Device and method for quantitatively determining an analyte, a method for determining an effective size of a molecule, a method for attaching molecules to a substrate, and a device for detecting molecules

Abstract

A device for quantitatively determining an analyte is provided to conspicuously improve the performance of the quantitative determination. This device is equipped with a flow channel, an analyte detecting unit for capturing and detecting the analyte, and a quantitative measurement unit for quantitatively determining the analyte, wherein a signal generated when the analyte detecting unit has detected the analyte is divided into a plurality of parts in the direction of the flow in the flow channel at the quantitative measurement unit for processing. Also provided are technologies including one for controlling the density of molecules attached to the surface of a solid. In these technologies, when molecules are attached to a substrate, the density of attached molecules is controlled, by having an electrolyte also present in a solution containing the molecules to adjust the screening effect by the electrolyte, and by taking into consideration the effective size of a molecule.

1 . A device for quantitatively determining an analyte equipped with a flow channel, an analyte detecting unit for capturing and detecting the analyte, and a quantitative measurement unit for quantitatively determining the analyte, wherein: 
 a signal generated when said analyte detecting unit has detected the analyte is divided into a plurality of parts in the direction of the flow in the flow channel at said quantitative measurement unit for processing.    
   
   
       2 . A device for quantitatively determining an analyte according to  claim 1 , wherein said analyte detecting unit has an analyte capturing unit for capturing said analyte.  
   
   
       3 . A device for quantitatively determining an analyte according to  claim 1 , wherein a plurality of analyte detecting units are disposed in the direction of the flow in the flow channel.  
   
   
       4 . A device for quantitatively determining an analyte according to  claim 1 , wherein the length of said analyte detecting unit in the direction of the flow in the flow channel is not less than twice the width of the flow channel.  
   
   
       5 . A device for quantitatively determining an analyte according to  claim 1 , wherein a plurality of analyte detecting units are disposed in the direction along the width of the flow channel.  
   
   
       6 . A device for quantitatively determining an analyte according to  claim 1 , wherein said quantitative measurement unit quantitatively determines the analyte, using an optical signal.  
   
   
       7 . A device for quantitatively determining an analyte according to  claim 1 , wherein said quantitative measurement unit quantitatively determines the analyte, using an electric signal.  
   
   
       8 . A device for quantitatively determining an analyte according to  claim 1 , wherein the thickness of the flow channel at the analyte detecting unit is not more than 100 times the effective height of a captured analyte.  
   
   
       9 . A device for quantitatively determining an analyte according to  claim 1 , wherein the thickness of the flow channel at the analyte detecting unit is made larger as the flow goes downstream.  
   
   
       10 . A device for quantitatively determining an analyte according to  claim 1 , wherein said analyte detecting unit is an electrode so that an electric potential for electrically attracting charged analytes to the electrode can be applied to the electrode.  
   
   
       11 . A device for quantitatively determining an analyte according to  claim 10 , wherein said electric potential for electrically attracting charged analytes to the electrode can be changed according to the location of the electrode in the direction of the flow in the flow channel.  
   
   
       12 . A device for quantitatively determining an analyte according to  claim 1 , wherein a micropump, electrophoretic flow or electroosmotic flow is utilized to make a solution containing said analyte flow in said flow channel.  
   
   
       13 . A device for quantitatively determining an analyte according to  claim 1 , wherein a plurality of analyte capturing units for specifically capturing different analytes, are disposed on said analyte detecting unit.  
   
   
       14 . A device for quantitatively determining an analyte according to  claim 13 , wherein said analytes are DNAs, and said analyte capturing units have a function to be specifically bound to DNAs.  
   
   
       15 . A device for quantitatively determining an analyte according to  claim 13 , wherein said analytes are proteins, and said analyte capturing units have a function to be specifically bound to proteins.  
   
   
       16 . A Micro Electro Mechanical System equipped with a device for quantitatively determining an analyte according to  claim 1 .  
   
   
       17 . A Micro Total Analysis System equipped with a device for quantitatively determining an analyte according to  claim 1 .  
   
   
       18 . A method for quantitatively determining an analyte comprising: 
 using a flow channel, an analyte detecting unit for capturing and detecting the analyte, and a quantitative measurement unit for quantitatively determining the analyte; and    dividing a signal generated when said analyte detecting unit has detected the analyte, into a plurality of parts in the direction of the flow in the flow channel at said quantitative measurement unit for processing.    
   
   
       19 . A method for quantitatively determining an analyte according to  claim 18 , wherein said analyte detecting unit has an analyte capturing unit for capturing said analyte.  
   
   
       20 . A method for quantitatively determining an analyte according to  claim 18 , wherein a plurality of analyte detecting units are disposed in the direction of the flow in the flow channel.  
   
   
       21 . A method for quantitatively determining an analyte according to  claim 18 , wherein the number of analytes captured by said analyte detecting unit in the direction of the flow in the flow channel is optimized.  
   
   
       22 . A method for quantitatively determining an analyte according to  claim 18 , wherein said optimization is performed by changing at least one factor selected from the group consisting of the supplying velocity of said analyte, the length of analyte detecting unit in the direction of the flow in the flow channel, the number of analyte detecting units in the direction along the width of the flow channel, and the thickness of the flow channel.  
   
   
       23 . A method for quantitatively determining an analyte according to  claim 18 , wherein said quantitative measurement unit quantitatively determines the analyte, using an optical signal.  
   
   
       24 . A method for quantitatively determining an analyte according to  claim 18 , wherein said quantitative measurement unit quantitatively determines the analyte, using an electric signal.  
   
   
       25 . A method for quantitatively determining an analyte according to  claim 18 , wherein said analyte detecting unit is an electrode so that an electric potential for electrically attracting charged analytes to the electrode, is applied to the electrode.  
   
   
       26 . A method for quantitatively determining an analyte according to  claim 25 , wherein said electric potential for electrically attracting charged analytes to the electrode is changed according to the location of the electrode in the direction of the flow.  
   
   
       27 . A method for quantitatively determining an analyte according to  claim 18 , wherein a plurality of analyte capturing units for specifically capturing different analytes, are disposed on said analyte detecting unit.  
   
   
       28 . A method for quantitatively determining an analyte according to  claim 27 , wherein said analytes are DNAs, and said analyte capturing units have a function to be specifically bound to DNAs.  
   
   
       29 . A method for quantitatively determining an analyte according to  claim 27 , wherein said analytes are proteins, and said analyte capturing units have a function to be specifically bound to proteins.  
   
   
       30 . A method for attaching molecules having an electric charge to a substrate, wherein the density of said attached molecules is controlled, by having an electrolyte also present in a solution containing said molecules to adjust the screening effect by said electrolyte, and by taking into consideration the effective size of a molecule when said molecules having an electric charge are attached to a substrate.  
   
   
       31 . A method for attaching molecules having an electric charge to a substrate according to  claim 30 , wherein the effective size of a molecule having an electric charge in a solution containing the electrolyte and the molecules having an electric charge is estimated from the screening effect by said electrolyte, and the thus obtained effective size is used as said effective size.  
   
   
       32 . A method for attaching molecules having an electric charge to a substrate according to  claim 30 , wherein an electrolyte comprising a monovalent cation and a monovalent anion is used as said electrolyte.  
   
   
       33 . A method for attaching molecules having an electric charge to a substrate according to  claim 32 , wherein said electrolyte comprising a monovalent cation and a monovalent anion is NaCl, KCl or a mixture thereof.  
   
   
       34 . A device for attaching molecules having an electric charge to a substrate, wherein the density of molecules attached to the substrate can be controlled, using the method for attaching molecules to a substrate according to  claim 30 .  
   
   
       35 . A device for detecting molecules, wherein the method for attaching molecules to a substrate according to  claim 30  is used, and a substrate of which the density of attached molecules is controlled so that the distance between adjacent molecules attached to the substrate is not less than twice the effective length of a molecule, is used as a detecting unit for said molecule.  
   
   
       36 . A device for detecting molecules, wherein the method for attaching molecules to a substrate according to  claim 30  is used, and a substrate of which the density of attached molecules is controlled so that the distance between adjacent molecules attached to the substrate is less than twice the effective length of a molecule, is used as a detecting unit for said molecule.  
   
   
       37 . A device for detecting molecules according to  claim 35 , wherein said molecule having an electric charge comprises a material selected from the group consisting of proteins, DNAs, RNAs, antibodies, natural or artificial single-stranded nucleotides, natural or artificial double-stranded nucleotides, aptamers, products obtained by limited decomposition of antibodies with a protease, organic compounds having affinity to proteins, biomacromolecules having affinity to proteins, complex materials thereof, ionic polymers charged positively or negatively, and arbitrary combinations thereof.  
   
   
       38 . A device for detecting molecules according to  claim 35 , wherein said molecule having an electric charge comprises a thiol group.  
   
   
       39 . A device for detecting molecules according to  claim 35 , wherein said molecule having an electric charge comprises a fluorescent pigment.  
   
   
       40 . A device for detecting molecules according to  claim 35 , wherein said substrate is made of an electroconductive material, a semiconducting material, or an insulating material.  
   
   
       41 . A device for detecting molecules according to  claim 40 , wherein said substrate is made of gold or platinum.  
   
   
       42 . A device for detecting molecules according to  claim 36 , wherein said molecule having an electric charge comprises a material selected from the group consisting of proteins, DNAs, RNAs, antibodies, natural or artificial single-stranded nucleotides, natural or artificial double-stranded nucleotides, aptamers, products obtained by limited decomposition of antibodies with protease, organic compounds having affinity of proteins, biomacromolecules having affinity to proteins, complex materials thereof, ionic polymers charged positively or negatively, and arbitrary combinations thereof.  
   
   
       43 . A device for detecting molecules according to  claim 36 , wherein said molecule having an electric charge comprise a thiol group.  
   
   
       44 . A device for detecting molecules according to  claim 36 , wherein said molecule having an electric charge comprises a fluorescent pigment.  
   
   
       45 . A device for detecting molecules according to  claim 36 , wherein said substrate is made of an electroconductive material, a semiconducting material, or an insulating material.  
   
   
       46 . A device for detecting molecules according to  claim 45 , wherein said substrate is made of gold or platinum.