Evaluating Antibody Quality via Simultaneous Size and Charge Measurement with Single Protein Oscillators
Rui Jia1, Ryan M Porter1,2, Rohit Singh Dangi3
1Biodesign Center for Biosensors and Bioelectronics, Arizona State University, Tempe, Arizona 85287, United States.
Analytical Chemistry
|May 13, 2026
Summary
A new label-free method measures single therapeutic antibody size and charge, revealing aggregate heterogeneity. This technique enhances quality assessment and supports therapeutic optimization beyond current limitations.
Area of Science:
- Biophysics
- Analytical Chemistry
- Protein Science
Background:
- Antibody aggregation impacts therapeutic efficacy and immunogenicity.
- Current methods offer ensemble-averaged data, lacking single-molecule insights.
- Accurate characterization of antibody aggregates is crucial for quality control.
Purpose of the Study:
- To introduce and validate a novel label-free single protein oscillator method.
- To simultaneously measure size and charge of therapeutic monoclonal antibodies.
- To differentiate aggregation levels and characterize aggregate heterogeneity.
Main Methods:
- Tethering single proteins to a sensor surface via a flexible polymer.
- Inducing oscillation with an alternating electric field.
- Imaging oscillations using near-field optical imaging.
Main Results:
- Simultaneous single-molecule measurement of size and charge for adalimumab, bevacizumab, and panitumumab.
- Detection of a wider size range of aggregates than SEC-HPLC.
- Identification of heterogeneous charge distributions in adalimumab aggregates of similar size.
- Validation of results against SEC-HPLC and icIEF methods.
Conclusions:
- The single protein oscillator method provides high-resolution, simultaneous size and charge characterization.
- This approach offers a more comprehensive understanding of antibody aggregation.
- Enables detection of structural changes not accessible by conventional techniques.
- Supports enhanced therapeutic antibody quality assessment and optimization.
