Saitama, Japan
Saitama, Japan

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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.


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.


Ueda H.,Osaka University | Agatsuma K.,Waseda University | Agatsuma K.,Japan National Institute of Advanced Industrial Science and Technology | Furuse M.,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 or immunoglobulin are important as medicine for cancer and other uses. Today, we can easily sort and analyze medical proteins using various types of commercially available affinity magnetic beads. However, separation systems for these medical proteins have a very low separation rate, and the cost of the product is extremely high. We successfully developed a high gradient magnetic separation system using a cryocooler-cooled low-temperature superconducting magnet and conducted experiments on separating affinity magnetic nanobeads. Our system demonstrated very high separation efficiency and can achieve low costs with a large production rate compared to systems now used in this field. The design of a filter to trap and recover the nanobeads is important to this application. In order to achieve a filter with a high trapping ratio of magnetic beads, the parameters need to be optimized because the ratio depends on the dimensions and arrangement of the filter made of fine magnetic metal fibers. In this study, we investigated the performance of filters in the high gradientmagnetic separation system. The test results show 97.8% of the magnetic nanobeads in pure water were captured, and 94.1% of the total beads were collected. © 2013 IEEE.

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