Methods and devices for biomolecular arrays
Provided herein are methods of assembling high density biomolecular arrays. The disclosed methods and devices combine a photolithographic step with the assembly of particles conjugated to biomolecules. The methods provided herein are particularly useful for the assembly of large, high density biomolecular arrays like protein arrays for chip-based assays and DNA arrays for genomic analysis.
1. A method for rapidly assembling a high density biomolecular array, the method comprising the steps of:
a) patterning an array of wells into photoresist on a surface by photolithography;
b) assembling a suspension of magnetic biomolecular particles into the array of wells;
c) immobilizing the magnetic biomolecular particles to the surface via affinity binding; and
d) removing the unbound suspension of magnetic biomolecular particles and photoresist from the surface to provide the high density biomolecular array.
2. The method of claim 1 , wherein the suspension of magnetic biomolecular particles is a suspension of superparamagnetic microbeads conjugated to a biomolecule, wherein the superparamagnetic microbeads are assembled into the array of wells using a magnet.
3. The method of claim 1 , wherein the surface is a glass surface.
4. The method of claim 3 , wherein the glass surface is derivatized with silane and biotin, and/or avidin and/or streptavidin.
5. The method of claim 4 , wherein the glass surface is spin-coated with photoresist.
6. The method of claim 5 , wherein the photoresist is sold under the trademark MICROPOSIT™ S1805™.
7. The method of claim 6 , wherein the array of wells are patterned by photolithography using a 0.2 second exposure to 365 nM light (−475 mW/cm 2 ) through a chrome-on-quartz photomask using a wafer stepper system sold under the trademark GCA™ Autostep™ 200) equipped with a lens sold under the trademark Olympus™ 2145 (5× reduction/0.45 NA).
8. The method of claim 7 , wherein the size of the array of wells varies with the exposure and chemical etching parameters of the photolithography technique.
9. The method of claim 8 , wherein the array of wells has a density of about 100 million wells per square centimeter.
10. The method of claim 9 , wherein the array of wells has a parabolic geometry wherein the top of a well is about 600 nm in diameter and the bottom of a well is about 250 nm in diameter.
11. The method of claim 2 , wherein the superparamagnetic microbeads are coated with biotin, and/or avidin and/or streptavidin.
12. The method of claim 11 , wherein the superparamagnetic microbeads are suspended in a buffer.
13. The method of claim 12 , wherein the assembly of the superparamagnetic microbeads into the array of wells occurs in a flow cell.
14. The method of claim 13 , wherein the superparamagnetic microbeads are assembled into the array of wells using a neodymium iron boron magnet.
15. The method of claim 14 , wherein each well contains a single superparamagnetic microbead.
16. The method of claim 15 , wherein the superparamagnetic microbeads are immobilized in the array of wells via biotin-avidin and/or biotin-streptavidin affinity binding.
17. The method of claim 2 , wherein the high density biomolecular array is a high density protein array, or a high density DNA array of biomolecules.