Microfluidic sensing device and cartridge, and corresponding methods

A microfluidic sensing cartridge, for conducting at least two substantially simultaneous measures on at least two liquid samples, comprising a general housing having at least two microfluidic sensing devices each of which includes:

• a first opening defining an inlet and/or an outlet for a liquid sample,
• a detection chamber provided with at least one sensor,
• a first microfluidic path connecting said first opening to said detection chamber, such that said detection chamber can be filled in with a predefined volume of the liquid sample so as to conduct at least one measure,
• a second opening designed so as to allow the application of a negative and/or positive pressure within said housing,
• a second microfluidic path connecting said second opening to said detection chamber,
• a third opening designed so as to allow the application of a negative and/or positive pressure within said housing,
• a third microfluidic path connecting said third opening to said first microfluidic path,
• a waste chamber arranged in said second microfluidic path, between said detection chamber and said second opening, and
• a first restriction organ, for restricting the circulation of fluids, arranged in said second microfluidic path, between said second opening and said waste chamber, said first restriction organ having a predefined fluidic resistance so as to restrict the circulation of fluids in said second microfluidic path
• said microfluidic sensing cartridge further comprising:
• a first distribution channel arranged in communication with said second opening of each of said at least two microfluidic sensing devices and having a first general opening designed so as to allow the application of a negative and/or positive pressure within said first distribution channel, and
• a second distribution channel arranged in communication with said third opening of each of said at least two microfluidic sensing devices and having a second general opening designed so as to allow the application of a negative and/or positive pressure within said second distribution channel.

A method for manufacturing a microfluidic sensing cartridge comprising at least two microfluidic sensing devices, comprising the steps consisting in:

• providing a general main plate having a first general side and a second general side and including at least two sets of recesses, one for each of said at least two microfluidic sensing devices, for defining a detection chamber, a first microfluidic path connecting said detection chamber to a first opening, a second microfluidic path connecting said detection chamber to a second opening, a third microfluidic path connecting said first microfluidic path to a third opening, and a waste chamber for each of said at least two microfluidic sensing devices, one of said recesses being provided in a first general side of said main plate for defining said detection chamber,
• providing a first additional recess arranged in said second microfluidic path, for each of said at least two microfluidic sensing devices, between said second opening and said waste chamber, for defining a first restriction organ for restricting the circulation of fluids, said first restriction organ being intended to have a predefined fluidic resistance so as to be able to restrict the circulation of fluids in said second microfluidic path,
• providing a second additional recess arranged in said third microfluidic path, for each of said at least two microfluidic sensing devices, for defining a second restriction organ for restricting the circulation of fluids, said second restriction organ being intended to have a predefined fluidic resistance so as to be able to restrict the circulation of fluids in said third microfluidic path,
• providing a general sealing plate bearing at least one sensor as well as at least one electrically conducting track for each of said at least two microfluidic sensing devices,
• sealing said first general side with said general sealing plate, so as to arrange said sensors substantially in alignment with said corresponding detection chambers,
• providing a general cover plate for said second general side, and
• sealing said second general side with said general cover plate.

A measurement method by implementation of a microfluidic sensing cartridge comprising a general housing having at least two microfluidic sensing devices each of which includes:

• a first opening defining an inlet and/or an outlet for a liquid sample,
• a detection chamber provided with at least one sensor,
• a first microfluidic path connecting said first opening to said detection chamber, such that said detection chamber can be filled in with a predefined volume of the liquid sample so as to conduct at least one measure,
• a second opening designed so as to allow the application of a negative and/or positive pressure within said housing,
• a second microfluidic path connecting said second opening to said detection chamber,
• a third opening designed so as to allow the application of a negative and/or positive pressure within said housing,
• a third microfluidic path connecting said third opening to said first microfluidic path,
• a waste chamber arranged in said second microfluidic path, between said detection chamber and said second opening, and
• a first restriction organ, for restricting the circulation of fluids, arranged in said second microfluidic path, between said second opening and said waste chamber, said first restriction organ having a predefined fluidic resistance so as to restrict the circulation of fluids in said second microfluidic path
• said microfluidic sensing cartridge further comprising:
• a first distribution channel arranged in communication with said second opening of each of said at least two microfluidic sensing devices and having a first general opening designed so as to allow the application of a negative and/or positive pressure within said first distribution channel, and
• a second distribution channel arranged in communication with said third opening of each of said at least two microfluidic sensing devices and having a second general opening designed so as to allow the application of a negative and/or positive pressure within said second distribution channel,
• wherein the measurement method is applied on N liquid samples, N being equal to or being a multiple of the number of microfluidic sensing devices in the microfluidic sensing cartridge, and wherein the measurement method comprises the steps consisting in:
• immersing said first opening of each of said at least two microfluidic sensing devices in a corresponding of said N liquid samples, in a substantially simultaneous manner,
• applying a negative pressure in said general housing at least through said second general opening until said detection chamber of each of said at least two microfluidic sensing devices is filled in with a predefined volume of the corresponding liquid sample,
• applying a positive pressure in said general housing through said second general opening until any excessive part of the liquid samples is removed at least from a portion of each of said first microfluidic paths located between said corresponding first opening and third microfluidic path,
• conducting at least one measure on each of the at least two liquid samples by means of said corresponding at least one sensor, in a substantially simultaneous manner, and
• extracting said first opening of each of said at least two microfluidic sensing devices out of the corresponding liquid samples before or after conducting said at least one measure, but before applying a negative pressure in said general housing through said first general opening to transfer the predefined volume of the liquid samples from each of said detection chambers into said corresponding waste chambers.