Density gradient formation with sample particles

A system for dispensing a density gradient in a container, the system comprising:

• a processing circuitry having a memory for storing instructions which, when executed by the processing circuitry, cause the processing circuitry to:
• pump sample particles and a density modifier into a mixing chamber in fluid communication with a proximal end of a probe, the mixing chamber mixing the sample particles and the density modifier together;
• and
• dispense the density gradient through a distal end of the probe into the container, the density gradient varying in density between first and second ends, at least a portion of the density gradient between the first and second ends includes a dispensed volume of the sample particles.