One-stop Aptamer In Vitro Selection Services

Overview of SELEX

The classic technique employed for aptamer selection, termed Systematic Evolution of Ligands by Exponential Enrichment (SELEX), rapidly identifies optimal binding sequences from a randomized sequence pool through iterative cycles of selection and amplification. Initiated from a DNA or RNA combinatorial library comprising as many as 1015 unique sequences, each sequence bears a randomized region of 20-60 nucleotides flanked by 5' and 3' fixed primer regions. Following iterative rounds of binding, partitioning, recovery, and re-amplification, specific sequences enriched through this process emerge as dominant aptamers within the library. Tailoring selection conditions, including buffer components, ion strength, pH, binding temperature, and time, allow for the isolation of specific products. These variables play a pivotal role in rigorously sieving for specific aptamers, influencing their affinity and functionality.

Fig. 1 Optimization of the capture-SELEX protocol for enhanced nucleic acid selection efficiency.¹

Procedure of SELEX

The SELEX technique, widely adopted for in vitro applications, is employed to isolate single-stranded oligonucleotides, referred to as aptamers, that exhibit precise affinity to a predetermined ligand within a collection of random single-stranded nucleic acid sequences. The foundational SELEX methodology encompasses:

1. Chemical synthesis of an in vitro single-chain oligonucleotide library;
2. Integration of the randomized library with the target ligand to facilitate oligonucleotide-target interactions;
3. Elimination of non-interacting nucleic acid molecules through ligand-mediated separation;
4. Elution of bound aptamers for isolation;
5. PCR-based amplification of captured aptamers, generating secondary libraries for subsequent iterations of screening;
6. Iterative repetition of steps ②-⑤ to obtain aptamers manifesting elevated affinity and selectivity toward the target ligand.

Fig. 2 The pipeline of SELEX.

Expert Team

A remarkable team of scientists with extensive experience in the field of aptamer development over numerous years.

Diverse Screening Modalities

Diverse screening methods are available for aptamers to fulfill the specific requirements of various projects.

Stronger Affinity

Exhibiting greater binding affinity than typical aptamers.

High Efficiency

Accelerating your project's success through the shortest possible delivery timeline.