  A new type of microfluidic system for biological cell manipulation, a
CMOS/microfluidic hybrid, is demonstrated. The hybrid system starts with a
custom-designed CMOS (complementary metal-oxide semiconductor) chip fabricated
in a semiconductor foundry using standard integration circuit technology. A
microfluidic channel is post-fabricated on top of the CMOS chip to provide
biocompatible environment. The motion of individual biological cells that are
tagged with magnetic beads is directly controlled by the CMOS chip that
generates localized magnetic filed patterns using an on-chip array of
micro-electromagnets. The speed and the programmability of the CMOS chip
further allow for the dynamic reconfiguration of the magnetic fields,
substantially increasing the manipulation capability of the hybrid system. The
concept of a hybrid system is verified by simultaneously manipulating
individual biological cells with microscopic resolution. A new operation
protocol that exploits the fast speed of electronics to trap and move a large
number of cells with less power consumption is also demonstrated. Combining the
advantages of microelectronics, the CMOS/microfluidic hybrid approach presents
a new model for a multifunctional lab-on-a chip for biological and medical
applications.
