Continuous variables logic via coupled automata using a DNAzyme cascade with feedback.
Continuous variables logic via coupled automata using a DNAzyme cascade with feedback.
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DOI：
10.1039/c6sc03892a
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发表时间：
2017-03-01
期刊：
影响因子：
8.4
通讯作者：
Levine RD
中科院分区：
文献类型：
--
作者：
Lilienthal S;Klein M;Orbach R;Willner I;Remacle F;Levine RD
通过DNA酶与其发夹底物的杂交实现具有随机输入和输出的与门。分子的浓度可以通过化学反应改变，从而提供连续的读数。然而，教科书中的计算机体系结构是以二进制值、布尔变量的形式出现的。为了使反应化学系统计算，我们展示了如何使用概率论的考克斯解释，可以转录的化学动力学方程作为一个序列的耦合逻辑门操作连续变量。它讨论了如何独特的化学身份的分子，使我们能够创建一个共同的语言，化学动力学和布尔逻辑。具体地说，逻辑与操作被证明是相当于一个双分子过程。逻辑异或运算表示同时发生的化学过程。速率常数的值作为输入进入逻辑方案。通过设计具有反馈的反应方案，我们赋予逻辑门内置存储器，因为它们的输出取决于输入以及系统的当前状态。从技术上讲，这样的逻辑机器是一个自动机。我们报告了三个这样的耦合自动机使用DNAzyme多层信号级联的实验实现。一个简单的模型验证分析，我们的实验方案提供了一个积分器生成的幂级数，是三阶的时间。该模型确定了两个参数，支配的动力学，并显示了如何在幂级数的系数的基板的初始浓度。
Implementing an AND gate with stochastic input and output by the hybridization of a DNAzyme and its hairpin substrate. The concentration of molecules can be changed by chemical reactions and thereby offer a continuous readout. Yet computer architecture is cast in textbooks in terms of binary valued, Boolean variables. To enable reactive chemical systems to compute we show how, using the Cox interpretation of probability theory, one can transcribe the equations of chemical kinetics as a sequence of coupled logic gates operating on continuous variables. It is discussed how the distinct chemical identity of a molecule allows us to create a common language for chemical kinetics and Boolean logic. Specifically, the logic AND operation is shown to be equivalent to a bimolecular process. The logic XOR operation represents chemical processes that take place concurrently. The values of the rate constants enter the logic scheme as inputs. By designing a reaction scheme with a feedback we endow the logic gates with a built in memory because their output then depends on the input and also on the present state of the system. Technically such a logic machine is an automaton. We report an experimental realization of three such coupled automata using a DNAzyme multilayer signaling cascade. A simple model verifies analytically that our experimental scheme provides an integrator generating a power series that is third order in time. The model identifies two parameters that govern the kinetics and shows how the initial concentrations of the substrates are the coefficients in the power series.