Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Composite having voids in a component
Reexamination Certificate
2000-04-07
2004-11-30
Morris, Terrel (Department: 1771)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Composite having voids in a component
C428S304400, C428S315500, C428S315700, C428S325000, C428S312200, C428S312600, C428S312800, C528S010000, C536S023100, C536S024300, C536S025300
Reexamination Certificate
active
06824866
ABSTRACT:
TECHNICAL FIELD
This invention pertains to preparation and use of very high surface area porous substrates that can be used to synthesize high density arrays of polymers.
BACKGROUND
Porous silica glass has been known for quite some time. U.S. Pat. No. 4,220,461 provides a historical perspective and discussion on the development of silica-rich phase-separable porous glass. Various methods for the manufacture of phase-separable porous glass are reviewed in U.S. Pat. No. 4,528,010. Both of these references are incorporated by reference in their entireties for all purposes.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to a porous substrate and methods for making and using the porous substrate. The porous substrate provides an increased surface area for polymers to attach to the substrate. Such porous substrates are often used to make an array of polymers, such as for genetic diagnostic purposes. The polymers may be placed or fabricated on the porous substrate by various methods.
The polymers can include those of biological interest such as nucleic acids, polynucleotides, proteins, polypeptides, polysaccharides, oligosaccharides, mixtures of these or other polymers on an array and combinations of the above polymer units in individual polymers. The porous substrates thus are useful in, for example, glass technology, polymer chemistry, molecular biology, medicine, and medical diagnostics.
The porous substrate generally has at least two regions, a support region and a porous region. The support region, which can serve as an underlayer region, basically provides mechanical support for ease of handling of a porous region. The porous region may be for example a layer (film). The support region can be selected or processed to provide additional features in the finished porous substrate. One advantage of using a porous region with higher surface area to make an array is that the array can be functionalized with a much higher density of polymers for a given two dimensional area without changing the spacing between polymers on the surface of the porous substrate.
One embodiment of this invention provides a primarily inorganic porous substrate including a support region, and a porous region in contact with the support region. The porous region for example includes pores with a pore size of 1-500 nm, or 2-500 nm, the porous region having a porosity of, e.g., 10-90%, 20-80%, or 70-90%, and a porous surface thickness of 0.01-20 &mgr;m, wherein the porous region has a surface capable of forming arrays of polymers thereon. The porosity is generally, for example, “open”, that is, some pores are connected to others to allow the infusion of polymers or other fluids. Not all the pores need to connect to another, that is, some of the pores may be closed. What is meant by “primarily inorganic” is that a small amount of organic material may remain in the porous region of the substrate, or may be intentionally applied onto the surface(s) of the porous region.
In one embodiment, a porous substrate is provided comprising:
a support region; and
a porous region on the support region, the porous region being primarily inorganic and having a surface capable of forming a polymer array thereon, the porous region comprising pores of a pore size of about 2 nm-500 nm or 1000 Angstroms to 500 nm, a porosity of about 10-90%, and a thickness of about 0.01 &mgr;m to about 70 &mgr;m.
The porous region can be formed by an additive method, which can include the application of colloidal silica on the support region. The additive method also may include the application of alkoxysilane on the support region. The porous region may comprise silica. The porous region may further comprise organic polymer of less than or equal to about 10% mole fraction. The porous region may comprise a plurality of pores, each of the plurality of pores having a size of from about 2 to about 100 nm. The porous region may comprise a plurality of pores, each of the plurality of pores having a size of from about 2 to about 50 nm. The porous region has, for example, a porosity of from about 20-80%, or 50-70%. The porous region for example comprises a plurality of particles, each of the plurality of particles having a size from about 5-500 nm, 5-200 nm, or 70-100 nm. The porous region has, for example, a thickness from about 0.1-1 microns, or about 0.1 &mgr;m to about 0.5 &mgr;m, or about 1 &mgr;m to about 20 &mgr;m.
An organic polymer may coat silica particles of the porous region. The porous region may be silylated with a silyating agent, such as N,N-bis(hydroxyethylaminopropyl)triethoxysilane and glycidoxypropyl trimethoxy silane. The porous region may be formed by codepositing an organic template material with silica, followed by removing the organic template material. The organic template material for example comprises particles of about 10-100 nm and the silica comprises particles of about 7-100 nm. The organic template particle size can be about equal to a silica particle size. The silica particle size is for example less than or equal to about ⅔ an organic template particle size. The silica particle size is in one embodiment, less than about 10% of an organic template particle size. The organic template material can be deposited in a volume ratio to the silica of about 10:1 to 1:10, e.g., 2:1. The organic template material is in one embodiment removed using a baking process at a temperature of above about 150° C. The silica may be densified using an annealing process. The porous region has in one embodiment an effective surface area about 15-40 times a flat substrate with an equivalent two dimensional structure. In one embodiment, the porous region is formed by a subtractive method. The organic template polymer may be a latex polymer. The porous substrate may comprise phase-separable glass, a surface portion of the phase-separable glass being treated to form the porous layer. The phase-separable glass may comprise for example a sodium borosilicate glass. The sodium borosilicate glass may be been annealed and leached to provide the porous layer having a thickness of about 70 microns and comprised of a plurality of pores, at least some of the plurality of pores having a pore size greater than about 1000 Å. The porous region has, e.g., an effective surface area about 50-400 times a flat substrate with an equivalent two dimensional structure.
The porous substrate may further comprise a high density array of polymers, such as nucleic acids immobilized on the surface.
In another embodiment, a porous substrate is provided comprising:
a support region; and
a porous region on the support region, said porous region being about 0.1-0.5 microns thick,
wherein the porous layer comprises an unsintered matrix formed from at least colloidal silica having a particle size of about 70-100 microns, the unsintered matrix defining at least a plurality of open pores having a pore size of about 10-20 nm, and
wherein the porous layer has a porosity of of about 10-90%.
In one embodiment, a method of forming a porous substrate is provided, the method comprising:
providing a substrate material comprising a surface;
dipping the substrate material in a solution including colloidal silica and a carrier, the colloidal silica having a particle size of about 12-100 nm; and
withdrawing the substrate material to provide an unsintered porous layer having a thickness of about 0.1-1 microns and a porosity of of about 10-90% on the substrate material.
Also provided is a method of forming a porous substrate, the method comprising:
providing a substrate material comprising a surface;
applying a solution including colloidal silica and a carrier to the surface of the substrate material, the colloidal silica having a particle size of about 12-100 nm;
spinning the substrate material and the applied solution to achieve a spun layer on the substrate material; and
removing the carrier from the spun layer to provide an unsintered porous layer having a thickness of about 0.1-1 microns and a porosity of about 10-90% on the substrate material.
Another embodiment
Fidanza Jacqueline A.
Frank Curtis W.
Glazer Marc I.
McGall Glenn
Vinci Richard
Affymetrix Inc.
Morris Terrel
Vo Hai
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