Chemical sensors from nanoparticle/dendrimer composite materials

• US 20030109056A1
• Filed: 07/18/2002
• Published: 06/12/2003
• Est. Priority Date: 07/19/2001
• Status: Active Grant

• Current Assignee: Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaften e.V. (Max-Planck-Gesellschaft zur Frderung der Wissenschaften e), Sony Deutschland GmbH (Sony Group Corp.)
• Original Assignee: Sony Deutschland GmbH (Sony Group Corp.)
• Inventors: Bauer, Roland E., Yasuda, Akio, Mullen, Klaus, Vossmeyer, Tobias
• Granted Patent: US 7,253,004 B2
• Time in Patent Office: Days
• US Class Current: 436/169
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01N 21/77 by observing the effect on a chemical indicator
• CPC Class Codes: G01N 27/126 comprising organic polymers
• CPC Class Codes: G01N 33/0001 by organoleptic means
• CPC Class Codes: Y10T 436/11 Automated chemical analysis

Abstract

The invention relates to a chemical sensor comprising a sensor film formed of a nanoparticle network in which the nanoparticles are interlinked by functionalized dendrimer molecules. The dendrimers support an efficient uptake of analyte molecules by the film material and therefore enable a high sensitivity of the sensor. In addition, the chemical nature of the dendrimers strongly determines the chemical selectivity of the sensor device. By cross-linking the components of the sensitive material the sensor displays a good mechanical stability.

Claims

1. Chemical sensor, comprising a substrate, a sensor medium formed on the substrate, and detection means for detecting a change of a physical property of the sensor medium, wherein the sensor medium comprises a network formed of non-linear polymer or oligomer molecules having linker units and of particles of at least one second component, wherein the linker units are bound to the surface of the particles of the at least one second component thereby interlinking said particles.

2. Chemical sensor according to claim 1, wherein the non-linear polymer or oligomer molecule is a dendrimer molecule.

3. Chemical sensor according to claim 2, wherein the dendrimer molecules comprise an interior formed of a core and a shell of branched repeating units, and an outer shell of linker units.

4. Chemical sensor according to one of claims 1 to 3, wherein the linker units are formed by polar groups.

5. Chemical sensor according to one of claims 1 to 4, wherein the linker unit comprises a sulphur-containing group.

6. Chemical sensor according to claim 4 or 5, wherein the linker unit is selected from a group consisting of disulfide group, thiol group, thiolate group, isocyanate group, thiocarbamate group, dithiocarbamate group, sulfonium group, and amino group.

7. Chemical sensor according to one of claims 3 to 6, wherein at least 40% of the carbon atoms of the core and the shell of branched repeating units are sp² or sp hybridized.

8. Chemical sensor according to one of claims 3 to 6, wherein the dendrimer core and/or the shell of branched repeating units comprise at least one structural unit, selected from the group consisting of adamantane, cyclodextrin, crown ether, porphyrin, and phthalocyanine.

9. Chemical sensor according to one of claims 3 to 8, wherein the core and/or the shell of branched repeating units comprise polar endo-receptor sites.

10. Chemical sensor according to one of claims 2 to 9, wherein the dendrimer molecule is a polyamidoamine (PAMAM) dendrimer.

11. Chemical sensor according to one of claims 2 to 9, wherein the dendrimer molecule is a poly(propylene imine) (PPI) dendrimer.

12. Chemical sensor according to one of claims 3 to 8, wherein the core and/or the shell of branched repeating units comprise electron-donating groups, which are complexed with metal cations.

13. Chemical sensor according to claim 3, wherein the interior of the dendrimer molecule has a hydrophobic structure.

14. Chemical sensor according to claim 13, wherein the hydrophobic structure is formed by a polyphenylene structure or comprises phenylene units.

15. Chemical sensor according to claim 2, wherein the dendrimer molecule is a metallodendrimer.

16. Chemical sensor according to one of claims 2 to 15, wherein the shell of linker units is connected to the shell of branched repeating units by a shell of spacer units.

17. Chemical sensor according to claim 16, wherein the spacer units have a flexible structure comprising alkylene chains which comprise at least three carbon atoms.

18. Chemical sensor according to one of the preceding claims, wherein the particle of the at least one second component is a nanoparticle.

19. Chemical sensor according to claim 18, wherein the nanoparticle consists of a metal.

20. Chemical sensor according to claim 19, wherein the metal is selected from the group consisting of Au, Ag, Pt, Pd, Co, Cu, Ni, Cr, Mo, Zr, Nb, Fe, or any combination of those metals.

21. Chemical sensor according to claim 18, wherein the nanoparticle consists of a semiconductor material.

22. Chemical sensor according to claim 21, wherein the semiconductor material is selected from the group consisting of II/VI semiconductors, III/V semiconductors, and Cd₃P₂.

23. Chemical sensor according to claim 18, wherein the nanoparticle consists of an insulator material.

24. Chemical sensor according to claim 1, wherein the particles of the at least one second component consist of a conducting or semiconducting oligomer or polymer.

25. Chemical sensor according to one of the preceding claims, wherein the chemical sensor is formed as a chemical sensitive resistor, a chemical sensitive transistor, a chemical sensitive diode, or a chemical sensitive capacitor.

26. Method for forming a chemical sensor according to one of claims 1 to 25, comprising the following steps:

a) providing a substrate

b) alternately depositing on the substrate a layer of nanoparticles and a layer of non-linear polymers having linker units thereby coupling the non-linear polymers to the nanoparticles until a homogenous sensor film is obtained.

27. Method according to claim 26, wherein the surface layer of the homogenous sensor film is formed by a layer of non-linear polymers having linker units

28. Method for forming a chemical sensor according to one of claims 1 to 25, wherein a mixture of at least non-linear polymers having linker units and nanoparticles in a solvent is prepared on the surface of a substrate or is applied to the surface of a substrate, and the solvent is removed to form a film of a sensor medium.

29. Method according to one of claims 26 to 28, wherein before deposition of the nanoparticles and/or the non-linear polymers having linker units, the surface of the substrate is functionalized to provide linker groups on the surface of the substrate.

30. Method for detecting an analyte, wherein a chemical sensor according to one of claims 1 to 25 is exposed to an analyte and a change of a physical property of the sensor film is measured by a detection means.

31. Method according to claim 30, wherein the change of a physical property is a change of conductivity, dielectric constant, reflectance, luminescence, absorbance, mass, volume, density, and/or heat capacity or any combination thereof.

32. Method according to claim 30, wherein the change of a physical property is a change of the electronic transport properties.