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Intercalator-Modified Oligonucleotides

Custom DNA and RNA oligonucleotides incorporating pyrene, thiazole orange, acridine, psoralen and related intercalators for fluorescence, duplex stabilization, photo-crosslinking and nucleic acid structure studies.

5′ / 3′ / Internal Placement Pyrene / TO / YO / Psoralen Signal-On Probe Design Duplex Stabilization Photo-Crosslinking HPLC / PAGE / MS QC Modification by Type
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Overview Families Selection Guide Products Technical Notes Applications QC FAQ Contact
Overview

Intercalating Aromatic Labels for Nucleic Acid Probes

Bio-Synthesis designs and manufactures intercalator-modified oligonucleotides: DNA and RNA labeled with planar aromatic systems that can stack between base pairs or interact strongly with duplex nucleic acids.

These modifications can boost fluorescence signal, enable excimer or exciplex readouts, drive photoinduced electron transfer (PeT), support photo-crosslinking or tune duplex stability for probes, sensors and mechanistic nucleic acid studies.

Intercalators may be placed at the 5′ end, 3′ end or internal positions. Spacer engineering with C3, C6, TEG or PEG linkers helps control sterics, stacking geometry, background fluorescence and hybridization behavior.

Intercalator-modified oligonucleotides are best classified as modified oligonucleotides by type because the defining feature is the incorporated aromatic intercalator chemistry rather than a single assay application. Common search terms include pyrene oligonucleotide, TO-dT oligo, psoralen oligonucleotide, acridine-modified oligo and anthraquinone oligonucleotide.

How Intercalators Work

free probe → intercalated duplex → measurable response
1

Free Probe

Before target binding, the intercalator may be flexible, partially quenched or weakly stacked.

  • Lower signal background
  • Minimal duplex stacking
  • Probe remains target-ready
2

Intercalated Duplex

After hybridization, the aromatic intercalator stacks between adjacent base pairs.

  • Stronger pi-stacking
  • More rigid local geometry
  • Sequence and spacer dependent
3
Signal ↑

Experimental Outcome

The intercalated state can change fluorescence, Tm, PeT behavior or photo-crosslinking efficiency.

  • Signal-on fluorescence
  • Duplex stabilization
  • Crosslinking or PeT readout
Intercalator Families

Organized by Readout Chemistry

Different intercalators are selected for signal-on fluorescence, excimer emission, duplex stabilization, photo-crosslinking or redox/electron-transfer studies.

EX

Pyrene & Perylene

Excimer, exciplex and stacking-sensitive probes for duplex stabilization and nucleic acid structure studies.

TO

Thiazole Orange

Signal-on cyanine intercalators with low background until hybridization or duplex binding occurs.

YO

YO / YOYO

High-brightness intercalative labels for sensitive hybridization probes and molecular sensor designs.

ACR

Acridine

Classic intercalator chemistry for triplex, footprinting, structural probing and duplex-stability studies.

AQ

Anthraquinone

Electron-acceptor intercalator family for PeT, redox chemistry and photoinduced charge-transfer studies.

Pso

Psoralen

UVA-activated photo-crosslinking chemistry for interstrand crosslinks, capture and structural mapping.

Fluorescent

TOYOYOYOPyrenePerylene

Photoactive

PsoralenPhotocrosslinking

Redox / PeT

AnthraquinonePhenanthroline

Structural

AcridineEthidiumNaphthalimide
Selection Guide

Intercalator Selection Guide

Research Goal Recommended Intercalator Design Note
Signal-On Fluorescence Thiazole Orange, YO Good for low-background hybridization probes.
High Brightness YOYO, YO linker Strong binding; monitor duplex over-stabilization.
Excimer / Exciplex Studies Pyrene, Perylene Spacing and proximity determine emission response.
Duplex Stabilization Pyrene, Acridine May increase Tm; shorten probe if needed.
Electron Transfer / PeT Anthraquinone, Phenanthroline Validate under working ionic strength and redox conditions.
Photo-Crosslinking Psoralen Requires UVA activation and light protection.
Supported Products

Supported Intercalator Modifications

The live-site product information is retained and reorganized into a scannable technical table with category badges, placement/use notes and shorthand codes.

Intercalator Product Table

Includes fluorescent, photoactive, redox, chemiluminescent and structural intercalator options for custom DNA/RNA oligonucleotide synthesis.

Product / Modification Category Description Typical Use Technical Note Code
Pyrene-dU Fluorescent / Excimer Internal pyrene on deoxyuridine Excimer/exciplex sensing; duplex stabilization Excimer emission with adjacent pyrenes; strong stacking Py-dU
Pyrene-dC Fluorescent / Excimer Internal pyrene on deoxycytidine Signal enhancement; FRET donor/acceptor Placement-sensitive; consider spacer to tune PeT Py-dC
Perylene-dU Fluorescent / Structural Internal perylene intercalator Bright far-green emission; hybridization probes High quantum yield; larger steric footprint Per-dU
Anthraquinone-dU Redox / PeT Electron-acceptor intercalator PeT studies; photocleavage mapping Efficient charge transfer; verify polymerase tolerance AQ-dU
Thiazole Orange-dT (TO-dT) Signal-On Fluorescent Cyanine intercalator tethered to dT Light-up bound-enhanced probes Low background until intercalated; FI principle TO-dT
Thiazole Orange linker Signal-On Fluorescent TO via flexible internal linker Signal-on hybridization probes Spacer length controls brightness and background TO-linker
Acridine-C6 Structural / Triplex Acridine via C6 spacer Triplex/footprinting; intercalative probing Classic intercalator; strong stacking; pH-dependent Acr-C6
Ethidium-C3 Fluorescent Reporter Ethidium tethered via C3 Fluorescent intercalation reporter Potent binder; avoid over-labeling Eth-C3
Daunomycin Anthracycline / Redox Anthracycline intercalator Red-channel reporting; redox studies Light/oxidation sensitive; protect from light Dau
1,10-Phenanthroline-dT Metallo-Intercalator Metal-binding intercalator at dT Metallo-intercalator probes; redox catalysis Coordinate metals such as Cu/Fe; control conditions Phen-dT
5′-Psoralen C6 Photoactive Crosslinker Psoralen crosslinker via C6 spacer UVA photo-crosslinking; interstrand crosslinks Activates ~320-365 nm; bias for 5′-TA steps 5-Pso-C6
3′-Psoralen C6 Photoactive Crosslinker Psoralen crosslinker via C6 spacer UVA photo-crosslinking; interstrand crosslinks Protect from light; placement affects crosslinking 3-Pso-C6
Psoralen-TEG Photoactive Crosslinker Psoralen via TEG spacer UVA photo-crosslinking; flexible placement Longer spacer improves accessibility; light-sensitive Pso-TEG
YO linker Signal-On Fluorescent Oxazole Yellow via flexible internal linker Signal-on hybridization probes; low background Emission increases on binding; minimize quenching YO-linker
YOYO dimer linker High-Brightness Intercalator Dimeric YOYO via flexible linker High-brightness intercalative probes Strong binding; may over-stabilize duplex YOYO-linker
Acridinium Ester-C6 Chemiluminescent Chemiluminescent acridinium via C6 Chemiluminescent readouts; intercalative binding Light-sensitive; avoid strong base Acrid-Ester-C6
Naphthalimide-C6 Environment-Sensitive Naphthalimide intercalator via C6 Green emission; environment-sensitive probes Photostable; stacking dependent; verify Tm Naph-C6
Rhodamine-C6 Red-Channel / FRET Rhodamine-based intercalator via C6 Red-channel probes; FRET donor/acceptor May partially bind externally; pilot background Rh-C6
Technical Notes & Design Considerations

Intercalator Design Considerations

Intercalator performance is strongly dependent on placement, spacer length, neighboring bases, salt, optical readout and whether the oligo must participate in enzymatic reactions.

Intercalators can increase duplex stability through aromatic stacking. Re-optimize probe length, salt conditions and assay temperature instead of assuming the native oligo Tm will transfer directly.
Pyrene pairs can produce excimer emission when brought into proximity. Design spacing, linker length and adjacent base context around the intended hybridization-dependent readout.
Electron donor/acceptor combinations, including anthraquinone designs, can quench or enhance signal depending on placement, ionic strength and duplex conformation.
Bulky intercalators may interfere with polymerases, ligases or nucleases. For enzymatic workflows, place the modification away from active junctions and validate extension, ligation or amplification.
Psoralen-modified oligos require UVA activation and should be protected from light. Crosslinking efficiency depends on sequence context, especially accessible pyrimidine-rich or TA-adjacent regions.
Protect light-sensitive labels, use HPLC or PAGE purification and confirm identity by mass spectrometry. Consider additional desalting, SEC or application-specific characterization for conjugates.
Applications

Applications for Intercalator-Modified Oligonucleotides

SIG

Signal-On Hybridization Probes

TO, YO and related cyanine intercalators for fluorescence increases upon duplex formation.

EX

Excimer & Exciplex Probes

Pyrene and perylene designs for proximity-sensitive emission and structural sensing.

Pso

Photo-Crosslinking

Psoralen oligos for UVA-triggered interstrand crosslinking, capture and mapping studies.

PeT

Electron Transfer

Anthraquinone and phenanthroline constructs for redox, PeT and charge-transfer studies.

Tm

Duplex Stabilization

Aromatic stacking modifications to tune duplex stability and probe binding behavior.

MAP

Structural Biology

Acridine, psoralen and pyrene designs for footprinting, triplex and conformation studies.

Purification & QC

Analytical Confirmation for Intercalator Oligos

PUR

Purification

  • RP-HPLC, IE-HPLC or PAGE
  • Method selected by hydrophobicity and length
  • Additional desalting or SEC for conjugates
MS

Identity & Purity QC

  • ESI-MS or MALDI-TOF confirmation
  • Analytical HPLC/UPLC trace when applicable
  • CoA and modification annotation
OPT

Optional Characterization

  • UV/Vis or fluorescence support
  • Crosslinking verification for psoralen
  • Tm or assay-support testing by request

Frequently Asked Questions

FAQ

What is an intercalator-modified oligonucleotide?
It is a DNA or RNA oligo carrying an aromatic molecule capable of stacking between base pairs or interacting strongly with duplex nucleic acids.
How do intercalators differ from standard fluorophores?
Standard fluorophores often emit independently of duplex formation. Intercalators can produce signal-on fluorescence, excimer/exciplex emission or PeT behavior because the signal depends on stacking and nucleic-acid binding.
Which intercalator is best for signal-on fluorescence?
Thiazole Orange, YO and related cyanine intercalators are commonly selected for signal-on hybridization probes.
Does psoralen require UV activation?
 Yes. Psoralen-modified oligonucleotides typically require UVA exposure, often around 320-365 nm, to form crosslinks.
Can intercalators be combined with other labels?
 Yes. They can often be combined with fluorophores, quenchers, biotin, click handles, spacers or affinity tags, but spacing and background should be reviewed.
What QC is recommended?
 Purification by HPLC or PAGE and identity confirmation by ESI-MS or MALDI are commonly recommended.
Where should the intercalator be placed?
 Internal placement usually maximizes stacking and signal effects. Terminal 5′ or 3′ placement can be simpler but may show weaker intercalation.
Can intercalators affect PCR, ligation or enzymatic processing?
 Yes. Bulky aromatic modifications can interfere with polymerases, ligases or nucleases, especially near active junctions.
More FAQ'sAll FAQ's
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