Profiling Protein Aggregate Size Using Single-Molecule Array Technology
Protein aggregation is a central feature of many neurodegenerative diseases, yet methods to characterize aggregate size in complex biological samples remain limited. Here, we show that fluorescence intensity from individual single-molecule array (Simoa) microwells encodes size-dependent information beyond conventional digital quantification. Using defined synthetic tau assemblies, we establish that increasing aggregate size produces higher microwell brightness. Applying this technique to human brain homogenate reveals a shift toward larger tau aggregates in Alzheimer's disease compared to age-matched controls, in agreement with orthogonal measurements by single-molecule super-resolution microscopy. Brightness profiling further captures time-dependent aggregate size increase in a neuronal cell model, demonstrating sensitivity to dynamic changes in aggregation. Although resolution is limited between similarly sized small species, Simoa brightness robustly reports population-level shifts in aggregate size distributions. These findings repurpose a widely used ultrasensitive detection platform to provide high-throughput structural as well as quantitative insight into protein aggregation in biological systems.
Authors
- Cara L. Croft (ORCID: https://orcid.org/0000-0001-7969-5084)
- Paula Beltran-Lobo (ORCID: https://orcid.org/0009-0006-2499-7740)
- María Jiménez-Sánchez (ORCID: https://orcid.org/0000-0002-2287-1582)
- Ashvini Keshavan (ORCID: https://orcid.org/0000-0003-1043-5721)
- Zengjie Xia (ORCID: https://orcid.org/0000-0002-5977-9691)
- Dorothea Böken (ORCID: https://orcid.org/0009-0008-8443-4469)
- Henrik Zetterberg (ORCID: https://orcid.org/0000-0003-3930-4354)
- Jianli Zhang
- J J Schott
- Yunzhao Wu
- Amanda Heslegrave
- David Klenerman
- David C. Duffy
- Savinu Weerasekera (ORCID: https://orcid.org/0009-0007-1101-292X)
Institutions
- Queen Mary University of London (GB)
- King's College London (GB)
- University of Cambridge (GB)
- Sahlgrenska University Hospital (SE)
- Institute for Neurodegenerative Disorders (US)
- Neuroscience Institute (IT)
- Quanterix (United States) (US)
- Institut des Sciences Cognitives Marc Jeannerod (FR)
- UK Dementia Research Institute (GB)
- Universitas Islam Syekh Yusuf (ID)
- National Hospital for Neurology and Neurosurgery (GB)
- University College London (GB)
- University of Gothenburg (SE)
Publication Details
- Journal
- Analytical Chemistry
- Published
- 2026-06-25
- DOI
- https://doi.org/10.1021/acs.analchem.6c03315
- Primary Topic
- Advanced Biosensing Techniques and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Alzheimer's Association
- University of Wisconsin-Madison
- Queen Mary University of London
- LifeArc
- Weston Brain Institute
- Brain Research UK
- Cancer Research UK
- National Institute for Health and Care Research
- British Heart Foundation
- King's College London
- University College London
- Wolfson Foundation
- Alzheimer’s Research UK
- Sahlgrenska Universitetssjukhuset
- Göteborgs Universitet
- UK Dementia Research Institute
- School of Medicine and Public Health, University of Wisconsin-Madison
- Medical Research Council
- Christ's College, University of Cambridge
- Sahlgrenska Akademin
- University College London Hospitals Biomedical Research Centre