A Microfluidic Chip System For Rapid Regulation Of Dynamic Biochemical Signals At Observation Points In Real Time

Dynamic biochemical signals in the extracellular microenvironment play an important role in regulating the physiological state of cells.Dynamic response of cells induced by dynamic biochemical signals has become an important research hotspot in the field of cell biology.The extracellular microenvironment is so complex that monitoring and regulation of dynamic signals in vivo are extremely difficult to achieve,which largely limits the further quantitative study of cell dynamics response.In recent years,the development of microfluidic technology shows the potenials in the generation and regulation of dynamic biochemical signals in vitro.Extensive microfluidic chips have been developed to generate dynamic biochemical signals.However,the existing microfluidic chips based on dynamic mixing and flow switching methods generally show the limitations of slow response and low frequency.In thses aspects,this study proposes a novel microfluidic chip according to the principle of fluid mechanics,which is capable of generating and rapidly regulating high-frequency dynamic biochemical signals at certain observation points by adjusting the flow rates.Firstly,the chip structure has been designed by combiningthe characteristics of the classic "Christmas tree" structure for generating a linear spatial concentration gradient and the Y-shaped microchannel.The "Christmas tree" structure is connected to one inlet of the Y-shaped microchannel to create a stable linear concentration gradient of the biochemical factors in the main microchannel,while the other inlet of Y-shaped microchannel serves as the control inlet by introducing a dynamic buffer solution.The dynamic characteristicsof biochemical signals at the observation points have been analyzed as well as the generation principle.Secondly,simulations of fluid dynamics were conducted to investigate the spatiotemporal distributions of biochemical factors in the microfluidic chip.The generation and transmission characteristics of biochemical signals with different waveforms and frequencies have been explored.By establishing the microfluidic system,experiments are conducted to verify the simulation results.Finally,the designed microfluidic chip were applied to the study on calcium response of cells.The calcium dynamics of cells induced by dynamic biochemical signals were measured and analyzed.where expected patterns of calcium signals have been obtained.The resultsdemonstrate the proposed micrfluidic chip can provide a reliable platform for quantitative studies of cell dynamics in vitro.