Method and device for isolating cells from heterogeneous solution using microfluidic trapping vortices

A method of exchanging solution around isolated cells comprising:

• providing a microfluidic device having at least one microfluidic channel coupled to an inlet and an outlet, the at least one microfluidic channel comprising at least one expansion region disposed along the length thereof, the at least one expansion region comprising an abrupt increase in a cross-sectional dimension of the at least one microfluidic channel configured to generate a vortex within the at least one expansion region in response to fluid flow;
• flowing a first solution containing a population of cells into the inlet;
• trapping at least a portion of the cells within the vortex created within the at least one expansion region;
• and
• flowing one or more solutions different from the first solution into the inlet while continuously maintaining the vortex containing the trapped cells.

A method of trapping particles or cells by size comprising:

• providing a microfluidic device having at least one microfluidic channel coupled to an inlet and an outlet, the at least one microfluidic channel comprising at least one expansion region disposed along the length thereof, the at least one expansion region comprising an abrupt increase in a cross-sectional dimension of the at least one microfluidic channel configured to generate a vortex within the at least one expansion region in response to fluid flow;
• flowing a solution containing a plurality cells or particles into the inlet;
• and
• trapping at least some of the cells or particles within the vortex created within the at least one expansion region, wherein the cells or particles having a size above threshold value are substantially trapped within the vortex and wherein cells or particles having a size below a threshold value substantially pass by the vortex.

A microfluidic system comprising:

• a substrate containing at least one microfluidic channel coupled to at least one inlet and an outlet, the at least one microfluidic channel comprising at least one expansion region disposed along the length of the at least one microfluidic channel, the at least one expansion region comprising an abrupt increase in a cross-sectional dimension of the at least one microfluidic channel configured to generate a vortex within the at least one expansion region in response to fluid flow;
• at least one pump configured to pump fluid into the at least one inlet containing particles or cells;
• and
• a computer operatively coupled to the at least one pump and configured to adjust the flow rate of fluid passing through the at least one microfluidic channel.