3,000+ DNA/RNA modification options with expert design help, fast quoting, and ISO/GLP/GMP-aligned workflows. Build exactly what your assay or program needs — fluorescent probes, conjugates, delivery lipids, caps, chelators, and more.
BSI offers one of the broadest portfolios of phosphoramidite-based reagents to support research, diagnostics, sequencing, and therapeutic development. Our Oligonucleotide Modifications Reference Guide helps you choose the right modification—or combination—for your application.
With over 3000 options and growing, we deliver high-quality, custom-modified oligonucleotides backed by expert technical support. If the modification you need is not listed, contact us—our team can provide tailored solutions to meet your specific requirements.
If the modification you need is not listed, please don’t hesitate to contact us—our team is ready to assist with custom solutions tailored to your specific requirements.
Browse key modification families. Each card summarizes what it is and common uses. Click any card to jump to details.
Natural or non-natural based used to tune binding, report environment, or mimic lesions.
Tune duplex stability, add labels, tolerate polymorphisms in primers/probes, model DNA damage/marks.
Modified ribobases (e.g., m6A, Ψ, 2‑thiouridine, fluorescent ribonucleotides).
Epitranscriptomics mapping, RNA stability and translation studies, fluorescent RNA probes.
Change 2'‑position or ribose ring,LNA/BNA, 2'-OMe/2'-F, GNA, TNA, exotic sugar system
Increase nuclease resistance, raise/lower Tm, control conformation in ASOs/siRNA/diagnostics.
Alter the phosphate linkage (PS, PS2, methylphosphonate, boranophosphate, PN backbones, PMO/PNA).
Adjust charge and stability, enable RNase‑H compatibility, enhance durability in vivo.
5′/3′ phosphorylation, caps, blocking groups, and reactive handles at the ends of oligos.
Enable ligation, prevent extension or degradation, add capture/labeling handles.
Internal base/sugar changes that introduce amines, thiols, azides, alkynes, fluorophores or haptens.
Enable internal fluorophores or haptens, add click handles, introduce cross-linking points, or probe folding and binding.
Synthetic 5′ cap analogs (e.g., m7GpppG, ARCA, CleanCap®) added to RNA.
Enhance mRNA stability and translation, reduce immunogenicity, and study cap-binding proteins.
Broad chemical attachments (PEG, haptens, dyes, peptides, antibodies, drugs) to DNA/RNA.
Add detection, targeting, or delivery functions; build antibody-oligo, drug-oligo, or nanoparticle conjugates; improve biodistribution.
Hydrophobic groups (cholesterol, tocopherol, fatty acids, squalene) covalently linked to oligos.
Improve membrane association and uptake, extend serum half-life, and support nanoparticle assembly.
Photo/chemical crosslinkers on the base (psoralen, diazirine, aryl‑azide, benzophenone, thio‑U).
Covalent capture of interactions, footprinting, mapping contacts under UV/visible light.
Bases bearing small antigenic tags (biotin, DIG, DNP, FITC, rhodamine).
Affinity capture (streptavidin) or antibody‑based detection in blots, ISH/FISH, ELISAs.
Enzyme Oligo Conjugates capture (streptavidin) or antibody‑based detection in blots, ISH/FISH, ELISAs.
Abasic spacers, HEG/PEG and alkyl linkers to define distance/flexibility and reduce steric clash.
Optimize FRET, minimize quenching, tune geometry and accessibility for enzymes/targets.
Trebler/doubler units, dendritic PEG, multivalent scaffolds for payload or barcode display.
Signal amplification, multivalent targeting, barcoded assemblies and scaffolds.
Disulfide/redox, photo‑ and acid‑labile linkers; non‑cleavable PEG linkers for permanence.
Condition‑triggered release vs. stable attachment, controlled delivery and tracking.
Fluorescent dyes (FAM, Cy dyes, Alexa, ATTO)
qPCR/probes, imaging, FRET pairs, single‑molecule and multiplex detection.
Base analogs with intrinsic fluorescence (e.g., 2-aminopurine, pyrrolo-dC, tC, tC°, perylene-dU).
Report on base stacking and environment, serve as FRET donors/acceptors, and monitor conformational changes or hybridization in real time.
Dark quenchers (BHQ, QSY, Eclipse, Iowa Black) to suppress donor emission.
Non‑emissive or dark quenchers to suppress donor fluorescence until target binding/cleavage.
Metal‑binding groups (DOTA/NOTA/DTPA, NTA/IDA) conjugated to bases or termini.
Radiolabeling (PET/SPECT), lanthanide labeling, metal‑assisted capture and imaging.
Planar aromatic systems (ethidium, acridines, pyrene/perylene) that insert into duplexes.
Stabilize or probe structure, create MGB effects, tune Tm and signal.
C5‑halogen on pyrimidines (5‑Br/5‑I dU/dC) and other halo variants.
Photocrosslink/cleavage, crystallography phasing, structure‑function studies.
Pre-actived oligo for fast, selective bioconjugation.
azide/alkyne (CuAAC), DBCO/BCN (SPAAC), TCO/tetrazine (IEDDA), thiol-maleimide, NHS-ester/amine, and aldehyde-oxime/hydrazone workflows.
Electroactive labels or backbones (methylene blue, ferrocene, borano).
E‑DNA/E‑RNA biosensors, label‑based voltammetry, point‑of‑care diagnostics.
Bioactive small molecules to DNA/RNA for display, delivery, sensing and crosslinking
Puromycin, doxorubicin, folic acid, tocopherol and ferrocene.
Our scientists will recommend the best option to fit your assay, conjugation strategy, or delivery needs — and guide you from design through QC.
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