Designing logic gates using active particles

In recent years, unconventional computing architectures that transcend traditional semiconductor-based systems have witnessed far-ranging research interest. Here we propose an approach to the construction of logic gates, using active particles, specifically 1-pentanol-infused disks, exploiting the principle of the Marangoni effect. In our experimental setup, we design a channel with arms designated for inputs and an arm to observe the output. The inputs are provided by disks, where active disks infused with pentanol are considered to have a truth value of 1, while passive disks are considered to have a truth value of 0. The movement of a controller disk placed in a decision-making region determines the output. We demonstrate that the complex interplay of surface tension, drag, and repulsive and attractive forces yields the fundamental AND and OR logic responses. Interestingly, the logic function can be switched by solely changing the activity of the controller by decreasing the pentanol concentration, thus giving the same channels the capacity to morph the logic functionality. Additionally, the complementary NAND and NOR logic can be obtained with a simple change in the output encoding. Such active-matter-based logic gates have the potential to perform in fluid conditions, making them ideal for biomedical applications, bio sensing, molecular computing, and targeted drug delivery by responding to biological signals without external power sources.