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

• US 8,945,944 B2
• Filed: 09/29/2010
• Issued: 02/03/2015
• Est. Priority Date: 08/19/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Arinaga, Kenji, Rant, Ulrich
• Primary Examiner(s): Brown, Melanie Y
• Assistant Examiner(s): Crawford, Erik B
• Application Number:
  US12/923,588
• Publication Number:
  US 20110100822A1
• Time in Patent Office: 1,588 Days
• Field of Search: 435/6.1, 435/6.11, 435/287.2
• US Class Current: 436/518
• CPC Class Codes: B01J 2219/00605 the compounds being directly bound or immobilised to solid supports
• CPC Class Codes: C12Q 2527/137 Concentration of a component of medium
• CPC Class Codes: C12Q 2527/143 Concentration of primer or probe
• CPC Class Codes: C12Q 2565/518 characterised by the immobilisation of the nucleic acid sample or target
• CPC Class Codes: G01N 33/543 with an insoluble carrier for immobilising immunochemicals
• CPC Class Codes: G01N 33/5438 Electrodes

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.

Claims

1. A method for attaching molecules having an electric charge to a substrate, comprising:

attaching said molecules to said substrate by bringing a solution containing said molecules into contact with said substrate;

having an electrolyte having an ion concentration also present in the solution; and

selecting a density of said molecules on said substrate by adjusting the ion concentration of the electrolyte to influence an effective size of said molecule attached to the substrate when said molecules having an electric charge are attached to the substrate, wherein;

said effective size attached to the substrate is a sum of the radius of said molecule and Debye length according to the following equation,

L_Debye=(2,000N_Acz²e²/(∈

_r∈

₀kT))<sup>−

1/2</sup>(m), and

said density is determined by the following equation,

Density=1/(2(r+L_Debye)²√

3)(cm<sup>−

2</sup>)

where L_Debye is the Debye length, N_A is Avogadro'"'"'s number, c is the ion concentration of the electrolyte (mol/L), z is the valence of the ion, e is a unit charge, ∈

_r is the relative dielectric constant of a medium, ∈

₀ is the dielectric constant of vacuum, k is the Boltzmann constant, T is the absolute temperature, and r is the radius of the molecule,

wherein said molecule having an electric charge comprises a strand-type 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, and arbitrary combinations thereof.

2. The method of claim 1, wherein said electrolyte comprises a monovalent cation and a monovalent anion.

3. The method of claim 2, wherein said electrolyte comprising a monovalent cation and a monovalent anion is NaCl, KCl or a mixture thereof.