SERS Reporter Molecules and Methods
A SERS tag comprising a core comprising at least two aggregated particles of a SERS enhancing material wherein the contact point between the particles defines a crevice; and a reporter molecule having a length sufficiently short to fit into the crevice and a conjugated path length which is as large as possible, provided the overall reporter molecule length is maintained sufficiently short to fit into the crevice.
1 . A SERS reporter molecule comprising:
a reporter molecule having a length sufficiently short to fit into a crevice formed by the enhancing surfaces of adjacent enhancement particles; and
a conjugated path length which is as large as possible, provided the overall molecule length is maintained sufficiently short to fit into the crevice formed by the enhancing surfaces of adjacent enhancement particles.
2 . The SERS reporter molecule of claim 1 wherein the reporter molecule length is selected or fabricated to be less than or equal to 1.2 nm.
3 . The SERS reporter molecule of claim 1 wherein the reporter molecule comprises one of 1,8-diethynyl-4,5-bis(4-pyridylethenyl)anthracene, 1,8,9-triethynyl-10-(4-pyridylethenyl)anthracene, 6,13-bisethynylpentacene, 5,7,12,14-tetraethynylpentacene, 9,10-bisethynylanthracene, 1,4,5,8,9,10-hexaethynylanthracene, 1,8-bisethynylanthracene, 9-ethynyl-10-(4-pyridylethynyl)anthracene, 1,8,9-tris(4-pyridyl)anthracene, 1,8-bis(4-pyridyl)-10-(4-pyridylethynyl)anthracene, 1,8-bis(4-pyridyl)-10-ethynylanthracene, 1,8-bis-(4-pyridyl)-10-(4-pyridylazo)anthracene, and 1,8-diethynyl-10-(4-pyridylazo)anthracene.
4 . The SERS reporter molecule of claim 1 further comprising at least one aromatic ring conjugated with one or more unsaturated groups.
5 . The SERS reporter molecule of claim 1 further comprising two or more metal binding groups.
6 . The SERS reporter molecule of claim 5 further comprising two or more metal binding groups that are no more than 1.2 nm apart.
7 . The SERS reporter molecule of claim 1 comprising at least one functional group capable of forming a stable bond with the enhancing surface, such that the bond positions the molecule in an orientation that is perpendicular to the enhancing surface.
8 . The SERS reporter molecule of claim 7 wherein the functional group comprises one of pyridyl, monosubstituted ethynyl or a thiol group.
9 . A SERS tag comprising:
a core comprising at least two aggregated particles of a SERS enhancing material wherein the contact point between the particles defines a crevice; and
a reporter molecule having a length sufficiently short to fit into the crevice and a conjugated path length which is as large as possible, provided the overall reporter molecule length is maintained sufficiently short to fit into the crevice.
10 . The SERS tag of claim 9 wherein the reporter molecule length is selected or fabricated to be less than or equal to 1.2 nm.
11 . The SERS tag of claim 9 wherein the reporter molecule comprises one of 1,8-diethynyl-4,5-bis(4-pyridylethenyl)anthracene, 1,8,9-triethynyl-10-(4-pyridylethenyl)anthracene, 6,13-bisethynylpentacene, 5,7,12,14-tetraethynylpentacene, 9,10-bisethynylanthracene, 1,4,5,8,9,10-hexaethynylanthracene, 1,8-bisethynylanthracene, 9-ethynyl-10-(4-pyridylethynyl)anthracene, 1,8,9-tris(4-pyridyl)anthracene, 1,8-bis(4-pyridyl)-10-(4-pyridylethynyl)anthracene, 1,8-bis(4-pyridyl)-10-ethynylanthracene, 1,8-bis-(4-pyridyl)-10-(4-pyridylazo)anthracene, and 1,8-diethynyl-10-(4-pyridylazo)anthracene.
12 . The SERS tag of claim 9 further comprising at least one aromatic ring conjugated with one or more unsaturated groups.
13 . The SERS tag of claim 9 further comprising two or more metal binding groups.
14 . The SERS tag of claim 13 further comprising two or more metal binding groups that are no more than 1.2 nm apart.
15 . The SERS tag of claim 9 comprising at least one functional group capable of forming a stable bond with the enhancing surface, such that the bond positions the molecule in an orientation that is perpendicular to the enhancing surface.
16 . The SERS tag of claim 15 wherein the functional group comprises one of pyridyl, monosubstituted ethynyl or a thiol group.
17 . A method of selecting a SERS reporter molecule to optimize the enhancement of the SERS signal provided by said reporter molecule upon excitation in association with a particulate or colloidal enhancing surface, said method comprising:
selecting or fabricating a reporter molecule length to be sufficiently short to fit into a crevice formed by the enhancing surfaces of adjacent enhancement particles; and
selecting or fabricating the reporter molecule to have as high a conjugated path length as is possible provided the overall molecule length is maintained sufficiently short to fit into the crevice formed by the enhancing surfaces of adjacent enhancement particles.
18 . The method of claim 17 wherein the reporter molecule length is selected or fabricated to be less than or equal to 1.2 nm.
19 . The method of claim 17 wherein the reporter molecule is one of 1,8-diethynyl-4,5-bis(4-pyridylethenyl)anthracene, 1,8,9-triethynyl-10-(4-pyridylethenyl)anthracene, 6,13-bisethynylpentacene, 5,7,12,14-tetraethynylpentacene, 9,10-bisethynylanthracene, 1,4,5,8,9,10-hexaethynylanthracene, 1,8-bisethynylanthracene, 9-ethynyl-10-(4-pyridylethynyl)anthracene, 1,8,9-tris(4-pyridyl)anthracene, 1,8-bis(4-pyridyl)-10-(4-pyridylethynyl)anthracene, 1,8-bis(4-pyridyl)-10-ethynylanthracene, 1,8-bis-(4-pyridyl)-10-(4-pyridylazo)anthracene, and 1,8-diethynyl-10-(4-pyridylazo)anthracene.
20 . The method of claim 17 wherein the reporter molecule comprises at least one aromatic ring conjugated with one or more unsaturated groups.
21 . The method of claim 17 further comprising selecting or fabricating the reporter molecule to include two or more metal binding groups.
22 . The method of claim 21 further comprising selecting or fabricating the reporter molecule to have two or more metal binding groups that are no more than 1.2 nm apart.
23 . The method of claim 17 wherein the reporter molecule comprises at least one functional group capable of forming a stable bond with the enhancing surface, such that the bond positions the molecule in an orientation that is perpendicular to the enhancing surface.
24 . The method of claim 23 wherein the reporter molecule comprises one of pyridyl, monosubstituted ethynyl or a thiol group.