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Viral Vector Quantification Service

The quantification of viral vectors is important for guiding the development and quality control of gene therapy biologics. Our company focuses on the latest advances in new technologies for virus quantitative detection to provide customers with services for measuring viral titers, offering meaningful improvements to mission-critical processes in gene therapy where viruses play an important role.


Gene therapy has reemerged as a promising treatment for a number of rare diseases such as hemophilia and spinal muscular atrophy (SMA). Viral vectors are the primary vectors used for gene delivery in this therapy, but the production of bioactive vectors for gene therapy can be problematic, such as the generation of vectors at the correct concentration to produce a safe and effective therapy. Therefore, it is important to develop various quantitative viral assays to accurately quantify the concentration of viral vectors.

Fig. 1 Quantification of AAV2/9 Vectors.

Fig. 1 Quantification of AAV2/9 Vectors. (Blessing D, et al., 2019)

Our company offers customers a wide range of services for the characterization of viral vectors, including confirming the identity of viral vectors and quantifying viral particles during growth, purification, final quality control, and release. We assess a number of factors such as the nature of the viral vector, sample purity and concentration, speed of detection, and method availability to establish the appropriate quantitative method for the sample. Our high-quality services help to accurately adjust the dose of viral vectors and the efficiency of cell transduction, accelerating the development of gene therapy for rare diseases.

Viral Vector Identification Services

We offer a variety of assays to help customers ensure the identity of the viral vector preparation. In addition, our complete stain-free western blotting workflow increases the efficiency and accuracy of protein quantification, thereby speeding up the identification of viral vectors. Our services include, but are not limited to:

  • Transgene expression analysis by qRT-PCR and ELISA.
  • Characterization of the viral proteome by liquid chromatography and mass spectrometry (LC-MS) analysis of the whole virus species.
  • Analysis of vector genome using PCR or high throughput next-generation sequencing (NGS) to ensure positive identity.
  • Screening of viral proteome fingerprinting by techniques such as chromatography (HPLC), gel electrophoresis (SDS-PAGE), and MALDI mass spectrometry.
  • Identification of viral proteins through detailed information obtained from LCMS and/or MALDI-MS analysis on digested isolated proteins.

Quantification Services of Viral Vectors for Gene Therapy

  • Measurement of physical titer
    • We offer real-time PCR-based assay and digital droplet PCR (ddPCR) to determine the physical titer of the virus. Compared to qPCR, ddPCR assays offer greater sensitivity and less variability and produce more accurate and reproducible data.
    • We offer new particle detection techniques such as nanoparticle tracking analysis (NTA) and tunable resistive pulse sensing (TRPS) to count individual particles of viruses, enabling quantitative analysis as well as analysis of the size distribution and aggregation of the sample.
  • Measurement of infectious or functional titer
    Viral infectivity determines the ability of a virus to infect and replicate in a host cell. We offer a variety of methods to determine the infectivity of viral vectors.
    • Quantification of infectious titers by in vitro cell transduction assays, such as endpoint dilution (TCID50), viral plaques (for cytopathic viruses), immunofluorescent foci (IFA), and fluorescence-activated cell sorter (FACS).
    • Stable and rapid real-time quantification of viral infectivity by measuring real-time changes in the electrical impedance of circuits formed in tissue culture dishes inoculated with virus-infected cells. Our methods include cell-substrate impedance sensing (ECIS) and real-time cell analysis (RTCA).

As a leading biotechnology company in the field of rapid virus quantification, our company is well-positioned to provide customers with flexible solutions to accurately quantify viral vectors, thereby providing important details to optimize growth conditions and maximize yields, accelerating the development of gene therapy products for rare diseases. If you are interested in our services, please feel free to contact us for more details.


  • Blessing, D. et al. Scalable production of AAV vectors in orbitally shaken HEK293 cells. Molecular Therapy-Methods & Clinical Development, 2019, 13: 14-26.

All of our services and products are intended for preclinical research use only and cannot be used to diagnose, treat or manage patients.

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