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Hybrid Supercharged Antibodies: A Rational Approach to Boost Immunoassay Sensitivity via Controlled Nanoparticle
Junichi Sato1,2, Keisuke Kasahara3,4, Satoru Nagatoishi3,5
1Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Langmuir : the ACS Journal of Surfaces and Colloids
|April 3, 2026
Summary
Researchers enhanced lateral flow immunoassay sensitivity by computationally designing supercharged antibodies. This novel approach optimizes antibody adsorption and orientation on nanoparticles, improving detection limits eightfold.
Area of Science:
- Biotechnology
- Immunotechnology
- Nanotechnology
Background:
- Lateral flow immunoassays (LFAs) are widely used for rapid diagnostics.
- Enhancing LFA sensitivity is crucial for early disease detection.
- Current methods for improving antibody immobilization on nanoparticles have limitations.
Purpose of the Study:
- To develop a computational strategy for designing supercharged antibodies to improve LFA sensitivity.
- To optimize antibody adsorption and molecular orientation on nanoparticle surfaces.
- To investigate the impact of antibody charge engineering on LFA performance.
Main Methods:
- Computational design of supercharged immunoglobulin G (IgG) antibodies with engineered charge distributions.
- Modification of Fc and Fab domains to create charge-polarized antibodies.
- Characterization of supercharged antibodies' physicochemical properties and antigen-binding affinity.
- Quantitative analysis of antibody adsorption and orientation on cellulose nanoparticles (NanoAct) using isothermal titration calorimetry.
- Performance evaluation of modified LFAs.
Main Results:
- Supercharged antibodies maintained wild-type antigen-binding affinity and physicochemical properties.
- Positively charged Fc domains enhanced antibody adsorption onto NanoAct.
- A specific charge-polarized design (c-10/Fc-pos14) promoted tail-on orientation and increased Fab accessibility.
- The optimized LFA demonstrated an 8-fold improvement in the limit of detection (3.13 ng/mL from 25 ng/mL) without increased nonspecific binding.
- Charge separation between antibody domains was key for orientation control.
Conclusions:
- Supercharging antibodies is an effective strategy to enhance LFA sensitivity.
- Controlled antibody orientation on nanoparticles significantly improves assay performance.
- This approach offers a promising method for developing next-generation diagnostic platforms.
- The design principle can be applied to other antibody-based assays.
