Advanced Methods
ddPCR, Refymn mass photometry, and dedicated genome integrity characterization provide higher-resolution readouts than traditional qPCR or AUC-only workflows.
AAV Quality Attribute Testing
AAV Characterization Services
Comprehensive quality attribute testing for AAV vectors - standalone, bundled, or third-party QC.
Core Advantages
Reliable AAV QC without forcing a single ordering path.
Use characterization as a built-in part of a Crossilico build project, as an independent third-party QC package, or as a custom method development engagement.
Flexible Ordering
Order single assays, standard panels, functional add-ons, or bundled QC within AAV optimization and RUO manufacturing projects.
Full Data Package
Each project can include a test report, raw instrument data, and structured CSV or JSON outputs for traceable downstream review.
Fast Turnaround
Standard characterization is designed for 5-7 business days from sample receipt, with complex functional assays typically scoped at 1-2 weeks.
QC Benchwork
AAV characterization is grounded in sample handling and instrument data.
Titer, empty/full ratio, genome integrity, and potency readouts are paired with raw data and reviewable visual evidence.
Sample receiptInstrument readoutsRaw data package
Testing Panels
Choose a complete panel or select individual assays.
The standard panel is embedded in Crossilico AAV Genome Optimization & Validation and AAV RUO Manufacturing workflows, and can also be purchased independently.
Standard Panel
Routine quality attribute testing for AAV products and batch-level QC decisions.
| Test Item | Method | Standard / Output | Turnaround | Notes |
|---|---|---|---|---|
| Titer Quantification | ddPCR | Target titer defined by project scope | 3-5 days | Digital PCR quantification with higher precision than traditional qPCR. |
| Purity Assessment | SDS-PAGE | At least 90% for INVIVO Grade; at least 95% for NHP Grade | 3-5 days | Protein purity and VP band profile assessment. |
| Empty/Full Ratio | Mass photometry (Refymn) | Empty, full, and partially packaged capsid ratio | 5-7 days | Single-particle method for distinguishing particle populations. |
| Genome Integrity | Dedicated method | Genome packaging integrity report | 5-7 days | Evaluates the proportion of functionally packaged genomes. |
| Residual DNA | qPCR | Host-cell residual DNA quantification | 3-5 days | Safety-related residual impurity readout. |
| HCP | Immunoassay method | Host Cell Protein residual level | 3-5 days | Safety-related process impurity readout. |
Functional Panel
For programs that need biological activity evidence beyond routine QC.
| Test Item | Method | Standard / Output | Turnaround | Notes |
|---|---|---|---|---|
| In Vitro Potency | Cell-level functional validation | Expression efficiency percentage / functional activity | 1-2 weeks | Validates transgene expression and functional activity in the target cell context. |
| In Vivo Biodistribution | Tissue tropism analysis | Tissue distribution profile | 2-4 weeks | Optional research module for tissue-specific delivery evaluation. |
Method Development
Custom assay development for special sequences, non-standard serotypes, or client-specific requirements.
| Test Item | Method | Use Case | Turnaround | Notes |
|---|---|---|---|---|
| Custom qPCR/ddPCR Method | Algorithmic multiplex PCR design | Non-standard serotypes, titer testing, or sequence-specific residual testing | 2-4 weeks | Primer/probe design with specificity and sensitivity validation. |
| Custom Characterization Plan | Project-specific design | Novel AAV variants, complex genome structures, or special QC needs | Project-based | Includes technical consultation and feasibility assessment. |
Method Details
Six assay modules with clear scientific outputs.
Each module is written for technical review: method, detection principle, output, and why it matters.
Titer Quantification
- Default method: ddPCR (droplet digital PCR).
- Alternative qPCR available for alignment with existing internal standards.
- Output: genome titer in VG/mL with raw ddPCR plot and CSV data.
- ddPCR supports absolute quantification without a standard curve.
Purity Assessment
- Method: SDS-PAGE under reducing or non-reducing conditions.
- Evaluates VP1/VP2/VP3 capsid protein ratios and impurity bands.
- Output: gel image and purity percentage from band-density analysis.
- Standard targets: at least 90% INVIVO Grade and at least 95% NHP Grade.
Empty/Full Capsid Ratio
- Method: mass photometry.
- Distinguishes empty, full, and partially packaged particles by mass.
- Output: particle ratio distribution and mass histogram.
- Label-free and calibration-light single-particle measurement.
Genome Integrity
- Method: dedicated characterization workflow.
- Evaluates packaged genome completeness and abnormal genome signatures.
- Output: genome integrity ratio and abnormal genome spectrum.
- Important for connecting vector quality to in vitro potency and in vivo expression.
Residual DNA & HCP
- Residual host-cell DNA quantified by qPCR.
- HCP (Host Cell Protein) assessed by immunoassay method.
- Supports process impurity review and batch-level QC documentation.
- Acceptance limits are defined according to project grade and context.
In Vitro Potency
- Cell-level functional validation in the requested target cell system.
- Evaluates transgene expression efficiency and functional activity when applicable.
- Output can include expression percentage, dose-response curve, and signal images.
- Typical turnaround: 1-2 weeks including cell culture cycle.
Ordering Modes
Three ways to buy characterization services.
The structure is intentionally flexible so teams can use Crossilico for complete build-test projects, independent QC, or long-term assay development.
Embedded in Build Service
Recommended when customers choose AAV Genome Optimization & Validation or AAV RUO Manufacturing.
- Standard Panel is included in the base workflow.
- QC data is integrated into the final project report.
- Functional Panel upgrades can be added when needed.
Standalone Third-Party QC
For customers with AAV batches from another supplier or from an internal lab.
- Order single assays, Standard Panel, Functional Panel, or a custom combination.
- Useful for vendor comparison, batch release decisions, and regulatory data supplements.
- Samples can be shipped to Crossilico via standard cold-chain logistics.
Method Development + Partnership
For special sequences, non-standard serotypes, or long-term batch monitoring needs.
- Develop customized detection methods for client-specific sequences.
- Transition validated methods into monthly or quarterly testing programs.
- Supports internal GMP manufacturing, consistency monitoring, and method validation planning.
Sample shipping: customers can ship AAV samples to the Crossilico laboratory through standard cold-chain logistics. Sample condition is confirmed within 1 business day after receipt before test scheduling begins.
Use Cases
Built for practical AAV program decisions.
Third-Party QC for Existing AAV Batches
Use standardized testing to support supplier audits, batch release decisions, internal QC confirmation, or regulatory data supplements.
Characterization Add-On for Build Projects
Add extra characterization items such as in vitro potency or biodistribution to a Crossilico AAV optimization or RUO production workflow.
Custom Method Development for Novel Serotypes
Develop qPCR or ddPCR methods for non-standard AAV serotypes, complex genome structures, or sequence-specific testing needs.
Multi-Batch Consistency Monitoring
Run standardized panels across multiple batches and receive statistical consistency reports for process stability and regulatory planning.
Deliverables
Traceable output for scientific and operational review.
DeliverableFormatDescription
Test ReportPDF
Methods, experimental conditions, result figures, conclusions, and method limitation notes.
Raw DataCSV / Excel / Native
Unprocessed instrument outputs such as ddPCR plots, mass photometry distributions, and SDS-PAGE images.
Structured DataJSON / CSV
Metadata-tagged data that can be imported into computational pipelines or LIMS systems.
Method DocumentPDF
For method development projects: method principle, primer/probe sequence, validation data, and applicability statement.
FAQ
Common questions.
Can I order AAV characterization as a standalone service, or only as part of a Build project?
Both. AAV Characterization Services can be embedded in our Build Service or ordered independently as third-party QC. If you have AAV batches from another supplier or from your own lab, you can ship them to us for standalone testing.
How do I ship my AAV samples to Crossilico?
We provide a detailed shipping guide with packaging requirements, shipping temperature, and carrier recommendations. Upon receiving your samples, we confirm sample integrity within 1 business day and begin scheduling.
What is the difference between ddPCR and qPCR for titer quantification?
ddPCR is our default method because it provides absolute quantification without standard curves, making it more precise and less prone to amplification bias. qPCR is available upon request when you need alignment with existing internal standards or regulatory filings.
What is mass photometry, and why use it instead of AUC?
Mass photometry measures the mass of individual viral particles at the single-particle level, directly distinguishing empty, full, and partially packaged capsids. It is label-free and provides strong resolution for empty/full ratio determination.
Can you develop a custom detection method for my novel serotype?
Yes. We offer custom qPCR and ddPCR method development based on algorithmic primer/probe design. The typical timeline is 2-4 weeks, including specificity validation and sensitivity testing.
How long does a standard characterization panel take?
Standard Panel testing typically takes 5-7 business days from sample receipt. Functional Panel items such as in vitro potency usually add 1-2 weeks. Custom method development is typically scoped at 2-4 weeks.
What data formats do you deliver?
Standard delivery includes PDF reports, CSV raw data, and image outputs such as SDS-PAGE images. Custom JSON with metadata is available upon request.
Can I get a quote before shipping samples?
Yes. Contact us with your sample details, serotype, expected titer, volume, sample count, and required tests. We will provide a formal quote before you ship samples.
Start Testing
Need AAV quality testing?
Submit your sample details for a free quote. Standalone testing or bundled with your project - flexible to your needs.