Filtration methods and devices
A method of filtering a liquid sample that includes passing a sample comprising at least one biological organism through a filter membrane at a passive water volume flux of at least 10 L/m 2 ·h·psi, wherein the filter membrane comprises a Bubble Point pore size of no more than 1.0 μm, thereby retaining at least one biological organism on the surface of the membrane; and detecting the at least one biological organism retained on the surface of the filter membrane.
1. A system comprising:
a liquid sample comprising at least one biological organism;
a filter device comprising:
a pocket comprising a pocket surface that defines a pocket volume;
an absorbent member disposed on at least a portion of the pocket surface, wherein the absorbent member is a hydrogel; and
a filter membrane disposed on at least a portion of the absorbent member in fluid communication with the pocket volume, wherein flow of liquid into the absorbent member occurs when a liquid flows through the filter membrane and a biological organism in the liquid sample is retained by the filter membrane, wherein the filter membrane forms the pocket.
2. The system of claim 1 , wherein the filter membrane is a multi-zone membrane.
3. The system of claim 2 , wherein the multi-zone membrane comprises an open side in functional communication with the absorbent member and a tight side in fluid communication with the pocket volume.
4. The system of claim 3 , wherein the tight side has a smaller Bubble Point pore size relative to the open side.
5. The system of claim 3 , wherein the functional communication is capable of generating a water flux gradient sufficient to draw liquid across the filter membrane and into the absorbent member.
6. The system of claim 1 , wherein the pocket further comprises a sample port.
7. The system of claim 5 , wherein the water flux gradient is at least 10 L/m2.h.psi.
8. The system of claim 1 , wherein the filter membrane has a Bubble Point pore size of no more than 1.0 μm.
9. The system of claim 1 , wherein the filter membrane comprises a polyolefin porous membrane, an ethylene-chlorotrifluoroethylene copolymer porous membrane, a polyacrylonitrile porous membrane, a polycarbonate porous membrane, a polyester porous membrane, a cellulose ester porous membrane, a polyamide porous membrane, a polyethersulfone porous membrane, a polysulfone porous membrane, a polyvinylidene fluoride (PVDF) porous membrane, a polyacrylonitrile nanofiber membrane, a PVDF nanofiber membrane, a cellulose ester nanofiber membrane, a polyvinyl acetate or alcohol nanofiber membrane, or a polyvinyl butyral nanofiber membrane.
10. The system of claim 1 , wherein the filter membrane comprises a Thermally Induced Phase (TIPS) membrane or a nanofiber membrane.
11. A system comprising:
a liquid sample comprising at least one biological organism;
a filter device comprising:
a pocket comprising a pocket surface that defines a pocket volume;
an absorbent member disposed on at least a portion of the pocket surface, wherein the absorbent member is a hydrogel; and
a filter membrane disposed on at least a portion of the absorbent member in fluid communication with the pocket volume, wherein flow of liquid into the absorbent member occurs when a liquid flows through the filter membrane and a biological organism in the liquid sample is retained by the filter membrane, wherein the absorbent member is enveloped by the filter membrane.
12. The system of claim 11 , wherein the filter membrane is a multi-zone membrane.
13. The system of claim 12 , wherein the multi-zone membrane comprises an open side in functional communication with the absorbent member and a tight side in fluid communication with the pocket volume.
14. The system of claim 13 , wherein the tight side has a smaller Bubble Point pore size relative to the open side.
15. The system of claim 13 , wherein the functional communication is capable of generating a water flux gradient sufficient to draw liquid across the filter membrane and into the absorbent member.
16. The system of claim 15 , wherein the water flux gradient is at least 10 L/m2.h.psi.
17. The system of claim 11 , wherein the pocket further comprises a sample port.
18. The system of claim 11 , wherein the filter membrane has a Bubble Point pore size of no more than 1.0 μm.
19. The system of claim 11 , wherein the filter membrane comprises a polyolefin porous membrane, an ethylene-chlorotrifluoroethylene copolymer porous membrane, a polyacrylonitrile porous membrane, a polycarbonate porous membrane, a polyester porous membrane, a cellulose ester porous membrane, a polyamide porous membrane, a polyethersulfone porous membrane, a polysulfone porous membrane, a polyvinylidene fluoride (PVDF) porous membrane, a polyacrylonitrile nanofiber membrane, a PVDF nanofiber membrane, a cellulose ester nanofiber membrane, a polyvinyl acetate or alcohol nanofiber membrane, or a polyvinyl butyral nanofiber membrane.
20. The system of claim 11 , wherein the filter membrane comprises a Thermally Induced Phase (TIPS) membrane or a nanofiber membrane.