siRNA/ASO Synthesis

Service Details

Genscript also offers custom synthesis services for miRNA, aptamer, tRNA, and saRNA. Contact us for more information or to request a quote

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Want to increase siRNA stability and reduce off-target effects? Try our proprietary modification combinations

GenScript has developed seven modification combinations (GS1-GS7) through bioinformatics screening and experimental selection. These strategies include specific modifications in type, number, and position to improve siRNA efficacy. AI-assisted predictions further accelerate selection, saving time and cost.

Preparation (1 Day)

Provide candidate siRNA sequences.

Design (2-3 Days)

Bioinformatic prediction of knockdown efficiency.

Synthesis (4+ Days)

Select and synthesize modified siRNA.

Validation (Optional)

Test actual knockdown efficiency, off-target effects, and stability.

Note: The effectiveness of modification combinations for off-target reduction and stability varies by siRNA sequence. We recommend first identifying unmodified candidates with strong knockdown efficiency, then testing test multiple predicted high-efficiency modification combinations for knockdown efficiency, off-target effects, and stability.

Need help designing your siRNA? Try our convenient online design tools*:

* GenScript offers a free siRNA design tool utilizing classic design logic. If you prefer an AI-enhanced design platform, please choose the siRNA guarantee package or send a request to oligo@genscript.com.

Case Studies

• Accurate MW, high purity and batch-to-batch consistency
  

  

  

  
• Highly-modified siRNA with purity up to 96.55%

  20 nt double-stranded siRNA with 29 2'-O-Methyl modifications, 3 phosphothioate groups, 13 2'-Fluoro modifications, and 1 GalNAc modification, exhibited purity up to 96.55%

  

  
• Advanced AI design ensures higher knockdown efficiency
  

  siRNA sequences designed for Gene B with GenScript's bioinformatic design platform achieved higher knockdown efficiency (KD%) than those created with other vendors' tools.

  
• Proprietary modification strategy: Enhancing siRNA stability and reducing off-target effects

  Case 1: Proprietary modifications significantly enhance siRNA stability.

  Method: For different modification schemes, the metabolic rate and metabolites in a serum environment were analyzed to select the most stable modification schemes for subsequent optimization and development.

  Results

  • siRNAs with modifications from groups GS1 to GS6 exhibited lower degradation levels and better stability compared to unmodified siRNA (sense strand SS/antisense strand AS).
  • Among these, the GS6 modification scheme demonstrated the lowest degradation level and the highest stability, making it the most optimal modification scheme.

  

  Case 2: Proprietary modifications significantly reduce siRNA off-target effects.

  Method

  RNA-Seq was used to detect and enumerate DEGs(differential expression genes) following treatment with both modified and unmodified siRNA, assessing the extent of mRNA upregulation or downregulation in off-target genes.

  Results

  • Table 1: Modified siRNA (siRNA93-GS) significantly reduced the number of DEGs compared with unmodified siRNA.
  • Figures 1A/B: Unmodified siRNA caused widespread changes in gene transcription, affecting multiple genes.
  • Figures 1C/D: Modified siRNA (siRNA93-GS) greatly reduced these transcriptional changes.
  • Figures 1A/C: Data point HAO1 showed similar mRNA changes along the horizontal axis, indicating that modified siRNA maintained target knockdown efficiency comparable to unmodified siRNA.

  Table 1: Modified siRNA (siRNA93-GS) significantly reduced the number of DEGs compared with unmodified siRNA.

  Target Gene	Sample	RNA-Seq Detection	Type I: Homologous off-target genes prediction		Type II: miRNA-like similar off-target genes prediction
  		DEGs	AS_blast	SS_blast	AS_mirna_off-target	SS_mirna_off-target	Total mirna_off-target	Down regulated off-target
  HAO1	siRNA93	58	0	0	26	6	28	23
  	siRNA93-GS	7	0	0	1	0	1	1

  Off-Target Effects of Unmodified siRNA - Gene Transcription Changes

  

  Off-Target Effects of GenScript’s Proprietary Modified siRNA – Gene Transcription Changes

  

  Case 3: siRNA modification combinations achieve a 27-fold IC₅₀ reduction compared with commercial options

  Method:

  qPCR was used to measure IC₅₀ of siRNAs with identical sequences but different modifications at the mRNA level.

  Results:

  Compared with the commercial siRNA modification scheme (Vutrisiran), GenScript's GS1-6 modifications significantly lowered IC₅₀. GS5 reduced IC₅₀ by up to 27-fold, enabling effective knockdown at much lower doses.

  Samples	IC50 (nM)	Knockdown（%）-10nM
  TTR_siRNA_naked	0.00257	97.93%
  TTR_siRNA_GS5	0.00517	98.05%
  TTR_siRNA_GS3	0.00704	97.35%
  TTR_siRNA_GS6	0.0133	97.34%
  TTR_siRNA_GS2	0.0149	97.77%
  TTR_siRNA_GS4	0.0553	97.37%
  TTR_siRNA_GS1	0.114	95.50%
  TTR_siRNA_Vutrisiran	0.142	94.95%
  TTR_siRNA_GS7	0.225	91.46%

  IC₅₀ Assessment Protocol: HepG2 cells were transfected with unmodified or modified siRNA targeting the TTR site using RNAiMAX across a 10-dose gradient (100 nM to 0.0000512 nM). RNA was extracted after 48 hours, reverse transcribed, and analyzed by qPCR to determine mRNA knockdown efficiency and IC₅₀ values.

Resources

siRNA Lipofection Protocol

Free Download

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