| Summary: | Precise control over flow rate and flow pattern is critical for investigating the contribution of shear force in cellular responses, biofluidic transport, and living matter in a flowing environment. Generation and control over the ultralow flow fields at microscale are, however, difficult, due to thermal agitation and fluctuations in the surrounding environment. Herein, pa novel microfluidic flow field generator is proposed, capable of generating stable flow field down to the limit of thermal noise. Integrated with a customized MATLAB program controlling timely open–close of 18 monolithic PDMS valves, the flow generator outperforms the existing methods by both achievable low flow rate, that is, 0.01 nL s−1, temporal resolution of flow rate fluctuation down to 100 ms, and provides complex flow patterns. Moreover, unlike external devices (e.g., the syringe pump), the design can be easily integrated into any fluidic chip and sealed from the disturbance of experimental conditions, for example, the airflow and the movement of connected pipelines. The methodology is, therefore, suitable for biological and biophysical studies requiring a well‐defined flowing environment.
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