Erythrocyte aggregation and leukocyte isolation
A device and/or methodology are described that include a mechanism for separating erythrocytes from other constituents of blood and for purifying leukocytes from blood. The separation and purification aspects may be provided in separate components or within the same component. The separation aspect assists in separating erythrocytes (red blood cells) from other cells in blood, such as by aggregation of the red blood cells. A suitable aggregation device or device component uses chambers with at least one small dimension (e.g., a microfluidic chip) to control the interaction of the blood with a solution containing a high molecular weight polymer (e.g., dextran) to achieve separation.
1. A multi-layer microfluidic device, comprising:
one or more loading wells accessible on a first surface of the multi-layer microfluidic device, wherein each of the one or more loading wells comprises a loading well outlet;
a longitudinal axis along a direction from a first layer of the multi-layer microfluidic device to a second layer of the multi-layer microfluidic device;
vertical aggregation channels, wherein each vertical aggregation channel comprises an aggregation channel inlet and an aggregation channel outlet, wherein each vertical aggregation channel is in continuous fluid communication with a respective loading well of the one or more loading wells via the aggregation channel inlet of the vertical aggregation channel coupled to the loading well outlet of the respective loading well at a first longitudinal position along the longitudinal axis;
at least one separate, respective output channel comprising an output channel inlet and an output channel outlet, wherein each aggregation channel of the aggregation channels is in continuous fluid communication with the at least one separate, respective output channel via the aggregation channel outlet of the vertical aggregation channels coupled to the output channel inlet of the output channel at a second longitudinal position along the longitudinal axis, wherein the second longitudinal position is downstream of the first longitudinal position relative to the longitudinal axis, wherein an inner diameter of each aggregation channel tapers towards the second longitudinal position, wherein each diameter of the output channel is substantially perpendicular to the longitudinal axis, wherein at least one diameter of the output channel is less than or equal to 450 μm, and wherein the aggregation channels are disposed on the first layer of the multi-layer microfluidic device;
at least one capture channel comprising a capture channel inlet, wherein the at least one capture channel is configured to receive an output fluid from the output channel of one or more of the aggregation channels when in use via the output channel outlet of the output channel and the capture channel inlet of the capture channel at a third longitudinal position along the longitudinal axis, wherein the third longitudinal position is downstream of the second longitudinal position relative to the longitudinal axis, and comprising an antibody coated surface configured to selectively bind at least one type of blood cell in the output fluid, wherein the at least one capture channel is downstream of the aggregation channels in the multi-layer microfluidic device, wherein a longest dimension of the at least one capture channel is substantially perpendicular to the longitudinal axis and is crosswise to a longest dimension of the aggregation channel that is substantially parallel to the longitudinal axis, wherein the at least one capture channel is disposed on the second layer of the multi-layer microfluidic device;
one or more reagent wells disposed adjacent to the one or more loading wells and having an opening at the first surface of the multi-layered microfluidic device, wherein the one or more reagent wells is fluidly coupled to the at least one capture channel and configured to hold reagents for treating or analyzing cells captured by the at least one capture channel; and
a valve positioned between the at least one capture channel and the one or more aggregation channels.
2. The multi-layer microfluidic device of claim 1 , further comprising: one or more microvalves.
3. The multi-layer microfluidic device of claim 1 , wherein the valve comprises a microvalve.
4. The multi-layer microfluidic device of claim 1 , wherein each aggregation channel of the aggregation channels has at least one dimension perpendicular to the longitudinal axis that is less than or equal to 225 μm.
5. The multi-layer microfluidic device of claim 1 , wherein the respective aggregation channels are proportioned so as to generate a surface tension between a blood sample and a solution of a high-molecular weight polysaccharide, when present, sufficient to stabilize the blood sample over the solution within the aggregation channels, wherein the blood sample is higher density than the solution.
6. The multi-layer microfluidic device of claim 1 , wherein the diameter of the output channel of each aggregation channel of the aggregation channels that is less than or equal to 450 μm is perpendicular to the longitudinal axis.
7. The multi-layer microfluidic device of claim 1 , wherein a dimension of the aggregation channels is variable along the longest dimension that is substantially parallel to the longitudinal axis.
8. The multi-layer microfluidic device of claim 1 , wherein the one or more loading wells comprise an inlet opening on the first surface, and wherein the inlet opening is smaller than the opening of the one or more reagent wells.