Magnetic probe with ferrite couples to bioligands for diagnostic and clinical uses

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1. Development of novel medical ferrite Nano-BeadsWe established the technique to immobilize physiologically active molecules onto the surfaces of ferrite (Fe_3O_<4+8>) nano beads (10-15 run in diameter) during the beads are synthesized from an aqueous solution. We prepared medical magnetic nano beads on the surfaces of which we strongly immobilized such physiologically active molecules as Trypsin FITC-avidin, anti-cancer drugs, glycidyl methacrylate (GMA), amino acids (e.g. aspartic acid) and similar-strusture molecules, polyacryl amino acid, etc.2. We revealed that in the above-mentioned fenite nano beads the physiologically active molecules are strongly couples to ferrite intermediated by S-H and COOH groups of the amino acids or similar-structure molecules contained in the physiologically active molecules. We named the intermediating amino acids (and similar structured molecules) connectors. Also we called the medical nano beads (with physiologically active molecules coupled to the … More surfaces intermediated by the connectors) "Connectors-Bonded Magnetic (CBM)" nano beads. Furthermore, we developed CBM nano beads having surfaces coated with (1)connectors and (2)polymers exhibiting low sensitivity to non-specific absorption of physiologically active molecules ; on their surfaces we can easily immobilize physiologically active molecules by biochemical technique.3. Preparation of human-type antibody and novel ferrite bioprobesWe have prepared human-type IGG antibody to human colon cancer cells by replacing the constant region of mouse monoclonal IGG antibody with that of human IGG antibody. The human-type IGG antibody fixed on the ferrite beads selectively reacted with the antigens present on human colon cancer cell membrane, which were visualized by staining with anti-IGG antibody conjugated with fluorescence. This shows that die IGG antibody-fixed ferrite beads are utilized for detection of cancer as diagnostic magnetic bioprobes.4. Power absorption rate of ferrite nano beads for hyperthermiaWe found that the fenite nano beads prepared in this study have specific power absorption rate for AC magnetic field induction 1.4 times higher than that of conventional ferrite beads. This indicates that our ferrite nano beads are advantageous for applying to hyperthermia. Less