Ultrasensitive Detection of Attomolar Protein Concentrations by Dropcast Single Molecule Assays
- 30 June 2020
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 142 (28), 12314-12323
- https://doi.org/10.1021/jacs.0c04331
Abstract
Measurements of very low levels of biomolecules, including proteins and nucleic acids, remain a critical challenge in many clinical diagnostic applications due to insufficient sensitivity. While digital measurement methods such as Single Molecule Arrays (Simoa), or digital ELISA, have made significant advances in sensitivity, there are still many potential disease biomarkers that exist in accessible biofluids at levels below the detection limits of these techniques. To overcome this barrier, we have developed a simple strategy for single molecule counting, dropcast single molecule assays (dSimoa), that enables more target molecules to be counted through increased sampling efficiency and with a simpler workflow. In this approach, beads are simply dropcast onto a microscope slide and dried into a monolayer film for digital signal readout. The dSimoa platform achieves attomolar limits of detection, with an up to 25-fold improvement in sensitivity over Simoa, the current state of the art for ultrasensitive protein detection. Furthermore, due to its simple readout process and improved cost-effectiveness compared to existing digital bioassays, dSimoa increases amenability to integration into point-of-care platforms. As an illustration of the potential utility of dSimoa, we demonstrate its ability to measure previously undetectable levels of Brachyury, a tissue biomarker for chordoma, in plasma samples. With its significantly enhanced sensitivity and simplicity, dSimoa can pave the way toward the discovery of new biomarkers for early disease diagnosis and improved health outcomes.Keywords
Funding Information
- National Institute of Biomedical Imaging and Bioengineering (1F32EB029777-01)
- Good Ventures
This publication has 43 references indexed in Scilit:
- Digital microfluidics-enabled single-molecule detection by printing and sealing single magnetic beads in femtoliter dropletsLab on a Chip, 2013
- Simultaneous Detection of Single Molecules and Singulated Ensembles of Molecules Enables Immunoassays with Broad Dynamic RangeAnalytical Chemistry, 2011
- Role of the transcription factor T (brachyury) in the pathogenesis of sporadic chordoma: a genetic and functional‐based studyThe Journal of Pathology, 2010
- Single-molecule enzyme-linked immunosorbent assay detects serum proteins at subfemtomolar concentrationsNature Biotechnology, 2010
- T (brachyury) gene duplication confers major susceptibility to familial chordomaNature Genetics, 2009
- Electric field directed assembly of high-density microbead arraysLab on a Chip, 2009
- Microsphere-Based Rolling Circle Amplification Microarray for the Detection of DNA and Proteins in a Single AssayAnalytical Chemistry, 2009
- Heterogeneous immunoassays using magnetic beads on a digital microfluidic platformLab on a Chip, 2008
- Direct observation of individual endogenous protein complexes in situ by proximity ligationNature Methods, 2006
- Digital Concentration Readout of Single Enzyme Molecules Using Femtoliter Arrays and Poisson StatisticsNano Letters, 2006