A Cmos Microsystem Combining Magnetic Actuation and In-Situ Optical Detection of Microparticles

Abstract

We present a CMOS-based hybrid microfluidic system that combines the manipulation of magnetic microparticles through a magnetic field with <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in</i> <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">situ</i> optical detection via single photon avalanche diodes (SPADs). Magnetic particles are actuated within a glass micro-capillary and are detected upon passage over the SPAD, where they block incident light and thus lower the photon count. The optical sensors, which are <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">not</i> influenced by the magnetic actuation forces, allow detecting the presence of magnetic particles of 30, 5 and 1 μm diameter, while being able to distinguish between different sizes.