Please refer to the product data sheet (accessible through the QR code on your vial or through visiting mysartorius.com → certificates) for the resuspension solution recommendation for your growth factor or cytokine and centrifuge briefly before reconstituting to make sure that all of the powder is at the bottom of the vial. Add the reconstitution solution to give a protein concentration of 0.5-1mg/ml. Leave to stand for 1 minute before gently agitating – do not vortex as this will make the solution foam which must be avoided. You can prepare stock aliquots or single use vials from the master mix.