Device and method for improving sample injection and stacking
Inventors
Assignees
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Publication Number
US-8834807-B2
Publication Date
2014-09-16
Expiration Date
Abstract
The invention provides devices and methods for isolating one or more sample components of a sample material following separation of the sample material into a plurality of sample components. A device includes a separation channel having a sample loading well. A low-conductivity buffer is disposed in the loading well, the buffer having a conductivity<0.2 mS/cm. In a method, a buffer is loaded into a loading well in fluid communication with a separation channel of a device. A sample material having a conductivity higher than that of the buffer is then loaded into the loading well such that the sample material is disposed beneath the buffer, the buffer disposed over and covering the sample material. The sample material is separated into a plurality of separated components in the separation channel, and a separated component is collected from a collection well disposed in a collection leg of the device.
Core Innovation
The invention relates to a microfluidic device/system for isolating one or more sample components following separation of a sample material into a plurality of sample components. A separation channel forms a stream of separated components, which passes into a switching region connected to a collection leg and a waste leg. The device includes a loading well disposed in the separation channel and a collection well disposed in the collection leg, supporting isolation and diversion of selected separated components.
The approach uses a low-conductivity stacking buffer loaded into the loading well and disposed over and covering the sample material such that the sample material is disposed beneath the buffer. The sample material has a conductivity higher than the first conductivity, with the buffer covering and confining the sample at the bottom of the loading well. By transporting buffer streams and the separated-component stream through the switching region, the buffer streams constrain and elongate the stream as it passes through the switching region.
In the switching region, first and second buffer streams are directed so that portions exit into the waste leg and the collection leg, while portions of the separated-component stream are directed into waste and collection. The device architecture includes pinching channels whose axes are arranged relative to the separation channel axis, and in one embodiment the switching region cross-sectional dimension is less than that of the separation channel. This constrains the component stream through the switching region to improve cut precision and to support isolation of separated components at the collection well.
Claims Coverage
The independent claims in the provided content are clm-00001, clm-00011, and clm-00019. Collectively, they define three main inventive features: a device architecture with separation channel, loading well, switching region, collection leg/well, and waste leg arranged with pinching channels; a method that uses a low-conductivity stacking buffer over the sample to confine the sample and uses first and second buffer streams to constrain and elongate the separated-component stream in the switching region; and a device variant requiring axis relationships and a switching-region cross-sectional dimension smaller than the separation channel, configured to constrain and elongate streams.
Device architecture for isolating separated components
A device for isolating one or more sample components after separation in a separation channel, including a loading well in the separation channel, a collection leg with a collection well, a waste leg, and a switching region with first and second pinching channels whose connection portion axes are arranged relative to the separation channel axis, with fluid communication between channel ends and the switching region inlet, and with the switching region outlet feeding the collection leg and waste leg.
Buffer-covered sample loading with conductivity-based stacking
A method that loads a buffer into a loading well in fluid communication with a separation channel, loads a sample material into the loading well so the sample material is disposed beneath the buffer with the buffer disposed over and covering the sample material, and separates the sample material into separated components forming a stream, where the sample material has a second conductivity higher than the first conductivity.
Constraining and elongating the component stream in the switching region
A method that transports the stream of separated components into a switching region and transports first and second buffer streams into the switching region on either side of the stream such that the first and second buffer streams constrain and elongate the stream as it is transported through the switching region, then directs portions of the buffer streams and portions of the stream of separated components out of the switching region into waste and collection legs to collect a separated component from a collection well.
Axis- and dimension-constrained switching-region device variant
A device for isolating one or more sample components that includes first and second pinching channels, a separation channel positioned between the pinching channels, and a switching region having a cross-sectional dimension less than the cross-sectional dimension of the separation channel, where the second ends of the pinching channels and separation channel are in fluid communication with the switching region inlet, the separation channel axis is perpendicular to each pinching-channel axis, and the pinching-channel axes are collinear.
Across the independent claims, the coverage centers on isolating selected separated components using a defined device layout with pinching-channel axis relationships, and on using a conductivity-contrasting buffer over the sample to form separated-component streams that are constrained and elongated in the switching region before directing portions into collection versus waste.
Stated Advantages
Improves cut precision of the separated-component isolation by constraining and elongating the component stream through the switching region.
Noted effects include improvements related to DNA separation resolution and changes in injection, meniscus, and wicking behavior.
Documented Applications
Isolating separated components in microfluidic devices, including embodiments discussed in the context of DNA separation resolution.
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