Patterning and alteration of molecules
A series of methods, compositions, and articles for patterning a surface with multiple, aligned layers of molecules, by exposing the molecules to electromagnetic radiation is provided. 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.
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 self-assembled monolayer.
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 exposing act comprises exposing the surface to light of at least a first wavelength and a second wavelength.
9. 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.
10. A method as in claim 4 , wherein the at least a first, second, and third region of the pattern are formed simultaneously.
11. A method as in claim 4 , wherein the pattern is formed upon exposing the surface to only a single exposure of the electromagnetic radiation.
12. A method as in claim 8 , 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.
13. A method as in claim 12 , 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.
14. A method as in claim 9 , 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 9 , 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.
16. A method as in claim 9 , 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.
17. 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.
18. A method as in claim 17 , 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.
19. A method as in claim 18 , 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.
20. A method as in claim 18 , wherein the molecules attached to the surface comprise a self-assembled monolayer-forming species that has been bound to the surface, so that the layer of molecules attached to the surface comprises a self-assembled monolayer.
21. A method as recited in claim 18 , wherein the molecules attached to the surface comprise a silane moiety containing species that has been bound to the surface.
22. A method as in claim 20 , wherein the layer of molecules comprises an alkane thiol that has been bound to the surface.
23. A method as in claim 22 , wherein the surface comprises Au, Ag, Pt, Pd, and/or Cu.
24. A method as in claim 20 , wherein the self-assembled monolayer-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.
25. A method as in claim 24 , wherein the self-assembled monolayer-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.
26. A method as in claim 24 , wherein the self-assembled monolayer-forming species that has been bound to the surface does not require presence of scavenger molecules during photocleavage.
27. A method as in claim 21 , wherein the surface comprises Si atoms.
28. A method as in claim 27 , wherein the surface comprises glass.
29. A method as in claim 1 , wherein at least one region of the pattern is characterized by a smallest cross-sectional dimension not exceeding about 10 microns.
30. A method as in claim 1 , wherein at least one region of the pattern is characterized by a smallest cross-sectional dimension not exceeding about 1 micron.