of 'deep pore cleaning' by actually reaching down into pores and cleaning them out. Other example of DNA robots in medical product is a mouthwash full of smart DNA nanorobots. They could identify and destroy pathogenic bacteria while allowing the harmless flora of the mouth to flourish in a healthy ecosystem. Further, the devices would identify particles of food, plaque, or tartar, and lift them from teeth to be rinsed away. Being suspended in liquid and able to swim about, devices would be able to reach surfaces beyond reach of toothbrush bristles or the fibers of floss.

Because of their size and properties, the DNA nanorobots, which are made by DNA origami, are powerful tools for the future of medicine. Even though, the DNA robots have been inserted into living Cockroaches, there are still more things to be done before DNA nano robots can be used to treat human diseases. The robustness of the DNA robot is still a challenge for the scientists to make “the fantastic voyage” become a reality in our lifetime.