Streptavidin Quantum Dots
Product Description
Alfa Chemistry can provide customers with tunable fluorescent color streptavidin quantum dots in the emission spectral range from 450 nm to 665 nm, with fluorescent color range covering the visible region from blue to red, excellent chemical and optical stability, good quality stability and high quantum yield. Streptavidin quantum dots are a set of water-soluble core/shell quantum dots conjugated to streptavidin. The streptavidin is covalently coupled to the surface of the quantum dots, allowing most biotin binding sites to be used to bind biotinylated molecules such as proteins, DNA and peptides.
Features
Our products have the characteristics of uniform particle size, broad absorption spectrum, symmetrical emission spectrum, high and stable fluorescence intensity.
Applications
Fluorescent Probes
Streptavidin functionalized quantum dots (SA-QDs) were used as a nanofluorescent probe to bind to Escherichia coli (E.coli) to detect and identify bacteria with immunoreactivity and biotin-streptavidin affinity, and the fluorescence image and fluorescence intensity of the bacteria were used to assess the binding effect at different incubation times. Where 20 min is a reasonable incubation time for SA-QDs to couple with E. coli cells. Fluorescence images of E. coli cells were obtained by immunoamplification and fluorescent probe enrichment steps, which produced greatly amplified and enhanced signals. In addition, the bleaching process of SA-QDs without any encapsulation at room temperature was clearly observed within 10 min of being excited. The work of Liu et al. provides a modular approach to sample processing using SA-QDs as nanofluorescent probes for cell imaging and biomarking.
Fig.1 Schematic representation of the SA-QDs binding toE. coli cells for immunoassay. (Liu et al., 2011)
Hybrid Nanobiosensors
Yu et al. used CdSe quantum dot-labeled streptavidin (CdSe QD-SAv) to amplify the current and impedance signals generated in electrical and electrochemical measurements of a nanogap biosensor to detect biotin-streptavidin binding. Surface properties in the microelectrode gap were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Electrical ( IV ) and electrochemical measurements (cyclic voltammetry, CV; electrochemical impedance spectroscopy, EIS) were performed to record the changing properties in the gap to analyze the sensitivity and signal intensity. UV light was used to excite CdSe quantum dots, which provided considerable signal enhancement for biosensing. Therefore, the biosensor studied in this work is considered as a hybrid nanobiosensor.
Fig.2 (a-c) Nanogap fabrication and (d) its top view. (a) Schematic illustrating the proposed microelectrode with a 2.5 μm gap. (b) Smaller AuNPs filling in the microgap, and (c) suitable size of AuNPs by in situ seeded growth, biotin–streptavidin binding gold nanogapped electrode. (d) The top view of the nanogap. (Yu et al., 2012)
Alfa Chemistry can provide a variety of complex and customized fluorescent quantum dot products. Our products involve perovskites precursors, perovskites quantum dots, quantum dot kit, single layer quantum dots, upconverting nanoparticles and other fluorescent quantum dots. Alfa Chemistry provides products with high fluorescence quantum yield, stable quality and relatively low price. Our products are constantly updated. If the product you need is not in our catalog, please feel free to contact us, we provide relevant custom services.
References
- Liu J., et al., Imaging Escherichia coli using streptavidin functionalized quantum dots as a Nano-fluorescent probe[J]. Journal of Harbin Institute of Technology, 2011, 2.
- Yu, Y. , et al. CdSe quantum dots enhance electrical and electrochemical signals of nanogap devices for bioanalysis.[J]. Small, 2012, 8(21):3225-3225.
* It should be noted that our service is only used for research, not for clinical use.
