Anti-human Fluorescein Conjugated Cd Quantum Dots
Cd quantum dots are conjugated with anti-human fluorescein have unique optical properties, such as uniform particle size, high luminescence quantum efficiency, good photostability, and are widely used in cell imaging, biosensors. Alfa Chemistry can provide customers with anti-human fluorescein conjugated Cd quantum dots in the emission spectral range from 525 nm to 665 nm.
Targeted Cell Imaging
The synthesis, characterization, bioconjugation and application of water-soluble thioglycolic acid TGA capped CdTe/CdS quantum dots (TGA-QDs) for targeted cell imaging are described by Ag et al. Anti-human epidermal growth factor receptor 2 (HER2) antibodies were conjugated to TGA-QDs to target HER2 overexpressing cancer cells. TGA-QDs and TGA-QDs/anti-HER2 bioconjugates were characterized by fluorescence and UV-Vis spectroscopy, X-ray diffraction (XRD), hydrodynamic calibrations, electron microscopy and gel electrophoresis. TGA-QDs and TGA-QDs/anti-HER2 were incubated with cells to examine cytotoxicity, targeting efficiency and cellular localization. The cytotoxicity of the particles was measured using the MTT assay and the no apparent adverse effect concentration (NOAEC), 50% inhibitory concentration (IC50) and total lethal concentration (TLC) were calculated. To assess the localization and targeting efficiency of TGA-QDs with or without antibodies, fluorescence microscopy and flow cytometry were performed. The results showed that antibody-conjugated TGA-QDs are well suited for targeted cell imaging studies.
Fig. 1 Fluorescence microscopy imaging of A549 cells. (Ag et al., 2014)
Wang et al. developed a rapid and sensitive method based on fluorescent carboxymethyl chitosan/CdS quantum dots (CMCS-CdS QDs) composites for the specific detection of Staphylococcus aureus in food and the environment. Fluorescent CMCS-CdS QDs were prepared in aqueous solution by a green method. Human immunoglobulin (IgG) antibodies were then bioconjugated with QDs in the presence of 1-ethyl-3-(3)-dimethylaminopropylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to make a novel monodisperse water-soluble fluorescent bioprobe. The fluorescent bioprobe was used to identify Staphylococcus aureus by incubating it with bacteria for a certain period of time and observing the labeled cells under a fluorescence microscope after removal of the free fluorescent QDs. Fluorescence microscopy images show that S. aureus cells were successfully identified by the bioprobe. Several other bacteria commonly found in the environment, such as E. coli and Bacillus subtilis, were also incubated with the bioprobe to test its specificity. The novel QDs-CMCS-IgG bioprobe was found to be specific for the recognition of S. aureus cells. Fluorescence measurements using a luminescence spectrometer can be used to quantify S. aureus cells. The fluorescence intensity of the sample at 600 nm is proportional to the cell concentration in the range of 103-107 CFU/mL, while the detection limit is as low as 900 CFU/mL. Considering the simplicity and cost-effectiveness of this method, it is expected to be applied for the identification and quantification of bacteria in clinical, food and environmental samples.
Fig.2 Fluorescence microscopy of S. aureus cell incubated with CMCS/QD (A, bright field; B, fluorescent) and IgG/CMCS/QD (C, bright field; D, fluorescent). (Wang et al., 2011)
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.
- Ag, D. , et al. Biofunctional quantum dots as fluorescence probe for cell-specific targeting[J]. Colloids and surfaces B: Biointerfaces, 2014, 114C(2):96-103.
- Wang, Xiaohui, et al. Fluorescent identification and detection of Staphylococcus aureus with carboxymethyl chitosan/CdS quantum dots bioconjugates[J]. Journal of Biomaterials Science, Polymer Edition, 2011, 22(14): 1881-1893.
* It should be noted that our service is only used for research, not for clinical use.