Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
2001-10-10
2004-04-13
Riley, Jezia (Department: 1637)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C536S024300, C536S024330, C536S026600, C435S006120
Reexamination Certificate
active
06720411
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to methods of detecting nucleic acids, whether natural or synthetic, and whether modified or unmodified. The invention also relates to materials for detecting nucleic acids and methods of making those materials. The invention further relates to methods of nanofabrication. Finally, the invention relates to methods of separating a selected nucleic acid from other nucleic acids.
BACKGROUND OF THE INVENTION
The development of methods for detecting and sequencing nucleic acids is critical to the diagnosis of genetic, bacterial, and viral diseases. See Mansfield, E. S. et al.
Molecular and Cellular Probes
, 9, 145-156 (1995). At present, there are a variety of methods used for detecting specific nucleic acid sequences. Id. However, these methods are complicated, time-consuming and/or require the use of specialized and expensive equipment. A simple, fast method of detecting nucleic acids which does not require the use of such equipment would clearly be desirable.
A variety of methods have been developed for assembling metal and semiconductor colloids into nanomaterials. These methods have focused on the use of covalent linker molecules that possess functionalities at opposing ends with chemical affinities for the colloids of interest. One of the most successful approaches to date, Brust et al.,
Adv. Mater.,
7, 795-797 (1995), involves the use of gold colloids and well-established thiol adsorption chemistry, Bain & Whitesides,
Angew. Chem. Int. Ed. Engl
., 28, 506-512(1989) and Dubois & Nuzzo,
Annu. Rev. Phys. Chem
43, 437-464 (1992). In this approach, linear alkanedithiols are used as the particle linker molecules. The thiol groups at each end of the linker molecule covalently attach themselves to the colloidal particles to form aggregate structures. The drawbacks of this method are that the process is difficult to control and the assemblies are formed irreversibly. Methods for systematically controlling the assembly process are needed if the materials properties of these structures are to be exploited fully.
The potential utility of DNA for the preparation of biomaterials and in nanofabrication methods has been recognized. In this work, researchers have focused on using the sequence-specific molecular recognition properties of oligonucleotides to design impressive structures with well-defined geometric shapes and sizes. Shekhtman et al.,
New J. Chem
., 17, 757-763 (1993); Shaw & Wang,
Science
, 260, 533-536 (1993); Chen et al.,
J. Am Chem. Soc
., 111, 6402-6407 (1989); Chen & Seeman,
Nature
, 350, 631-633 (1991); Smith and Feigon,
Nature
, 356, 164-168 (1992); Wang et al.,
Biochem
., 32, 1899-1904 (1993); Chen et al.,
Biochem
., 33, 13540-13546 (1994); Marsh et al.,
Nucleic Acids Res
., 23, 696-700 (1995); Mirkin,
Annu. Review Biophys. Biomol. Struct
., 23, 541-576 (1994); Wells,
J. Biol. Chem
., 263, 1095-1098 (1988); Wang et al.,
Biochem
., 30, 5667-5674 (1991). However, the theory of producing DNA structures is well ahead of experimental confirmation. Seeman et al.,
New J. Chem
., 17, 739-755 (1993).
SUMMARY OF THE INVENTION
The invention provides methods of detecting nucleic acids. In one embodiment, the method comprises contacting a nucleic acid with a type of nanoparticles having oligonucleotides attached thereto (nanoparticle-oligonucleotide conjugates). The nucleic acid has at least two portions, and the oligonucleotides on each nanoparticle have a sequence complementary to the sequences of at least two portions of the nucleic acid. The contacting takes place under conditions effective to allow hybridization of the oligonucleotides on the nanoparticles with the nucleic acid. The hybridization of the oligonucleotides on the nanoparticles with the nucleic acid results in a detectable change.
In another embodiment, the method comprises contacting a nucleic acid with at least two types of nanoparticles having oligonucleotides attached thereto. The oligonucleotides on the first type of nanoparticles have a sequence complementary to a first portion of the sequence of the nucleic acid. The oligonucleotides on the second type of nanoparticles have a sequence complementary to a second portion of the sequence of the nucleic acid. The contacting takes place under conditions effective to allow hybridization of the oligonucleotides on the nanoparticles with the nucleic acid, and a detectable change brought about by this hybridization is observed.
In a further embodiment, the method comprises providing a substrate having a first type of nanoparticles attached thereto. The first type of nanoparticles has oligonucleotides attached thereto, and the oligonucleotides have a sequence complementary to a first portion of the sequence of a nucleic acid. The substrate is contacted with the nucleic acid under conditions effective to allow hybridization of the oligonucleotides on the nanoparticles with the nucleic acid. Then, a second type of nanoparticles having oligonucleotides attached thereto is provided. The oligonucleotides have a sequence complementary to one or more other portions of the sequence of the nucleic acid, and the nucleic acid bound to the substrate is contacted with the second type of nanoparticle-oligonucleotide conjugates under conditions effective to allow hybridization of the oligonucleotides on the second type of nanoparticles with the nucleic acid. A detectable change may be observable at this point. The method may further comprise providing a binding oligonucleotide having a selected sequence having at least two portions, the first portion being complementary to at least a portion of the sequence of the oligonucleotides on the second type of nanoparticles. The binding oligonucleotide is contacted with the second type of nanoparticle-oligonucleotide conjugates bound to the substrate under conditions effective to allow hybridization of the binding oligonucleotide to the oligonucleotides on the nanoparticles. Then, a third type of nanoparticles having oligonucleotides attached thereto, the oligonucleotides having a sequence complementary to the sequence of a second portion of the binding oligonucleotide, is contacted with the binding oligonucleotide bound to the substrate under conditions effective to allow hybridization of the binding oligonucleotide to the oligonucleotides on the nanoparticles. Finally, the detectable change produced by these hybridizations is observed.
In yet another embodiment, the method comprises contacting a nucleic acid with a substrate having oligonucleotides attached thereto, the oligonucleotides having a sequence complementary to a first portion of the sequence of the nucleic acid. The contacting takes place under conditions effective to allow hybridization of the oligonucleotides on the substrate with the nucleic acid. Then, the nucleic acid bound to the substrate is contacted with a first type of nanoparticles having oligonucleotides attached thereto, the oligonucleotides having a sequence complementary to a second portion of the sequence of the nucleic acid. The contacting takes place under conditions effective to allow hybridization of the oligonucleotides on the nanoparticles with the nucleic acid. Next, the first type of nanoparticle-oligonucleotide conjugates bound to the substrate is contacted with a second type of nanoparticles having oligonucleotides attached thereto, the oligonucleotides on the second type of nanoparticles having a sequence complementary to at least a portion of the sequence of the oligonucleotides on the first type of nanoparticles, the contacting taking place under conditions effective to allow hybridization of the oligonucleotides on the first and second types of nanoparticles. Finally, a detectable change produced by these hybridizations is observed.
In another embodiment, the method comprises contacting a nucleic acid with a substrate having oligonucleotides attached thereto, the oligonucleotides having a sequence complementary to a first portion of the sequence of the nucleic acid. The contacting takes place under conditions effective to allow hybridizat
Elghanian Robert
Letsinger Robert L.
Mirkin Chad A.
Mucic Robert C.
Storhoff James J.
McDonnell & Boehnen Hulbert & Berghoff
Nanosphere Inc.
Riley Jezia
LandOfFree
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