Microfluidic chip and valve, production process and uses

A process for producing a microfluidic valve, the process comprising the following steps:

• a. providing at least one microfluidic valve comprising:
• a basic substrate,
• an elastomeric membrane, and
• a top substrate,
• wherein the basic substrate has an upper surface and lower surface and comprises on the upper surface a valve seat with a perimeter pV=x comprising a central recess with a perimeter pCR<x, and a projection surrounding the valve seat with an inner perimeter pPi≥x and an outer perimeter pPo>PPi,
• wherein the central recess comprises an inlet opening and a separate outlet opening, which are respectively connected to microfluidic channels upstream and downstream of the valve seat by respective connection channels, and wherein the connection channels are independently of each other arranged in angular position to the upper surface of the basic substrate, and wherein the central recess forms on the upper surface of the basic substrate a recess of longitudinal shape,
• wherein the elastomeric membrane has opposed upper and lower surfaces and a thickness d in relaxed state,
• wherein the top substrate has opposed upper and lower surfaces and has a through hole from the top substrate lower surface to the top substrate upper surface with a perimeter pTH≤pPi,
• b. arranging the lower surface of the elastomeric membrane on the upper surface of the basic substrate and arranging the lower surface of the top substrate on the upper surface of the elastomeric membrane, thereby arranging the through hole of the top substrate having a perimeter pTH≤pPi in register to the perimeter pV of the valve seat, and
• c. securing the top substrate to the basic substrate thereby clamping the elastomeric membrane to the basic substrate such that the valve seat is sealed in an upper direction, whereby the elastomeric membrane is configured to not be in contact with a surface of the central recess in an open valve state, thereby forming a valve cavity which fluidly connects the connection channels upstream and downstream of the valve seat, and to be deformable by a valve actuator so that in a closed valve state, the elastomeric membrane closes the fluidic connection between the inlet and outlet openings in the central recess;
• wherein:
• the thickness d ranges between 0.7 mm and 1.8 mm;
• the elastic membrane is deformable and has a hardness on a Shore scale in a range of 30 to 75;
• the perimeter of the valve seat pV ranges between 1 mm and 25 mm;
• the perimeter of the central recess pCR ranges between 600 μm to 12.5 mm;
• the inner perimeter pPi of the projection ranges between 1 mm and 25 mm;
• the outer perimeter pPo of the projection ranges between 1.5 mm and 40 mm:
• the perimeter pTH is ≥25 mm;
• the distance dBTLS ranges between d to 1.2d;
• the distance dCR ranges between 1.1d to 1.8d;
• and
• the distance dP ranges between 0.3d to 0.65d.

A method for controlling flow of a liquid composition in a microfluidic channel of a microfluidic channel network, comprising:

• providing at least one microfluidic valve comprising:
• a basic substrate having opposed upper and lower surfaces,
• an elastomeric membrane with a thickness d in relaxed state,
• a top substrate respectively having opposed upper and lower surfaces,
• wherein the top substrate is secured to the basic substrate, thereby lamping the elastomeric membrane between the upper surface of the basic substrate and the lower surface of the top substrate,
• wherein the basic substrate comprises on the basic substrate upper surface a valve seat with a perimeter pV=x comprising a central recess with a perimeter pCR≥x, and a projection surrounding the valve seat with an inner perimeter pPi≤x and an outer perimeter pPo>PPi,
• wherein a distance between the upper surface of the basic substrate and the lower surface plane of the top substrate measured perpendicular to the lower surface plane respectively is dBTLS≤d outside the perimeter pPo of the projection, is dCR>d within the perimeter pCR of the central recess, and is dP<d between the perimeters pPi and pPo of the projection,
• wherein the top substrate has a through hole from the top substrate lower surface to the top substrate upper surface with a perimeter pTH≥pPi, which is arranged in register to the valve seat, thereby providing access for a valve actuator,
• wherein the central recess forms on the upper surface of the basic substrate a recess of longitudinal shape and comprises an inlet opening and a separate outlet opening, which are respectively connected to microfluidic channels upstream and downstream of the valve seat by respective connection channels, and wherein the connection channels are independently of each other arranged in angular position to the upper surface of the basic substrate, and
• the elastomeric membrane is configured to not be in contact with a surface of the central recess in an open valve state, thereby forming a valve cavity, which fluidly connects the connection channels upstream and downstream of the valve seat, and to be deformable by the valve actuator so that in a closed valve state, the elastomeric membrane closes the fluidic connection between the inlet and outlet openings in the central recess, wherein:
• the thickness d ranges between 0.7 mm and 1.8 mm;
• the elastic membrane is deformable and has a hardness on a Shore scale in a range of 30 to 75;
• the perimeter of the valve seat pV ranges between 1 mm and 25 mm;
• the perimeter of the central recess pCR ranges between 600 μm to 12.5 mm;
• the inner perimeter pPi of the projection ranges between 1 mm and 25 mm;
• the outer perimeter pPo of the projection ranges between 1.5 mm and 40 mm:
• the perimeter pTH is 25 mm;
• the distance dBTLS ranges between d to 1.2d;
• the distance dCR ranges between 1.1d to 1.8d;
• and
• the distance dP ranges between 0.3d to 0.65d;
• operating the valve actuator to place the at least one microfluidic valve in the open state to connect the connection channels upstream and downstream of the valve seat or to place the at least one microfluidic valve in the closed state to disconnect the connection channels upstream and downstream of the valve seat.