1. Bio-sensor G. Reiss, et al. Univ. of Bielefeld Magnetic wireless actuator for medical applications K. Ishiyama, et al. Research Institute of Electrical Communication,Tohoku University Lecture 6

2. Increased sensitivity by lock-in technique, uncovered references, layout-Optimization possible: single molecule detection Signal prop. Number of Beads R H Vertical magnetic field induces dipol field of bead Detection by GMR / TMR Sensor Special applications : - Bio-Chip

3. GMR (Giant MagnetoResistance) TMR (Tunnel MagnetoResistance)  detection of single beads / molecules Fixed DNA single strand XMR Sensor 1) Immobilisation of target molecules Si- Substrate Haftschicht S magnetic bead, coated with Streptavidin, binds to a selected molecule N 3) Hybridisation with beads and detection with XMR sensor XMR sensor detects stray field hybridized DNA 2) Hybridisation of the probe molecules Biotin Detection: Magnetoresistive biochip sensor IEEE Trans. Magn., (2002), ICM’03

4. Biochip for DNA analysis Loading of the chip with single stranded DNA molecules Hybridization with 5'- biotinylated, single stranded DNA or RNA probes Addition of magnetic beads, coated with Streptavidin, binding to Biotin Detection of the beads with XMR sensor 1 2 3 4 Detection: GMR sensor Specific binding of DNA 20 µm negative probe (100 ng/µl salmon sperm) positive probe (10 ng/µl PCR)

5. Special applications 0° 90° 0° 90° Characteristic Design Tunnelelement I oben I unten U oben U unten -50-40-30-20-10010203040 50 0 2 4 6 8 10 12 14 16 18 20 22 TMR-Amplitude in % Feld in Oe GMR TMR

6. 77 µV102 µV267 µV284 µV557 µV Signal Sensor coverage 1) 5 %2) 6 %3) 20 %4) 23 %5) 40 % Ref 1 - Sensor 3 Ref 1 - Ref 2 DC-measurements with Bangs 0.8 µm-beads mit beads ohne beads

7. DC-measurements with Bangs 0.8 µm-beads J. Schotter, P.B. Kamp, A. Becker, A. Pühler, D. Brinkmann, W. Schepper, H. Brückl, G. Reiss: A Biochip based on Magnetoresistive Sensors, IEEE Trans. Magnet., 2002

8. TMR = Tunneling MagnetoResistance 5 nm hard magnetic layer sense layer MnIr CoFe Al 2 O 3 NiFe DC-measurement, Bangs 0.8 µm Beads parallel Bias-Field of -6.4 Oe -100-80-60-40-20020406080100 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 TMR Amplitude (%) perpendicular field (Oe) ~5 % coverage 50 µm TMR Biochip Sensor: 2x2 µm 2 elements T=300K T=10K Detection: TMR sensor

9. Advantages of MAGNETIC micro-machine Wireless operation Simple structure Ways to supply energy –F = M (dH/dx) →T = M H sin  –Magnetostriction –V = d  /dt K.I.Arai, W.Sugawara, K.Ishiyama, T.Honda, M.Yamaguchi, “Fabrication of Small Flying Machines Using Magnetic Thin Films,” IEEE Trans. Mag., vol.31, No.6, pp.3758-3760 (1995). Flying machine

10. 0 Oe 150 Oe 300 Oe Bending by DC magnetic field Rotation by rotating magnetic field Two principles to move

11. Lower invasive surgery What is the challenge to obtain the medical robots? →Wireless energy supply

12. Spiral-type Magnetic Micro-Machine Rotational magnetic field Thrust (swimming direction) Magnetization

13. Controlling the swimming direction STARTGOAL STARTGOAL Field rotation plane

14. 3D coil-system and controller

15. Very small machine: 0.3mm 

16. Synchronized swimming of small machine (0.3mm  )

17. Miniaturization of the machine Tungsten wire : 20  m  Machine diameter : 0.15mm NdFeB : sputtered

18. Burrowing Machine Driven by Magnetic Torque Rotational Magnetic Field: 150 Oe, 5 Hz The machine can burrow into organismal tissue. Machine