Liquid core photonic crystal fiber biosensors using surface enhanced raman scattering and methods for their use

Abstract

The invention is drawn to a photonic crystal fiber that can be used with nanoparticles to detect and quantify components in a test sample. The invention further relates to methods of using the photonic crystal fiber for detecting chemical and biological analytes, and in use in optical communications.

We claim: 
     
         1 . A photonic crystal fiber, the fiber comprising a proximal end and a distal end, the ends defining a first lumen through the fiber, the fiber further comprising an outer surface, the first lumen comprising an inner surface, a plurality of second lumens, wherein both ends of the fiber comprises a plurality of sealed apertures of each second lumen, the inner surface further comprising, in part, a first metallic nanoparticle composition. 
     
     
         2 . The photonic crystal fiber of  claim 1 , the inner surface further comprising, in part, a second metallic nanoparticle composition. 
     
     
         3 . The photonic crystal fiber of  claim 1 , the outer surface further comprising, in part, a metallic nanoparticle composition. 
     
     
         4 . The photonic crystal fiber of  claim 1 , wherein the lumen further comprises a solid composition. 
     
     
         5 . The photonic crystal fiber of  claim 1  wherein the photonic crystal fiber has a cylindrical shape and having an approximately circular cross-section. 
     
     
         6 . The photonic crystal fiber of  claim 1  wherein the photonic crystal fiber is flexible. 
     
     
         7 . The photonic crystal fiber of  claim 1  wherein the lumen further comprises a composition, the composition selected from the group consisting of a liquid, a plasma, and a gas. 
     
     
         8 . The photonic crystal fiber of  claim 1 , wherein the first metallic nanoparticle composition comprises a double substrate sandwich structure. 
     
     
         9 . The photonic crystal fiber of  claim 1 , wherein the first metallic nanoparticle composition comprises a single layer. 
     
     
         10 . The photonic crystal fiber of  claim 1 , wherein the first metallic nanoparticle composition comprises a plurality of layers. 
     
     
         11 . The photonic crystal fiber of  claim 1 , wherein the metallic nanoparticle composition comprises a metal selected from the group consisting of gold, silver, platinum, copper, aluminum, palladium, cadmium, iridium, and rhodium. 
     
     
         12 . The photonic crystal fiber of  claim 11  wherein the metal is silver. 
     
     
         13 . The photonic crystal fiber of  claim 1  wherein the first metallic nanoparticle composition comprises silver citrate. 
     
     
         14 . The photonic crystal fiber of  claim 1  wherein the cross-section of the photonic crystal fiber has dimensions selected from the group consisting of about between 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, and 100 μm. 
     
     
         15 . The photonic crystal fiber of  claim 1  wherein the length of the photonic crystal fiber has dimensions of about between 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1 cm, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm, 25 cm, 30 cm, 35 cm, 40 cm, 45 cm, 50 cm, 55 cm, 60 cm, 65 cm, 70 cm, 75 cm, 80 cm, 85 cm, 90 cm, 95 cm, and 100 cm 
     
     
         16 . The photonic crystal fiber of  claim 1  wherein the cross-section of the lumen of the photonic crystal fiber has dimensions of about between 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, and 100 μm. 
     
     
         17 . The photonic crystal fiber of  claim 3 , wherein the metallic nanoparticle composition comprises a double substrate sandwich structure. 
     
     
         18 . The photonic crystal fiber of  claim 3 , wherein the metallic nanoparticle composition comprises a single layer. 
     
     
         19 . The photonic crystal fiber of  claim 3 , wherein the metallic nanoparticle composition comprises a plurality of layers. 
     
     
         20 . The photonic crystal fiber of  claim 3 , wherein the metallic nanoparticle composition comprises a metal selected from the group consisting of gold, silver, platinum, copper, aluminum, palladium, cadmium, iridium, and rhodium. 
     
     
         21 . The photonic crystal fiber of  claim 20  wherein the metal is silver. 
     
     
         22 . The photonic crystal fiber of  claim 3  wherein the metallic nanoparticle composition comprises silver citrate. 
     
     
         23 . A method for sensing an analyte in a test sample, the method comprising the steps of: (i) providing the photonic crystal fiber of  claim 1 ; (ii) providing a test sample; (iii) immersing the photonic crystal fiber in the test sample; (iv) irradiating the photonic crystal fiber and the test sample with an excitation light, the excitation light having a wavelength in the visible to the near infra-red (near-IR) portion of the spectrum; (v) measuring the Raman spectrum of a photonic crystal fiber of  claim 1  and a control sample, thereby determining the background Raman spectrum; (vi) detecting the surface enhanced Raman scattering (SERS) signal emitted from the photonic crystal fiber and the test sample; (vii) measuring the Raman spectrum of the photonic crystal fiber and the test sample, thereby determining the analyte Raman spectrum; subtracting the background Raman spectrum from the analyte Raman spectrum, thereby sensing the analyte in the sample; (viii) determining the enhancement factor of the SERS signal from the control sample; (ix) determining the enhancement factor of the SERS signal from the test sample; wherein the enhancement factor of the SERS signal from the test sample is at least 100-fold compared with a SERS signal from the control sample, the method resulting in sensing the analyte. 
     
     
         24 . The method of  claim 23 , wherein the analyte is a biological composition. 
     
     
         25 . The method of  claim 24 , wherein the biological composition is selected from the group consisting of a protein, a peptide, a polyketide, an antibody, an antigen, a nucleic acid, a peptide nucleic acid, a sugar, a lipid, a glycophosphoinositol, and a lipopolysaccharide. 
     
     
         26 . The method of  claim 23  wherein the analyte is selected from the group consisting of an explosive, a chemical warfare agent, a biological warfare agent, a toxin, a virus particle, and a biological cell. 
     
     
         27 . A method for measuring the quantity of an analyte in a test sample, the method comprising the steps of: (i) providing the photonic crystal fiber of  claim 1 ; (ii) providing a test sample; (iii) immersing the photonic crystal fiber in the test sample; (iv) irradiating the photonic crystal fiber and the test sample with an excitation light, the excitation light having a wavelength in the visible to the near infra-red (near-IR) portion of the spectrum; (v) measuring the Raman spectrum of a photonic crystal fiber of  claim 1  and a control sample, thereby determining the background Raman spectrum; (vi) detecting the surface enhanced Raman scattering (SERS) signal emitted from the photonic crystal fiber and the test sample; (vii) measuring the Raman spectrum of the photonic crystal fiber and the test sample, thereby determining the analyte Raman spectrum; subtracting the background Raman spectrum from the analyte Raman spectrum, thereby determining the quantity of the analyte in the sample; (viii) determining the enhancement factor of the SERS signal from the control sample; (ix) determining the enhancement factor of the SERS signal from the test sample; wherein the enhancement factor of the SERS signal from the test sample is at least 100-fold compared with a SERS signal from the control sample, the method resulting in measuring the quantity of the analyte. 
     
     
         28 . The method of  claim 27 , wherein the analyte is a biological composition. 
     
     
         29 . The method of  claim 28 , wherein the biological composition is selected from the group consisting of a protein, a peptide, a polyketide, an antibody, an antigen, a nucleic acid, a peptide nucleic acid, a sugar, a lipid, a glycophosphoinositol, and a lipopolysaccharide. 
     
     
         30 . The method of  claim 27  wherein the analyte is selected from the group consisting of an explosive, a chemical warfare agent, a biological warfare agent, a toxin, a virus particle, and a biological cell.