Method and apparatus for the filtration of biological samples
A separation module and method are disclosed for processing a liquid sample and providing high conversion by operating a single-pass tangential-flow process without a recirculation loop. In one embodiment, the separation module includes three reservoirs and has at least one long, thin channel with a large ratio of channel membrane area to: channel void volume; volume of a sample feed reservoir; and volume of the feed sample. In another embodiment, the separation module includes two reservoirs and a hydrophobic vent. The single-pass process provides high conversion while operating with relatively low pressure sources.
1. A module for the filtration of a liquid sample comprising:
a housing having a first section forming a first reservoir and a first flow passage;
a core disposed within the housing forming a second reservoir having a first end adapted to connect to a pressure source;
a separation element surrounding a portion of the core comprising at least one flow channel having an inlet, an outlet and a wall having a surface comprising an ultrafiltration membrane, the at least one flow channel fluidly coupling the first reservoir through the first flow passage to the second reservoir through a second flow passage in the core;
a permeate reservoir disposed within a second section of the housing and fluidly coupled to the separation element; and
wherein the first reservoir is one of a feed reservoir and a retentate reservoir, and the second reservoir is a different one of the feed reservoir and the retentate reservoir.
2. The module of claim 1 wherein the flow channel comprises at least one hollow fiber wound annularly around the core.
3. The module of claim 1 further comprising a plug disposed at the second end of the core.
4. The module of claim 1 further comprising:
a support ring surrounding the core the first flow passage passing through the support ring;
a support seal surrounding the support ring and adjacent to the housing; and a permeate port passing through the support seal adapted to be coupled to a second pressure source.
5. The module of claim 1 wherein the ratio of the membrane area of the separation element to the volume of the feed reservoir within the housing is greater than about 30 cm −1 .
6. The module of claim 1 wherein the ratio of the membrane area of the separation element to the volume of the feed reservoir within the housing is greater than about 2 cm −1 .
7. The module of claim 1 wherein the flow channel comprises at least one flat-sheet membrane in a spiral-wound configuration wound annularly around the core.