Nanomachines - the Overview and Future Development of Nanomachines

Nanomachines

The overview and future development of nanomachines

Frank Zhang

Engineering Innovation

Salem Ahmed & Paul Hoyt

July 15, 2016

Nanomachines are the extremely small mechanical or electromechanical devices that have nanometers (10-9 meter) dimensions. These devices can work fast in their tiny sizes, replicate themselves, or work together to form larger machines with their durability and low operating energy. For the application, they can be used in a variety of fields such as medical technology and environment sciences. However, the major disadvantages are the manufacture method and cost (Rouse, 2011).

This idea of nanomachines is generate from the structure of Escherichia Coli by Berg in 1973, which E-Coli uses molecule motors to rotate their helical flagella (Wang, 2013). That is when the concept of nanomachines first generated. However, the questions were also raised: how we produce the nanomachines? How we make them move? How we control their move?

Different from the mechanical structures such as gear, the nanomachines are much simpler and smaller, which means the way to produce nanomachines should be totally different and complex. Scientists and engineers are striving to find method to make nanomachines efficiently, and generally they come up with the ideas from the biological systems. As the first goal, scientists and engineers need to make a molecular assembly to produce single nanomachines. Theoretically, we can manipulate single atom and build complex machinery at the micron scale, which the machinery lays the foundation for producing nanomachines (Crandall, 1999). However, besides the need of extreme accuracy, manufacturing a tiny device is really slow and it needs a long time to produce enough quantity we want, since we need at least 1012 devices to form a 1mm*1mm accumulation of nanomachines. Then, in order to avoid the waste of time and, the most important, the waste of money, we need to find the way to produce effectively. If a nanomachine can act like a biological molecule, like DNA, to replicate itself, it will extremely effective and cost saving. Actually, that is the way which scientists and engineers looking forward to achieve with the use of polymerase chain reaction. The only drawback is the uncontrollable replication may lead to serious problem.

As same as E-Coli, the molecular movement is totally different from the macro-scope. Needless to say, we cannot use the fuel energy for sure. Instead, since the concept of motor is maintained, nanomachines need to be driven with different energy resources. The possible energy resources may generate from chemical, electricity, or light. ATP synthase will spin when a proton pass through, which can be represent as chemical energy source; Rused ring will move with the gain or loss of the copper ion, which can be represent as electrical energy source; Azo compounds will change the shape by the effect of light, which can be represent as light energy source. After gaining the energy, nanomachines can therefore move in different way. By the inertial forces like surface-tension gradient, propulsion, and implosion, nanomachines, or nanorod in specific, can move with the interface between air and water, where viscous drag will be reduced (Ozin, Manners, Fournier-Bidoz, & Arsenault, 2005).

The control and communicate method will also be different from the macro-scope because there will be no Bluetooth or Wi-Fi in such tiny devices. Instead, we can also learn from human brain that it transfers the signal by chemical and electric potential. “We are currently designing possible molecular communication systems by choosing and combining appropriate system components and mechanisms from the biological systems (Suda, Moore, Nakano, & Enomoto, 2012).” As illustrated in Figure 1, molecule will encode some signals and send to receiver to execute some action. People can send some specific chemicals, which induces senders to send the chemicals as proteins, ions, and DNA. After receivers get the signals, they can perform a specific motion in their workplace. The similar thing will happen in electric communications, which people can release some harmless ions and increase the concentration gradient. Therefore, different concentration will induce the different potential, which allows electrons to pass through the nanomachines.[pic 1]

Figure 1. Communication processes in molecular communication

In order to overcome these problems, scientists and engineers spare no effort in it. Recently, people are putting efforts on DNA nanomachines. On March 11th, 2015, the self-replication DNA rings were deduced: DNA is the basic material for a system to replicate, and the DNA T-motifs are rings that can self-replicate through toehold-mediated strand displacement reactions, which derive a quantitative metric of the self-replicability of the rings (Kim, Lee, Hamada, Murata, & Park, 2015). On, September 3rd, 2015, DNA nanotechnology is transited from the test tube to the cell, which succeeded in the development of DNA-based imaging probes and prototypes of smart therapeutics as well as drug delivery systems (Chen, Groves, Muscat, & Seelig, 2015). On November 30th, 2015, the rolling motors are made from DNA-coated spherical particles that hybridize to a surface modified with complementary RNA, which the motion is achieved through the addition of RNase H; plus, motors can be used to detect single nucleotide polymorphism by measuring particle displacement using a smartphone camera (Yehl, Mugler, Vivek, Liu, Zhang, Fan, Weeks, & Khalid, 2015). On April 11th, 2016, it was found that an autonomous cascade of DNA hybridization reactions could create oligomers, from building blocks linked by olefin or peptide bonds, with a sequence defined by a reconfigurable molecular program. The system can also be programmed to achieve combinatorial assembly. The sequence of assembly reactions and thus the structure of each oligomer synthesized is recorded in a DNA molecule, which enables this information to be recovered by PCR amplification followed by DNA sequencing (Meng, Muscat, McKee, Milnes, El-Sagheer, Bath, Davis, Brown, O'Reilly, & Turberfield, 2016).

Needless to say, the nanomachines are getting increasing popularity among the world. Although recently the most efficient way to produce nanomachines is self-replication, we now are getting close to the controllable and economical ways. Maybe we can make the replication happen only at specific PH or temperature, and then it would not cause some unpredictable consequences. Moreover, China successfully removed some atoms on the gold panel, which means the potential ability to control extremely nano-scale matter. With the combination of accurate control and efficient producing method, the nanomachines can lead to unprecedented future.