chemically-modified siRNA synthesis-in vitro

siRNA is a double strand RNA that is 20 to 25 nucleotides. After transfection of siRNA into the cell, it will cause knockdown of its specific gene.

Biotools provides customized siRNA design and synthesis. We also provide customized siRNA set, which guarantees at least 70% knockdown efficiency.

● Free siRNA design
● Provides multiple chemically modify to choose
● High stability and long effect
● Guarantee at least 70% knockdown efficiency for sets



Chemically modified siRNA

in vitro stability



Reaction time

shorter, 1 week

Longer, 2 weeks

in vivo activity






All you need to do is to provide the gene sequence or NCBI number, we will design and choose the siRNA that has the best knockdown effect. We also have chemically modified siRNA which has longer effect and better efficiency.

Product specification


Product Price(USD)
chemically modified siRNA 2OD/4OD/10OD 260 / 316.67 / 733.33
Negative control siRNA 1OD 83.33
FAM labeled negative control siRNA 117.24
Positive control siRNA 83.33

siRNA set 

Chemically-modified siRNA set Price(USD)
  3 x 2 OD negative control siRNA
  1 OD negative control siRNA
  1 OD FAM labeled negative control siRNA
  1 OD positive control siRNA

*Guaranteed>70% knock-down in mRNA level


Working day not including delivery time: 2 weeks

1. Please provide the accurate gene ID, species or gene sequence
2. Please confirm if you need chemically modified siRNA
3. Please confirm product specificity (single or set)


  • Jung-Lin Wu, Hsin-Yi Wu, Kuo-I Lin, et al., Temporal regulationof Lsp1 O-GlcNAcylation and phosphorylation during apoptosis ofactivated B cells. nature communications, 2016.

  • *Shu-Yi Yin, Feng-Yi Jian, Ning-Sun Yang, et al., Induction of IL-25 secretion form tumor-associated fibroblasts suppresses mammary tumor metastasis. nature communications, 2016.                                                                                                                                                                                                       ​

  • Lin LP, Yu TY, Chang HN, Tsai WC, Pang JS. Simvastatin Downregulates Cofilin and Stathmin to Inhibit Skeletal Muscle Cells Migration. Int J Mol Sci. 2022 Mar 5;23(5):2848.
Q1.  Is there any difference in the negative control of normal and chemically-modified siRNA?
A:  The sequence is the same, but there will be a chemical modification for the siRNA in our chemically-modified set

Q2.  How do you check the off-target effect of siRNA?
A:  We will avoid this situation when we first design the sequence but the customer must check

Q3.  What is the highest concentration for siRNA? Can we pool the 3 siRNAs together?
A:  The most we suggest is 4 times more than our recommendation, and we do not suggest you pool the 3 siRNAs together

Q4.  Can you evaluate the knockdown efficiency when designing siRNA sequence?
A:  No. The knockdown efficiency depends on the cell type

Q5. ​ Where is the exact location of the chemical modification at siRNA?
A: ​Depends on what type of modification. For O-Me, it will be on the 2' of every ribonucleotide