Product Advantages: Uniform particle size, high luminous efficiency, narrow half-peak width, low cadmium, high stability.
Product Applications: Biofluorescent labeling, bioimaging, molecular diagnosis, etc.
Storage Conditions: Sealed, avoid light, and keep at 4°C.
Product Description
Water-soluble CdSe/ZnS quantum dots (QDs) are semiconductor nanocrystals with a core of cadmium selenide (CdSe) and a shell of zinc sulfide (ZnS). ZnS is non-toxic and chemically stable under any conditions. It can not only reduce the toxicity of cadmium ions, but also improve the quantum yield and the photostability of QDs. Water-soluble CdSe/ZnS QDs prepared by Alfa Chemistry are known for their tunable emission properties. If you need, please contact us immediately.
Product Parameters
| Catalog Number | PL Emission | FWHM | Surface Ligand | Quantum Yield |
| GH-QD0119 | 450±10 nm | ＜25 nm | MPA-COOH | ＞50% |
| GH-QD0120 | CA | ＞50% | ||
| GH-QD0121 | GSH | ＞50% | ||
| GH-QD0122 | PEG-COOH | ＞40% | ||
| GH-QD0123 | PEG-NH2 | ＞40% | ||
| GH-QD0124 | 470±10 nm | ＜25 nm | MPA-COOH | ＞50% |
| GH-QD0125 | CA | ＞50% | ||
| GH-QD0126 | GSH | ＞50% | ||
| GH-QD0127 | PEG-COOH | ＞40% | ||
| GH-QD0128 | PEG-NH2 | ＞40% | ||
| GH-QD0129 | 500±10 nm | ＜25 nm | MPA-COOH | ＞50% |
| GH-QD0130 | CA | ＞50% | ||
| GH-QD0131 | GSH | ＞50% | ||
| GH-QD0132 | PEG-COOH | ＞40% | ||
| GH-QD0133 | PEG-NH2 | ＞40% | ||
| GH-QD0134 | 525±10 nm | ＜25 nm | MPA-COOH | ＞70% |
| GH-QD0135 | CA | ＞70% | ||
| GH-QD0136 | GSH | ＞70% | ||
| GH-QD0137 | PEG-COOH | ＞60% | ||
| GH-QD0138 | PEG-NH2 | ＞60% | ||
| GH-QD0139 | 545±10 nm | ＜28 nm | MPA-COOH | ＞70% |
| GH-QD0140 | CA | ＞70% | ||
| GH-QD0141 | GSH | ＞70% | ||
| GH-QD0142 | PEG-COOH | ＞60% | ||
| GH-QD0143 | PEG-NH2 | ＞60% | ||
| GH-QD0144 | 625±10 nm | ＜28 nm | MPA-COOH | ＞70% |
| GH-QD0145 | CA | ＞70% | ||
| GH-QD0146 | GSH | ＞70% | ||
| GH-QD0147 | PEG-COOH | ＞60% | ||
| GH-QD0148 | PEG-NH2 | ＞60% | ||
| GH-QD0149 | 645±10 nm | ＜30 nm | MPA-COOH | ＞70% |
| GH-QD0150 | CA | ＞70% | ||
| GH-QD0151 | GSH | ＞70% | ||
| GH-QD0152 | PEG-COOH | ＞60% | ||
| GH-QD0153 | PEG-NH2 | ＞60% |
*MPA: 3-Mercaptopropionic acid; CA: Cysteamine; GSH: Glutathione
*If you can't find the needed QDs in the table, please send us an inquiry.
Alfa Chemistry can customize quantum dots for you based on your unique requirements, which allows you to fine-tune the size, emission wavelength, and surface groups. This level of customization gives you greater control over the performance of your QDs and ensures their seamless integration into your application. In addition, Alfa Chemistry places a strong emphasis on transparency and traceability in our supply chain. We provide detailed documentation and product information to give you confidence in the quality and origin of our water-soluble CdSe/ZnS QDs. If you have any need, please contact us immediately. We look forward to establishing a stable cooperative relationship with you.
Related Products
Water-soluble CdSe/ZnS Quantum Dots Passivated by Poly(glycino amino acid) Phosphazenes
Zhang, Teng, Hui-Ping Yuan, and Hong-Li Suo. Transactions of Nonferrous Metals Society of China 19 (2009): s645-s650.
Poly(organophosphazenes) are promising materials for creating water-soluble and biocompatible quantum dots (QDs) due to their diverse properties. In this study, green-emitting CdSe QDs and red-emitting core-shell CdSe/ZnS QDs were synthesized. The trioctylphosphine oxide (TOPO)-stabilized CdSe/ZnS QDs were then transferred from chloroform into water through a ligand exchange process with poly(glycino amino acid) phosphazenes. These phosphazenes can be obtained by saponifying poly(glycino amino ester) phosphazenes at room temperature. The resulting QDs–polymer nanocomposite particles form colloidally stable suspensions in water and exhibit excellent photostability.
Preparation of Water-soluble CdSe/ZnS QDs (CdSe/ZnS/PGAAP)
1) Preparation of QDs in Chloroform
CdSe/ZnS QDs (5 mL, 100 µmol/L) in chloroform were transferred to a three-necked flask. To this, 5 mL of dimethyl sulfoxide (DMSO) and 2 mL of mercaptoethanol were added successively. The chloroform was removed under vacuum at room temperature, and the mixture was stirred under argon for an additional 2 hours.
2) Precipitation and Purification
The QDs were precipitated by adding an excess of a cold acetone-chloroform mixture (1:1 volume ratio). The precipitate was collected via centrifugation, washed with acetone, and then dried under vacuum.
3) Suspension and Degassing
The QDs coated with mercaptoethanol were resuspended in DMSO and centrifuged to remove any aggregates. The nanocrystals were diluted to a concentration of about 5 µmol/L. The suspension was then degassed extensively at room temperature under argon.
4) Polymer Addition and Heating
An anhydrous DMSO solution of poly(glycino amino acid) phosphazene (5 mg/mL) was added to the QD suspension under vigorous stirring. The solution was heated to 60°C and maintained for 2 hours.
5) Saponification and Dialysis
After cooling to room temperature, ice-cold aqueous sodium hydroxide (50 mmol/L, twice the volume of DMSO) was added slowly. The mixture was stirred for 2 hours. Finally, the QDs were dialyzed extensively against basic water for 2–3 days using a 25 kDa molecular weight cutoff dialysis tubing.
The resulting water-soluble CdSe/ZnS QDs passivated with poly(glycino amino acid) phosphazenes are stable in aqueous environments and retain their photoluminescent properties, making them suitable for various biological and optical applications.
Conjugation of Antibodies with Water-soluble Photoluminescent CdSe/ZnS Quantum Dots
Liu, Dan, et al. Sensors and Actuators B: Chemical 186 (2013): 235-243.
A multiplexed immunoassay biosensor was developed for detecting serum biomarkers using water-soluble photoluminescent (PL) CdSe/ZnS quantum dots (QDs) as fluorescence labels and carboxyl-functionalized microporous nylon membranes as the matrix. The CdSe/ZnS QDs were chosen for their high efficiency and stability in fluorescence.
The conjugation of the water-soluble CdSe/ZnS PL QDs with antibodies was achieved through an EDC/sulfo-NHS-mediated procedure. The process is described as follows:
1) Preparation of QD Solution
200 μL of water-soluble PL QDs was mixed with 800 μL of MES-buffered saline (pH 4.7), containing 5 mM sulfo-NHS and 2 mM EDC. The mixture was shaken for 40 minutes at room temperature to activate the QDs by forming an amine-reactive sulfo-NHS ester.
2) Washing and Buffer Exchange
The activated QDs were washed using 50 mM borate buffer (pH 8.5) via centrifugation (Beckman Coulter Optima L-100 × P). Red PL QDs were centrifuged at 20,000 rpm, and green PL QDs at 60,000 rpm for 30 minutes. After washing, the activated QDs were resuspended in the same buffer.
3) Antibody Conjugation
In the case of red PL QDs, 1.25 μL of β-HCG antibodies were added to the QD mixture, and for green PL QDs, 19.2 μL of AFP antibodies were used. The solution was incubated at 37°C for 3 hours, allowing the formation of stable amide bonds between the antibodies and the water-soluble PL QDs.
4) Blocking and Storage
The conjugates were blocked by adding 1% BSA solution and incubating at 37°C for 30 minutes to prevent nonspecific binding. The final conjugate solution was stored at 4°C until use.
This method efficiently conjugates antibodies to water-soluble CdSe/ZnS QDs, creating stable bioconjugates suitable for use in multiplexed biosensors for serum biomarker detection.
