Ultrafilteration device and method of forming same

Abstract

An ultrafiltration device has a filter membrane sealed inside a reservoir body, such as a tube. The tube has one or more ports and a closed portion distal to the port(s), and the filter membrane is sealed to the body along a closed contour widely surrounding the port(s) to provide a large area filtered outflow path. The method is effective to rapidly isolate a predetermined amount of a desired retentate in the distal portion of the tube. The method and device are also useful for quantitative transfer of smaller molecules and for multi-step processing of sample arrays. A frusto-conical peripheral filter provides high ratio of effective filter area, and may be configured for hydrostatic deadstopping and little or no wicking, greatly enhancing recovery time and efficiency. Linear array strips of such chambers may be formed by bonding together mating halves with filter areas over the chamber ports. The vessel may include a rib to guide and orient filter during assembly, and/or a ledge or recess to engage and align the filter, assuring that the filter is precisely positioned and does not wander during manufacture and bonding. In one embodiment a deflectable lip or other integral feature of the vessel geometry seals the vessel in a capped receiving tube, and opens under pressure to pass pressure between the tube and vessel during centrifugation, to permit overfilling of the vessel in a tilted rotor assembly without spillage or leakage, and increasing the concentration ratio. The vessels have a high filter area to volume ratio, maintain open filter surfaces and high rates of filtration throughout the spin, and are fully compatible with robotic loading, multistage operation and in situ multiwell plate filtrate and/or retentate assay or transfer. Attachment of the filter may be effected by heat welding. Preferably the vessel and filter are positioned between a press member and a heat sink and a superheated tool contacts the press member to selectively deliver a defined bolus of heat to the weld areas.

Dependencies are inferred from the claim text.