Aptamer Screening Services for Protein

has an experienced team of technical staff to provide aptamer screening services for different targets ranging from purified proteins to whole cells and tissues. We are committed to providing our customers aptamer screening services for protein with high-quality and high affinity aptamers.

Aptamers are an excellent alternative or complement to monoclonal antibodies, with high immunogenicity and low production costs. Aptamers have several clear advantages over antibodies due to their smaller size and nucleic acid properties, which can improve their clinical applicability and industrial applicability.

Fig 1. Important advantages of aptamer over antibody ^[1].

Numerous in vitro screens have shown that the screened aptamers can specifically bind any target, including ions, nucleotides, peptides, large glycoproteins, viral particles, cells, etc., and even tissues and organs in animals can be used as targets for aptamer screening. However, different targets have different affinity for aptamers, for example, small molecule targets have weaker affinity for aptamers. At present, aptamer screening is still mainly focused on the protein field.

Aptamer Screening for Purified Protein

The protein-targeted aptamer is usually a short oligonucleotide sequence or short polypeptide obtained by in vitro screening, which can bind to the corresponding ligand with high affinity and strong specificity. And the biomedical community provides a new research platform for efficient and rapid identification, and shows good application prospects in many aspects.

Although traditional SELEX technologies and dozens of variants have been successfully used to develop aptamers for hundreds of targets, including synthetic peptides or purified proteins, aptamers developed through these types of SELEX technologies are not always effective for in vivo applications. This is because the conformations of target molecules during in vitro selection are usually different from their natural conformations in vivo. Therefore, maintaining the natural conformation of the target is an important part of aptamer screening.

The main target materials of this method are cells, bacteria or viruses, etc. The operation is performed by centrifugation and precipitation to isolate and remove unbound aptamers, and then obtain specific aptamer sequences by thermal dissociation or enzymatic cleavage.

Advantages of Cell-SELEX

No prior knowledge of the target molecule conformation is required, and the cell surface molecules show natural conformation and distribution, which can avoid the destruction of the target structure during purification, and has the potential to screen unknown molecular aptamers.

Since aptamers screened in vitro may not function in vivo because they are not tissue permeable, direct in vivo screening using mice in disease-related models can be used to generate aptamers specific to the target tissue.

Advantages of In Vivo SELEX

This technique uses a retrovirus-based replication system to perform selection and amplification steps within living cells, providing a method to transfer aptamer selection and amplification from in vitro to in vivo.