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AmNA™ — Amido-Bridged Nucleic Acid for Advanced ASO Design

Explore conformationally constrained nucleic acid chemistry for RNA-targeting oligonucleotides, gapmer ASOs, splice-switching strategies and next-generation therapeutic design.

2′,4′-Bridged Nucleic Acid RNA Affinity ASO / Gapmer Research Nuclease Stability Proprietary Chemistry
Discuss AmNA Feasibility Explore Design Considerations
Overview Benefits Design Guide Gapmer Placement Applications Manufacturing Patent & Licensing Related Services Reding FAQ Contact
Scientific Overview

What Is Amido-Bridged Nucleic Acid (AmNA)?

Amido-bridged nucleic acid (AmNA) is a chemically modified nucleic acid designed to improve how oligonucleotides recognize and bind complementary RNA. It belongs to the family of 2′,4′-bridged nucleic acids, in which an amide-containing bridge restricts the flexibility of the sugar structure.

This structural constraint can improve RNA-binding affinity and resistance to enzymatic degradation. These properties make AmNA an interesting option for antisense oligonucleotide (ASO) research, particularly when optimizing stability, target recognition and biological activity.

One promising application is gapmer ASO design. Selected AmNA modifications can be introduced into the outer regions, or wings, while preserving a central DNA region needed for RNase H-mediated RNA cleavage. Researchers can compare different placements to evaluate binding, target knockdown and overall performance.

AmNA may also be explored in splice-switching oligonucleotides and other RNA-targeting designs. Results depend on the sequence, backbone chemistry, modification placement and intended application. Bio-Synthesis can review design feasibility, specialty phosphoramidite access, purification and analytical requirements, subject to applicable licensing.

Chemical structure of N-methyl amido-bridged nucleic acid (AmNA) showing the constrained sugar ring and amide bridge

AmNA sugar structure (illustrative; Base and backbone attachment positions shown).

Structure note: Illustrative N-methyl AmNA-type structure. Confirm the specific amidite, stereochemistry, nucleobase and protecting groups before synthesis.

Why Consider AmNA?

Four Research-Driven Advantages of AmNA Chemistry

Published research and Luxna's technical materials describe AmNA as a candidate modification for affinity, stability and ASO design optimization. Effects should be evaluated in the complete oligonucleotide architecture.

Tm

RNA-Binding Affinity

Conformational restriction can increase affinity for complementary RNA, supporting evaluation of shorter or more selective antisense designs.

Stab

Nuclease Resistance

Modified sugar chemistry can help reduce susceptibility to enzymatic degradation in certain oligonucleotide contexts.

ASO

Architecture Flexibility

Selected AmNA positions can be explored in gapmer wings and steric-blocking designs while preserving the intended mechanism.

R&D

Tolerability Research

AmNA-containing constructs have been investigated for potential tolerability improvements; safety is sequence-, dose- and chemistry-dependent.

Evidence boundary: AmNA is not automatically more potent or safer than LNA, cEt or 2′-MOE. Head-to-head comparisons require matched sequences and appropriate biological models.

Interactive Design Guidance

Select an AmNA Design Strategy

Choose a topic to review practical questions for sequence architecture, mechanism and analytical development.

Modified Wings + DNA Gap

Consider AmNA incorporation in flanking wings while retaining a DNA gap of suitable length and composition for RNase H recruitment. Test placement effects on duplex Tm, RNA cleavage, off-target activity and tolerability.

Critical: A fully AmNA-modified strand should not be assumed to support RNase H-mediated RNA cleavage.

Choose chemistry by mechanism, affinity target, stability, cost, and access—not by a universal potency ranking.

Modification Structural class When to evaluate Important trade-off
AmNA Amide-containing 2′,4′ bridge Exploratory wing substitutions, affinity and nuclease-resistance screening Proprietary reagent access; sequence-specific validation
LNA 2′,4′ methylene bridge High-affinity wings and steric-blocking oligos Strong binding does not ensure favorable safety
cEt Constrained ethyl bridge High-affinity gapmer wing optimization IP, availability and sequence-dependent performance
2′-MOE Unbridged 2′-O-methoxyethyl Established ASO wing comparator for stability and tolerability Different affinity profile and chemistry than bridged sugars

Compare matched sequences using duplex Tm, target knockdown, RNase H cleavage where applicable, stability, and safety readouts.

Plan Monomer Access Before Production

Confirm licensed monomer availability, nucleobase choices, protecting groups, activator/coupling conditions, cleavage and deprotection compatibility, and stability of the amide bridge. Define HPLC/UPLC purification, mass confirmation and application-specific assays.

Commercial status: Bio-Synthesis feasibility and quotations are subject to reagent supply, applicable licensing and method development.

Supplier-Informed Design Guidance

AmNA Gapmer Design & Incorporation Strategy

A gapmer uses modified-nucleotide wings around a central DNA region. The Summit/Luxna technical brochure presents an illustrative AmNA substitution strategy and mixed-chemistry options. The brochure's “2–4 substitutions” wording should be interpreted in the context of its own figure; it is not established here as a fixed number per wing or per oligonucleotide.

Representative wing–gap–wing architecture Schematic only — segment lengths and dots do not specify an experimentally validated sequence
5′ → 3′ ASO
Illustrative modified wing (possible AmNA) DNA gap Other chemistries may be evaluated separately
Conventional comparator

PS-DNA gap with an established modified-wing chemistry, selected for the intended RNase H mechanism.

Experimental AmNA-wing design

Evaluate selected AmNA substitutions in the wings while keeping an RNase H-compatible DNA region. Compare against the same-sequence control.

5′ Modified Wing

Evaluate AmNA placement

Central DNA Gap

Preserve RNase H-compatible region

3′ Modified Wing

Evaluate AmNA placement

01 Start with the wings

Screen selected wing positions. Summit illustrates a 2–4 substitution concept; confirm the exact placement from the source figure before specifying an order.

02 Protect the DNA gap

For RNase H-dependent ASOs, retain a DNA region and verify RNA cleavage experimentally; modifications near gap boundaries can change activity.

03 Compare mixed-XNA designs

The brochure also illustrates combining AmNA or scpBNA in wing regions with 5′-CP placement near the DNA gap. Treat this as a separate development route.

04 Measure performance

Compare Tm, nuclease stability, target knockdown, off-target effects, tolerability, HPLC purity and MS identity before selecting a lead.

Source and attribution: Design concepts adapted and redrawn from Summit Pharmaceuticals Europe's Modified Phosphoramidites technical brochure ↗ (page 3), describing Luxna XNA technology. The diagram above is an original educational schematic, not a reproduction of the supplier artwork. AmNA™ and related proprietary technologies are associated with Luxna; reagent access and applicable licensing must be confirmed. Note: The green and gray dots illustrate chemical regions only; their count is not a prescription for a 4–7–4 gapmer.
Applications

Where AmNA-Modified Oligonucleotides May Be Evaluated

Application choice determines whether the primary goal is RNase H-mediated cleavage, steric blocking, RNA binding or comparative therapeutic optimization.

ASO

Antisense Therapeutics

Explore AmNA placement in RNA-targeting antisense constructs, with affinity, stability and activity testing.

Explore ASO Services →
Gap

Gapmer ASOs

Evaluate AmNA-modified wings alongside a DNA gap designed for RNase H-mediated target RNA cleavage.

Explore Gapmer Synthesis →
SSO

Splice-Switching Oligos

Investigate steric-blocking RNA binding in designs that do not rely on RNase H cleavage.

Explore Splice Switching →
Dev

Therapeutic Candidate Optimization

Compare modification patterns for potency, nuclease stability, sequence specificity and tolerability.

Explore Development Support →
Technical Feasibility

From AmNA Sequence Concept to Analytical Characterization

Specialty monomers require a sequence-specific chemistry review rather than assuming standard DNA/RNA synthesis conditions will transfer unchanged.

AmNA phosphoramidite for custom oligonucleotide synthesis: feasibility depends on the specific nucleobase, protected monomer, coupling/deprotection compatibility, permitted use, and supply terms. Bio-Synthesis can evaluate a proposed AmNA-modified ASO design before confirming an offer or timeline.

01

Define Target

Sequence, mechanism, modification positions and intended assay.

02

Verify Reagents

Monomer source, license, base set, purity and lead time.

03

Develop Chemistry

Coupling, sulfurization, deprotection and bridge compatibility.

04

Purify & Identify

Fit-for-purpose HPLC/UPLC and LC-MS or MS analysis.

05

Evaluate Function

Tm, nuclease stability and relevant biological assays as scoped.

Bio-Synthesis: U.S.-based oligonucleotide chemistry development and analytical support, with ISO 9001:2015 and ISO 13485:2016 quality systems and GMP-aligned development capabilities. AmNA-specific manufacturing is subject to feasibility review.

Intellectual Property & Commercial Supply

AmNA™ Is Proprietary Chemistry: Luxna and Summit Have Different Roles

Luxna Biotech identifies AmNA™ as part of its proprietary modified nucleic acid technology portfolio, which has origins in research at Osaka University. Relevant intellectual property and use rights should be evaluated for each intended commercial application.

Summit Pharmaceuticals International Corporation (SPI) is a commercial partner. In December 2024, Luxna announced a license agreement with Summit covering the manufacture and sale of Luxna's artificially modified nucleic acid amidites. This does not establish Summit as a co-owner of every AmNA patent.

Patent and licensing notice: AmNA™ is identified as a Luxna technology/trademark. This page is provided for scientific education and feasibility discussion; it does not imply Bio-Synthesis has an AmNA license, authorization, supplier relationship or right to offer unrestricted commercial manufacture.

Luxna technology overview ↗  ·  Luxna–Summit licensing announcement ↗  ·  Summit modified phosphoramidites flyer ↗

AmNA Chemistry FAQ

FAQ

Can Bio-Synthesis quote AmNA-modified oligonucleotides?
Bio-Synthesis can review the proposed sequence, design, reagent availability, applicable permissions, scale, purification and analytical requirements before confirming feasibility and providing a quotation.
What is AmNA?
AmNA is an amido-bridged nucleic acid, a conformationally constrained 2′,4′-bridged nucleic acid analog developed for oligonucleotide design.
Is AmNA the same as 2′-O-NMA?
No. AmNA refers to an amido-bridged nucleic acid; 2′-O-NMA denotes a different modification and should not be used as a synonym without structural verification.
Can AmNA be used in gapmer ASOs?
AmNA can be evaluated in modified gapmer wings while retaining an appropriate central DNA gap for RNase H activity. Placement and biological performance require testing.
Does AmNA reduce liver toxicity?
Some published and developer-reported results suggest potential tolerability benefits in particular designs. This is not a universal safety guarantee and depends on sequence, chemistry, dose and model.
Is AmNA commercially available?
Luxna Biotech identifies AmNA as a proprietary technology, and Summit Pharmaceuticals International has a license arrangement for manufacture and sale of Luxna modified nucleic acid amidites. Access and use rights must be confirmed.
More FAQsAll FAQs
Scientific Collaboration

Discuss Your Next AmNA or Advanced ASO Project

Share your sequence and research objective. Our team can review the design, analytical requirements and feasibility of specialty monomer sourcing.

CUSTOM OLIGONUCLEOTIDE DEVELOPMENT

From an AmNA concept to a practical synthesis plan.

Whether you are comparing AmNA with LNA or cEt, optimizing gapmer wings, or evaluating a steric-blocking design, start with a technical discussion of the intended mechanism and available chemistry.
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01

Design Consultation

Sequence, AmNA positions, RNA target, RNase H compatibility and comparator chemistry.

Gapmer ASO Splice switching
02

Feasibility & QC Review

Monomer sourcing, licensing considerations, synthesis conditions, purification and analytical identity.

HPLC LC-MS Custom scale

AmNA is proprietary technology. Availability is subject to reagent access, technical feasibility and applicable intellectual-property or licensing requirements. No synthesis availability is implied before review.

Scientific Validation & Recommended Reading

Selected Scientific and Technology Sources

Primary technology sources and examples of AmNA-related synthesis and research. These do not establish guaranteed clinical benefit.

Peer-reviewed AmNA research

Supplier, licensing and technical documents

Research citations support specific experimental findings. Supplier design diagrams and licensing announcements serve different purposes and should not be interpreted as clinical performance guarantees.

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, write-ups, 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 design of products intended for their experiments before submitting
their designs to Biosynthesis for production feasibility review.

Thank you for your understanding.

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