Highly sensitive spin-valve devices for chip-cytometers

The highly sensitive spin-valve devices integrated with a microfluidic channel have been studied for cell counting in a chip-cytometer. The presence or absence of a single magnetic bead was successfully detected by direct measurement of fringe fields emanating from magnetic beads using spin-valve devices. The real-time detection was also successfully con-firmed by the direct measurement of magnetic fields generated from the magnetic beads passing an active sensing area of a spin-valve device integrated with a microfluidic channel. Our results show the possibility of implementing a chipcytometer for biological applications using the highly sensitive spin-valve devices integrated with a microfluidic device.