Design of a “nano” robot to explore human cells

56 years ago, the sci-fi movie “Fantastic Voyage” was released, in which scientists shrunk a team of doctors and sent them through human arteries to save a famous scientist from a blood clot in the brain.

That 1966 movie was a precursor to another set of films that used the idea of ​​”miniaturizing” things to the size of a cell to treat incurable diseases.

Today, nanomedicines with a size of a few millionths of a millimeter can be used to treat many classes of diseases, especially cancer. The word “nanotechnology” has become popular; Whether in science fiction movies or in our real world.

In the study published Thursday in the journal Nature, researchers at the French Center for Structural Biology announced the design of a “nanobot” made of DNA, which can be used to study cellular processes that are not visible to the naked eye. .

Nanobots are miniature tools; Sometimes their size reaches 5 millionths of a millimeter. Because of its small size, it can be easily injected into the bloodstream to reach infected cells or vital organ to be studied.

This newly invented technique allows the study of mechanical forces applied to cells at microscopic levels.

Some cells are subject to a set of mechanical forces that the body exerts on the single cell, and these forces can lead to the release of biological signals that are necessary for many cellular processes involved in the normal functioning of the body or in the development of illnesses.

cancer cell migration

For example, the sense of touch is partially conditioned by the application of mechanical forces to specific cellular receptors.

In addition to touch, these receptors that are sensitive to mechanical forces (known as mechanoreceptors) help to regulate other important biological processes such as blood vessel renewal, pain perception, breathing or even the detection of sound waves in the ear.

Dysfunction of this cellular mechanical sensitivity is associated with several diseases. Cancer cells “migrate” within the body by constantly adapting to the mechanical properties of their microenvironment, the peritumor environment, including blood vessels and fibroblasts, or preventing the immune system from attacking those malignant cells.

Such adaptation only occurs because certain forces are detected by mechanoreceptors that transmit information to the cytoskeleton of the cancer cell.

“DNA Origami”

Our knowledge of these molecular mechanisms involved in the cell’s mechanical sensitivity is still very limited, although many techniques are available to study them, due to their high cost, which does not allow studying many cell receptors simultaneously.

To find an alternative to the expensive traditional methods in terms of time and money; The research team decided to use a method called ‘DNA origami’.

Like a devotee of the Japanese art of paper folding, the scientists can assemble and fold DNA like paper to create three-dimensional nanostructures in a predetermined shape. Instead of using paper in origami, scientists use DNA as building material.

Over the course of a decade, this technology enabled significant advances in nanotechnology. This allowed the researchers to design a “nanobot” made up of 3 DNA structures.

In terms of size, the nanorobot corresponds to the size of a human cell. It therefore makes it possible for the first time to apply and control a force with an accuracy of 1 piconewton, i.e. one trillionth of a newton (a unit of force).

This is the first time a man-made, self-assembled DNA-based body has been able to apply force with such precision.

unknown mechanisms

The team of researchers began by attaching the robot to a molecule that recognizes mechanoreceptors. This made it possible to direct the robot to certain cells and apply specific forces to mechanoreceptors on the surfaces of the target cells to activate them.

This tool is considered to be of great research value, as it can be used to better understand the molecular mechanisms involved in ‘cell mechanosensitivity’ and to discover new cellular receptors that are sensitive to mechanical forces.

Thanks to the robot, scientists will also be able to study cells more precisely at any given moment. Upon application of force, key signaling pathways for many biological and pathological processes are activated at the cellular level.

The robot design also meets a growing demand in the scientific community and represents a major technical advance, as the biocompatibility of the robot can be considered an advantage for in vivo applications.

But the robot has a major weakness. The DNA is sensitive to the enzymes produced by the body, so the components of the robot can deteriorate if exposed to the secretion of enzymes.

The researchers say the next step in the development of the robot is to overcome this problem and study how its surface can be modified to be less sensitive to the action of enzymes.

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