Viral Vector Characterization for Gene Therapy

Find Powerful Tools for Physical and Functional Characterization of Your Viral Vector

Move forward efficiently while ensuring accurate and consistent results when you are characterizing viral vectors for gene therapy applications.

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Develop Viral Vector Characterization Assays to Inform Development and Evaluate Potency

Across the gene therapy development process, from early R&D to full-scale manufacturing, viral vector characterization is critical for process optimization, ensuring safety, and maximizing efficacy. At every stage, you need to understand the physical properties of your viral vector, such as purity, intactness, and identity, as well functional properties such as cargo protein expression and efficacy.

But the inexpensive assays that deliver quick and good-enough answers for early development are not always sensitive, accurate, and precise enough for QC release.

With Bio-Rad, you get a range of platform technologies, ready-to-use assays, and custom assays that enable viral vector characterization and potency evaluation at multiple stages of development. And whether you are prioritizing speed, sensitivity, accuracy, or consistency, you can be confident in your decision-making when you choose Bio-Rad’s proven products.

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Did you know?

The first successful human gene therapy — the 1990 treatment of a young girl with severe combined immunodeficiency disease (SCID) — used a retroviral vector to transduce an ADA transgene into CD34+ peripheral blood cells isolated from the patient.1,2

Evaluate Viral Vector Purity and Identity at Every Stage

In order to continue progressing development, your AAV vector must have the appropriate levels of characterization. Characterization requires the rAAV genome to be intact and determination of proper capsid assembly in order to enhance AAV efficacy and, most importantly, safety. Researchers use numerous analytical techniques to obtain high yields of properly assembled rAAV particles, which enhances gene therapy potency, and how they choose the technique is dependent on their priority.

Learn More about Techniques for Viral Vector Purity and Identity »

Priority: Speed

When you are part of a team working in the early stages of viral vector development, SDS-page analysis is a quick and relatively inexpensive way to check for the presence of non-viral proteins in your prep. But while conventional fluorescent protein stains such as SYPRO Ruby, are highly sensitive, they can slow you down with their requirement for overnight staining and destaining.

Bio-Rad’s Stain-Free Imaging enables detection of contaminating proteins in minutes rather than hours or overnight, for rapid assessment of protein purity when your priority is speed.

Learn More about Stain-Free Imaging »

In addition, our complete Stain-Free Western Blotting Workflow can speed viral vector identification. With the Stain-Free Western Blotting Workflow, you can increase throughput compared to traditional blotting by reducing electrophoresis and transfer time to less than 30 minutes, enhancing efficiency and accuracy of protein quantitation.

Learn More about Western Blotting »

Western Blotting Webinar Series Cover

Western Blotting Webinar Series

Join Bio-Rad western blotting expert Kenneth Oh and his guest speakers for a webinar series that explores the many factors that go into the design and execution of successful and repeatable western blots.

Our All-in-One Flexible Imaging Solution for Gel and Western Blot Analysis:

Instead of relying on one instrument to image stained gels and another instrument for imaging western blots, you can save lab space and accomplish more with the ChemiDoc MP Imaging System, an all-in-one flexible western blot imaging system solution for gel and western blot analysis.

This user-friendly platform makes it easy to rapidly process multiple gels and blots in parallel on the same instrument for efficient analysis of viral purity, viral identity, and expression of the transgene-encoded protein.

In addition, the Security Edition of the associated Image Lab Software allows for rapid assessment of viral capsid protein ratios and meets the needs of a GMP manufacturing and QC environment.

Our Software and Imaging Systems:

  • Compatible with commonly used protein stains for viral purity assessment
  • Offers optimal blot detection for confirming AAV identity
  • Enables rapid capsid protein ratio analysis
  • Provides automated analysis using Image Lab Software
  • Comes with IQ/OQ and software enabling CFR 21 Part 11 compliance​

Learn More about ChemiDoc and ChemiDoc MP Imaging Systems »

Assess Viral Vector Integrity

Moreover, we demonstrate that the integrity of the rAAV vector can be monitored using two-dimensional qPCR (2D ddPCR) of fluorescein (FAM)- and hexachloro-6-carboxy-fluorescine (HEX)-labeled probes targeting different positions of the same rAAV genome.

— Furuta-Hanawa, et al.3

One of the more complex viral vector characterization assays is to understand how much of the viral genome has been packaged into the capsid. Without an accurate measurement of the percentage of capsids that have fully intact vector versus completely empty or partially filled capsids, you may be overestimating the potency of your gene therapy. Especially with partially-filled capsids, you may or may not have enough vector to elicit a therapeutic response, leading to a great deal of uncertainty around potency.

Fortunately, with ddPCR technology, you can develop a robust assay that detects multiple parts of the viral genome to evaluate viral vector intactness.

New to ddPCR? Learn More Here »

Find and Buy a ddPCR Assay for Your Viral Vector Characterization Needs

Multiplex Mutation Screening 
Multiplex Mutation 
Residual DNA Quantification 
Residual DNA 
Copy Number 
Copy Number
IVD Kits 
Library Quantification
Mycoplasma Detection 
Mycoplasma Detection
HEK DNA Quantification 
HEK DNA Quantification
HEK DNA Sizing
Gene Expression 
Gene Expression
Cell and Gene Therapy 
Cell and Gene Therapy
Expert Design 
Expert Design
Genome Edit Detection 
Genome Edit 
Mutation Detection 
Copy Number Determination 
Copy Number 

Measure Protein Expression

Verifying that your viral vector delivers sufficient protein expression from the transgene is another critical assay where speed is important early in development, whereas sensitivity, multiplexing, and reproducibility is important for the final stages of development and manufacturing.

Priority: Speed

Get a quick look at target protein expression levels during the early stages of viral vector development with Bio-Rad’s western blotting family of products and ChemiDoc MP Imaging System. With labor-saving features that reduce hands-on time and enable rapid imaging, Bio-Rad’s products can streamline western blotting workflows for quick insights into protein expression levels.



  • Can We Trust Western Blots Webinar Cover

    Can We Trust Western Blots?

    Learn how to build confidence in western blotting data and tips for producing high-quality western blots in less time.


Two-Dimensional Droplet Digital PCR as a Tool for Titration and Integrity Evaluation of Recombinant Adeno-Associated Viral Vectors 
Furuta-Hanawa B, et al. Hum Gene Ther Methods. 2019 Aug 1; 30(4): 127–136. doi: 10.1089/hgtb.2019.031

Using ddPCR to Accurately Quantify AAV Viral Titre and Integrity 
The Manufacturing Chemist, 29 July 2021. Accessed July 15, 2022



  1. Blaese RM, Culver KW, Chang L, et al. Treatment of severe combined immunodeficiency disease (SCID) due to adenosine deaminase deficiency with CD34+ selected autologous peripheral blood cells transduced with a human ADA gene. Amendment to clinical research project, Project 90-C-195, January 10, 1992. Hum Gene Ther. 1993;4(4):521-527. doi:10.1089/hum.1993.4.4-521
  2. Anderson WF. September 14, 1990: the beginning. Hum Gene Ther. 1990;1(4):371-372. doi:10.1089/hum.1990.1.4-371
  3. Furuta-Hanawa B, Yamaguchi T, Uchida E. Two-Dimensional Droplet Digital PCR as a Tool for Titration and Integrity Evaluation of Recombinant Adeno-Associated Viral Vectors. Hum Gene Ther Methods. 2019;30(4):127-136. doi:10.1089/hgtb.2019.031

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