Novel gold nanoparticle aggregates and their applications

Abstract

The invention is drawn to novel gold nanoparticles that are used in a dual optical method for sensitive and selective detection of antigens. The gold nanoparticle aggregates are synthesized from gold hydrochloride and sulfur salts in an aqueous solution. The aggregates can be selectively sized using a spectral notch filter that results in an improved product with versatile uses. The gold nanoparticles can also be used in improved optical communications devices.

1 . A chemical sensor comprising a plurality of particles, each particle comprising: a core, a shell having at least one surface and having contact with the core and wherein the shell comprises a sulfur-oxygen molecular species, and wherein the particle has been selectively sized using a notch filter and electromagnetic radiation, the electromagnetic radiation having a spectral wavelength of between about 350 nm and about 1075 nm. 
     
     
         2 . The chemical sensor of  claim 1  wherein the core comprises a metal selected from the group consisting of gold, silver, platinum, copper, aluminum, palladium, cadmium, iridium, and rhodium. 
     
     
         3 . The chemical sensor of  claim 1  wherein the core comprises gold. 
     
     
         4 . The chemical sensor of  claim 1  wherein the shell that further comprises a linker molecule, the linker molecule selected from the group consisting of a thiol group, a sulphide group, a phosphate group, a sulphate group, a cyano group, a piperidine group, an Fmoc group, and a Boc group. 
     
     
         5 . The chemical sensor of  claim 1  wherein the electromagnetic radiation has a spectral wavelength of between about 350 nm and about 650 nm and between about 950 nm and about 1075 nm. 
     
     
         6 . The chemical sensor of  claim 1  wherein the electromagnetic radiation has a spectral wavelength of between about 350 nm and about 775 nm and between about 875 nm and about 1075 mn. 
     
     
         7 . The chemical sensor of  claim 1  wherein the particle has a size in the range of about 60 and 200 nm. 
     
     
         8 . The chemical sensor of  claim 1  further comprising a support. 
     
     
         9 . The chemical sensor of  claim 8  wherein the support comprises a medium that is permeable to an analyte of interest. 
     
     
         10 . The chemical sensor of  claim 1  wherein the surface can induce surface enhanced Raman scattering. 
     
     
         11 . The chemical sensor of  claim 1  further comprising a detecting molecule, wherein the detecting molecule is bound to the surface. 
     
     
         12 . The chemical sensor of  claim 11  wherein the detecting molecule is selected from the group consisting of proteins, peptides, antibodies, antigens, nucleic acids, peptide nucleic acids, sugars, lipids, glycophosphoinositols, and lipopolysaccharides. 
     
     
         13 . The chemical sensor of  claim 11  wherein the detecting molecule is an antibody. 
     
     
         14 . The chemical sensor of  claim 11  wherein the detecting molecule is an antigen. 
     
     
         15 . The chemical sensor of  claim 1  further comprising a semiconductor quantum dot. 
     
     
         16 . The chemical sensor of  claim 15  wherein the semiconductor quantum dot further comprises a linker molecule, the linker molecule selected from the group consisting of a thiol group, a sulphide group, a phosphate group, a sulphate group, a cyano group, a piperidine group, an Fmoc group, and a Boc group. 
     
     
         17 . The chemical sensor of  claim 15  wherein the semiconductor quantum dot further comprises a detecting molecule, wherein the detecting molecule is bound to the semiconductor quantum dot. 
     
     
         18 . The chemical sensor of  claim 15  wherein the detecting molecule is selected from the group consisting of proteins, peptides, antibodies, antigens, nucleic acids, peptide nucleic acids, sugars, lipids, glycophosphoinositols, and lipopolysaccharides. 
     
     
         19 . The chemical sensor of  claim 15  wherein the detecting molecule is an antibody. 
     
     
         20 . The chemical sensor of  claim 15  wherein the detecting molecule is an antigen. 
     
     
         21 . The chemical sensor of  claim 20  wherein the detecting molecule is an antigen that binds to an ovarian cancer marker antibody with an affinity (K a ) of at least 10 6  l/mole. 
     
     
         22 . The chemical sensor of  claim 21  wherein the K a  is at least 10 8  l/mole. 
     
     
         23 . A method for detecting an analyte in a sample using a chemical sensor, the method comprising the steps of:
 i) providing a sample;   ii) providing a semiconductor quantum dot comprising a linker molecule (LM-SQD)   iii) conjugating the analyte in the sample with the LM-SQD thereby producing an analyte-LM-SQD conjugate;   iv) providing the chemical sensor of  claim 11 ;   v) incubating the analyte-LM-SQD conjugate with the chemical sensor for a predetermined time period; and   vi) measuring the extent of binding between the analyte-LM-SQD conjugate and the chemical sensor; thereby detecting the analyte in the sample.   
     
     
         24 . The method of  claim 23  wherein the analyte is an ovarian cancer marker antibody. 
     
     
         25 . The method of  claim 23  wherein the detecting molecule in the chemical sensor is an antigen that binds to an ovarian cancer marker antibody with an affinity (K a ) of at least 10 6  l/mole. 
     
     
         26 . The method of  claim 25  wherein the K a  is at least 10 8  l/mole. 
     
     
         27 . An optical communications device comprising a fiber and the chemical sensor of  claim 1 . 
     
     
         28 . The optical communications device of  claim 27  wherein the fiber is selected from the group consisting of ceramics, glasses, and polymers. 
     
     
         29 . The optical communications device of  claim 27  wherein the fiber cross-section is D-shaped. 
     
     
         30 . The optical communications device of  claim 27  wherein the chemical sensor is disposed upon a surface of the fiber.