Devices and methods for liquid to liquid biological particle concentration

Inventors

Alburty, David S. • Page, Andrew E. • Packingham, Zachary A. • Marske, Daniel B.

Assignees

Innovaprep LLC

Abstract

A rapid one-pass liquid filtration system efficiently concentrates biological particles that are suspended in liquid from a dilute feed suspension. A sample concentrate or retentate suspension is retained while eliminating the separated fluid in a separate flow stream. Suspended biological particles include such materials as proteins/toxins, viruses, DNA, and/or bacteria in the size range of approximately 0.001 micron to 20 microns diameter. Concentration of these particles is advantageous for detection of target particles in a dilute suspension, because concentrating them into a small volume makes them easier to detect. Additional concentration stages may be added in “cascade” fashion, in order to concentrate particles below the size cut of each preceding stage remaining in the separated fluid in a concentrated sample suspension. This process can also be used to create a “band-pass” concentration for concentration of a particular target size particle within a narrow range.

Core Innovation

The disclosure describes a rapid one-pass tangential-flow filtration system that concentrates dilute biological particles into a small retentate volume. The system uses hollow fiber filters and a foam wash generated from a wash liquid and a water-soluble gas under pressure. The foam wash is biologically and analytically compatible with the biological particulates and is used to move and concentrate the biological particulates within the hollow fiber filter for subsequent collection and analysis.

The approach creates the foam wash by releasing and agitating a pressurized wash liquid and water-soluble gas mixture, optionally including agitation and vibration during release. A valve opening time is controlled to dispense the foam wash into the hollow fiber filter, and a rotary valve can be used to release the foam wash from one end of the interior feed side to another end of the interior feed side. The biological particulates become concentrated in the foam wash, and the concentrate is collected for analysis.

The system further supports concentrating by separating and trapping biological particulates on an interior feed side of the hollow fiber filter, while optionally pulling a vacuum on an exterior permeate side to pull process feed through the filter. The disclosure also describes concentrator cell embodiments, including multi-fiber and compact or modular length configurations, and features such as size fractionation using band-pass or cascade arrangements. The documented embodiments include strategies intended to inhibit microbial growth by storing the hollow fiber filter under high pressure, and supporting data showing improved filtration efficiency and concentration factors for biological particulates across particle sizes.

Claims Coverage

The independent claims cover three main inventive groupings: a foam-wash based filtration method with controlled valve dispensing and collection of concentrated biological particulates; a corresponding device using a wash reservoir, hollow fiber filter, and rotary valve with biologically and analytically compatible foam wash; and an expanded foam-wash method that includes agitation and vibration during foam generation and collecting concentrates for analysis. Across the independent claims, the central inventive features are the pressurized foam wash generation from a wash liquid and a water-soluble gas, transport/dispensing into a hollow fiber filter using controlled valve opening time and rotary valve, and concentrating biological particulates by trapping on an interior feed side with subsequent collection for analysis.

The independent claims define a foam-wash based concentration approach centered on generating foam from a wash liquid and a water-soluble gas under pressure, dispensing the foam wash into a hollow fiber filter using controlled valve opening time and rotary valve, and concentrating biological particulates by trapping them on an interior feed side with collection for analysis. The claim set further includes optional vacuum on the exterior permeate side to pull feed through the filter and expands foam generation to include agitation and vibration during release.

Stated Advantages

Documented Applications