Introduction of aptamer-siRNA conjugates
siRNA is the fragment of dsRNA in the cell when it is cleaved into 21-23 nucleotides by a specific nuclease. Aptamers are single-stranded DNA or RNA oligonucleotides that bind to a specific target molecule by folding into a unique three-dimensional structure. Combinations of siRNAs and aptamers are called as AsiCs or aptamer-siRNA conjugates. When they are combined, upon endocytosis, AsiCs are internalized into the cell and at least temporarily, end up in vesicles of the endosome or lysosome. Molecules escaping the endosomal compartment will be recognized by RNA interference (RNAi) machinery. The ribonuclease Dicer will bind to the siRNA part of the AsiC (black double strand), cut it off the aptamer and load it into the RNA-induced silencing complex (RISC), an assembly of proteins further mediating the specific degradation of messenger RNAs (mRNAs). The Argonaute protein AGO2, one major component of the RISC, unwinds the siRNA double strand and retains only one of the two strands, the guide strand. As a result, mRNAs matching this RISC-loaded guide strand can be cleaved, and the expression of the gene corresponding to this mRNA will be decreased. Aptamer-siRNA conjugates have been one of the most promising approaches for the therapy of many diseases. Such as cancer, cardiovascular disease, and viral infections.
Fig.1 Concept of aptamer siRNA chimera (AsiC) delivery into a target cell. ( Kruspe Sven, 2017)
The advantages of aptamer-siRNA conjugates
- No immunogenicity and toxicity
- Lower production cost
- Relatively easily screened, synthesized, programmable designed, and chemically modified
Based on professional technical support, BOC Sciences is dedicated to providing design and synthesis of siRNA based on target genes and high quality aptamer. Additionally, we will optimize the chemical junction to enable direct coupling of RNAi to the end of the aptamer strand or complementary assembly.
The whole service flow
- BOC Sciences offers a free siRNA design or you can submit selected siRNA sequences.
- Comprehensive modification and labeling. From conventional modification to fluorescent/non-fluorescent labeling, even dual and multiple labeling.
- Synthetic scale, 0.015 µmol, 50 nmol, 100 nmol, 200 nmol, 1 µmol, 5 µmol, 10 µmol, and > 10 µmol.
- Quality control by analytical HPLC, mass spectrometry, annealing in RNase-free water, and double-stranded analysis by analytical gels.
- BOC Sciences provides aptamer development services. We use the SELEX method to select and obtain aptamers from nucleic acid sequence libraries with high affinity and high specificity for the target ligand. Your aptamer will purify by PAGE or HPLC and verify by mass spec.
- BOC Sciences provides aptamer modifications services, such as biotin modifications are used in EMSA or Southern blotting. Fluorescence modifications are used for many imaging and diagnostic research with high sensitivity. 3' inverted thymidine modifications, 2'-O-methyl (OCH3) modifications, 2'-fluoro modifications and 2'-NH2 modifications to enhance their stability to nucleases.
- BOC Sciences provides aptamer optimization services. Including but not limited to, basic sequence optimization, structure stability optimization, hydrophobic/hydrophilic part optimization, SELEX optimization, SELEX post-optimization.
- BOC Sciences provides aptamer in vitro analysis services. Such as stability analysis and cytotoxicity assays.
- Coupling siRNA with target aptamer based on the chemical properties.
- BOC Sciences establishes multiple engineering strategies for aptamer design to improve siRNA loading efficiency.
- Functional optimization of aptamer-siRNA conjugates
- Tertiary structural analysis
- Thermodynamic analysis
- Combined with affinity measurements
- Competition assays
- Stable and reproducible aptamer products
- Aptamer with higher siRNA loading efficiency
- Top technology supports multiple aptamer modifications
- High quality raw materials
- Free design
- Experienced experts
- Strict QA and QC
- Advanced analytical equipments
- Professional technical support
- 1 on 1 customer service
- Competitive price
- Fast delivery
With much experience in aptamer design and coupling, BOC Sciences is fully capable and committed to providing you with a one-stop service for aptamer-siRNA conjugates services. Please feel free to contact us or send us an inquiry directly and we will be happy to assist you.
- Sven K; et al. Aptamer-siRNA Chimeras: Discovery, Progress, and Future Prospects. Biomedicines. 2017, 5(3).
- Aishwarya S; et al. Advances in siRNA delivery in cancer therapy. Artificial cells, nanomedicine, and biotechnology. 2018, 46(2).