In Vitro Selections (SELEX)

Velocity’s Proprietary Directed Evolution process​

Find out how HPAs may help you in diagnostics, research, or therapeutics​

The Ultimate in Versatility

Our proprietary in vitro selection methods are optimized for high binding affinity, specificity, and association/dissociation rates. Our use of next-generation sequencing (NGS) and proprietary artificial intelligence enables us to identify unique candidates that can be designed for specific purposes. For instance, HPAs can be selected to bind to specific post-translational modifications or splice variants, multiple epitopes on a single target for sandwich assays, and cell surface antigens for therapeutic targeting.

Our In-Vitro Selection (SELEX) Process Yields High Quality Binders

Velocity’s Proprietary in-vitro SELEX process​


The types of targets that can be used in SELEX, include proteins, cells, and small molecules to produce nucleic acid ligands, or binders, in applications such as biosensors, therapeutics, and diagnostics.

  • 1. Library Generation:

    A random pool of nucleic acid sequences is generated by chemical synthesis.

  • 2. Selection & Separation:

    The library is incubated with a target molecule, and the sequences that bind specifically to the target are selected.​  The bound sequences are separated from the unbound sequences using methods such as filtration or centrifugation.

  • 3. Amplification:

    The selected sequences are amplified by PCR, generating a new pool of sequences that are enriched for the target-binding sequences.

  • 4. Repeating:

    The selection and amplification steps are repeated for several rounds, with the selection conditions becoming increasingly stringent to isolate the sequences with the highest affinity for the target.

  • 5. Validation:

    ​​The selected sequences are validated for their specificity and affinity to the target using methods such as mass spectrometry, sequencing, or binding assays.

In vitro HPA Selection can be Tailored​

Selections Can be Designed to Maximize the Yield of HPAs with Desired Characteristics​


  • Employ Selection Strategies using Novel Targets, such as selecting HPAs to specific Cell Types

  • Ensure Binding to Multiple Variants of Your Defined Target​

  • Optimised to Bind a Single Variant of Your Target​

  • Generate an HPA with Optimal On/Off Rates, According to Your Application ​

  • Generate HPA Combinations That Bind to Distinct Epitopes of the Same Target Enabling Highly Specific Sandwich Assays​ ​

Directed Evolution Summary

Velocity Capacity:​

  • Discovery Capacity: 1,000 Targets a Year ​
  • 6-8 Weeks from Target to HPA Candidate Cycle Time​
  • SOPs in Place for Automated In Vitro Selection Process for New HPAs​
  • Scalable Synthetic Chemistry Manufacturing​
  • Substantial Competitive advantage in Scale, Cost, and Performance ​
  • HPAs can be Easily Functionalized for Nearly Any Applications​

Benefits of Velocity IVS methods and HPA benefits:​

  • High Affinity Translates Into Increased Analytical Sensitivity and Specificity​
  • Capable of Detecting/Measuring Proteins in Their Native State​
  • Suitable for the Development of Highly Multiplexed Assays​
  • Uniquely Adaptable to a Variety of Molecular Biology Based Readouts