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Tsurugashima, Japan

Fuchino S.,Japan National Institute of Advanced Industrial Science and Technology | Furuse M.,Japan National Institute of Advanced Industrial Science and Technology | Agatsuma K.,Waseda University | Agatsuma K.,Japan National Institute of Advanced Industrial Science and Technology | And 5 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2014

Medical proteins such as monoclonal antibodies and immunoglobulins are important substances for the manufacture of medicines for cancer, etc. However, the conventional separation system for these medical proteins has very low separation rate and the cost is extremely high. To address these issues, we have developed a high gradient magnetic separation system for medical proteins using affinity magnetic nanobeads. Our system shows very high separation efficiency and can achieve low cost owing to its large production rate compared with conventional systems. The system consists of a 3T superconducting magnet cooled by a cryocooler, a filter made of fine magnetic metal fibers of about 30 μm in diameter with demagnetization circuit and liquid circulation pump for the solvent containing the medical proteins. Reducing the size of the system entails reduction of the cryocooler size, thereby resulting in reduced cooling capacity. Therefore, the heat load on the cryocooler has been considered carefully in the design of the cryogenic system. The calculated heat load of the 1st and 2nd stages was made to satisfy the cooling capacity of the cryocooler. As a result, a magnet temperature of 4.2 K and a thermal shield temperature of 60 K have been achieved, enabling smooth operation and good performance of the HGMS separation system. © 2002-2011 IEEE. Source


Kajikawa K.,Kyushu University | Ueda H.,Osaka University | Kamioka Y.,NETS Corporation | Agatsuma K.,Waseda University | And 4 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2014

We have successfully developed a high-gradient magnetic separation system for medical proteins using affinity magnetic nanobeads. Our system shows very high separation efficiency and can also be expected to realize lower cost due to larger production rate compared to the conventional system. The developed system consists of a 3-T superconducting magnet and a filter made of fine magnetic metal fibers. The superconducting magnet is wound with a NbTi twisted multifilamentary wire, and cooled by a 4-K Gifford-McMahon cryocooler. In order to achieve high recovery ratio of the magnetic nanobeads trapped on the filter located in a room-temperature clear bore of the cryostat, the ac degaussing system for the filter is fabricated using an inductance-capacitance resonance circuit composed of a series connection with the superconducting magnet and an additional capacitor. To perform the inductance-capacitance resonance more than a few cycles between superconducting magnet and capacitor, the superconducting magnet has a slit in the bobbin to prevent an eddy current coupled with an alternating magnetic field. It also has a control system for a high-speed switching circuit. This magnet can successfully generate a magnetic field of 3.0 T in the clear bore of the cryostat with a diameter of 30 mm in a relatively fast sweep time of 150 s due to the slit in the magnet bobbin. Using our degaussing system, a high recovery ratio of the nanobeads in pure water has been performed about 94.1%. © 2002-2011 IEEE. Source

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