Control of cell concentration

An apparatus for controlling a cell concentration of a biologic sample, comprising:

• a fluidic input to receive the biologic sample containing cells;
• a die including a microfluidic chamber, wherein the microfluidic chamber includes:
• a foyer in fluidic contact with a reservoir containing the biological sample, the foyer having a defined chamber structure configured to contain a portion of the biologic sample;
• an inlet impedance-based sensor having a pair of electrodes positioned proximate the foyer and the reservoir and configured to detect passage of a cell of the biologic sample into the foyer;
• a target nozzle having a defined aperture in fluidic contact with the foyer and configured to eject a first volume of the portion of the biologic sample into a target location, the first volume corresponding with a target concentration of cells of the biologic sample;
• a spittoon nozzle having a defined aperture in fluidic contact with the foyer and configured to eject a second volume of the portion of the biologic sample into a spittoon location;
• and
• a first output impedance-based sensor having a pair of electrodes positioned proximate the foyer, disposed within a threshold distance of 5-100 micrometers of the target nozzle, and configured to detect passage of a cell of the biologic sample into the target nozzle;
• and
• circuitry comprising a processor and a non-transitory computer-readable medium storing instructions thereon that, when executed by the processor, cause the processor to:
• responsive to detecting passage of a cell into the foyer by the inlet impedance-based sensor, switch from firing the spittoon nozzle to firing the target nozzle to draw the cell from the foyer through the target nozzle;
• and
• responsive to detecting passage of the cell into the target nozzle by the first output impedance-based sensor, switch from firing the target nozzle to firing the spittoon nozzle,
• to selectively concentrate the cells of the biologic sample in the target location.