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DNA SENSOR

Foreign code F110003435
File No. A111-43WO
Posted date Jun 27, 2011
Country EPO
Application number 05768375
Gazette No. 1788383
Gazette No. 1788383
Date of filing Aug 4, 2005
Gazette Date May 23, 2007
Gazette Date Apr 5, 2017
International application number JP2005014283
International publication number WO2006025180
Date of international filing Aug 4, 2005
Date of international publication Mar 9, 2006
Priority data
  • P2004-250303 (Aug 30, 2004) JP
  • JP2005014283 (Aug 4, 2005) WO
Title DNA SENSOR
Abstract (EP1788383)
A DNA sensor is provided which is capable of identifying unknown DNA with enhanced detection sensitivity of the hybridization.
A p-channel field-effect transistor having an electrolyte solution gate 8 and having as a p-channel 5 a diamond surface 2 which contains a mixture of at least a hydrogen-terminated surface and a surface terminated with an amino group or a molecule with an amino group is configured along with a probe DNA 11 constituted of a single-stranded DNA with known nucleotide sequence which is directly immobilized by a linker to the diamond surface 2 and with a target DNA constituted of an unknown single-stranded DNA which is dropped on the diamond surface 2.
When the target DNA is in complementary relationship to the probe DNA 11, negative electric charge of the phosphate group of a double-stranded DNA produced by the hybridization of the probe DNA 11 with the target DNA both constituted of a single-stranded DNA is doubled, thereby resulting in increase of the hole density in the p-channel and shift of the threshold voltage of the p-channel field effect transistor toward positive direction.
By detecting this shift of the threshold voltage toward positive direction, an identification can be made on whether or not the target DNA is in complementary relationship to the probe DNA 11.
Scope of claims [claim1]
1. A DNA sensor operable to detect mismatched single nucleotide and triple nucleotides, comprising a p-channel field-effect transistor having as a gate (8) an electrolyte solution and having as a channel (5) a diamond surface (2) which contains a mixture of at least a hydrogen-terminated surface and an amino-terminated surface, the amino-terminated surface being terminated by an amino group or a molecule with an amino group, wherein the sensor is configured to: receive a probe DNA (11) constituted of a single-stranded DNA with known nucleotide sequence which is directly immobilized by a linker to the amino termination of the diamond surface (2); receive a target DNA constituted of an unknown single-stranded DNA which is dropped on the diamond surface (2); and set a temperature of the buffer solution to 40 deg.C or lower during hybridization to identify whether or not the target DNA is complementary to the probe DNA (11) by detecting a shift of the threshold voltage of the p-channel field effect transistor toward positive direction, the shift resulting from a double-stranded DNA produced by hybridization of the probe DNA (11) with the target DNA both constituted of the single-stranded DNA when the target DNA is complementary to the probe DNA (11).
[claim2]
2. A measuring method operable to detect mismatched single nucleotide and triple nucleotides using a DNA sensor, the sensor comprising a p-channel field-effect transistor having as a gate (8) an electrolyte solution and having as a channel (5) a diamond surface (2) which contains a mixture of at least a hydrogen-terminated surface and an amino-terminated surface, the amino-terminated surface being terminated by an amino group or a molecule with an amino group as an amino termination, the method comprising: directly immobilizing a probe DNA (11) constituted of a single-stranded DNA with known nucleotide sequence by a linker to the amino termination of the diamond surface (2); dropping a target DNA constituted of an unknown single-stranded DNA on the diamond surface (2); and identifying whether or not the target DNA is complementary to the probe DNA (11) by detecting a shift of the threshold voltage of the p-channel field effect transistor toward positive direction, the shift resulting from a double-stranded DNA produced by hybridization of the probe DNA (11) with the target DNA both constituted of the single-stranded DNA when the target DNA is complementary to the probe DNA (11), wherein: a temperature of the buffer solution is 40 deg.C or lower during hybridization.
[claim3]
3. The DNA sensor or method according to any preceding claim, wherein the diamond surface (2) contains an oxygen-terminated surface.
[claim4]
4. The DNA sensor or method according to any preceding claim, wherein the linker is: divalent or trivalent carboxylic acid or divalent or trivalent aldehyde.
[claim5]
5. The DNA sensor or method according to any preceding claim, further comprising the probe DNA (11) and the target DNA, wherein the density of the probe DNA is equal to or greater than 10 **10 cm **-2 and the concentration of the target DNA is from 10 **-12 M to 10 **-6 M.
[claim6]
6. The DNA sensor or method according to any preceding claim, wherein the shifting difference of the threshold voltage toward positive direction is detected as a change in the gate voltage under a constant drain current.
[claim7]
7. The DNA sensor or method according to any preceding claim, wherein the shifting difference of the threshold voltage toward positive direction is detected as a change in the drain current under a constant gate voltage.
[claim8]
8. The DNA sensor or method according to any preceding claim, wherein the shifting difference of the threshold voltage toward positive direction is detected as a change in the drain current under a constant drain voltage.
[claim9]
9. The DNA sensor or method according to any preceding claim, wherein the temperature of the buffer solution containing the electrolyte solution is 25 deg.C or lower during hybridization.
[claim10]
10. The DNA sensor or method according to any preceding claim, wherein an NaCl concentration of the buffer solution is between 0.3M to 0.01 M, and a Debye length is between 0.56nm to 3.04nm.
  • Applicant
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • Inventor
  • KAWARADA HIROSHI
IPC(International Patent Classification)
Reference ( R and D project ) CREST Function Evolution of Materials and Devices based on Electron/Photon Related Phenomena AREA
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