Simoa® (Single Molecule Array) is Quanterix's proprietary digital immunoassay technology designed for ultra-sensitive biomarker detection across multiple biological matrices, including blood, cerebrospinal fluid (CSF), and tissue samples[@quanterix2026][@rissin2010]. This platform represents a breakthrough in ultrasensitive immunoassays, enabling the detection of protein biomarkers at concentrations previously undetectable by conventional ELISA methods.
The Simoa technology is now the leading platform for single-molecule array detection in [neurodegenerative disease](/diseases/neurodegeneration) research, with over 5,000 peer-reviewed publications and 2,300+ instruments deployed globally[@quanterix2026]. It is particularly critical for detecting phosphorylated tau (p-tau) isoforms and neurofilament light chain (NfL), which are essential biomarkers for [Alzheimer's Disease (AD](/diseases/alzheimers-disease)) and [Parkinson's Disease (PD](/diseases/parkinsons-disease)) research.
Technology Principles
Single Molecule Array (Simoa) Technology
Simoa technology utilizes a proprietary array-based digital immunoassay approach that achieves femtogram-level sensitivity by isolating individual antibody-coated microspheres in femtoliter-sized wells[@quanterix2026][@rissin2010]. This digital approach provides:
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Overview
Simoa® (Single Molecule Array) is Quanterix's proprietary digital immunoassay technology designed for ultra-sensitive biomarker detection across multiple biological matrices, including blood, cerebrospinal fluid (CSF), and tissue samples[@quanterix2026][@rissin2010]. This platform represents a breakthrough in ultrasensitive immunoassays, enabling the detection of protein biomarkers at concentrations previously undetectable by conventional ELISA methods.
The Simoa technology is now the leading platform for single-molecule array detection in [neurodegenerative disease](/diseases/neurodegeneration) research, with over 5,000 peer-reviewed publications and 2,300+ instruments deployed globally[@quanterix2026]. It is particularly critical for detecting phosphorylated tau (p-tau) isoforms and neurofilament light chain (NfL), which are essential biomarkers for [Alzheimer's Disease (AD](/diseases/alzheimers-disease)) and [Parkinson's Disease (PD](/diseases/parkinsons-disease)) research.
Technology Principles
Single Molecule Array (Simoa) Technology
Simoa technology utilizes a proprietary array-based digital immunoassay approach that achieves femtogram-level sensitivity by isolating individual antibody-coated microspheres in femtoliter-sized wells[@quanterix2026][@rissin2010]. This digital approach provides:
True pg/mL resolution: Enables measurement at picogram per milliliter levels
Femtogram sensitivity: Up to 1,000 times more sensitive than conventional ELISA
Unmatched precision: High coefficient of variation (CV) control for reproducible results
Multi-analyte capability: Can measure multiple biomarkers simultaneously
How Simoa Works
The Simoa assay workflow involves:
Capture: Target biomarkers in patient samples bind to antibody-coated paramagnetic microspheres
Labeling: A detection antibody conjugated to β-galactosidase (β-gal) binds to the captured target
Enzymatic reaction: The enzyme generates a fluorescent resorufin product
Digital detection: Individual microspheres are loaded into Simoa arrays with ~50,000 femtoliter wells
Analysis: Fluorescence from each well is measured — if a well contains an enzyme-labeled bead, it registers as active
This digital counting approach enables absolute quantification of biomarker concentrations with unprecedented sensitivity.
Applications in Neurodegenerative Disease
Alzheimer's Disease Biomarkers
Simoa is the premier platform for detecting amyloid and tau biomarkers in blood and [CSF](/biomarkers/csf-biomarkers-neurodegenerative-disease)[@quanterix2026][@janelidze2024]:
| Biomarker | Application | Significance | |-----------|-------------|--------------| | p-Tau 217 | Early AD detection, differentiate AD from other dementias | Highest accuracy for early diagnosis | | p-Tau 205 | Disease progression tracking | Correlates with disease severity | | p-Tau 212 | Tau pathology staging | Identifies specific tau isoforms | | Brain-Derived Tau (BD-Tau) | Neurodegeneration identification and staging | Directly measures neuronal injury | | LucentAD Panel | Multi-analyte approach | Combines amyloid, tau, neurodegeneration, and neuroinflammation markers |
Parkinson's Disease and Related Disorders
Simoa technology enables high-plex spatial proteomics studies that reveal distinct cell phenotypes and pathological signatures in [Parkinson's disease](/diseases/parkinsons-disease)[@quanterix2026][@okuzumi2023]:
[Alpha-synuclein](/proteins/alpha-synuclein): Detection of aggregation-prone species in CSF and blood
[Neurofilament Light Chain](/biomarkers/neurofilament-light-chain-nfl) (NfL): Blood-based biomarker for neuro-axonal injury
High-plex profiling: Simultaneous measurement of multiple proteins from limited samples
Neurofilament Light Chain (NfL)
NfL detected via Simoa is now established as a critical blood-based biomarker for[@quanterix2026][@preische2019]:
Early diagnosis of neurogenerative conditions
Patient care and treatment monitoring
Disease progression tracking
Clinical trial enrichment
Differentiating [Parkinson's disease](/diseases/parkinsons-disease) from atypical parkinsonian syndromes
Clinical and Research Use
CLIA-Validated Assays
Quanterix offers CLIA-ready validated assays for clinical use, enabling[@quanterix2026]:
Diagnostic applications: Laboratory-developed tests (LDTs) for clinical diagnosis
Clinical trials: Biomarker validation in pharmaceutical trials
Longitudinal studies: Patient monitoring over extended periods