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A spherical poly(acrylic acid) brush–enzyme block with high catalytic capacity for signal amplification in digital biological assays
- Source :
- RSC Advances. 9:23658-23665
- Publication Year :
- 2019
- Publisher :
- Royal Society of Chemistry (RSC), 2019.
-
Abstract
- Ultrasensitive determination of some ultra-low abundance biological molecules closely related to diseases is currently a wide concern and urgent issue to be addressed. Here, a spherical poly(acrylic acid)–alkaline phosphatase (SP–AKP) signal amplification block using spherical poly(acrylic acid) brush nanoparticles (SP) as the immobilized carriers was designed and synthesized optimally first. The results show that a single SP–AKP with high enzyme binding capacity and high catalytic ability (up to about 4800 effective free AKP per SP–AKP) has much greater fluorescence signal amplification ability than a single free AKP or SiO2–COOH–AKP. Then, a droplet generation microfluidic chip was prepared successfully, and the SP–AKP was loaded and confined in a 14 pL droplet by adjusting its concentration to ensure at most one SP–AKP was encapsulated in each droplet according to Poisson's theory. Finally, the fluorescence signals produced by 4-methylumbelliferyl phosphate (4-MUP) catalyzed via SP–AKP within 6 min were sufficient to be detected by a fluorescence microscope. Thus, the digital signal distribution of “1/0” (signal/background) was obtained, making this SP–AKP signal amplification block a promising enzyme label for potential high sensitivity digital biological detection applications.
- Subjects :
- chemistry.chemical_classification
General Chemical Engineering
Biomolecule
Nanoparticle
02 engineering and technology
General Chemistry
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
Fluorescence
Signal
0104 chemical sciences
Enzyme binding
chemistry.chemical_compound
chemistry
Chemical engineering
Fluorescence microscope
Digital signal
0210 nano-technology
Acrylic acid
Subjects
Details
- ISSN :
- 20462069
- Volume :
- 9
- Database :
- OpenAIRE
- Journal :
- RSC Advances
- Accession number :
- edsair.doi.dedup.....692ff536a89cfef6e022345c4f2a42c5