Small interfering RNA (siRNA) represents a cornerstone technology in the field of functional genomics and oligonucleotide therapeutics. As a short, double-stranded RNA molecule typically 19–27 base pairs in length, siRNA is the core mediator of the RNA interference (RNAi) pathway. When introduced into a cell, siRNA is integrated into the RNA-induced silencing complex (RISC), where the guide strand directs the complex to complementary messenger RNA (mRNA) sequences, leading to targeted cleavage and subsequent gene knockdown. The ability of siRNA to specifically "turn off" the expression of virtually any gene makes it an indispensable tool for disease target validation and the development of sequence-specific drugs. CD BioGlyco leverages many years of experience to deliver synthetic siRNA products engineered for optimal stability, specificity, and potency across diverse experimental and clinical needs.
At the heart of our superior oligonucleotide production capability is our refined automated solid-phase chemical synthesis platform. This technology is the established gold standard for manufacturing short-chain, high-purity RNA oligomers like siRNA.
In contrast to enzymatic methods like in vitro transcription (IVT), chemical synthesis offers unparalleled control over sequence incorporation and, crucially, the precise installation of non-natural and chemically modified nucleotides. This precision is essential for building therapeutic-grade siRNA molecules that resist nuclease degradation and facilitate targeted delivery in vivo.
Our high-throughput synthesizers utilize phosphoramidite chemistry to sequentially build every single strand of RNA. This process allows for the integration of vital chemical modifications—such as 2'-O-methyl (2'-OMe) or phosphorothioate (PS) linkages—at specific, pre-determined positions. The final double-stranded siRNA duplex is formed through a rigorous annealing process following purification, ensuring maximum homogeneity and biological activity. This level of technical mastery guarantees that the complex structures necessary for enhanced half-life and delivery, which are essential, are achieved with exceptional fidelity.
We offer synthesis scales ranging from research-grade (nanomoles) up to large-scale, production-grade (micromoles and grams) quantities suitable for preclinical testing. Purity options are application-driven: from standard desalting for initial screening to highly stringent HPLC and in vivo grade purification, where endotoxin levels and trace impurities must be minimized for sensitive cell culture or animal administration.
A cornerstone of our offering is the extensive library of chemical modifications available to enhance the molecule's function. We routinely incorporate modifications at the critical 2'-position, including 2'-OMe and 2'-fluoro, which dramatically improve the siRNA's resistance to nuclease degradation, thereby extending its half-life in serum and complex biological media. For improved drug delivery, we specialize in conjugating molecules to the 3' or 5' termini, such as cholesterol, lipids, N-acetylgalactosamine (GalNAc) for hepatocyte targeting, and various fluorescent dyes for visualization and cellular tracking. We also offer backbone modifications like phosphorothioate linkages to further boost nuclease resistance, providing the pharmacological stability necessary for systemic application. Our ability to synthesize specialized constructs, including single-stranded siRNAs, locked nucleic acid (LNA)-modified chimeras, and various controls (positive, negative, scrambled), ensures that researchers have the optimal tool for every experiment. This depth of customization, combined with our rigorous analytical capabilities, positions CD BioGlyco as the premier partner for complex siRNA synthesis projects. We provide detailed QC reports and are committed to helping you navigate the complexities of RNA design.
Our expert team collaborates with clients or uses advanced proprietary algorithms to design the most potent and specific sense and antisense strands, minimizing off-target effects. This stage includes advising on appropriate chemical modifications (e.g., 2'-fluoro, LNA) based on the intended application (e.g., in vitro vs. in vivo).
Each single-strand RNA oligomer is synthesized base-by-base on a solid support using high-fidelity phosphoramidite chemistry. Any specified modifications and labeling moieties are incorporated at this stage.
The synthesized oligomers are chemically cleaved from the solid support and subjected to deprotection steps to remove protecting groups from the nucleobases, phosphate backbone, and 2'-hydroxyl groups, yielding the full-length, crude RNA strands.
For high-purity applications, the single strands undergo rigorous purification, typically utilizing reverse-phase or ion-exchange high-performance liquid chromatography (RP-HPLC/IEX-HPLC), to remove truncated sequences and other impurities. Quality is verified by MALDI-TOF mass spectrometry (MS) to confirm the exact molecular weight and by analytical HPLC to confirm purity percentage.
The purified sense and antisense strands are mixed in defined stoichiometric ratios and subjected to a controlled thermal annealing process to form the stable, active double-stranded siRNA duplex. The final product is lyophilized, and a certificate of analysis (COA) is generated, guaranteeing quality specifications before shipment.
Journal: International Journal of Molecular Sciences
DOI: 10.3390/ijms26199731
IF: 4.9
Published: 2025
Results: In this study, the authors investigated a combination siRNA therapy to inhibit Enterovirus 71 (EV71) replication and prevent the emergence of resistant viral escape mutants. They designed siRNAs targeting multiple viral genes—VP4, VP3, 2B, and 3A—and compared the efficacy of individual siRNA treatments against a cocktail of all four in an in vitro model using HeLa cells. Their results demonstrated that while treatment with a single siRNA initially suppressed viral replication, serial passaging led to a rapid loss of efficacy as mutations appeared in the siRNA target sites, allowing viral titers to rebound. In contrast, the combination siRNA cocktail achieved a sustained and significant inhibition of viral replication over five passages, with no detectable escape mutations, indicating a high genetic barrier to resistance. The study concludes that a multi-targeting siRNA strategy is a promising approach for developing robust antiviral therapies that minimize the risk of resistance, a critical advantage for managing RNA viruses known for their high mutation rates.
Functional Genomics
Rapid, sequence-specific gene knockdown for high-throughput screening, target validation, and determining the function of novel genes or pathways.
Drug Target Discovery and Validation
Utilizing siRNA to validate candidate genes associated with disease pathways, providing critical data for the early stages of drug development.
Oncology and Disease Modeling
Developing siRNAs against oncogenes, viral targets, or genetic disorder mutations to study disease mechanisms and test therapeutic efficacy in cellular and animal models.
Preclinical Studies
Implementing chemically stabilized and conjugated siRNAs (e.g., GalNAc conjugates, LNP encapsulation) for systemic delivery and targeted gene silencing in living organisms, paving the way for clinical applications.
Exceptional Fidelity and Purity
Our state-of-the-art solid-phase synthesis platform and proprietary HPLC purification protocols ensure high-yield production of full-length, high-purity siRNA duplexes. We guarantee purity levels specifically tailored for the most demanding in vivo and therapeutic applications.
Guaranteed Silencing Efficacy
We offer a specialized guaranteed silencing package where our bioinformatics experts design and synthesize multiple siRNA candidates against your target gene. We guarantee that at least one of the delivered sequences will achieve a minimum of 70% knockdown efficiency under optimized cell culture conditions.
Comprehensive Modification Expertise
Our deep expertise allows for the incorporation of virtually any commercially available chemical modification or conjugation moiety, including complex non-nucleotidic conjugates (e.g., peptide, polymer), crucial for targeted delivery.
Decades of Proven Success
Our synthetic oligonucleotides have been instrumental in numerous breakthrough research projects, spanning target validation and preclinical drug development.
Their HPLC-purified siRNAs performed flawlessly in our primary cell culture system. The turnaround time was fast, and the COA was incredibly detailed. Their technical support team was instrumental in helping us refine our 2'-OMe strategy. Truly a world-class provider.
— Dr. T.M., Research Scientist, Genetics Department
We rely on CD BioGlyco for all our large-scale screening projects. The consistency batch-to-batch is what sets them apart. The ability to seamlessly order fluorescently-labeled siRNAs alongside our unlabeled ones simplifies our workflow dramatically. A trusted partner.
— Manager A.K., Project Management, Molecular Biology Unit
Our complex in vivo study required cholesterol-conjugated siRNA with proprietary modifications. CD BioGlyco handled the synthesis and rigorous QC expertly. The product was delivered on time and exceeded our purity requirements, leading directly to successful delivery data.
— Dr. H.L., Group Leader, Pharmacology Lab
Successful RNAi research often requires expertise beyond siRNA synthesis. CD BioGlyco offers a full suite of complementary services designed to accelerate your project from discovery to therapeutic development. Our fundamental chemistry expertise extends to the building blocks of nucleic acids, ensuring complete control over raw material quality:
CD BioGlyco is your definitive partner for high-quality, custom siRNA synthesis. Our combination of advanced solid-phase chemistry, rigorous quality control (HPLC/MS), expert modification capabilities, and our industry-leading guaranteed silencing package ensures you receive molecules optimized for stability and potent gene knockdown, regardless of your application—from fundamental research to preclinical therapeutic development. Contact us!
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