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Gapmer ASO Synthesis

Custom gapmer antisense oligonucleotide synthesis for RNase H-mediated RNA knockdown. Bio-Synthesis provides custom gapmer ASO synthesis using LNA, BNA, 2′-MOE, cEt, phosphorothioate backbones, and conjugation chemistries for research and therapeutic oligonucleotide applications.

RNase H Knockdown LNA / BNA Gapmers 2′-MOE Gapmers cEt Gapmers PS Backbone 100 g/batch ISO 9001:2015 / ISO 13485:2016 U.S. Facilities - Texas
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Overview Mechanism of action Architecture LNA / BNA / MOE / cEt ASO comparison Advanced chemistry Applications Synthesis options Add-ons FAQ Contact

Gapmer ASO Overview

Gapmer antisense oligonucleotides (gapmer ASOs) are sequence-specific RNA-targeting oligonucleotides designed for RNase H-mediated RNA degradation and gene knockdown. Gapmer ASOs contain a central DNA region flanked by chemically modified nucleotide “wings” that improve binding affinity, nuclease resistance, specificity, and biological stability while enabling RNase H-mediated target RNA cleavage.

Gapmer ASOs are widely used for mRNA knockdown, lncRNA targeting, target validation, functional genomics, pathway analysis, and therapeutic oligonucleotide development. After hybridizing to the complementary RNA target, the DNA gap forms a DNA/RNA duplex recognized by RNase H1, resulting in selective degradation of the RNA strand while the ASO can remain allowing continued RNA targeting activity.

Bio-Synthesis provides advanced custom gapmer ASO synthesis services using a broad range of chemistries including LNA, BNA, 2′-MOE, cEt, phosphorothioate (PS), mixed-wing architectures, and advanced conjugation strategies. Our team supports customized gapmer workflows ranging from early discovery research through preclinical and scale-up oligonucleotide manufacturing programs.

Bio-Synthesis specializes in custom gapmer ASO synthesis for research, translational, and therapeutic RNA knockdown applications, including challenging target sequences, high-affinity gapmer architectures, advanced conjugation strategies, and complex modification patterns requiring specialized oligonucleotide synthesis capabilities.

Why Bio-Synthesis for Gapmer ASO development?

  • Specialized gapmer chemistry support including LNA, BNA, 2′-MOE, cEt, phosphorothioate (PS), mixed-wing architectures, stereopure backbone strategies, and custom conjugation workflows
  • Broad modification capability with Broad modification capabilities including standard and specialized base, sugar, backbone, and linkage chemistries for customized ASO optimization workflows for difficult RNA targets and specialized ASO optimization
  • Flexible synthesis support from early discovery screening through preclinical and scale-up programs up to 100 g/batch
  • High-purity manufacturing with HPLC, PAGE, LC-MS, analytical QC, and custom release testing tailored to project requirements
  • Expertise supporting gapmer optimization, RNase H-mediated knockdown workflows, conjugation strategies, and preclinical and therapeutic oligonucleotide development
  • ISO 9001:2015 / ISO 13485:2016 quality systems with U.S.-based manufacturing facilities in Texas and GLP/GMP-aligned project support

Development Scale

From early discovery screening through preclinical and scale-up programs, Bio-Synthesis supports custom gapmer ASO synthesis up to 100 g/batch, depending on sequence, chemistry, purity, and documentation requirements.

Specialized Chemistry

Extensive modification capabilities across LNA, BNA, 2′-MOE, cEt, PS backbone, mixed-wing architectures, conjugates, and custom modified gapmer designs.

Analytical QC

Quality control options include LC-MS, analytical HPLC, PAGE purification, OD260 quantification, purity analysis, and custom release testing tailored to project requirements.

Regulatory & Manufacturing

ISO 9001:2015 / ISO 13485:2016 systems, GLP/GMP-aligned workflows, documentation support, and U.S.-based manufacturing facilities in Texas for advanced oligonucleotide programs.

Gapmer ASO Mechanism of Action

Gapmer ASOs bind complementary RNA targets and recruit RNase H1 through their central DNA gap. RNase H1 recognizes the DNA/RNA duplex and cleaves the RNA strand, supporting efficient target RNA degradation.

Gapmer ASO RNase H-Mediated RNA Knockdown

Gapmer ASO mechanism showing LNA BNA MOE or cEt modified wings, central DNA gap, RNase H recruitment, target RNA cleavage, transcript degradation, and ASO recycling

Gapmer mechanism overview. The modified wings improve affinity and stability, while the central DNA gap enables RNase H1-mediated cleavage of the target RNA.

Note: The DNA gap is essential for RNase H1 recognition and cleavage, while the modified wings enhance binding affinity, nuclease resistance, and in vivo stability

Gapmer ASO Architecture

Gapmer design balances affinity, stability, specificity, and RNase H activity through strategic placement of modified wings, a DNA gap, and backbone chemistry.

Gapmer Component Typical Design Role Common Options Why It Matters
Modified Wings Increase target binding affinity and nuclease resistance LNA, BNA, 2′-MOE, cEt, 2′-OMe Improves potency, stability, and target engagement
Central DNA Gap Forms DNA/RNA duplex required for RNase H1 recognition Common gap lengths vary by design, target, and chemistry Enables target RNA cleavage
PS Backbone Improves nuclease resistance and in vivo persistence Full or patterned phosphorothioate linkages Supports stability, exposure, and manufacturability
Conjugation Site Supports delivery, targeting, or detection GalNAc, cholesterol, lipids, peptides, fluorophores, biotin Improves application-specific functionality
Design note: Bio-Synthesis can support common layouts such as 3-10-3, 5-10-5, and custom gap-wing architectures depending on target sequence, chemistry, potency goals, and QC requirements.

Gapmer ASO Design Recommendations

Effective gapmer ASO performance depends on balanced optimization of target accessibility, wing chemistry, gap length, backbone composition, affinity, specificity, and RNase H recruitment. Design strategies vary depending on transcript type, target region, delivery approach, and intended application.

General Gapmer Design Guidelines

  • Typical gapmer lengths range from 14–22 nucleotides depending on chemistry and target
  • Common architectures include 3-10-3, 4-8-4, and 5-10-5 wing-gap arrangements
  • Central DNA gaps are required for RNase H1-mediated RNA cleavage
  • LNA, BNA, 2′-MOE, and cEt wings improve affinity and nuclease resistance
  • Phosphorothioate (PS) backbones are commonly used to improve stability and exposure
  • Avoid excessive self-complementarity and strong secondary structure formation

Target Selection Considerations

  • Prioritize accessible RNA regions with reduced secondary structure
  • Evaluate exon, intron, UTR, splice-site, or lncRNA target regions based on application goals
  • Screen for sequence uniqueness to reduce off-target hybridization
  • Consider transcript isoforms and alternative splicing patterns
  • GC balance can influence affinity, specificity, and manufacturability
  • Species homology should be reviewed for translational and in vivo studies

Chemistry Optimization Strategies

  • LNA and BNA wings support high-affinity and shorter gapmer designs
  • 2′-MOE wings are widely used for balanced affinity and tolerability
  • cEt chemistry can improve potency and structural stability
  • Mixed-wing architectures may improve optimization flexibility
  • Stereopure PS designs can support advanced optimization workflows
  • Conjugation strategies may improve delivery or tissue targeting

Bio-Synthesis Design Support

  • Custom gapmer synthesis using LNA, BNA, 2′-MOE, cEt, and PS backbone strategies
  • Support for mixed-modification and conjugated gapmer architectures
  • Scale-up synthesis and advanced analytical QC workflows
  • Optimization support for difficult or low-accessibility RNA targets
  • Flexible purification, release testing, and documentation support
  • Research, translational, and preclinical oligonucleotide program support
Design note: Optimal gapmer ASO design depends on the target transcript, chemistry selection, delivery strategy, intended mechanism, and experimental model. Bio-Synthesis can support customized gapmer synthesis workflows for research and therapeutic oligonucleotide development.

LNA, BNA, MOE & cEt Gapmer Chemistries

LNA / BNA Gapmers

LNA and bridged nucleic acid (BNA) gapmer ASOs use high-affinity modified wings to improve target binding and support potent RNase H-mediated knockdown.

  • High-affinity RNA binding
  • Useful for shorter, potent ASO designs
  • Supports strong mismatch discrimination
  • Common in advanced gapmer optimization
Explore LNA / BNA Modifications →

2′-MOE Gapmers

2′-MOE gapmers use methoxyethyl-modified wings to balance affinity, stability, tolerability, and therapeutic-style gapmer performance.

  • Improves nuclease resistance
  • Supports stable RNA binding
  • Widely used in therapeutic ASO development
  • Compatible with PS backbone strategies
Explore 2′-MOE Gapmers →

PACE Gapmers

Phosphonoacetone (PACE) backbone chemistry supports advanced gapmer optimization through backbone engineering and mixed-linkage oligonucleotide design strategies.

  • Advanced backbone modification
  • Supports mixed-linkage architectures
  • Can tune pharmacological behavior
  • Useful for specialized therapeutic ASO research
Explore PACE Gapmers →

cEt & Advanced Gapmers

cEt and constrained analog chemistries support optimized gapmer designs with enhanced binding affinity and optimized structural stability.

  • High-affinity constrained chemistry
  • Optimized wing design strategies
  • Supports difficult RNA targets
  • Can pair with stereopure or conjugated designs
Explore Advanced Gapmers →
Bio-Synthesis capability: We support LNA, BNA, 2′-MOE, cEt, PS backbone, and custom modified gapmer ASO synthesis for research and preclinical RNA knockdown applications.

ASO Design Comparison: Gapmer vs Steric-Blocking vs Splice-Switching

This comparison helps users choose the correct ASO strategy based on whether the intended outcome is RNA degradation, functional blocking, or splice modulation.

Feature Gapmer ASO Steric-Blocking ASO Splice-Switching ASO
Primary Mechanism RNase H-mediated RNA degradation Physical blocking of RNA function Modulation of pre-mRNA splicing
RNA Cleavage Yes No No
Typical Structure Central DNA gap + modified wings Fully modified oligonucleotide Fully modified oligonucleotide
Common Chemistries PS, DNA gap, LNA, BNA, 2′-MOE, cEt PNA, PMO, TMO, 2′-OMe, 2′-MOE, LNA PMO, 2′-OMe, 2′-MOE, LNA, BNA, TMO analogs
Primary Applications Gene knockdown, mRNA degradation, lncRNA knockdown Translation blocking, miRNA inhibition, RNA-protein blocking Exon skipping, exon inclusion, transcript engineering
Target Location mRNA, pre-mRNA, lncRNA, nuclear or cytoplasmic transcripts mRNA, miRNA, or regulatory RNA Pre-mRNA in nucleus
Advantages Potent RNA knockdown through RNase H-mediated cleavage High specificity without RNA degradation Precise control of transcript structure
Limitations Requires careful sequence and off-target screening Requires strong binding affinity and accessible target site Requires accurate splice-site targeting
Best Use Case Reduce RNA expression Block RNA function without destroying RNA Modify gene expression at the splicing level
Design guidance: Gapmer ASOs are selected for RNA knockdown, while steric-blocking and splice-switching ASOs are used when RNA function or transcript structure must be modulated without degradation.

Gapmer Modification Chemistry Comparison

The table below summarizes common and advanced gapmer ASO chemistry options. Bio-Synthesis supports broader base, sugar, backbone, linkage, terminal, and conjugation modifications beyond those listed here.

Chemistry / Modification Type Key Advantages Best Applications Notes
Phosphorothioate (PS) Backbone Nuclease resistance, increased stability, improved exposure Most gapmer ASO designs Industry-standard backbone
Phosphonoacetone (PACE) Backbone/ linkage modification Can tune backbone charge, nuclease resistance, protien binding, and pharacological behavior Advanced gapmer optimization, mixed-backbone ASO designs, and therapeutic oligonucleotide research Useful for specialized gapmer designs where linkage strategiesare desired
DNA Gap Central gap region Enables RNase H1 recognition and RNA cleavage Core gapmer function Gap length depends on design
LNA Bridged sugar Very high affinity, strong potency, shorter designs Potent LNA gapmers Placement and spacing matter
BNA Bridged nucleic acid High binding affinity, enhanced stability, strong target engagement BNA gapmer ASOs and bridged nucleic acid gapmer designs Useful for affinity tuning
2′-MOE Sugar Improves stability, affinity, and therapeutic-style performance MOE gapmer wings Widely used in ASO development
cEt Constrained sugar analog High affinity, potency, and structural control Advanced gapmer designs Advanced constrained wing chemistry
2′-OMe Sugar Stability and binding improvement Custom mixed-modification designs Can support optimization strategies
2′-F Sugar Duplex stabilization and nuclease resistance Hybrid ASO designs Useful in mixed chemistries
Stereopure PS Gapmer Backbone optimization Defined chirality, potency tuning, reduced variability Therapeutic oligonucleotide development Next-generation backbone control
GalNAc Gapmer Conjugate Liver-targeted delivery and improved uptake Hepatic targets and metabolic disease research Common delivery strategy
Peptide Conjugate Conjugate Cell penetration and tissue targeting Extrahepatic delivery research Customizable targeting option
Cholesterol / Lipid Conjugate Conjugate Membrane interaction, exposure, and biodistribution tuning Systemic and preclinical studies Can improve delivery behavior

Need a specialized gapmer chemistry?

This table highlights representative gapmer chemistry options commonly used in ASO development. Bio-Synthesis supports additional specialized base, sugar, backbone, linkage, and conjugation modifications. Contact us or request a quote for custom gapmer ASO synthesis.

Typical Applications of Gapmer ASOs

Gapmer ASOs provide potent, sequence-specific RNA knockdown for research, validation, and preclinical and scale-up oligonucleotide programs.

Typical applications of gapmer ASOs including mRNA knockdown, lncRNA knockdown, target validation, functional genomics, pathway analysis, and therapeutic oligonucleotide development

Custom Synthesis Options

Bio-Synthesis offers flexible gapmer ASO synthesis tailored to discovery, translational research, and preclinical oligonucleotide programs.

Design & Chemistry

  • LNA, BNA, 2′-MOE, cEt, and mixed-wing gapmer designs
  • Central DNA gap architecture for RNase H activity
  • PS backbone and custom linkage strategies
  • Specialized oligonucleotide chemistry support for challenging RNA targets

Scale & Purification

  • Research to development-scale synthesis
  • Project support up to 100 g/batch
  • HPLC and PAGE purification options
  • Salt exchange, desalting, and lyophilization support

Quality Control

  • Mass spectrometry confirmation
  • Analytical HPLC
  • OD260 quantification
  • Custom release testing upon request

Quality System Support

  • ISO 9001:2015 / ISO 13485:2016
  • GLP/GMP-aligned project support
  • U.S.A. facilities in Texas
  • 45+ years of oligonucleotide expertise

Optional Add-On Services

Custom Formulation & Packaging →

Buffers, aliquoting, concentrations, tubes or plates, OEM labels/barcodes.

Custom Quality Control →

LC-MS, CE, extended HPLC traces, endotoxin/bioburden, water content, residual chemical analysis, stability program.

Regulatory & OEM →

RUO→GLP→cGMP pathways, document packages, tech transfer, and sequence masking.

Need something not listed?

We routinely implement bespoke gapmer ASO chemistries, conjugations, and QC workflows.

Get in Touch

FAQ

What is a gapmer ASO?

A gapmer ASO is an antisense oligonucleotide with a central DNA gap flanked by modified wings. The DNA gap enables RNase H1-mediated cleavage of the target RNA.

What chemistries are used in gapmer ASO design?

Common gapmer chemistries include PS backbone, DNA gap, LNA, BNA, 2′-MOE, cEt, 2′-OMe, 2′-F, and conjugates such as GalNAc, cholesterol, lipids, peptides, and fluorescent labels.

How is a gapmer different from a steric-blocking ASO?

Gapmers are designed to recruit RNase H and degrade RNA. Steric-blocking ASOs bind RNA without cleavage and instead block RNA function or interactions.

Does Bio-Synthesis support BNA gapmer designs?

Yes. Bio-Synthesis supports BNA and other bridged nucleic acid gapmer ASO designs, along with LNA, 2′-MOE, cEt, PS backbone, and custom modification strategies.

More FAQ'sAll FAQ's

Contact & Quote Request

For the fastest review, send your target sequence, target gene or transcript, species, desired knockdown strategy, gapmer chemistry preference, scale, purification, QC requirements, and any conjugation or delivery needs.

Fast quote checklist

  • Target gene/transcript and species
  • Desired mechanism: RNase H-mediated knockdown
  • Preferred chemistry: LNA, BNA, 2′-MOE, cEt, PS, or custom
  • Scale, purity, and QC requirements
  • Conjugation, labeling, or documentation needs

Fastest path

Request a Quote Speak to a Scientist

Scientific Validation & Recommended Reading

Gapmer antisense oligonucleotide technologies are supported by extensive peer-reviewed literature covering RNase H-mediated RNA degradation, LNA/BNA chemistry, phosphorothioate backbones, therapeutic oligonucleotide optimization, and RNA-targeting strategies.

Why Choose Bio-Synthesis

Trusted by biotech leaders worldwide for over 45+ years of delivering high quality, fast and scalable synthetic biology solutions.

Greetings Researchers,

Please be advised that any information, guidelines, writeups, and oral/video/graphic content on our website are intended solely as general guidelines.
It is the researcher's sole responsibility to conduct thorough research on the designs of the products intended for their experiments before submitting
their designs to Biosynthesis for review of production feasibility.
Thank you for your understanding.

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