An integrated system of RBCs sorting and Brownian motion bio-sensing technique

A clinical sorting chip integrated with new protein sensing technique has been developed in this work. Antibody-coated nanobeads reacted with antigen was separated from blood plasma based on dielectrophoresis (DEP) forces. MEMS fabrication process was used to produce the bio-chip and only two photo masks were required in the experiment. By using oxygen-plasma direct bonding method, the assembly of an electrode chip and the microchannels will form a set of RBCs and nanobeads separating chip. The original concentration of antigen can be rapidly estimated by nanobeads´ Brownian motion measurement in varies of the viscous solutions. During the antibody-antigen reacting, the mean value of the beads diameter increased so that the Brownian velocity decreased with increasing time. The Brownian motion of nanobeads was observed and measured by micro-particle tracking velocimetry (μ-PTV).