Reagents and methods for elemental mass spectrometry of biological samples
Embodiments of the present invention relate to reagents and their use for elemental imaging mass spectrometry of biological samples. The embodiments comprising methods for quantifying one or more analytes within a sample, comprising the steps of: (a) providing the sample, wherein the one or more analytes are immobilized to a sample carrier, wherein the sample has been labelled with one or more mass tags comprising one or more labelling atoms, (b) performing mass cytometry on the sample to determine the level of the one or more labelling atoms, wherein the level of the one or more labelling atoms corresponds to the copy number of the one or more analytes.
1. A sample carrier for mass cytometry, the sample carrier comprising:
a planar surface, the planar surface including a first region for binding a sample;
a polydopamine layer disposed on the planar surface;
a self-assembled monolayer disposed on the polydopamine layer;
a 3D polymer brush attached to the self-assembled monolayer;
an element standard, the element standard comprising one or more elements or isotopes, wherein:
the element standard comprises an element film applied to a second region of the planar surface using an adhesive,
the element film is a polymer element film, and
the first region does not overlap with the second region.
2. The sample carrier of claim 1 , wherein the element standard comprises consistent abundance of the one or more elements or isotopes across the element standard.
3. The sample carrier of claim 1 , wherein the element standard comprises separate regions, each with a different amount of the one or more elements or isotopes.
4. The sample carrier of claim 1 , wherein different regions of the element standard may comprise a different combination of elements or isotopes.
5. The sample carrier of claim 1 , wherein the element standard comprises reference particles of known elemental or isotopic composition, wherein the reference particles comprise metal elements or isotopes.
6. The sample carrier of claim 5 , wherein the reference particles are optically resolvable.
7. The sample carrier of claim 5 , wherein the reference particles comprise a metallic nanocrystal core and/or polymer surface.
8. The sample carrier of claim 1 , wherein the element film is a polyester element film.
9. The sample carrier of claim 1 , wherein the polymer element film comprises a long chain polymer that was mixed with a metal solution and volatile solvent prior to the solvent being evaporated.
10. The sample carrier of claim 1 , wherein the element film comprises at least 10 different elemental isotopes, wherein the elemental isotopes have masses over 60 amu.
11. The sample carrier of claim 10 , wherein the average number of the majority of elemental isotopes across the element film has a coefficient of variation (CV) of less than less than 10%.
12. A method of normalizing data obtained from a sample based on the element standard of the sample carrier of claim 1 , wherein the sample comprises mass tags comprising labelling atoms, and wherein the method comprises analysing the sample by mass spectrometry.
13. The method of claim 12 , further comprising using the element standard to generate a standard curve.
14. The method of claim 12 , wherein the sample carrier is a sample slide comprising the sample, and further comprising applying the element film to the sample slide after tagging the sample with mass tags.
15. The method of claim 12 , wherein normalization comprises quantification of the labelling atoms.
16. The sample carrier of claim 9 , wherein the polymer is poly (methyl methacrylate) and the solvent is toluene.
17. The sample carrier of claim 9 , further comprising the sample bound to the first region, wherein the sample is a biological sample.
18. The sample carrier of claim 9 , wherein the element film is at least 100 square millimeters.
19. The method of claim 12 , wherein the normalizing the data comprises analysing the element standard by mass spectrometry after analysing the sample.
20. A method comprising:
binding the sample to the sample carrier of claim 1 ;
ablating the element standard to form an ablation plume;
transferring the ablation plume to a detector; and
analysing the sample using the detector after transferring the ablation plume to the detector.