Microfluidic or millifluidic chip comprising a pressure sensing unit using colour-switching hydrogels

Microfluidic or millifluidic chip comprising:

• a microfluidic circuit with an embedded flow channel through which a fluid circulates and along which the fluid flow pressure is to be measured, and
• at least one integrated pressure sensing unit able to measure the fluid flow pressure at a position along said main flow channel,
• said microfluidic chip being characterized in that it comprises two layers made of a liquid-tight material and a membrane,
• wherein one at least of said two layers is made of a material that is also light transparent,
• wherein said membrane is impermeable to the fluid circulating in the channel and is able to deform under the pressure exerted by the fluid,
• said layers and said membrane being arranged according to the following configuration:
• one layer is a top layer in which the main flow channel is embedded at a surface of the top layer facing
• another layer is a bottom layer comprising one lower cavity formed at its surface and containing a slab of a photonic hydrogel immersed in a aqueous buffer solution,
• wherein said lower cavity is positioned so as to be placed directly under the main flow channel,
• wherein said lower cavity containing the photonic gel and the part of the membrane covering said lower cavity form the sensing unit.