RNA Detection
Methods for RNA detection in biological samples include (a) contacting a biological sample with a first composition featuring multiple different types of unlabeled oligonucleotide probes that hybridize to RNA species in the sample; (b) contacting the biological sample with a hybridization agent featuring a chaotropic compound; (c) contacting the biological sample with a second composition that includes multiple different types of labeled oligonucleotide probes, where each of the different types of labeled oligonucleotide probes selectively hybridizes to one of the different types of unlabeled oligonucleotide probes; (d) obtaining at least one image of the biological sample with the multiple different types of labeled oligonucleotide probes bound to the sample; and (e) identifying spatial locations of the RNA species in the sample based on components of the at least one image that correspond to the different types of labeled oligonucleotide probes, where the biological sample is contacted with the second composition under isothermal conditions.
1 . A method, comprising:
(a) contacting a biological sample with a first composition comprising multiple different types of unlabeled oligonucleotide probes that hybridize to RNA species in the sample;
(b) contacting the biological sample with a hybridization agent comprising a chaotropic compound;
(c) contacting the biological sample with a second composition comprising multiple different types of labeled oligonucleotide probes, wherein each of the different types of labeled oligonucleotide probes selectively hybridizes to one of the different types of unlabeled oligonucleotide probes;
(d) obtaining at least one image of the biological sample with the multiple different types of labeled oligonucleotide probes bound to the sample; and
(e) identifying spatial locations of the RNA species in the sample based on components of the at least one image that correspond to the different types of labeled oligonucleotide probes,
wherein the biological sample is contacted with the second composition under isothermal conditions.
2 . The method of claim 1 , further comprising:
(f) removing the labeled oligonucleotide probes from the sample.
3 . The method of claim 2 , further comprising repeating steps (c)-(e) with a different set of labeled oligonucleotide probes to identify spatial locations of at least one additional RNA species in the sample.
4 . The method of claim 3 , further comprising repeating step (b) prior to repeating steps (c)-(e).
5 . The method of claim 3 , further comprising, prior to repeating steps (c)-(e):
contacting the biological sample with a third composition comprising multiple different types of unlabeled oligonucleotide probes that hybridize to RNA species in the sample,
wherein the multiple different types of unlabeled oligonucleotide probes of the third composition are also present in the first composition.
6 . The method of claim 1 , wherein the chaotropic compound comprises dimethylsulfoxide.
7 . The method of claim 1 , wherein the chaotropic compound comprises formamide.
8 . The method of claim 1 , wherein a weight percentage of the chaotropic compound in the hybridization agent is between 5% and 20%.
9 . The method of claim 2 , further comprising removing the labeled oligonucleotide probes from the sample by reductive cleavage.
10 . The method of claim 2 , further comprising removing the labeled oligonucleotide probes from the sample by enzymatic cleavage.
11 . The method of claim 2 , further comprising removing the labeled oligonucleotide probes from the sample by exposing the sample to a dehybridization agent to dehybridize the labeled oligonucleotide probes from the unlabeled oligonucleotide probes.
12 . The method of claim 11 , wherein the dehybridization agent comprises a chaotropic compound.
13 . The method of claim 12 , wherein the chaotropic compound of the dehybridization agent comprises at least one member selected from the group consisting of dimethyl sulfoxide and formamide.
14 . (canceled)
15 . The method of claim 12 , wherein a weight percentage of the chaotropic compound in the dehybridization agent is 50% or more.
16 . (canceled)
17 . The method of claim 1 , wherein the hybridization agent comprises at least one member selected from the group consisting of a buffer agent, a salt, and a surfactant.
18 - 19 . (canceled)
20 . The method of claim 1 , wherein the hybridization agent comprises at least one chelating agent.
21 . The method of claim 1 , wherein the hybridization agent comprises at least one azide-based antibacterial agent.
22 . The method of claim 12 , wherein the dehybridization agent comprises at least one member selected from the group consisting of a buffer agent, a salt, and a surfactant.
23 - 24 . (canceled)
25 . The method of claim 12 , wherein the dehybridization agent comprises at least one chelating agent.
26 . The method of claim 12 , wherein the dehybridization agent comprises at least one azide-based antibacterial agent.
27 . The method of claim 1 , wherein the first composition comprises 20 or more different types of unlabeled oligonucleotide probes.
28 . The method of claim 1 , wherein the second composition comprises 4 or more different types of labeled oligonucleotide probes.
29 . (canceled)
30 . The method of claim 1 , wherein each type of unlabeled oligonucleotide probe comprises at least 5 bases.
31 . (canceled)
32 . The method of claim 1 , wherein each type of labeled oligonucleotide probe comprises at least 5 bases.
33 . (canceled)
34 . The method of claim 1 , wherein each type of labeled oligonucleotide probe comprises a different optical label.
35 . The method of claim 34 , wherein the different optical labels comprise at least one member selected from the group consisting of different fluorescent dyes, different chromogenic moieties, and different quantum dot-based species.
36 . (canceled)
37 . The method of claim 34 , wherein the different optical labels comprise different peptide-containing moieties.
38 . (canceled)
39 . The method of claim 3 , wherein:
the second composition comprises a first type of labeled oligonucleotide probe among the multiple different types of labeled oligonucleotide probes;
the different set of labeled oligonucleotide probes comprises the first type of labeled oligonucleotide probe;
the at least one image of the biological sample with the multiple different types of labeled oligonucleotide probes bound to the sample comprises a first image comprising a measurement signal corresponding to the first type of labeled oligonucleotide probe;
the at least one image of the biological sample with the different set of labeled oligonucleotide probes bound to the sample comprises a second image comprising a measurement signal corresponding to the first type of labeled oligonucleotide probe; and
the method further comprises registering the at least one image of the biological sample with the multiple different types of labeled oligonucleotide probes bound to the sample and the at least one image of the biological sample with the different set of labeled oligonucleotide probes bound to the sample based on the measurement signals corresponding to the first type of labeled oligonucleotide probe in the first and second images.