Microfluidic device and analyzing device using the same

Abstract

The conventional micropump and the conventional micromixer have the following problems. In a mechanical or hydrodynamic method, the structure of the inside of a flow path is complex so as to easily cause clogging, and manufacturing cost is high, and dead volume is large. Additionally, in an electrical method, the conventional micropump or the conventional micromixer was incapable of operating with a liquid having the concentration of a physiological saline that is important in the medical or biological field although the structure of the flow path is simple. These problems are solved by applying an AC voltage to a pair of electrodes in which an electrode-to-electrode gap between the pair of electrodes is vertically arranged and by generating the flow of a fluid in the direction opposite to gravity along the electrode-to-electrode gap. A micropump ( 43, 44 ) can be realized especially by forming a micro-sized flow path ( 11 ) in the vertical direction along the electrode-to-electrode gap, and a micromixer ( 41 ) can be realized by forming a micro-sized flow path ( 11 ) in the horizontal direction to cross at right angle to the electrode-to-electrode gap.

1 . A microfluidic device comprising:
 a first substrate and a second substrate that are disposed to face each other with a fluid between the first and second substrates; and   a pair of electrodes disposed to face each other on a surface of the first substrate, the fluid being in contact with the surface;   wherein an electrode-to-electrode gap between the pair of electrodes is directed in a vertical direction, and   wherein the fluid flows in a direction opposite to gravity along the electrode-to-electrode gap by applying an AC voltage to the pair of electrodes.   
   
   
       2 . The microfluidic device of  claim 1 , wherein a micro-sized flow path is formed that is in contact with the pair of electrodes and that moves the fluid in a vertical direction. 
   
   
       3 . The microfluidic device of  claim 1 , wherein a micro-sized flow path is formed that is in contact with the pair of electrodes and that moves the fluid in a horizontal direction. 
   
   
       4 . The microfluidic device of  claim 1 , wherein the fluid flows in circle between the first substrate and the second substrate. 
   
   
       5 . An analytical instrument using the microfluidic device of  claim 1 . 
   
   
       6 . A microfluidic device comprising:
 a first substrate and a second substrate that are disposed to face each other with a fluid between the first and second substrates; and   a pair of electrodes disposed to face each other on a surface of the first substrate, the fluid being in contact with the surface;   wherein an electrode-to-electrode gap between the pair of electrodes is directed diagonally to a vertical direction, and   wherein the fluid flows diagonally in a direction opposite to gravity along the electrode-to-electrode gap by applying an AC voltage to the pair of electrodes.   
   
   
       7 . The microfluidic device of  claim 6 , wherein the pair of electrodes is a first pair of electrodes in which the electrode-to-electrode gap is directed in a vertical direction, a second pair of electrodes in which the electrode-to-electrode gap is directed diagonally with respect to the vertical direction, and a third pair of electrodes in which the electrode-to-electrode gap is directed diagonally symmetrically to the electrode-to-electrode gap of the second pair of electrodes with respect to the vertical direction, and
 wherein ends of the three pairs of electrodes are disposed to be adjacent to each other so as to have a trifurcate structure.