By Agile Bioscience
Understanding the molecular weight, aggregation behaviour, and structural integrity of therapeutic proteins is fundamental to developing safe, stable, and effective biopharmaceutical products. Yet traditional analytical tools often fall short—especially when dealing with complex, heterogeneous, or highly modified molecules.
Size-Exclusion Chromatography coupled with Multi-Angle Light Scattering (SEC-MALS) has emerged as one of the most powerful and precise techniques for absolute molecular weight measurement and aggregation profiling. At Agile Bioscience, SEC-MALS is a cornerstone technology that enables high-resolution, high-confidence structural analytics across peptides, proteins, fusion molecules, glycoproteins, and biologics.
What is SEC-MALS?
SEC-MALS combines the separation ability of Size-Exclusion Chromatography (SEC) with the absolute quantification strength of Multi-Angle Light Scattering (MALS).
- SEC separates molecules purely based on hydrodynamic size.
- MALS measures scattered light at multiple angles, enabling calculation of absolute molecular weight and radius of gyration without relying on calibration standards.
This synergy produces unparalleled structural clarity—especially for proteins whose elution profiles may not correlate with their true molecular weights.
Why SEC-MALS Matters
- Absolute Molecular Weight (No Standards Needed)
Unlike conventional SEC-UV/RI, MALS does not rely on assumptions of shape or behaviour, providing direct, physics-derived molecular weight values. - Accurate Aggregate Profiling
From dimers and oligomers to high-molecular-weight (HMW) species, SEC-MALS quantifies aggregation with precision essential for comparability and stability programs. - Ideal for Complex and Modified Proteins
Glycosylated proteins, PEGylated biologics, ADCs, and fusion constructs often deviate from globular protein calibration curves. SEC-MALS avoids these errors entirely. - In-Solution, Native-State Analysis
The technique preserves protein conformation—an important advantage over mass spectrometry, which often requires denaturing conditions.
How SEC-MALS Works: Step-by-Step
- Sample Injection and SEC Separation
The sample is injected into the SEC column, where species separate based on hydrodynamic volume.
- Multi-Detector Flowpath
Eluted species sequentially pass through:
- UV Absorbance Detector
- MALS Detector
- Refractive Index (RI) Detector
Each detector contributes key parameters required for absolute molecular weight calculation.
- MALS Data Interpretation
Light scattering intensity across multiple angles allows computation of:
- Weight-average molecular weight (Mw)
- Radius of gyration (Rg)
- Aggregate proportions and distribution
- Final Data Output
SEC-MALS produces a high-resolution profile showing monomer, dimer, oligomers, and HMW species—providing key insights into product quality.
Applications of SEC-MALS at Agile Bioscience
✔ Aggregate Quantification
Essential for stability studies, biosimilar comparability, and formulation development.
✔ Molecular Weight Confirmation
Critical for identity, purity, and lot-to-lot consistency.
✔ Glycoprotein & Bioconjugate Characterization
Deconvolution of protein mass vs. glycan or polymer contribution.
✔ Self-Association and Oligomerization Studies
Determine equilibrium shifts under varying pH, ionic strength, or concentration.
✔ Formulation & Stress Testing
Compare aggregate levels under buffer conditions, temperature stress, and excipient combinations.
Why Agile Bioscience for SEC-MALS?
- Cutting-edge MALS instrumentation with high-angle resolution
- Strong method development experience for challenging molecules
- Regulatory-compliant documentation suitable for IND/BLA filings
- Integration with orthogonal techniques including CD, FTIR, AUC, LC-MS, and bioassays
- Experienced scientists with deep expertise in protein analytics
SEC-MALS is not just an analytical tool—it is a scientific lens that reveals molecular behaviour with clarity unmatched by traditional methods.
Ready to leverage SEC-MALS for your protein characterization needs? Contact Agile Bioscience to learn how our analytical expertise can support your biopharmaceutical development programs.
