# US 7,611,907 B2 · Nano-sized optical fluorescence labels and uses thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,907 B2 - Document ID: US7611907B2 - Status: Granted - Kind: B2 - Application number: 10/519,267 - Filed: 2003-06-27 - Published: 2006-03-09 - Granted: 2009-11-03 - Earliest claimed: 2003-06-27 - Assignees: Georgia Tech Research Corporation - Inventors: Robert Martin Dickson; Jie Zheng - Web page: https://patentgrep.com/patent/US7611907B2 ## CPC - G01N 33/588: {with semiconductor nanocrystal label, e.g. quantum dots} - B82Y 15/00: Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors - G01N 33/582: {with fluorescent label} - Y10S 436/805: Optical property - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract A composition is disclosed which is capable of being used for detection, comprising an encapsulated noble metal nanocluster. Methods for preparing the encapsulated noble metal nanoclusters, and methods of using the encapsulated noble metal nanoclusters are also disclosed. The noble metal nanoclusters are preferably encapsulated by a dendrimer or a peptide. The encapsulated noble metal nanoclusters have a characteristic spectral emission, wherein said spectral emission is varied by controlling the nature of the encapsulating material, such as by controlling the size of the nanocluster and/or the generation of the dendrimer, and wherein said emission is used to provide information about a biological state. ## Claims ### Claim 1 A method of monitoring a molecule of interest comprising: a) attaching a water-soluble fluorescent label comprising an encapsulated noble metal nanocluster to a molecule of interest, wherein the noble metal nanocluster is about 0.1 nm to 2 nm in diameter without encapsulation, and wherein the fluorescent label exhibits an emission spectrum; and b) detecting the emission spectrum of the fluorescent label, and c) correlating the detected fluorescent emission spectrum to the presence of the attached molecule of interest, thereby monitoring the molecule of interest. ### Claim 2 (depends on 1) The method of claim 1, wherein the noble metal nanocluster comprises between 2 and 8 noble metal atoms. ### Claim 3 (depends on 1) The method of claim 1, wherein the noble metal is selected from the group consisting of gold, silver, and copper. ### Claim 4 (depends on 1) The method of claim 1, wherein the encapsulated noble metal nanocluster fluoresces at a low excitation intensity and wherein the encapsulated noble metal nanocluster has a saturation intensity ranging from approximately 1 to 1000 W/cm2 at a nanocluster excitation maximum. ### Claim 5 (depends on 4) The method of claim 4, wherein the low excitation intensity at approximately 460 nm. ### Claim 6 (depends on 1) The method of claim 1, wherein the fluorescent label exhibits a polarized spectral emission and exhibits a dipole emission pattern. ### Claim 7 (depends on 1) The method of claim 1, wherein the fluorescent label has a spectral emission that provides information about a biological state. ### Claim 8 (depends on 7) The method of claim 7, wherein the biological state is selected from the group consisting of a quantitative and qualitative presence of a biological moiety; structure, composition, and conformation of a biological moiety; localization of a biological moiety in an environment; an interaction between biological moieties, an alteration in structure of a biological compound, and an alteration in a cellular process. ### Claim 9 (depends on 1) The method of claim 1, wherein when the fluorescent label is excited, it is capable of fluorescing over a pH range of approximately 3 to 9. ### Claim 10 (depends on 1) The method of claim 1, wherein the noble metal nanocluster emits greater than approximately 106 photons before photobleaching. ### Claim 11 (depends on 1) The method of claim 1, wherein when a composition comprising more than one noble metal nanocluster is excited, greater than approximately 80% of the noble metal nanoclusters fluoresce for greater than approximately 30 minutes. ### Claim 12 (depends on 11) The method of claim 11, wherein the noble metal nanoclusters fluoresce at a continuous excitation intensity of approximately 300 W/cm2 at 514.5 nm or 476 nm, and wherein the fluorescence is a saturated or an unsaturated fluorescence. ### Claim 13 (depends on 1) The method of claim 1, further comprising the initial step of attaching a linker molecule to the encapsulated noble metal nanocluster, wherein the linker molecule is capable of attaching the fluorescent label to the molecule of interest. ### Claim 14 (depends on 1) The method of claim 1, wherein the molecule of interest is present in a biological sample. ### Claim 15 (depends on 1) The method of claim 1, wherein the size of the fluorescent label is from approximately less than 1 nm to 15 nm in diameter. ### Claim 16 (depends on 1) The method of claim 1, wherein the noble metal nanocluster is encapsulated in a dendrimer. ### Claim 17 (depends on 16) The method of claim 16, wherein the dendrimer comprises poly (amidoamine). ### Claim 18 (depends on 17) The method of claim 17, wherein the poly(amidoamine) dendrimer is selected from the group consisting of a 0th generation, 1st generation, 2nd generation, 3rd generation, a 4th generation, and a higher generation poly(amidoamine) dendrimer. ### Claim 19 (depends on 17) The method of claim 17, wherein the poly(amidoamine) dendrimer is a 2nd generation, or a 4th generation OH-terminated poly(amidoamine) dendrimer. ### Claim 20 (depends on 1) The method of claim 1, wherein the noble metal nanocluster is encapsulated in a peptide. ### Claim 21 (depends on 20) The method of claim 20, wherein the peptide is expressed in a cell. ### Claim 22 (depends on 20) The method of claim 20, wherein the peptide comprises a fusion polypeptide. ### Claim 23 (depends on 20) The method of claim 20, wherein the peptide is from approximately 5-500 amino acids in length. ### Claim 24 (depends on 20) The method of claim 20, wherein the peptide is from approximately 5-20 amino acids in length. ### Claim 25 (depends on 20) The method of claim 20, wherein the peptide is from approximately 20-40 amino acids in length. ### Claim 26 (depends on 20) The method of claim 20, wherein the peptide comprises a polypeptide sequence as defined in SEQ ID NO: 1. ### Claim 27 (depends on 1) The method of claim 1, wherein the noble metal nanocluster is less than about 1 nm in diameter prior to encapsulation. ### Claim 28 (depends on 1) The method of claim 1, wherein the noble metal nanocluster comprises between 2 and 27 noble metal atoms. ### Claim 29 (depends on 1) The method of claim 1, wherein the noble metal nanocluster comprises between 2 and 20 noble metal atoms. ### Claim 30 (depends on 1) The method of claim 1, wherein the noble metal nanocluster comprises between 2 and 15 noble metal atoms.