Aptamer Loaded Superparamagnetic Beads For Selective Capturing And Gentle Release of Activated Protein C

Activated protein C (APC) is a serine protease with anticoagulant and cytoprotective activities which make it an attractive target for diagnostic and therapeutic applications. In this work, we present one-step activation of APC from a commercial source of protein C (PC, Ceprotin®) followed by rapid and efficient purification using the APC-specific aptamer HS02-52G loaded on MyOne superparamagnetic beads. Due to the Ca 2+ -dependent binding of APC to HS02-52G, an efficient capturing of APC was applied in the presence of Ca 2+ ions, while a gentle release of captured APC was achieved in the elution buffer containing low EDTA concentration (5 mM). The captured and eluted APC showed more than 95% purity according to an enzyme-linked fluorescent assay (VIDAS® Protein C). The purification yield of 45% was calculated when 4.2 µg APC was used, however this yield reduced to 21% if the starting amount of PC increased to 28.5 µg. Altogether, this method is recommended for rapid and efficient PC activation and APC purification. The purified APC can be used directly for downstream processes where high concentration of pure and active APC is needed.