Cell concentration devices and methods including a syringe and a syringe holder

A system for separating components of different densities from a fluid containing cells using a centrifuge, the system comprising:

• a syringe having a top, a sidewall extending from the top forming a syringe tube, and a plunger slidably disposed inside the syringe tube and in sealing engagement with the sidewall, the sidewall being substantially straight from the top to a distal end of the syringe tube, the distal end of the syringe tube including an opening, the syringe defining a cavity for receiving the fluid containing cells;
• a Luer port disposed in the top of the syringe to transfer the fluid containing cells into the syringe and to extract one or more separated layers containing cells from the syringe;
• and
• a syringe holder at least partially closing the opening of the distal end of the syringe tube, the syringe holder not connected to the plunger inside the syringe tube,
• the syringe and syringe holder configured for placement in a centrifuge and for exposure of the syringe and syringe holder to elevated g force in the centrifuge, the elevated g force urging the plunger toward the syringe holder, wherein the syringe holder is in physical contact with the syringe tube on the distal end and includes a surface arranged to contact the plunger at a bottom perimeter of the plunger during centrifugation, to provide support and maintain the sealing engagement of the plunger with the sidewall of the syringe tube, to prevent fluid from leaking outside the syringe.