A method of separating a PRP fraction from a sample of whole blood in a collection tube including a polymerizable separator substance, wherein the polymerizable separator substance is flowable with the whole blood, has a first average molecular weight, and has a density between an average density of a PRP fraction and an average density of a non-PRP fraction, wherein the separator substance comprises an oligomer, a photoinitiator and a stabilizer, the method comprising: centrifuging the sample of whole blood in the collection tube including the polymerizable separator substance, for a period of between one and thirty minutes at between 500 and 5000 RPM; wherein centrifuging causes the polymerizable separator substance to flow between the PRP fraction and the non-PRP fraction without substantial activation of platelets in the PRP fraction, wherein substantial activation is measurable based on the ability of platelets in the PRP fraction to aggregate to at least one of Ristocetin and Collagen; hardening the separator substance, via exposure to a UV energy for a period of less than ten minutes, to form a solid barrier, wherein the polymerizable separator substance of the solid barrier has a second average molecular weight that is greater than the first average molecular weight, wherein the solid barrier, after exposure to the UV energy, is stationary with respect to the collection tube and at an intermediate position below the PRP fraction and above the non-PRP fraction that allows removal of at least 95% of the PRP fraction from the collection tube; and drawing up the PRP fraction, in a closed process that maintains sterility of the PRP fraction, from the collection tube to a fluid dispenser using a transfer needle that contacts the PRP fraction and a first end of the fluid dispenser simultaneously, wherein the fluid dispenser comprises a second end distinct from the first end, the second end configured to dispense the PRP fraction. centrifuging the sample of whole blood in the collection tube including the polymerizable separator substance, for a period of between one and thirty minutes at between 500 and 5000 RPM; wherein centrifuging causes the polymerizable separator substance to flow between the PRP fraction and the non-PRP fraction without substantial activation of platelets in the PRP fraction, wherein substantial activation is measurable based on the ability of platelets in the PRP fraction to aggregate to at least one of Ristocetin and Collagen; hardening the separator substance, via exposure to a UV energy for a period of less than ten minutes, to form a solid barrier, wherein the polymerizable separator substance of the solid barrier has a second average molecular weight that is greater than the first average molecular weight, wherein the solid barrier, after exposure to the UV energy, is stationary with respect to the collection tube and at an intermediate position below the PRP fraction and above the non-PRP fraction that allows removal of at least 95% of the PRP fraction from the collection tube; and drawing up the PRP fraction, in a closed process that maintains sterility of the PRP fraction, from the collection tube to a fluid dispenser using a transfer needle that contacts the PRP fraction and a first end of the fluid dispenser simultaneously, wherein the fluid dispenser comprises a second end distinct from the first end, the second end configured to dispense the PRP fraction.