**4.3 Synthesis and characterization of magnetized Dacron-heparin composite employed for antithrombin affinity purification**

The focus of this work was to produce a Dacron magnetic composite with heparin (mDAC-HEP) for the use in the purification of antithrombin from human plasma [21]. To obtain mDAC-HEP, heparin was activated by carbodiimide and N-hydroxysuccinimide, allowing covalent attachment. Purified antithrombin was released from the magnetic bio-derivative using solutions with increasing ionic strength (NaCl). The affinity properties of mDAC-HEP after 2 years of storage were preserved, and the magnetic bio-derivative was able to be reused for at least tenfold. The presence of the expected antithrombin size (58 kDa) was revealed in the bands by electrophoresis of the eluates. The composite synthesis was considered easy, low-cost, magnet-based affinity purification steps, and reusable.
