We offer a comprehensive platform supporting nucleic acid therapeutic discovery and development at all stages. Our one-stop service offers monomer and oligonucleotide synthesis for a broad range of nucleic acid therapeutics, including special modifications, chiral oligos, and oligo-conjugations. Our expertise in formulation, state-of-the-art in vitro bioassays, toxicity testing and in vivo PoC can further accelerate the discovery and development processes. View our mRNA services flyer here, and our oligonucleotide services flyer here.

Oligonucleotide Biology Platform: View our brochure here

mRNA, RNA, messenger RNA molecule, siRNA, antisense oligonucleotide, micro RNA
Oligonucleotide, oligo, conjugation, formulation, synthesis, GalNAc, siRNA, micro RNA, ASO, lipid, PMO, miRNA
Monomer/linker/conjugate synthesis
  • Synthesis of bridged and bicyclic nucleic acids, novel amidites, and GalNAc ligands
  • Oligonucleotide custom synthesis of siRNA, miRNA, ASO/gapmers, aptamers, CpG ODN, PMO, and DNA
  • GalNAc-siRNA conjugation, for targeted delivery to hepatocytes
  • Lipid conjugation, to increase cellular uptake and enhance stability of oligonucleotides
  • Peptide conjugation of ASOs and siRNAs, to improve cell targeting and permeability
  • Conjugation of oligos to small molecules, toxins, PEG, and antibodies
Oligo Library
  • Library of GalNAc-conjugated siRNAs
  • Custom oligonucleotide library synthesis services, including siRNA duplex libraries and PMO libraries
  • Comprehensive library of special monomers
  • High-throughput oligo synthesis and purification
Oligo Optimization
  • Nucleobase and sugar-skeleton modifications
  • Sequence substitution and back bone optimization
  • Optimization of conjugation, for delivery and release
  • Stability testing of siRNAs and conjugates
Target Validation and Sequence Design
  • In silico sequence selection
  • Library-based in vitro and in vivo screening
  • sgRNA library screens (sgRNAi and sgRNAa)
  • Cell-line engineering: overexpression, shRNA knockdown, KO/KI
  • Phenotypic profiling: cell proliferation, cell death, cell cycle profiling
  • Genetically engineered mouse models
In vitro and in vivo efficacy/early tox screening, off-target
  • Knockdown effect in cell lines and primary cells (mRNA & protein assessment)
  • Functional evaluation via cell cycle analysis and downstream signaling pathways
  • Assessment of cell-based delivery using GalNAc/ASGPR binding & uptake assays
  • In vitro toxicity: immune response profiling and cytotoxicity assessment in primary human hepatocytes
  • Off-target effects (transcriptome analysis): off-target profiling by RNAseq
  • Quantification of siRNA in the RNA-induced silencing complex (RISC)
  • In vivo PD studies in HDI, transgenic, and AAV mouse models; confirm cellular location of knockdown
  • In vivo PD studies in NHPs, determine duration of knockdown effect
  • Analysis of biomarkers to predict PD/efficacy studies of oligos
ADME and in vivo PK
  • PK studies in mice: siRNA levels in plasma, kidney and liver quantified by stem-loop qRT-PCR
  • Plasma protein binding assays and biodistribution studies
  • Metabolic stability assessment and metabolite profiling/identification
  • Mass balance and excretion analysis (including biliary excretion)
  • Bioanalytical platforms for measuring oligo levels, including LC-MS/MS, LC-HRMS, qPCR, and ligand binding assays
  • Polymeric, lipid nanoparticles (LNPs) for siRNA and ASO delivery
  • Advanced technology offering high homogeneity, robust reproducibility, and scalability for all types of liposomes
  • LNPs exhibiting high encapsulation efficiency and narrow particle size distribution at <100 nm

Learn more on oligo.wuxiapptec.com

Scale-up and Manufacture
  • State-of-the-art facilities supporting oligo process development and manufacturing at any scale, from nmol to mol
  • Covering a variety of oligo types including, ASOs, siRNAs, aptamers, oligo conjugates, PMOs and PPMOs
  • Oligo production services from lab scale to commercial scale, with more than 10 R&D production lines

Learn more on oligo.wuxiapptec.com

  • Full toxicology capabilities, core battery of testing available
  • Discovery toxicity studies include exploratory, genetic, and in vitro assays
  • General toxicology studies (rodent, rabbit, dog, NHP, minipig) for 14-days, 28-days, and 13-weeks, 26/39-weeks
  • TK bioanalytical method development and validation
  • Immunology-related tox services, including tissue cross reactivity and Immunohistochemistry studies

Target Selection

Off-target, in silico, bioinformatics, oligo sequence, homology, SNP, transcripts, RNA, ASO

Selection and validation of target and modality

Bioinformatics for in silico sequence pre-selection• Overview of target: expression pattern, isoform, SNPs
• Homology comparison cross species
• Off-target consideration
• Efficiency prediction

Oligonucleotide Design

Semi-automated in silico oligo sequence and modification design  

siRNA, RISC complex, knockdown, FRET, qPCR, GPCR, Tm, splicing

Sequence Design for Candidate siRNAs

Transcripts of target gene
Expression & Isoform
Gene expression/mutation information
SNP & genetic sequence
Fragmentation• SNP avoidance
• GC ratio/distribution
• Position at transcripts
Off-target filter in human• Target microRNA
Homology comparison• NHP
• Mouse/Rat
Efficiency evaluation• Sequence context
• Thermodynamic features

In vitro activity assessment

  • In vitro cell-based knock down assessments (transfection and free uptake)
  • Splicing analysis
  • Functional assays
  • Tm (melting temperature) determination
  • Quantification of siRNA in RISC complex

Cell Lines for Knockdown Assessment

> 400 cell lines available lines in WuXi Biology cell bank

  • Patient derived cell lines
  • Customized stable cell lines with lentivirus system 

Primary Cells for Knockdown Assessment

  • Primary human and animal hepatocytes
  • Primary monkey, rat  and mouse fibroblast cells; neuronal cells and muscle cells 
  • Customized additional primary cells available upon request
Reporter assays psiCHECK reporter assay and other reporter assays
Evaluation of knockdown effect• mRNA assessment by RT-qPCR, bDNA, ddPCR, capillary electrophoresis, Sanger sequencing and NGS 
• Protein assessment of by ELISA, Luminex, MSD, CBA, Western/Capillary Western, FACS, HCS, IF, HiBiT luciferase reporter assay, AlphaLISA, and ICW
Tm (melting temperature) determinationFRET method with qPCR
Cell-based functional assays• GPCR & other receptor assays
• Ion channels & transporters
• Apoptosis/cell cycle
• Angiogenesis
• Downstream signaling pathway analysis
• Cell structure and morphology analysis
• Virus infection assays
• Customized assays
RT-PCR, mRNA, electroporation, primary cells, LDH
siRNA, gapmer, aptamers, lentivirus, RNAseq, psiCHECK reporter assay

Early Toxicology

Cytotoxicity assessment

  • Cancer cell lines (HUH-1, HEPG-2)
  • Non-cancer cell lines (HEK-293, HK-2, HFL-1, HUVEC)
  • Cryopreserved primary human hepatocytes


  • HEK-Blue-hTLR3, 5, 7, 8, 9, RIG-I, MAD5 cell-based reporter assays
  • Cytokine induction and immune cell activation in PBMCs

Off-target profiling

  • In silico analysis
  • NanoString, single-cell RNAseq analysis
  • psiCHECK reporter assay
Cell viability and apoptosis• CellTiter-Glo
• LDH assay
• Caspase-Glo 3/7
In vitro immunogenicity assays• Cell-based reporter assays: TLRs, RIG-I and MAD5 reporter
• Cytokine stimulation in hPBMCs or animal immune cells/whole blood
Off-target effects• PPHs transfected with siRNA; RNA extraction and analysis by RNAseq
• Generation of volcano plots, heatmaps, CNET plots
• Analysis of pathways not involving the target gene
siRNA, psiCHECK, RT-PCR, NHP models, in silico, GalNAc-ASGPR delivery, SPR screening
siRNA activity in RT-PCR reporter assay, KD

In vivo Efficacy and PK/PD studies

  • Humanized mouse models
    • Transgenic
    • HDI
    • AAV mouse models
  • NHP models
  • Pharmacology models
  • Various dosing routes
  • Short and long-term KD efficacy/pharmacology readouts
Humanized mouse models, transgenic, HDI, AAV mouse models, NHPs

Learn about our anti-tumor nucleic acid drug discovery platform by clicking HERE

Read our blog: “Biological Evaluation of Oligonucleotide Drugs” by clicking HERE

Download our White Paper: “Oligonucleotide Therapeutics: Drug Discovery Through Tightly Coupled Chemistry and Biology” by clicking HERE

Delivery and Analysis

  • Delivery tool discovery
    • Ligand discovery for conjugation: HTS, ASMS, DEL, On-bead DEL, Phage display
    • LNP discovery: novel lipids, SORT lipid, Target LNP (small molecule, peptide, antibody, aptamer conjugated LNP)
  • Binding and Internalization
  • Transcytosis
  • Endosome release
  • RISC loading or other functional protein complex formation
  • In vitro stability and Protein-Protein Binding
  • Mouse, rat, NHP in vivo delivery/RISC PK
GalNAc-ASGPR delivery system, SPR screening, RISC PK, protein-protein binding

Oligonucleotide Synthesis & Conjugation

A One-stop Shop to Create Your ‘Monomer-Oligo-Conjugate’

  • Focus on Discovery Scales to Support Early-stage Development | Accelerate Oligo-based Drug Discovery
  • Delivering a broad spectrum of special monomers, diversified oligonucleotides, and custom-tailored solution for oligo-conjugation
    • Special monomer synthesis bicyclic nucleic acid, stereo-defined amidite, GalNAc, PMO monomers
    • Comprehensive panel of oligonucleotides: siRNAs, antisense oligonucleotide (ASO), CpG, aptamer , PMO
    • Modified oligonucleotides: various bicyclic nucleic acids, 2’-modification , inverted abasic, 5’-VP
    • Linker-attached oligonucleotides: single-strand and duplex with 3’- or 5’-linker modification, including amino, azido, alkyne, tetrazine, and maleimide, toward antibody conjugation.
    • Long RNA sequences: up to 100 bp, >90% purity
    • Oligo conjugation: siRNA and ASO with 3’- or 5’-conjugation, including GalNAc, [eptide, small molecule, cholesterol, lipid, PEG, and fluorescent tags
oligonucleotide, nucleic acid synthesis and conjugation
oligonucleotide synthesis and conjugation, GalNAc, PMO monomers, antisense

Learn more on oligo.wuxiapptec.com

RNAi Therapies
Antisense Oligonucleotide Therapies
Peptide Oligonucleotide Conjugates
Individualized Oligonucleotide Therapies

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