Used for immobilizing, purifying, or isolating specific molecules—including amino modifiers, biotinylation, and thiol modifications—these tags function by selectively binding to complementary ligands,enhancing affinity, streamlining processes such as detection and functional analysis.
Applications: Protein interaction studies, EMSA probes, functionalized chips.
Affinity & Capture Tags
Affinity and capture tags are essential tools in molecular biology and biotechnology, designed to facilitate the specific immobilization, purification, or pull-down of target molecules (e.g., proteins, nucleic acids, or complexes). These tags enable highly selective interactions with complementary ligands or surfaces, streamlining processes such as detection, isolation, and functional analysis.
| Sub-category | Name (full) | Abbreviation / Code | Product Type | Applies to | Position | Function & mechanism (including like products) | Typical applications |
| Biotin | Biotin | BIO | Like | DNA / RNA | 5′ / 3′ / Internal (dT, dC) | Binds streptavidin / avidin with extremely high affinity (Kd ~ 10⁻¹⁵ M). Used for capture, purification, surface immobilization, and sandwich assay construction. | Streptavidin capture, microarray, ELISA-type assays, pull-down |
| Biotin | Biotin-TEG | BIO-TEG | Like | DNA / RNA | 5′ / 3′ | Biotin attached via a TEG (tetraethylene glycol) spacer. Reduced steric hindrance for streptavidin binding compared to direct biotin attachment. | Surface immobilization, bead capture, biosensor arrays |
| Biotin | Triple Biotin | triple BIO | Like | DNA | 5′ | Three biotin groups linked via a branched scaffold. Provides 3× streptavidin binding sites for ultrasensitive signal amplification. | Ultrasensitive detection, signal amplification assays |
| Click chemistry handles | Azide (N3) | Azide | Like | DNA / RNA | 5′ / 3′ / Internal (dT, dC) | Bio-orthogonal azide group for copper-catalyzed (CuAAC) or strain-promoted (SPAAC) click chemistry with alkyne or DBCO partners. Enables site-specific conjugation to any alkyne-bearing molecule. | Click conjugation, oligonucleotide-drug conjugation, labeling |
| Click chemistry handles | DBCO | DBCO | Like | DNA / RNA | 5′ / 3′ | Strain-promoted cyclooctyne for copper-free click chemistry with azide partners. Enables bioorthogonal conjugation in biological environments without toxic copper catalysts. | In-cell labeling, ADC conjugation, copper-free click chemistry |
| Thiol / Amine reactive groups | Amino (C6-NH2 / C7-NH2 / C12-NH2) | C6-NH2 / C12-NH2 | Like | DNA / RNA | 5′ / 3′ / Internal (dT) | Primary amine groups tethered via C6, C7, or C12 carbon spacers. React with NHS esters, isocyanates, and isothiocyanates for covalent conjugation to activated surfaces or reporter molecules. | Surface immobilization on NHS-coated chips, amine-reactive fluorophore labeling |
| Thiol / Amine reactive groups | Thiol (C6-SH / C3-S-S / Triple SH) | SH / SS | Like | DNA / RNA | 5′ / 3′ | Thiol groups for conjugation to gold surfaces, maleimide-functionalized molecules, or disulfide exchange reactions. Triple SH provides amplified surface attachment density. | Gold nanoparticle functionalization, biosensor surface attachment, disulfide conjugation |
| Thiol / Amine reactive groups | Maleimide | Maleimide | Like | DNA / RNA | 5′ / 3′ | Thiol-reactive group for Michael addition conjugation to cysteine residues or thiol-modified oligos. Commonly used for antibody–oligonucleotide bioconjugates. | Antibody-oligo conjugation, site-specific protein labeling |
| Thiol / Amine reactive groups | SMCC | SMCC | Like | DNA / RNA | 5′ / Internal (C12-SMCC) | Bifunctional crosslinker (succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate). Links amine-containing oligos to thiol-bearing targets (proteins, surfaces). | Protein-oligo crosslinking, ADC construction, biosensor conjugation |
| Targeting ligands | Cholesterol / Cholesteryl TEG | Chol / Chol-TEG | Like | DNA / RNA | 5′ / 3′ | Lipophilic cholesterol group enabling passive membrane incorporation and endocytosis-mediated cellular uptake without transfection reagents. TEG spacer reduces aggregation. | Antisense ASO delivery, siRNA cellular uptake, lipid nanoparticle co-formulation |
| Targeting ligands | GalNAc (N-Acetylgalact osamine) | GalNAc | Like | RNA | 5′ / Internal | Triantennary GalNAc ligand targeting the asialoglycoprotein receptor (ASGPR) highly expressed on hepatocytes. Enables highly efficient liver-specific delivery of ASO and siRNA without nanoparticle carriers. | Liver-targeted siRNA (GalNAc-siRNA), ASO hepatic delivery, Alnylam-type conjugate design |
| Detection labels | DIG (Digoxigenin) | DIG | Like | DNA / RNA | 5′ / 3′ / Internal (dT, dC) | Plant steroid hapten recognized by anti-DIG antibodies. Used in ELISA-type sandwich assays, Southern blotting, and non-radioactive ISH detection. | Non-radioactive ISH, ELISA, lateral flow immunoassay |
| Detection labels | DNP (Dinitrophenol) | DNP | Like | DNA | Internal (dT) | Small hapten recognized by anti-DNP antibodies. Used as a secondary detection label in dual-label assays alongside biotin. | Dual-label sandwich assays, lateral flow assays |
| Detection labels | Acrydite | Acrydite | Like | DNA / RNA | 5′ | Acrylamide-reactive group that co-polymerizes into polyacrylamide gels. Enables covalent immobilization of oligonucleotides in hydrogel matrices. | DNA hydrogel arrays, embedded probe gels, polyacrylamide bead conjugation |
| Detection labels | Phosphate (5′ PHO) | PHO | Like | DNA / RNA | 5′ / 3′ | 5′-phosphate enables ligation reactions with DNA/RNA ligases. Required for blunt-end ligation, adapter ligation in NGS library prep, and circularization. | Ligation-based NGS library construction, adapter ligation, RNA circularization |
Modification: Biotin
Download the order form "Tsingke_DNA_Order Form.1.1.1.250815.csv" for DNA modifications or "Tsingke_RNA_Order Form.1.1.1.250815.csv" for RNA modifications below and email it to info@tsingke.com.cn, or "Send Your Request" to submit your inquiry online. Please refer to "Tsingke_DNA_Modification List_1.1.1.250815.csv" or "Tsingke_RNA_Modification List_1.1.1.250815.csv" sheet to paste special base and internal modification codes in your sequence.
Amino modification introduces a reactive-NH2 group into an oligonucleotide, enabling covalent coupling to dyes, biotin, or solid surfaces.
Key considerations:
5' Aminolinker (C6) is incorporated via phosphoramidite chemistry on the 5' sugar, not on the terminal base.
The amino group absorbs at 210 nm, not 260 nm, and therefore cannot be visualized by standard gel electrophoresis.
3' Aminolinker (C7) is compatible only with selected 5' modifications (e.g., FAM, HEX, TET, fluorescein, biotin, phosphate) and is incompatible with dyes that also require an amine (e.g., Alexa Fluor® dyes).
Amino modification is a simple and cost-effective strategy; 5' C6-NH2 is recommended for most applications.
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