Living cells respond to external cues to transmit and process information encoded in small molecules. The discovery of recurrent patterns in biology (i.e., network motifs) infers that small sets of chemical reaction networks (CRNs) orchestrate spatiotemporal dynamics in and across living cells. Feedback mechanisms in CRNs, essentially, facilitate fast and nonlinear response to stimuli from the environment and systems-level properties such as bistability, oscillations, and homeostasis. Recent advances in out-of-equilibrium networks underline the outstanding successes in systems chemistry in translating the design principles of biological networks into a practical 'chemical programming language'. Strategies to rationally encode, process and integrate chemical signals akin regulatory networks in a living cell, however, remains elusive. Theory suggests that placing components of CRNs on a surface could create local feedback loops capable of dynamic and spatial aspects of intracellular communication. Among other approaches that focus on surface-driven methods to engineer chemical communication, we recently reported a microfluidic strategy that could bestow an acid-base network with the capacity of signal transduction. Briefly, fixating a polyelectrolyte (or more specifically, poly-L-lysine, PLL) on a surface in a microfluidic channel allowed us to work under flow so that the lysine residues can bind and release protons at the liquid-surface interface. The introduction of polyelectrolyte multilayers (PEMs) enhanced the rate of deprotonation of PLL, thereby enabling an output that can be tuned based on the relative timing of input 'spikes' in pH.