Conventional SELEX Aptamer Screening Service
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Conventional SELEX Aptamer Screening Service

Date：2026-01-17

Core Principle & Typical Service Workflow

A professional service for Conventional SELEX typically follows this established, iterative cycle (8-15 rounds), as visualized below:

Key Service Characteristics

  1. Target Immobilization: The target molecule is fixed to a solid support (e.g., magnetic beads, column resin, nitrocellulose membrane).

  2. Positive Selection: The library is passed over the immobilized target. Sequences with some binding affinity are retained, while others are washed away.

  3. Stringency Control: The service provider systematically increases selection pressure across rounds (e.g., by reducing target concentration, increasing wash stringency, adding counter-targets in Negative SELEX steps) to drive the evolution of high-affinity, specific binders.

  4. Monitoring: Enrichment is tracked via quantitative PCR, and final pools are analyzed by Next-Generation Sequencing (NGS) to identify convergent sequence families.

Common Applications for this Service

This classic approach is ideal for:

  • Proteins that are stable and can be immobilized without losing native conformation (e.g., antibodies, enzymes, recombinant tags).

  • Large molecules or complexes (e.g., viruses, whole cells—though Cell-SELEX is now more common for cells).

  • Establishing proof-of-concept for a new target class where simpler, robust methodology is preferred.

Deliverables

Similar to other SELEX services, clients receive:

  • A final report detailing the selection process and conditions.

  • A list of top-ranked aptamer sequences with affinity (Kd) and specificity data.

  • Aliquots of synthesized, validated aptamer candidates.

In summary, a Conventional SELEX Aptamer Screening Service is the robust, time-tested workhorse for generating aptamers against a wide array of immobilized targets. While newer methods offer advantages for specific challenges (like small molecules or cross-reactivity), Conventional SELEX remains a highly effective and commonly offered service for many standard aptamer discovery projects.