Method for analysis using X-ray fluorescence
The present invention is a method to quantify biomarkers. The method uses an X-ray fluorescence spectrometer to perform an X-ray fluorescence analysis on the sample to obtain spectral features derived from the biomarker; and quantifying the X-ray fluorescence signal of the biomarker.
1. A method for measuring a response to a therapy, comprising
providing a sample which has been exposed to a therapy and a sample which has not been exposed to a therapy, the samples each comprising a biomarker comprising one or more chemicals that are related to a physiological condition;
preparing the samples for X-ray analysis by exposing the samples to a solution;
using an X-ray fluorescence spectrometer to perform an X-ray fluorescence analysis on the samples to obtain spectral features derived from the biomarker; and
quantifying the X-ray fluorescence signal of the biomarker and comparing the signal of the sample which has been exposed to a therapy and a sample which has not been exposed to a therapy;
wherein the X-ray fluorescence spectrometer irradiates the sample with polychromatic X-rays.
2. The method of claim 1 , wherein the solution is selected from a pH buffer, a redox buffer, a preservative, a fixative, and a sterilizing solution.
3. The method of claim 1 , wherein the solution is free of at least one chemical element having an atomic number greater than eight, where the element is present in the sample.
4. The method of claim 1 , wherein the solution is free of at least one of the chemicals or functional groups selected from the group consisting of dimethylsulfoxide, thiols, sulfate anion, sulfonate anions, chloride anion, bromide anion, fluoride anion, iodide anion, perchlorate anion, phosphate anion, and phosphonate anions.
5. The method of claim 1 , wherein the solution comprises one or more chemicals selected from the group consisting of amine, imine, nitrate anion, nitrite anion, ammonium cation, acetate anion, carboxylate anion, conjugate bases of carboxylic acids, carbonate anion, formalin, formaldehyde, ethanol, 2-propanol, and iminium cation.
6. The method of claim 1 , wherein the samples are fractionated to provide sample fractions.
7. The method of claim 6 , wherein the fractionating is performed using a technique selected from centrifugation, mechanical separation, chemical separation, enzymatic separation, condensation, chromatographic methods, gel electrophoresis, isoelectric focusing, 2-dimensional electrophoresis, precipitation, density gradient fractionation and immobilization of analytes to solid formats.
8. The method of claim 7 , wherein the solid format is selected from beads, membranes, arrays, microarrays, spin plate, or well plates.
9. The method of claim 1 , wherein at least one sample is disposed on or in a sample holder, and the sample holder comprises at least one chemical element which is not present in the sample.
10. The method of claim 1 , wherein the samples are biological samples.
11. The method of claim 10 , wherein the biological samples are selected from tissue samples, biological fluids, biopsy samples, cells, dried biospecimens, fresh biospecimens, immortalized cell lines, membranes, plasma, primary cell cultures, and subcellular fractionates.
12. The method of claim 1 , wherein the fluorescence analysis comprises multiple X-ray fluorescence analyses.
13. The method of claim 12 , wherein the multiple fluorescence analyses are obtained by disposing one or more of the samples at two or more different angles relative to an excitation source.