Microchip and channel structure for the same

Abstract

A microchip includes a channel permitting a sheath liquid to flow therethrough; and a microtube for introducing a sample liquid into a laminar flow of the sheath liquid flowing through the channel; wherein liquid feeding is performed in the condition where a laminar flow of the sample liquid introduced through the microtube is surrounded by the laminar flow of the sheath liquid.

1 . A microchip comprising:
 a channel permitting a sheath liquid to flow therethrough; and   a microtube configured to introduce a sample liquid into a laminar flow of said sheath liquid flowing through said channel;   wherein liquid feeding is performed in a condition where a laminar flow of said sample liquid introduced through said microtube is surrounded by said laminar flow of said sheath liquid.   
     
     
         2 . The microchip according to  claim 1 , wherein said channel has a narrow-down section in which an area thereof in a section orthogonal to the liquid feed direction decreases gradually or stepwise along the liquid feed direction; and
 said sheath liquid laminar flow and said sample liquid laminar flow are made to pass while the laminar flow widths of said laminar flows are narrowed down in said narrow-down section.   
     
     
         3 . The microchip according to  claim 2 , wherein said narrow-down section has a configuration in which one of a channel bottom surface and a channel upper surface is formed as an inclined surface so that said sheath liquid laminar flow and said sample liquid laminar flow are made to pass while being deflected toward the upper side or the lower side of the microchip and being narrowed down. 
     
     
         4 . The microchip according to  claim 3 , wherein said microtube is formed from a metal permitting a voltage to be impressed thereon, and an electric charge can be imparted to said sample liquid flowing inside said microtube. 
     
     
         5 . The microchip according to  claim 4 , further comprising branch channels which branch from said channel on the downstream side of said narrow-down section of said channel;
 wherein the flow direction, at a branching section of said branch channels, of said sample liquid given said electric charge can be controlled by electrodes disposed at said branching section.   
     
     
         6 . The microchip according to  claim 5 , further comprising a fluid introduction section which joins said channel on the upstream side of said branching section from at least one lateral side and through which either fluid of a gas and an insulating liquid is introduced into said channel; and
 said sheath liquid laminar flow and said sample liquid laminar flow passing through said channel are made to pass while being split into droplets by said fluid introduced via said fluid introduction section.   
     
     
         7 . The microchip according to  claim 5 , further comprising a piezoelectric element capable of giving a pressure difference to said sample liquid flowing through said microtube, and said sample liquid is introduced in a dropletized state into said sheath liquid laminar flow passing through said channel. 
     
     
         8 . The microchip according to  claim 5 , the flow direction at said branching section of said sample liquid which contains particulates and which has been dropletized and given said electric charge is controlled, whereby fractionation of said particulates can be performed. 
     
     
         9 . The microchip according to  claim 1 , wherein a plurality of said microtubes are arranged in a bundled state, and said sample liquid is introduced through at least one of said microtubes. 
     
     
         10 . The microchip according to  claim 2 , wherein said narrow-down section has a configuration in which a channel bottom surface and a channel upper surface are formed as inclined surfaces. 
     
     
         11 . The microchip according to  claim 2 , wherein said narrow-down section has a configuration in which at least one of a bottom surface and an upper surface of the channel thereof is formed in a stairway-like shape. 
     
     
         12 . The microchip according to  claim 2 , wherein said narrow-down section further has a channel side wall for gradual or stepwise constriction along the liquid flow direction. 
     
     
         13 . A channel structure comprising:
 a channel permitting a fluid to flow therethrough; and   a microtube configured to introduce another fluid into a laminar flow of said fluid flowing through said channel;   wherein fluid feeding is performed in the condition where a laminar flow of said another fluid introduced through said microtube is surrounded by said laminar flow of said fluid flowing through said channel.   
     
     
         14 . A fluid analyzing apparatus comprising:
 a microchip;   a channel permitting a sheath liquid to flow therethrough; and   a microtube configured to introduce a sample liquid into a laminar flow of said sheath liquid flowing through said channel;   wherein liquid feeding is performed in a condition where a laminar flow of said sample liquid introduced through said microtube is surrounded by said laminar flow of said sheath liquid.   
     
     
         15 . A particulate fractionating apparatus comprising:
 a microchip;   a channel permitting a sheath liquid to flow therethrough; and   a microtube configured to introduce a sample liquid into a laminar flow of said sheath liquid flowing through said channel;   wherein liquid feeding is performed in a condition where a laminar flow of said sample liquid introduced through said microtube is surrounded by said laminar flow of said sheath liquid.   
     
     
         16 . A liquid feeding method for a microchip channel, the method comprising introducing a sample liquid by a microtube into a laminar flow of a sheath liquid flowing through a channel; and performing liquid feeding under a condition where a laminar flow of said sample liquid is surrounded by said laminar flow of said sheath liquid. 
     
     
         17 . The liquid feeding method according to  claim 16 , wherein said sample liquid, with an electric charge given thereto by a metallic microtube permitting a voltage to be impressed thereon, is introduced into said laminar flow of said sheath liquid flowing through said channel having a branching section; and
 the flow direction, at said branching section of said channel, of said sample liquid is controlled by electrodes disposed at said branching section.   
     
     
         18 . The liquid feeding method according to  claim 17 , wherein either fluid of a gas and an insulating liquid is introduced into said channel through which said sheath liquid laminar flow and said sample liquid laminar flow pass, whereby said sheath liquid laminar flow and said sample liquid laminar flow which are flowing are split into droplets and, simultaneously, an electric charge is given to said sample liquid by said metallic microtube. 
     
     
         19 . The liquid feeding method according to  claim 17 , wherein a pressure difference is applied by a piezoelectric element to said sample liquid flowing through said microtube, whereby said sample liquid is introduced in a dropletized state into said laminar flow of said sheath liquid flowing through said channel and, simultaneously, an electric charge is given to said sample liquid by said metallic microtube. 
     
     
         20 . The liquid feeding method according to  claim 17 , wherein the flow direction at said branching section of said sample liquid which contains particulates and which has been dropletized and given said electric charge is controlled, whereby fractionation of said particulates is performed.