Sensor surface for surface plasmon resonance assays
The present invention relates to a method for production of an improved sensor surface for an SPR instrument, comprising forming a self assembled monolayer (SAM) on a surface and attaching ligands and protein resistant groups, preferably polyethylene glycol (PEG), directly to functional groups on said surface. The invention also relates to a sensor surface produced by these methods use thereof in SPR (surface plasmon resonance) assays or interactions.
1. A method for preparing a sensor surface for a surface plasmon resonance (SPR) instrument, comprising forming a self assembled monolayer (SAM) on a surface by reacting said surface with one or more thiol C10-C30 alkane reagent(s) having at least one type of functional groups, wherein one or more protein resistant compound(s) is/are coupled to a first fraction of said functional group(s), wherein the one or more protein resistant compound(s) comprise polyethylene glycol (PEG) or a derivative thereof; and wherein one or more capturing molecule(s) is/are coupled directly or via a linker which is not said protein resistant compound(s) to a second fraction of said functional group(s) on said surface, wherein no capturing molecule(s) is/are coupled to the protein resistant compound(s), wherein the second fraction of said functional group(s) comprises a portion of the at least one type of functional groups not coupled to the one or more protein resistant compound(s) after the coupling of the protein resistant compound(s) via the first fraction of the functional group(s), and wherein the first and second fraction of said functional group(s) are of the same or different type.
2. The method according to claim 1 , wherein the surface is a metal plated surface.
3. The method according to claim 1 , wherein the functional group of the one or more C10-C30 thiol alkane reagent(s) is one or more of a carboxyl, a hydroxyl, an amino, an aldehyde, an epoxy, a vinyl, a carbonyl or thiol group.
4. The method according to claim 1 , wherein the C10-C30 thiol alkane reagent is MHA (mercapto hexadecanoic acid) or derivatives thereof.
5. The method according to claim 1 , wherein the one or more protein resistant compound(s) have a molecular weight (mw)<20000.
6. The method according to claim 1 , wherein the polyethylene glycol (PEG) has a mw of 100-20000.
7. The method according to claim 1 , wherein the second fraction of the functional group(s) are activated with an activation reagent before coupling of the one or more capturing molecule(s) and an amount of the one or more capturing molecule(s) coupled to the second fraction of the functional group(s) is inversely proportional to a length of activation time; and wherein the activation reagent is selected from N-Ethyl-N′-(3-Dimethylaminopropyl) Carbodiimide/N-Hydroxy-succinimide (EDC/NHS), epichlorhydrine or bifunctional reagents.
8. A method for running an SPR assay using a sensor surface produced according to claim 1 , comprising adding an analyte; interacting the analyte with the capturing molecule on the sensor surface and performing a kinetic assay and/or concentration assay.
9. A sensor surface produced according to claim 1 , comprising a substrate with a self assembled monolayer (SAM) provided with functional group(s) available on said SAM, wherein the SAM is a thiol-alkane C10-C30, wherein a protein resistant compound is coupled to a first fraction of the functional group(s), wherein the protein resistant compound is polyethylene glycol (PEG) or a derivative thereof, and wherein a capturing molecule is coupled to a second fraction of the functional group(s) on the surface, and wherein no capturing molecule is coupled to the protein resistant compound, wherein the second fraction of said functional group(s) comprises a portion of said functional group(s) not coupled to the protein resistant compound after the coupling of the protein resistant compound via the first fraction of the functional group(s), and wherein the first and second fraction of said functional group(s) are of the same or different type.
10. The sensor surface according to claim 9 , wherein the protein resistant compound and the capturing molecule are coupled to the same type of functional group.
11. The sensor surface according to claim 9 , wherein the protein resistant compound and the capturing molecule are coupled to different types of functional groups.
12. The sensor surface according to claim 9 , wherein the surface is a metal plated surface and the thiol-alkane C10-C30 is MHA-SAM.
13. The sensor surface according to claim 9 , wherein the protein resistant compound is PEG mw 5000 in a concentration of 0.5-5 mM.