Aptamer Development Service
Aptamers are a class of single-stranded oligonucleotides with a length of less than 100nt and a certain sequence, also known as chemical antibodies. The three-dimensional structure formed by itself is similar to the recognition of antibody and target with high affinity and high specificity. This novel recognition molecule is currently widely used in the fields of diagnosis, purification and therapy.
Compared with the antibody, the main components of the aptamer, the way of acquisition, and other target types are different. The specific differences are shown in the following table:
Table 1 The main differences between aptamers and antibodies
| Item | Aptamer | Antibody |
|---|---|---|
| Ingredients | Nucleic acid | Protein |
| Identifiable target species | Protein, polypeptide, small molecule, virus, drug resistant bacteria, etc | Large limitation and the antigen are required to have strong immunogenicity |
| Synthetic way | Chemical synthesis, low production cost, high purity of products, good batch repeatability, can be a variety of biological and chemical modification | In vivo or tissue culture of animals |
| Others | Strong specificity | High affinity |
Aptamers were selected from random oligonucleotide sequence libraries synthesized in vitro using the ligand index enrichment systematic evolution (SELEX) technique. The basic idea of SELEX technology is to chemically synthesize a single-chain oligonucleotide library in vitro, mix it with the target substance, and through repeated screening and amplification, wash away the nucleic acid molecules that are not bound to the target substance or have high affinity with the target substance, and isolate and purify the aptamers that have high affinity with the target substance. SELEX technology and aptamers have a large storage capacity and a wide range of applications. High resolution, strong practicability; High affinity; The screening process is relatively simple, rapid and economical. Aptamer small size and other advantages. This technique has been applied in the field of in vitro diagnosis, in vivo therapy and drug development (The SELEX filter is shown in the figure).
To meet the diverse needs of our customers, our platform has established three SELEX technologies: (1) Conventional SELEX, (2) Capture-SELEX, and (3) CE-SELEX. Therefore, we can provide the best screening solution for any target.
- Conventional SELEX fixes the target on a solid carrier and uses repeated binding/washing cycles to enrich sequences with the highest affinity.
- Capture-SELEX directly imparts the aptamer library and uses Aptamer-target j binding to induce conformational changes in aptamer, thereby releasing aptamer bound to the target. This strategy is particularly convenient for small molecules that are difficult to immobilize.
- CE-SELEX takes advantage of the changes in the electrophoretic mobility of the Aptamer-target complex to enable high-resolution separation of bound Aptamers in one to four rounds and preserve precious or low-abundance samples.
| Feature | Conventional SELEX | Capture-SELEX | CE-SELEX |
| Immobilized entity | Target molecule | Nucleic-acid library | None |
| Core principle | Physical washing to isolate sequences bound to immobilized target | Target-induced conformational change releases bound sequences from the carrier | Separation based on electrophoretic mobility difference of complexes before/after binding |
| Screening rounds | Many (8–15) | Medium (4–18) | Very few (1–4) |
| Screening time | Lengthy | Long | Relatively fast |
| Sample purity requirement | High purity recommended | High purity required | Highest purity required |
| Sample volume & concentration | Relatively large volume and high concentration | Flexible | Minimal volume and concentration required |
| Key advantages | Well-established; Cell-SELEX enables screening against intact cells | Ideal for small-molecule targets; circumvents target-immobilization problems | High efficiency and quality; homogeneous reaction mimics physiological conditions |
| Main limitations | Long cycle time Non-specific adsorption, Possible target inactivation |
Relies on conformational change, may reduce library diversity | Limited library capacity, expensive equipment required, depends on mobility difference |
| Typical applications | Stable large proteins, intact cells (Cell-SELEX), pathogen detection | Small molecules (antibiotics, toxins, hormones), ions, biosensor development | Rare/low-abundance targets, medical diagnostics, any scenario demanding rapid acquisition of high-affinity aptamers |
By combining these methods, we can shorten the R&D time of our clients' projects and accelerate the progress of their drug research and development
Workflow of Aptamer development service in Profacgen:
If you are interested in our aptamer development service, Profacgen looks forward to cooperating with you.