Streptavidin Quantum Dots as a Universal Labeling Strategy

Streptavidin quantum dots are obtained by covalent coupling of streptavidin and active quantum dots with functional groups. Streptavidin has high affinity and specificity with biotin. The biotin-avidin system is used to combine streptavidin quantum dots with biotinylated antibodies, nucleic acids, and receptors. In this way, quantum dots can be labeled on cells, nucleic acids, and proteins for tracer detection and functional research, providing a universal labeling strategy for the application of quantum dots.

Characteristics of Streptavidin Quantum Dots

Streptavidin quantum dots exhibit several key characteristics that make them ideal for a wide range of applications.

• High Quantum Yield: Streptavidin quantum dots have high quantum yields, ensuring bright and stable fluorescence signals for robust imaging applications.
• Narrow Emission Spectra: They possess narrow emission spectra, allowing for multiplexed imaging and precise detection of multiple targets simultaneously.
• Biocompatibility: Streptavidin quantum dots are biocompatible, making them suitable for various biomedical applications without inducing cytotoxic effects.
• Stability: They exhibit exceptional photostability and resistance to photobleaching, ensuring prolonged imaging without signal degradation.

Streptavidin Quantum Dots from Alfa Chemistry

Catalog	Product Name
ACMA00022664	Streptavidin Quantum Dots, Dispersion, λex = 425nm
ACMA00022665	Streptavidin Quantum Dots, Dispersion, λex = 525nm
ACMA00022666	Streptavidin Quantum Dots, Dispersion, λex = 540nm
ACMA00022667	Streptavidin Quantum Dots, Dispersion, λex = 560nm
ACMA00022668	Streptavidin Quantum Dots, Dispersion, λex = 580nm
ACMA00022669	Streptavidin Quantum Dots, Dispersion, λex = 600nm
ACMA00022670	Streptavidin Quantum Dots, Dispersion, λex = 620nm

Synthesis of Streptavidin Quantum Dots

The synthesis of streptavidin quantum dots involves a series of intricate steps to control their size, shape, and surface properties.For example, Monika Bäumle et al. used glutathione as a stabilizing molecule to synthesize CdSe quantum dots (QDs) with a high fluorescence quantum yield of 25% and a narrow size distribution in water in one step, and further modified streptavidin on their surface.[1] Generally, the synthesis process of streptavidin quantum dots includes the following steps:

• Core Formation: Semiconductor core nanoparticles are synthesized using high-temperature reactions to control the size and composition of the nanocrystals.
• Surface Functionalization: The synthesized quantum dots are then coated with a layer of streptavidin, ensuring specific binding capabilities for biotinylated molecules.
• Surface Modifications: Additional surface modifications can be made to enhance stability, biocompatibility, and functionality for specific applications.

CdSe QDs coated with streptavidin. [1]

Applications of Streptavidin Quantum Dots

• Bioimaging

Quantum dots are extensively used in fluorescent labeling for cellular imaging, live-cell tracking, and in vitro diagnostics due to their bright and stable fluorescence properties.

• Biosensing

Streptavidin quantum dots are utilized in biosensors for sensitive detection of biomolecules, enabling rapid and accurate analysis in diagnostics and environmental monitoring. Linh Tran et al. developed a highly sensitive immunosensor using streptavidin-conjugated quantum dots (QDs/SA). The sensor can be used to detect very low concentrations of the dengue biomarker nonstructural protein 1 (NS1), allowing detection of dengue infection even in its early stages.

Streptavidin QDs for the quantitative analysis of dengue NS1 Ag. [2]

• Drug Delivery

These quantum dots can be functionalized with therapeutic agents and targeted to specific biological sites, showing promise in targeted drug delivery systems.

• Biological Research

They play a crucial role in molecular and cellular biology research, facilitating the visualization and study of biological processes at the nanoscale. Jing Jing Wang et al. designed a quantum dot molecular beacon (QD-MB) functionalized MoS₂ (QD-MB@MoS₂) fluorescent probe based on streptavidin quantum dots, which can be used for multiple myeloma (MM) dual detection of related miRNA-155 and miRNA-150.

The QD-MB@MoS₂ fluorescent probes based on streptavidin QDs. [3]

References

1. Monika Bäumle, et al. Langmuir, 2004, 20(10), 3828-3831.
2. Linh Tran, et al. Scientific Reports, 2021, 11(1), 15196.
3. Jing Jing Wang, et al. Bioactive Materials, 2022, 17, 360-368.

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