Flow cells

A kit, comprising:

• a flow cell including at least one surface functionalized with a polymeric hydrogel including azide functional groups or amine functional groups;
• a primer fluid including a plurality of alkyne-containing primers, each alkyne-containing primer having an amino cleavable group attaching a primer sequence of the alkyne-containing primer to an alkyne-containing moiety of the alkyne-containing primer;
• a cleaving fluid that is reactive with the amino cleavable group;
• and
• a regeneration fluid including i) azide terminated molecules selected from the group consisting of azido-PEG4-C2-carboxylic acid, trifluoromethanesulfonyl azide, imidazolium sulfonyl azide hydrochloride, 1-(fluorosulfuryl)-2,3-dimethyl-1H-imidazol-3-ium trifluoromethanesulfonate, fluorosulfuryl azide, perfluorobutanesulfonyl azide, azido-PEG4-N-Hydroxysuccinimide ester, and imidazole-1-sulfonyl azide hydrochloride, or ii) tetrazine terminated molecules selected from the group consisting of tetrazine-N-Hydroxysuccinimide ester and methyltetrazine-sulfo-N-Hydroxysuccinimide ester.

A kit, comprising:

• a flow cell including at least one surface functionalized with a polymeric hydrogel including azide functional groups or amine functional groups;
• a primer fluid including a plurality of alkyne-containing primers, each alkyne-containing primer having an amino cleavable group attaching a primer sequence of the alkyne-containing primer to an alkyne-containing moiety of the alkyne-containing primer;
• a cleaving fluid that is reactive with the amino cleavable group;
• and
• a linker fluid including one of:
• a tetrazine molecule to react with the amine functional groups of the flow cell, the tetrazine molecule being selected from the group consisting of tetrazine-N-Hydroxysuccinimide ester, methyltetrazine-sulfo-N-Hydroxysuccinimide ester, and methyltetrazine-PEGn-N-Hydroxysuccinimide ester where n=4 or 5 or 8;
• or a tetrazine molecule to react with the azide functional groups of the flow cell, the tetrazine molecule being sulfo-6-methyl-tetrazine-dibenzocyclooctyne.

A method, comprising:

• grafting a plurality of alkyne-containing primers to respective azide functional groups or tetrazine functional groups of a polymeric hydrogel on a surface of a flow cell, each of the plurality of alkyne-containing primers having an amino cleavable group attaching a primer sequence of the alkyne-containing primer to an alkyne-containing moiety of the alkyne-containing primer;
• performing a nucleic acid analysis involving the grafted plurality of alkyne-containing primers;
• introducing a cleaving fluid to cleave the grafted plurality of alkyne-containing primers at the amino cleavable group, thereby leaving a plurality of amine functional groups at the surface of the flow cell;
• and
• reacting respective azide terminated molecules or tetrazine terminated molecules with at least some of the plurality of amine functional groups to introduce new azide functional groups or new tetrazine functional groups to the surface of a flow cell.