Transmission of dynamic biochemical signals in the shallow microfluidic channel: nonlinear modulation of the pulsatile flow

A controlled quantitative loading of dynamic biochemical signals on cells in vitro is essential for cell dynamic analysis. Microfluidics provides the potential for reproducing and controlling spatio-temporal biochemical signals through the various microfluidic channels. Herein we investigate the transmission characteristics of dynamic biochemical signals in pulsatile flows by analytically solving the convection-diffusion equation for the time-dependent Taylor-Aris dispersion with perturbation method. We prove that the transmission of dynamic biochemical signals in pulsatile flows is subject to the two correlate effects: low-pass filtering and nonlinear amplitude-frequency modulation. These two effects are systematically characterized and the influence factors are studied, including the biochemical signal frequency, the pulsatile flow frequency, the transmission distance and the average pulsatile flow rate. We concluded that the balance of multiple factors should be taken into account for better loading biochemical signals on cells cultured in the microfluidic channel.