Patterning and alteration of molecules

Abstract

The present invention provides a series of methods, compositions, and articles for patterning a surface with multiple, aligned layers of molecules, by exposing the molecules to electromagnetic radiation. In certain embodiments, a single photomask acts as an area-selective filter for light at multiple wavelengths. A single set of exposures of multiple wavelengths through this photomask may make it possible to fabricate a pattern comprising discontinuous multiple regions, where the regions differ from each other in at least one chemical and/or physical property, without acts of alignment between the exposures. In certain embodiments, the surface includes molecules attached thereto that can be photocleaved upon exposure to a certain wavelength of radiation, thereby altering the chemical composition on at least a portion of the surface. In some embodiments, the molecules attached to the surface may include thiol moieties (e.g., as in alkanethiol), by which the molecule can become attached to the surface. In some embodiments, the molecules may be terminated at the unattached end with photocleavable groups. In other embodiments, a molecule that was photocleaved may be exposed to another molecule that binds to the photocleaved molecule. In certain cases, the molecules may be terminated at the unattached end with hydrophilic groups that may, for example, be resistant to the adsorption of proteins. In other cases, the molecules may be terminated at the unattached end with end groups that are not resistant to the adsorption of proteins. In certain embodiments, the techniques are used to pattern simultaneously two different regions that are resistant to the adsorption of proteins, and a third region that does not resist the adsorption of proteins.

1 . A method comprising acts of: 
 providing a surface, at least a portion of which comprises molecules attached thereon;    exposing the surface to electromagnetic radiation; and    altering the layer of molecules with the electromagnetic radiation to form a pattern comprising at least a first, second, and third region, wherein    the first, second, and third regions differ from each other in at least one chemical and/or physical characteristic.    
     
     
         2 . A method as in  claim 1 , wherein the molecules are arranged on the surface in a layer.  
     
     
         3 . A method as in  claim 2 , wherein the layer comprises a monolayer.  
     
     
         4 . A method as in  claim 3 , wherein the monolayer comprises a SAM.  
     
     
         5 . A method as in  claim 1 , wherein the first, second, and third regions differ from each other in their hydrophobicity, ability to resist binding of proteins, ability to bind to cells, and/or ability to be etched by exposure to an etching solution.  
     
     
         6 . A method as in  claim 1 , wherein at least one of the first, second, and third regions of the pattern is non-continuous.  
     
     
         7 . A method as in  claim 1 , wherein each of the first, second, and third regions of the pattern is non-continuous.  
     
     
         8 . A method as in  claim 1 , wherein the at least a first, second, and third region of the pattern are formed simultaneously.  
     
     
         9 . A method as in  claim 8 , wherein the pattern is formed upon exposing the surface to only a single exposure of the electromagnetic radiation.  
     
     
         10 . A method as in  claim 1 , wherein the exposing act comprises exposing the surface to light of at least a first wavelength and a second wavelength.  
     
     
         11 . A method as in  claim 10 , wherein the exposing act comprises passing light through a photomask having a first region that is substantially transparent to light at the first wavelength but is not substantially transparent to light at the second wavelength.  
     
     
         12 . A method as in  claim 11 , wherein the photomask comprises a second region that is substantially transparent to light at the first wavelength and to light at the second wavelength, and a third region that is not substantially transparent to light at the first or second wavelengths.  
     
     
         13 . A method as in  claim 1 , wherein in the altering act, the pattern is formed by chemically and/or physically altering molecules attached to the surface.  
     
     
         14 . A method as in  claim 13 , wherein at least the first region of the pattern is formed via cleavage of at least a portion a molecular species attached on the surface within the first region.  
     
     
         15 . A method as in  claim 14 , wherein at least the second region of the pattern is formed via cleavage of at least a portion a molecular species attached on the surface within the second region.  
     
     
         16 . A method as in  claim 15 , wherein a point of cleavage of the molecular species attached on the surface within the first region is different from a point of cleavage of the molecular species attached on the surface within the second region.  
     
     
         17 . A method as in  claim 16 , wherein the point of cleavage of the molecular species attached on the surface within the second region comprises a bond formed between the surface and the molecular species.  
     
     
         18 . A method as in  claim 13 , further comprising after the altering act: 
 exposing at least a portion of the surface with another entity to form a new chemical species attached to the surface.    
     
     
         19 . A method as in  claim 13 , further comprising: 
 exposing at least a portion of molecules that have been chemically and/or physically altered in the altering step with another entity to form a new chemical species attached to the surface.    
     
     
         20 . A method as in  claim 16 , wherein the molecules attached to the surface comprise a SAM-forming species that has been bound to the surface, so that the layer of molecules attached to the surface comprises a SAM.  
     
     
         21 . A method as in  claim 20 , wherein the layer of molecules comprises an alkane thiol that has been bound to the surface.  
     
     
         22 . A method as in  claim 21 , wherein the surface comprises Au, Ag, Pt, Pd, and/or Cu.  
     
     
         23 . A method as in  claim 20 , wherein the SAM-forming species that has been bound to the surface comprises at least a first photoclevable moiety that is able to be cleaved with light having a first wavelength of at least 250 nm.  
     
     
         24 . A method as in  claim 23 , wherein the SAM-forming species that has been bound to the surface further comprises at least one bond connecting at least a portion of a molecule of the species to the surface that is able to be cleaved with light having a wavelength of at least 200 nm but less than the first wavelength.  
     
     
         25 . A method as in  claim 23 , wherein the SAM-forming species that has been bound to the surface does not require presence of scavenger molecules during photocleavage.  
     
     
         26 - 27 . (canceled)  
     
     
         28 . A method as recited in  claim 16 , wherein the molecules attached to the surface comprise a silane moiety containing species that has been bound to the surface.  
     
     
         29 . A method as in  claim 28 , wherein the surface comprises Si atoms.  
     
     
         30 . A method as in  claim 29 , wherein the surface comprises glass.  
     
     
         31 . (canceled)  
     
     
         32 . A method as in  claim 31 , wherein at least one region of the pattern is characterized by a smallest cross-sectional dimension not exceeding about 10 microns.  
     
     
         33 . A method as in  claim 32 , wherein at least one region of the pattern is characterized by a smallest cross-sectional dimension not exceeding about 1 micron.  
     
     
         34 . (canceled)  
     
     
         35 . A composition, comprising: 
 a compound having a structure:      X—R-Q,    wherein X is an attachment moiety able to chemically bind a surface, Q comprises a photocleavable moiety, and R is a moiety connecting X and Q.    
     
     
         36 - 81 . (canceled)  
     
     
         82 . An article, comprising:  
       
         
           
           
               
               
           
         
         wherein | comprises a surface, X is an attachment moiety able to chemically bind a surface, Q comprises a photocleavable moiety, and R is a moiety connecting X and Q, such that  
         
           
             
             
                 
                 
             
           
         
         is not:  
         
           
             
             
                 
                 
             
           
         
       
     
     
         83 - 96 . (canceled)