Tiny DNA Nano Walker Walk with Record Fuel Efficiency


Previously, I have written an article about ‘Bionic spine: enables paralyzed a person to walk again‘. This ‘bionic spine’ has a size similar to the small paper clip. It is a tiny device that is just 3 cm long and a few millimeters wide.

Scientists at the National University of Singapore, have developed a DNA Nanomotor. This DNA Nanomotor can walk” along a track with tenable motion. The Nanomotor has the maximum fuel effectiveness for any type of walking Nanomotor or Nano walker. It uses, using almost one fuel molecule on each step.

The tiny motor shows, at the single-molecule level how physical effects can enable the effective intake of chemical energy. This new motor operates totally different than any macroscopic motor by functioning on chemical energy. It makes researchers for taking a step closer to copying the highly effective bio-motors. These effective bio-motors delivers baggage in living cells.

The main aspect of this Nano walker:

  • It is an enzyme similar to bio-motors in living cells.
  • It helps to start the fuel-producing chemical reaction that produces its motion without permanently changing itself or its track.
  • Allows for repeated, continuous motion, which has not been gain by any chemically powered synthetic Nano walker until now.

Producing enzymatic Nano walkers was very tuff, and so progress in this area has been relatively slow over the past few years. The only other demonstration of an enzymatic walker was in 2009 when researchers designed a Nano walker that, despite being enzymatic, cannot achieve sustainable motion because its track coils over time and eventually halts the motor. This Nano walker uses more than two fuel molecules on each level. It examines that two fuel molecules on each level are a general beginning for enzymatic Nano-motors.

This new Nano walker shows an increase of progress in this area, because of its ability of continuous motion and the fuel effectiveness of almost one molecule on each step.

Scientists have found a physical mechanism for effectively intaking chemical energy at the single-molecule level. This mechanism consists of three “chemo-mechanical gates”. This chemo-mechanical gate basically makes sure that this Nano walker walks by always raising its back leg and not its front leg.

To do this, these gates physically control the order in which the products are released in the chemical reaction. This makes this Nano walker move forward. As a result, first, the DNA Nano walker’s back leg separates from the track and takes a step forward before the front leg separates. Then when the front leg becomes the back leg, that leg takes a step forward, and the walking cycle repeats. The separation of each leg takes place when an enzyme “cuts” one fuel molecule that is bound to the leg. Thus, one molecule is all that is needed to take one step. The researchers noticed that this Nano walker is 20-nm-long by using a radiance microscope. It could move at speeds of up to 3 nm per minute.

Researchers explained the product control mechanism is different for chemically powered Nano-motors. It is not used by other kinds of Nano-motors, like those driven by light or electric/magnetic fields, nor by macroscopic motors. This type of Nano walker usually burns a lot of fuel molecules to produce heat. It then uses the heat to produce movement for working.

Although, product control is used inside bipedal bio-motors inside living cells. This bipedal bio-motors consumes ATP (adenosine triphosphate) as fuel. When the smaller phosphate molecule in ATP is free before the larger ADP (adenosine diphosphate) molecule, the bio-motor moves in one direction. Similarly, when the products are free in the opposite order, the bio-motor moves in the opposite direction.

Researchers hope that it will guide future development on chemically powered Nano-motor approaches to the final goal of copying the highly effective transport exhibited in living cells. One possible next step in this sector to manufacture a Nano walker train to develop collective transport. This is common characteristics of bio-motors and could be used in new applications.

Zhison Wang, a physicist at the National University of Singapore said, “Enzymatic Nano walkers are a key element for replicating the autonomous, repeatable and efficient intracellular transport. This capability is important as it causes various Nanotechnological applications, such as motor-mounted drug delivery wherever the track leads, down to nanoscale resolution for localization; sensing and signal transduction (by capturing and concentrating chemical agents); automated multi-step synthesis and nanoscale assembly lines; and energy conversation for energy technology.”

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