Chiral Oligonucleotide Synthesis (Stereospecific & Stereopure PS Oligos)

Custom stereospecific phosphorothioate (PS) oligonucleotide synthesis with defined Rp/Sp stereochemical control for antisense, siRNA, and advanced oligo therapeutics.

Bio-Synthesis supports stereodefined, stereospecific, and stereopure oligonucleotide synthesis for programs where phosphorothioate chirality, backbone uniformity, and sequence-level control are important to development strategy.

chiral oligonucleotide synthesis stereospecific oligo synthesis stereopure phosphorothioates Rp / Sp control ASO & siRNA support

Overview

Chiral oligonucleotide synthesis addresses the stereochemical complexity introduced by phosphorothioate (PS) linkages, where each phosphorothioate linkage introduces a chiral phosphorus center (Rp or Sp configuration). In conventional phosphorothioate oligo synthesis, these linkages are typically formed as mixed stereochemical populations, resulting in heterogeneous products.

Stereospecific oligo synthesis enables controlled formation of phosphorothioate linkages with defined stereochemistry, supporting programs that require greater molecular uniformity, structured backbone design, or sequence-specific stereochemical exploration.

Depending on program goals, this may include fully stereopure oligonucleotides, partially defined stereochemical patterns, or targeted stereochemical optimization at selected backbone positions. These approaches are relevant to antisense, siRNA, and other advanced oligonucleotide platforms where backbone design can influence overall behavior.

stereodefined phosphorothioates reduced heterogeneity sequence-level control development-stage optimization advanced oligo design
Comparison figure showing stereopure oligonucleotides versus conventional stereorandom phosphorothioate oligos.
Figure: Representative comparison of stereopure versus conventional stereorandom phosphorothioate oligonucleotides.

chiral backbone design platform

Define • Pattern • Optimize

Flexible stereochemical design strategies for phosphorothioate oligonucleotides, from conventional mixed backbones to targeted stereodefined and fully stereopure constructs.

Stereopure

Full control

Defined backbone stereochemistry across the sequence

Patterned

Selective definition

Targeted Rp/Sp assignments at chosen positions

Conventional

Mixed PS

Standard stereorandom phosphorothioate backbone population

Synthesis Formats

Chiral oligonucleotide programs may be approached using fully stereopure, selectively patterned stereodefined, or conventional stereorandom phosphorothioate formats depending on design intent, development stage, and analytical goals.

Single defined population Maximum control

Stereopure Oligonucleotides

Fully defined phosphorothioate stereochemistry across the backbone for programs requiring the highest degree of structural control.

  • Defined stereochemical sequence architecture
  • Reduced backbone heterogeneity
  • Suitable for advanced optimization programs

Best fit

Programs prioritizing maximum stereochemical definition and sequence-level backbone control.

Discuss Stereopure Oligos →

Selective Rp/Sp design Flexible optimization

Patterned Stereodefined Oligos

Controlled stereochemistry at selected phosphorothioate positions to support focused structure-activity exploration.

  • Position-specific stereochemical control
  • Useful for backbone optimization studies
  • Balances design precision and flexibility

Best fit

Programs evaluating targeted Rp/Sp placement without requiring a fully stereopure backbone.

Discuss Patterned Designs →

Mixed Rp / Sp Conventional PS

Conventional Stereorandom PS Oligos

Standard phosphorothioate oligonucleotides produced as mixed stereochemical populations for discovery and reference workflows.

  • Standard phosphorothioate synthesis format
  • Mixed stereochemical backbone population
  • Useful for baseline comparison and early-stage work

Best fit

Early discovery, reference comparisons, and programs where defined chirality is not required.

Compare with Stereopure →

Stereopure vs Conventional PS Oligonucleotides

This comparison highlights the main differences between stereopure, patterned stereodefined, and conventional stereorandom phosphorothioate oligonucleotides.

Stereopure / Stereodefined Oligos
  • Defined phosphorothioate stereochemistry
  • Reduced backbone heterogeneity
  • Greater structural control for advanced programs
  • Useful for targeted design and optimization workflows
Conventional PS Oligos
  • Mixed Rp / Sp phosphorothioate populations
  • Higher stereochemical heterogeneity
  • Conventional discovery-stage synthesis format
  • Useful where defined chirality is not required
Format Stereochemical control Primary advantage Typical limitation Typical use
Stereopure oligos Defined across the full backbone Maximum sequence-level stereochemical control More specialized synthesis strategy Advanced development programs
Patterned stereodefined oligos Defined at selected positions Flexible backbone optimization Requires design planning SAR and targeted optimization
Conventional PS oligos Mixed stereorandom population Established standard synthesis format Higher stereochemical heterogeneity Discovery and reference studies

The most appropriate format depends on target biology, development stage, and whether defined phosphorothioate stereochemistry is part of the optimization strategy.

Program Support

How We Support Your Chiral Oligo Program

We work with research teams to align stereochemical design strategy with sequence, modality, analytical scope, and development-stage goals.

Design Input

Sequence Review

Assess sequence context, modality, and stereochemical objectives.

Strategy

Format Selection

Compare stereopure, patterned, and conventional PS formats for fit.

Execution

Synthesis & Analysis

Support synthesis planning, purification, and fit-for-purpose analytics.

Chiral Oligo Design Workflow

A typical stereospecific oligonucleotide project starts with defining the target biology and backbone design goal, followed by stereochemistry planning, synthesis, and analytical confirmation.

Workflow diagram for chiral oligonucleotide synthesis from design through analytical confirmation.
Figure: Representative workflow for chiral oligonucleotide synthesis, from design strategy through synthesis and analytical review.

1) Define the objective

Confirm sequence, modality, application, and whether stereopure or patterned stereochemical control is desired.

2) Select stereochemical strategy

Determine the level of Rp/Sp definition needed across the phosphorothioate backbone.

3) Synthesize & verify

Execute synthesis, purification, and fit-for-purpose analytical confirmation aligned to the project goal.

Fastest quoting tip: Share the oligonucleotide sequence, application, desired stereochemistry strategy if known, quantity, purity target, and whether you need a stereopure, patterned, or conventional comparison format.

Applications

Antisense oligonucleotides

Chiral backbone design can be relevant for antisense programs exploring backbone-dependent performance and sequence-specific optimization.

  • ASO lead optimization
  • Sequence-level backbone design
  • Comparative stereochemistry studies

siRNA and RNA-targeting programs

Defined phosphorothioate stereochemistry may be incorporated into selected RNA-targeting designs where backbone architecture is under active evaluation.

  • siRNA support
  • Backbone pattern exploration
  • Development-stage comparisons

Advanced oligo R&D

Useful for groups studying how controlled phosphorothioate stereochemistry affects oligonucleotide behavior across screening and optimization workflows.

  • Structure–activity exploration
  • Backbone engineering studies
  • Reference vs optimized format comparisons

Analytical Support

Identity confirmation

  • LC-MS identity confirmation
  • Sequence and modification review
  • Fit-for-purpose analytical documentation

Purity assessment

  • Analytical HPLC/UPLC profiling
  • Purification strategy aligned to program needs
  • Batch-specific review as applicable

Project-aligned deliverables

  • COA and method summary
  • Modification and backbone format summary
  • Support for comparative synthesis sets
Note: Final analytical scope can vary depending on whether the request is for stereopure, patterned stereodefined, or conventional phosphorothioate oligonucleotides.

Quality & Project Support

Bio-Synthesis supports oligonucleotide programs with controlled project workflows, fit-for-purpose purification, and analytical review aligned to research and development requirements. For chiral oligonucleotide projects, emphasis is placed on clear backbone format definition, stereochemistry strategy alignment, and program-specific documentation.

Typical support areas

  • Stereopure vs conventional comparison planning
  • Patterned backbone design support
  • Sequence and scale alignment
  • Research-stage documentation

Program inputs

  • Sequence and modification summary
  • Desired stereochemistry approach
  • Scale and purity target
  • Application context and timeline

Contact & Quote Request

For the fastest quote on chiral oligonucleotide synthesis, share your sequence, target application, desired stereochemistry strategy if known, scale, purity target, and any preferred comparison format.

Information for a Fast Quote

  • Oligonucleotide sequence and modification summary
  • Desired format: stereopure, patterned, or conventional PS
  • Scale, purity target, and delivery needs
  • Application context, comparison plan, and timeline

Contact Bio-Synthesis

Why Choose Bio-Synthesis

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