With the progress of DNA computing, DNAbased cryptography becomes an emerging interdisciplinary research field. In this paper, we present a novel DNA cryptography that takes advantage of DNA self-assembled structure. Making use of the toehold strands recognition and strand displacement, the bit-wise exclusive-or(XOR)operation is carried out to fulfill the information encryption and decryption in the form of a one-time-pad. The security of this system mainly comes from the physical isolation and specificity of DNA molecules. The system is constructed by using complex DNA self-assembly, in which technique of fluorescent detection is utilized to implement the signal processing. In the proposed DNA cryptography,the XOR operation at each bit is carried out individually,thus the encryption and decryption process could be conducted in a massive, parallel way. This work may demonstrate that DNA cryptography has the great potential applications in the field of information security.
In this study,the DNA logic computing model is established based on the methods of DNA self-assembly and strand branch migration.By adding the signal strands,the preprogrammed signals are released with the disintegrating of initial assembly structures.Then,the computing results are able to be detected by gel electrophoresis.The whole process is controlled automatically and parallely,even triggered by the mixture of input signals.In addition,the conception of single polar and bipolar is introduced into system designing,which leads to synchronization and modularization.Recognizing the specific signal DNA strands,the computing model gives all correct results by gel experiment.
DNA computing, currently a hot research field in information processing, has the advantages of parallelism, low energy consumption, and high storability, therefore, it has been applied to a variety of complicated computational problems. The emerging field of DNA nanotechnology has also developed quickly; within it, the method of DNA strand displacement has drawn great attention because it is self-induced, sensitive, accurate, and operationally simple. This article summarizes five aspects of the recent developments of DNA-strand displacement in DNA computing:(1) cascading circuits;(2) catalyzed reaction;(3) logic computation;(4) DNA computing on surfaces; and(5) logic computing based on nanoparticles guided by strand displacement. The applications and mechanisms of strand displacement in DNA computing are discussed and possible future developments are presented.
Because of the simplicity of cells, the key to building biological computing systems may lie in constructing distributed systems based on cell–cell communication. Guided by a mathematical model, in this study we designed,simulated, and constructed a genetic double-branch structure in the bacterium Escherichia coli. This genetic double-branch structure is composed of a control cell and two reporter cells.The control cell can activate different reporter cells according to the input. Two quorum-sensing signal molecules, 3OC12-HSL and C4-HSL, form the wires between the control cell and the reporter cells. This study is a step toward scalable biological computation, and it may have many potential applications in biocomputing, biosensing, and biotherapy.
