Advantages of pressure-based microfluidics

Microfluidic experiment often require a high level of control of fluids to permits reproducible results and the success of different application. To this purpose Pressure based flow controller are well suited for a various number of microlfuidic application when high stability is required such as cell perfusion and shear stress control or in droplet production when monodispersity is of high importance.

It also allows to generate complex flow profil such as sequential injection with aortic profil or when real time flow rate measurement is needed, a parameter that other fluid handling system can't offer.

Droplet production using microfluidic systems was implemented for applications where monodispersity is of high importance. Syringe pumps are commonly used for generating droplets in microfluidic experiments, but can show limited flow control.. An alternative to syringe pumps are pressure-based flow controllers. 

In microfluidic instrumentation, stability refers to the ability of an instrument to maintain a certain physical property at a constant value, while rejecting any perturbations in the environment. It is a very important parameter, as even small variations in physical quantities during microfluidic experiments can dramatically change the results. A stable instrument ensures that results are repeatable and reproducible.

To perform effective experiments in microfluidics, one needs to master the different flow control technologies available to use the most suitable way to control microfluidic flows. This article aims at presenting a short review of the existing techniques.

 In microfluidics, response time is the duration between a command and the the start of flow (the first reaction of the microfluidic pump). When using a pressure controller, flow will start once a sufficient pressure rise occurs in the fluidic reservoir. The electrical and mechanical response times of the hardware components such as valves need to be as low as possible in order to decrease the response time.