Vacuum-assisted drying of filters in microfluidic systems

Inventors

MADADI, Hojjat • PAGE, Robin • JOWSEY, Molly Rose • Willshare, Thomas Michael • RIMSA, Roberts

Assignees

QuantumDx Group Ltd

Abstract

Improved methods and devices using reduction of pressure for removing ethanol from filters in a fluidic or microfluidic system in point of care devices involve filters that are solid state extraction filters used to capture and/or concentrate nucleic acids prior to further downstream processing such as amplification by polymerase chain reaction. The method uses the induction of negative pressure with respect to atmospheric pressure to improve the efficiency of the ethanol removal process.

Core Innovation

The invention relates to a microfluidic device with a fluidic channel that includes a filter positioned within a sealable portion of the fluidic channel. A valve releasably seals the sealable portion that contains the filter therein, and the filter divides the sealable portion into a first volume between the valve and the filter and a second volume between the displacement pump and the valve.

A displacement pump in the sealable portion is configured to displace a volume greater than a volume of the sealable portion and to reduce a pressure in the sealable portion containing the filter. The displacement pump is configured to substantially simultaneously draw fluid through or over the filter while reducing the pressure in the sealable portion containing the filter, with the first volume smaller than the second volume and the volume of the fluidic channel downstream of the valve larger than the volume of the sealable portion.

The device architecture supports nucleic-acid purification using a solid phase extraction filter, where ethanol acts as a PCR inhibitor. Ethanol present on the filter is removed by inducing negative gauge pressure below atmospheric pressure in a sealed channel portion, with drying further improved by heating the filter, and nucleic acids are eluted and routed to an amplification zone for polymerase chain reaction (PCR).

Claims Coverage

The independent claim coverage centers on a microfluidic device geometry and pressure-drawing arrangement using a valve-sealed filter-containing portion and a displacement pump configured to reduce pressure while simultaneously drawing fluid through or over the filter, with three inventive features.

The claim coverage centers on a valve-sealed, filter-containing sealable portion with defined first and second volumes, a displacement pump that reduces pressure while substantially simultaneously drawing fluid through or over the filter, and a larger downstream volume relative to the sealed portion.

Stated Advantages

Documented Applications