Microfluidic assay assemblies and methods of manufacture
A method of making at least a portion of at least one microfluidic actuator having a flexible diaphragm portion and an opposite surface portion, the diaphragm and opposite surface each having opposed faces, at least one of the faces comprising surface-activated PDMS, and the opposed faces being arranged such that when the opposed faces contact each other, they form a fluidic seal, including performing repeated make-and-break-contact protocol on the contacting opposed faces until the tendency for permanent bonds to form between the contacting faces has been neutralized, thereby enabling the diaphragm portion to perform actuated movements to engage and disengage with the opposite surface portion, without the diaphragm sticking to the opposite surface portion.
1. A microfluidic valve disposed in a microfluidic channel, the valve having a valve diaphragm and a valve seat, the diaphragm and seat each having opposed faces, at least one of the faces comprising surface-activated PDMS, and the opposed faces being arranged such that when the diaphragm engages the seat, fluid is blocked from flowing along the channel, the valve being made by a process, comprising:
performing repeated make-and-break-contact protocol on the contacting faces of the valve diaphragm and valve seat until the tendency for permanent bonds to form between the contacting faces has been neutralized, thereby enabling the valve diaphragm to perform actuated movements to engage and disengage with the valve seat, without the diaphragm sticking to the valve seat.
2. The microfluidic valve of claim 1 , wherein the diaphragm is made of a material comprising PDMS throughout its thickness.
3. The microfluidic valve of claim 1 , wherein one of the faces comprises surface-activated PDMS and the other of the faces comprises at least one of: surface-activated PDMS, plastic having OH groups at the surface, glass, a material having OH groups at the surface, and a silane-treated surface.
4. The microfluidic valve of claim 1 , wherein the make-and-break-contact protocol is performed by applying, respectively, positive and negative air pressure to a back face of the diaphragm.
5. The microfluidic valve of claim 1 , wherein the make-and-break-contact protocol is performed by applying, respectively, positive and negative air pressure between the opposed faces.
6. A microfluidic actuator having a flexible diaphragm portion and an opposite surface portion, the diaphragm and opposite surface each having opposed faces, at least one of the faces comprising surface-activated PDMS, and the opposed faces being arranged such that when the opposed faces contact each other, they form a fluidic seal, the actuator being made by a process, comprising:
performing repeated make-and-break-contact protocol on the contacting opposed faces until the tendency for permanent bonds to form between the contacting faces has been neutralized, thereby enabling the diaphragm portion to perform actuated movements to engage and disengage with the opposite surface portion, without the diaphragm sticking to the opposite surface portion.
7. The microfluidic actuator of claim 6 , wherein the make-and-break-contact protocol is performed simultaneously on a plurality of actuators.
8. The microfluidic actuator of claim 6 , wherein the diaphragm portion is made of a material comprising PDMS throughout its thickness.
9. The microfluidic actuator of claim 6 , wherein one of the faces comprises surface-activated PDMS and the other of the faces comprises at least one of: surface-activated PDMS, plastic having OH groups at the surface, glass, a material having OH groups at the surface, and a silane-treated surface.
10. The microfluidic actuator of claim 6 , wherein the make-and-break-contact protocol is performed by applying, respectively, positive and negative air pressure to a back face of at least one of the diaphragm portion and the opposite surface portion.
11. The microfluidic actuator of claim 6 , wherein the make-and-break-contact protocol is performed by applying, respectively, positive and negative air pressure between the opposed faces.
12. The microfluidic actuator of claim 6 , wherein the microfluidic actuator comprises a microfluidic valve disposed in a microfluidic channel and the opposite surface comprises a valve seat.
13. The microfluidic actuator of claim 6 , wherein the microfluidic actuator comprises a microfluidic piston disposed in a microfluidic channel and the diaphragm portion defines a piston diaphragm of a membrane pump.
14. The microfluidic actuator of claim 6 , wherein both of the opposed faces comprises surface-activated PDMS.
15. A method of preventing permanent bonds from forming between opposed faces of two materials, at least one of the faces comprising surface-activated PDMS, comprising:
performing repeated make-and-break-contact protocol on the opposed faces until the tendency for bonds to form between the opposed faces has been neutralized.
16. The method of claim 15 , wherein one of the faces comprises surface-activated PDMS and the other of the faces comprises at least one of: surface-activated PDMS, plastic having OH groups at the surface, glass, a material having OH groups at the surface, and a silane-treated surface.
17. The method of claim 15 , wherein the make-and-break-contact protocol comprises causing the faces to contact each other for a predetermined “make” period of time and then causing the faces to detach from each other for a predetermined “break” period of time, in repetitive fashion.
18. The method of claim 15 , wherein both of the opposed faces comprises surface-activated PDMS.
19. The method of claim 15 , wherein at least one of the materials comprises PDMS throughout its thickness.
20. The microfluidic valve of claim 15 , wherein both of the materials comprises PDMS throughout its thickness.