SV-AUC – The Gold Standard for Empty/Partial/Full Capsid Assay
At BioAnalysis, we understand that precise product characterization is critical to your gene therapy program success. Our team partners with you to deliver the industry’s most trusted empty/partial/full capsid analysis using SV-AUC technology.
Sedimentation Velocity Analytical Ultracentrifugation (SV-AUC) has emerged as the gold standard technique for the empty/partial/full capsid assay in gene therapy product development. With unmatched resolution, accurate quantitation, and regulatory compatibility, SV-AUC is the preferred method for characterizing viral vectors such as AAV (Adeno-Associated Virus), lentivirus, and other delivery systems.
SV-AUC For Gene Therapy
Sedimentation Velocity Analytical Ultracentrifugation (SV-AUC) is a high-precision biophysical technique used to analyze the size, mass, and shape of particles in solution.
Using high-speed centrifugation, SV-AUC separates these species based on their molecular and solution properties, producing detailed c(s) distribution plots that offer absolute quantification—no reference standards or calibration curves required, providing you with clear, actionable data that drives confident decision-making.
What Can SV-AUC Measure?
For gene therapy applications, SV-AUC excels in measuring and distinguishing between:
- Empty Capsids: Viral particles that do not contain genetic material
- Partial Capsids: Capsids with incomplete or truncated genomes
- Full Capsids: Properly loaded vectors carrying the therapeutic payload
- Impurities: residual DNA and protein, broken capsids
- Aggregates: High molecular weight assemblies or aggregates of viral capsids that can impact safety and efficacy
BioAnalysis is Modernizing AUC for Today’s Gene Therapy Needs
Accessible Technology: Our SMEs make SV-AUC data analysis, interpretation, and reporting straightforward for your team.
cGMP-Ready Platform: BASIS is actively validated and routinely used in cGMP testing for IND and BLA submissions. The software has been audited by FDA and many industry partners.
Flexible Sample Requirements: Our team’s experience with thousands of viral projects (across all titers and serotypes) allow for the lowest sample volumes required (100 µL for higher titer to 400 µL for low titers)
Rapid Results: BioAnalysis is believed to have the largest fleet of AUC instruments at a CRO which allows for streamlined workflows that can deliver comprehensive results in less than 14 days (or faster for expedited samples) without compromising quality.
Importance of Empty/Full Capsid in Gene Therapy
The ratio of full to partial to empty capsids is a critical quality attribute (CQA) that may impact safety, potency, and efficacy of viral gene therapy products. High levels of empty or partial capsids could:
- Reduce therapeutic efficacy by diluting the active dose
- Increase immunogenicity and risk of immune response
- Complicate dosing strategies across patient populations
Regulatory agencies require robust and validated methods for empty/full capsid measurement for:
- IND (Investigational New Drug) submissions
- Lot release testing
- Commercial manufacturing quality control
SV-AUC enables confident decision-making by offering consistent and reproducible quantitation of AAV and other viral vectors under cGMP conditions.
1. Absolute Quantification
SV-AUC is a first principle technique that directly measures capsid species without relying on external calibration or reference standards, allowing for direct and accurate measurement.
2. Native-State Measurements
SV-AUC operates in the product formulation buffer without labels, dyes, or matrix changes. The native structure and integrity of viral vectors is preserved.
3. High Sensitivity & Resolution
| Metric | Value |
|---|---|
| LOD of capsids | < 0.5% to 5% |
| LOQ of capsids | < 1.5% to 15% |
| %CV for S-values | < 0.5% |
| %CV for Quantitation | < 10% |
This precision allows for reliable detection and quantification of even low-abundance species, such as trace levels of empty capsids and aggregates.
4. cGMP and 21 CFR Part 11 Compliance
- With unique proprietary platforms like BASIS™ (BioAnalysis SEDFIT Integrated Software), BioAnalysis has made SV-AUC uniquely suited as a regulatory-grade assay. BASIS™ is fully compliant with FDA requirements:
- Electronic signatures
- Secure audit trails
- Data integrity
*Details about BASIS™, BioAnalysis’ cGMP compliant AUC software can be found in the publication listed below and here
SV-AUC methods are easily developed, qualified, and validated for gene therapy products across Phase I–III drug development. BASIS™ is routinely evaluated in internal reviews, external client audits, and regulatory inspections.
SV-AUC vs. Other Empty/Full Capsid Methods
While multiple methods exist for capsid analysis, here’s why SV-AUC remains the gold standard:
| Technique | Limitations | SV-AUC Advantages |
| Transmission Electron Microscopy | Expensive, time-consuming, not QC-friendly | SV-AUC is faster, scalable, and QC-compatible |
| UV/Vis Spectroscopy | Lacks specificity; cannot resolve partial vs. full | SV-AUC separates and quantifies individual species accurately |
| Charge Detection Mass Spectrometry | Gas-phase, relative quantitation only, high cost | SV-AUC offers in-solution, absolute quantification |
| Mass Photometry | Limited dynamic range, semi-quantitative, requires dilution | SV-AUC offers better resolution, quantitation, and robustness |
| Size Exclusion Chromatography with Multi-Angle Light Scattering | Cannot distinguish empty from full due to similar hydrodynamic size | SV-AUC resolves capsids by sedimentation coefficient, enabling clear separation |
Why Industry Leaders Choose SV-AUC
SV-AUC offers an unmatched combination of:
- Quantitative precision
- Regulatory readiness
- Native-state analysis
- High sensitivity and reproducibility
It remains the most reliable platform for AAV capsid analysis, playing a critical role in quality control, IND submissions, and commercial release testing.
Complementary Technologies
While SV-AUC is the most robust method for full/empty capsid quantification, it can be complemented with:
- Density Gradient Equilibrium (DGE)-AUC for adding more detail to % E/P/F characterization via buoyancy measurements
- Dynamic Light Scattering (DLS) for measuring hydrodynamic size and polydispersity (aggregation)
- Size Exclusion Chromatography with Multi-Angle Light Scattering (SEC-MALS) for size exclusion profiling
- Liquid Chromatography-Mass Spectrometry (LC-MS) for capsid protein characterization
- Charge Detection Mass Spectrometry (CDMS) for orthogonal confirmation of mass
- FRET (Förster Resonance Energy Transfer) or SPR (Surface Plasmon Resonance) for analyzing functional binding or kinetics
For sponsors developing gene therapy programs, investing in SV-AUC testing with BioAnalysis ensures alignment with FDA expectations and provides high-confidence data that supports product safety, consistency, and efficacy.
Need help with your empty/partial/full capsid assay? Contact our SV-AUC experts to design a validated, compliant solution tailored to your gene therapy program.