Materials that perform complex chemical signal processing are ubiquitous in living systems. Their synthetic analogs would transform developments in biomedicine, catalysis, and many other areas. By drawing inspiration from biological signaling dynamics, we show how simple hydrogels have a previously untapped capacity for non-equilibrium chemical signal processing and integration. Using a common polyacrylic acid hydrogel, with divalent cations and acid as representative stimuli, we demonstrate the emergence of non-monotonic osmosis-driven spikes and waves of expansion/contraction, as well as traveling color waves. These distinct responses emerge from different combinations of rates and sequences of arriving stimuli. A non-equilibrium continuum theory we developed quantitatively captures the non-monotonic osmosis-driven deformation waves and determines the onset of their emergence in terms of the input parameters. These results suggest that simple hydrogels, already built into numerous systems, have a much larger sensing space than currently employed.

中文翻译：

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水凝胶中的非平衡信号整合。

在生命系统中，执行复杂化学信号处理的材料无处不在。他们的合成类似物将改变生物医学，催化和许多其他领域的发展。通过从生物信号动力学中汲取灵感，我们展示了简单的水凝胶如何具有非平衡化学信号处理和整合先前尚未开发的能力。使用常见的聚丙烯酸水凝胶，以二价阳离子和酸为代表刺激，我们证明了非单调渗透驱动的尖峰和膨胀/收缩波以及色波传播的出现。这些不同的响应来自到达刺激的速率和顺序的不同组合。我们开发的非平衡连续体理论定量地捕获了非单调渗透驱动的形变波，并根据输入参数确定了它们出现的起点。这些结果表明，已经内置到众多系统中的简单水凝胶具有比当前使用的感测空间大得多的感测空间。