High density molecular arrays on porous surfaces

Abstract

The present invention provides a unique and highly accurate method for generating molecular arrays of very high density on porous surfaces. The method involves the application of focused acoustic energy to each of a plurality of fluid-containing reservoirs to eject a small fluid droplet—on the order of 1 picoliter or less—from each reservoir to a site on a porous substrate surface. High density molecular arrays are provided as well, in which greater than about 62,500 molecular moieties, serving as array elements, are present on a porous surface. Biomolecular arrays that can be generated using focused acoustic ejection include oligonucleotide arrays and peptidic arrays.

We claim:  
     
         1 . A method for generating an array of molecular moieties on a porous substrate surface divided into a plurality of discrete surface sites, the method comprising successively applying focused acoustic energy to each of a plurality of reservoirs each containing a molecular moiety in a fluid, wherein the focused acoustic energy is applied by (a) acoustically coupling an acoustic ejector comprised of an acoustic radiation generator and a focusing means to one of the reservoirs and then (b) activating the acoustic ejector in a manner effective to eject a droplet from the reservoir toward the porous substrate surface, and repeating (a) and (b) with each of the reservoirs in succession such that the molecular moiety in each droplet attaches to a localized region within a discrete surface site, wherein no longer than about 1 second elapses between each repetition of (a).  
     
     
         2 . The method of  claim 1 , wherein each molecular moiety is different.  
     
     
         3 . The method of  claim 2 , wherein a droplet is ejected toward each surface site, such that every surface site has a molecular moiety attached thereto.  
     
     
         4 . The method of  claim 3 , wherein each molecular moiety is different.  
     
     
         5 . The method of  claim 1 , wherein the molecular moieties are biomolecules.  
     
     
         6 . The method of  claim 5 , wherein the biomolecules are nucleotidic.  
     
     
         7 . The method of  claim 6 , wherein the biomolecules are oligonucleotides.  
     
     
         8 . The method of  claim 7 , wherein the biomolecules are nucleotidic monomers, and the method further comprises stepwise synthesis of an oligonucleotide within each surface site by repeated deposition of individual nucleotidic monomers at each site using focused acoustic energy.  
     
     
         9 . The method of  claim 5 , wherein the biomolecules are peptidic.  
     
     
         10 . The method of  claim 3 , wherein the porous substrate surface is comprised of at least 62,500 discrete surface sites.  
     
     
         11 . The method of  claim 10 , wherein the porous substrate surface is comprised of at least 250,000 discrete surface sites.  
     
     
         12 . The method of  claim 11 , wherein the porous substrate surface is comprised of at least 1,000,000 discrete surface sites.  
     
     
         13 . The method of  claim 12 , wherein the porous substrate surface is comprised of at least 1,500,000 discrete surface sites.  
     
     
         14 . The method of  claim 1 , wherein no longer than about 0.1 seconds elapses between each repetition of (a).  
     
     
         15 . The method of  claim 14 , wherein no longer than about  0 . 001  seconds elapses between each repetition of (a).  
     
     
         16 . The method of  claim 1 , wherein the acoustic ejector and the reservoirs move continuously throughout the method until the array is generated.  
     
     
         17 . The method of  claim 16 , wherein the acoustic ejector and the reservoirs are moved at a rate effective to provide reservoir transitions of over 10 Hz.  
     
     
         18 . The method of  claim 17 , wherein the acoustic ejector and the reservoirs are moved at a rate effective to provide reservoir transitions of over 100 Hz.  
     
     
         19 . A method for generating an array of molecular moieties on a porous substrate surface divided into a plurality of discrete surface sites, the method comprising applying focused acoustic energy to each of a plurality of reservoirs each containing a molecular moiety in a fluid, wherein the distance between the centers of any two adjacent reservoirs is less than about 1 centimeter, and further wherein the focused acoustic energy is applied using an acoustic ejector comprised of an acoustic radiation generator and a focusing means in a manner effective to eject a droplet from each reservoir toward the substrate surface such that the molecular moiety in each droplet attaches to a localized region within a discrete surface site.  
     
     
         20 . The method of  claim 19 , wherein each molecular moiety is different.  
     
     
         21 . The method of  claim 20 , wherein a droplet is ejected toward each surface site, such that every surface site has a molecular moiety attached thereto.  
     
     
         22 . The method of  claim 21 , wherein each molecular moiety is different.  
     
     
         23 . The method of  claim 19 , wherein the molecular moieties are biomolecules.  
     
     
         24 . The method of  claim 23 , wherein the biomolecules are nucleotidic.  
     
     
         25 . The method of  claim 24 , wherein the biomolecules are oligonucleotides.  
     
     
         26 . The method of  claim 25 , wherein the biomolecules are nucleotidic monomers, and the method further comprises stepwise synthesis of an oligonucleotide within each surface site by repeated deposition of individual nucleotidic monomers at each site using focused acoustic energy.  
     
     
         27 . The method of  claim 23 , wherein the biomolecules are peptidic.  
     
     
         28 . The method of  claim 21 , wherein the porous substrate surface is comprised of at least 62,500 discrete surface sites.  
     
     
         29 . The method of  claim 28 , wherein the porous substrate surface is comprised of at least 250,000 discrete surface sites.  
     
     
         30 . The method of  claim 29 , wherein the porous substrate surface is comprised of at least 1,000,000 discrete surface sites.  
     
     
         31 . The method of  claim 30 , wherein the porous substrate surface is comprised of at least 1,500,000 discrete surface sites.  
     
     
         32 . The method of  claim 19 , wherein the distance between the centers of any two adjacent reservoirs is less than about 1 millimeter.  
     
     
         33 . The method of  claim 32 , wherein the distance between the centers of any two adjacent reservoirs is less than about 0.5 millimeter.  
     
     
         34 . The method of  claim 33 , wherein at least one of the reservoirs is adapted to contain more than about 100 nanoliters of fluid.  
     
     
         35 . The method of  claim 34 , wherein at least one of the reservoirs is adapted to contain more than about 10 nanoliters of fluid.  
     
     
         36 . The method of  claim 34 , wherein the reservoirs are adapted to contain more than about 100 nanoliters of fluid.  
     
     
         37 . The method of  claim 36 , wherein the reservoirs are adapted to contain more than about 10 nanoliters of fluid.  
     
     
         38 . The method of  claim 37 , wherein each of the ejected droplets has a volume of about 1 pL or less.  
     
     
         39 . The method of  claim 38 , wherein each of the ejected droplets has a volume in the range of about 0.025 pL to about 1 pL.