Metal-enhanced fluorescence from plastic substrates
The present invention relates to methods for functionally modifying a polymeric surface for subsequent deposition of metallic particles and/or films, wherein the polymeric surface is modified by increasing hydroxyl and/or amine functional groups thereby providing an activated polymeric surface for deposition of metallic particles to form a fluorescence sensing device. The device can be used for metal-enhanced fluorescence of fluorophores positioned above the metallic particles that can be readily applied to diagnostic or sensing applications of metal-enhanced fluorescence.
1. A method for depositing a noble metal on a polymeric surface, the method comprising:
a) providing a polymeric material with low density of hydroxyl surface functionality;
b) modifying the polymeric material with a chemical or physical etching agent, wherein the modified polymeric material comprises an increased number of exposed hydroxyl groups or amine group on the polymeric surface relative to an unmodified surface;
c) silylating the modified polymeric material with an amine containing silane to provide an amino-terminated polymeric material; and
d) depositing a noble metal on the amino-terminated polymeric material.
2. The method according to claim 1 , wherein the polymeric material is selected from the group consisting of polyamide, polycarbonate, polyester, polyetherimide, polyimide, polynitrocellulose, polyethylene, polypropylene, poly(ethylenevinylacetate), poly-2-pentene, polyphenylene oxide, polyphenylene sulfide, polysulfone, and polystyrene.
3. The method according to claim 1 , where in the polymeric material is polycarbonate.
4. The method according to claim 1 , wherein the chemical etching agent is selected from the group consisting of NaOH, NH 4 OH, LiOH, KOH or N(CH 3 ) 4 OH.
5. The method according to claim 1 , wherein the amine-containing silane is selected from the group consisting of 3-(aminopropyl)triethoxysilane (APS), dimethylsilyldimethyl amine (DMSDMA), 1,1,3,3-tetramethyl disilazane (TMDS), N,N-dimethylamino trimethylsilane (TMSDMA), N,N-diethylaminotrimethylsilane (TMSDEA), hexamethyldisilazane (HMDS), Bis(dimethylamino)methylsilane, Bis-(dimethylamino)dimethylsilane and 1,1,3,3,5,5-hexamethylcyclotrisilazane (HMCTS).
6. The method according to claim 1 , wherein the amine-containing silane is 3-(aminopropyl)triethoxysilane (APS).
7. The method according to claim 1 , further comprising applying to the metal surface a spacer to provide a required distance from the metal surface to a fluorophore for metal enhanced fluorescence of the fluorophore.
8. A method for forming a patterned metallic surface on a polymeric substrate, the method comprising:
(a) providing a carbonate polymeric substrate;
(b) etching the surface of the polymeric substrate with an etching agent to increase hydroxyl groups on the surface of polymer substrate relative to an unetched polymeric surface;
(c) contacting the polymeric substrate having increased hydroxyl groups with a silylating agent to replace at least some of the hydroxyl groups with amine groups to form an amino-activated surface; and
(d) depositing noble metal particles on the amino-activated polymeric substrate.
9. The method according to claim 8 , wherein etching the surface of the polymeric substrate is performed in aqueous NaOH at a temperature ranging from about 15° C. to about 45° C. for a time ranging from about 1 minute to about 1 hour.
10. The method according to claim 8 wherein etching the surface of the polymeric substrate is performed by irradiation of the surface of the substrate with a dose of UV radiation, in the presence of oxygen.
11. The method according to claim 8 , wherein the silylating agent is selected from the group consisting of 3-(aminopropyl)triethoxysilane (APS), dimethylsilyldimethyl amine (DMSDMA), 1,1,3,3-tetramethyl disilazane (TMDS), N,N-dimethylamino trimethylsilane (TMSDMA), N,N-diethylaminotrimethylsilane (TMSDEA), hexamethyldisilazane (HMDS), Bis (dimethylamino)methylsilane, Bis-(dimethylamino)dimethylsilane and 1,1,3,3,5,5-hexamethylcyclotrisilazane (HMCTS).