1. Activate capture and digital counting (AC + DC) assay for protein biomarker detection integrated with a self-powered microfluidic cartridge
- Author
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Qinglan Huang, Miguel Ángel Aguirre, Brian T. Cunningham, Kenneth D. Long, Nantao Li, Utkan Demirci, Taylor D. Canady, Congnyu Che, Universidad de Alicante. Departamento de Química Analítica, Nutrición y Bromatología, Universidad de Alicante. Instituto Universitario de Materiales, and Espectroscopía Atómica-Masas y Química Analítica en Condiciones Extremas
- Subjects
Materials science ,Activate capture and digital counting ,Protein biomarker detection ,Surface Properties ,Point-of-Care Systems ,Microfluidics ,HIV Core Protein p24 ,Biomedical Engineering ,Metal Nanoparticles ,Bioengineering ,02 engineering and technology ,01 natural sciences ,Biochemistry ,Limit of Detection ,Humans ,Particle Size ,Surface plasmon resonance ,chemistry.chemical_classification ,biology ,business.industry ,Dynamic range ,Biomolecule ,010401 analytical chemistry ,General Chemistry ,Microfluidic Analytical Techniques ,021001 nanoscience & nanotechnology ,Primary and secondary antibodies ,0104 chemical sciences ,chemistry ,Colloidal gold ,biology.protein ,Optoelectronics ,Self-powered microfluidic cartridge ,Química Analítica ,Gold ,Target protein ,0210 nano-technology ,business ,Biosensor ,Biomarkers - Abstract
We demonstrate a rapid, 2-step, and ultrasensitive assay approach for quantification of target protein molecules from a single droplet test sample. The assay is comprised of antibody-conjugated gold nanoparticles (AuNPs) that are “activated” when they are mixed with the test sample and bind their targets. The resulting liquid is passed through a microfluidic channel with a photonic crystal (PC) biosensor that is functionalized with secondary antibodies to the target biomarker, so that only activated AuNPs are captured. Utilizing recently demonstrated hybrid optical coupling between the plasmon resonance of the AuNP and the resonance of the PC, each captured AuNP efficiently quenches the resonant reflection of the PC, thus enabling the captured AuNPs to be digitally counted with high signal-to-noise. To achieve a 2-step assay process that is performed on a single droplet test sample without washing steps or active pump elements, controlled single-pass flow rate is obtained with an absorbing paper pad waste reservoir embedded in a microfluidic cartridge. We use the activate capture and digital counting (AC + DC) approach to demonstrate HIV-1 capsid antigen p24 detection from a 40 μL spiked-in human serum sample at a one thousand-fold dynamic range (1–103 pg mL−1) with only a 35-minute process that is compatible with point-of-care (POC) analysis. The AC + DC approach allows for ultrasensitive and ultrafast biomolecule detection, with potential applications in infectious disease diagnostics and early stage disease monitoring. This work is supported by the National Institutes of Health (NIH) R01 AI20683, F30AI122925, and the Carl Woese Institute for Genomic Biology postdoctoral fellowship.
- Published
- 2019