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Production and Targeting of Monovalent Quantum Dots
Published on: October 23, 2014
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Dithiocarbamates: Reliable Surface Ligands for NIR-Emitting Quantum Dots
Jakub Cichos1, Edyta Wysokińska2, Wojciech Kałas2
1Faculty of Chemistry , University of Wrocław , ul. F. Joliot-Curie 14 , 50-383 Wrocław , Poland.
Langmuir : the ACS Journal of Surfaces and Colloids
|April 2, 2019
Summary
Researchers developed a new method to transfer hydrophobic quantum dots (QDs) into water using amino acid dithiocarbamate ligands. Lysine dithiocarbamate provided the best stability and transfer efficiency for these near-infrared emitting PbS/CdS QDs.
Area of Science:
- Materials Science
- Nanotechnology
- Biotechnology
Background:
- Hydrophobic quantum dots (QDs) require effective strategies for aqueous phase transfer for biological applications.
- Dithiocarbamate (DTC) derivatives of amino acids offer potential as stabilizing ligands for quantum dots.
- Amino acid-DTC ligands present advantages over commonly used dihydrolipoic acid (DHLA) derivatives.
Purpose of the Study:
- To develop a reliable method for transferring hydrophobic PbS/CdS core-shell quantum dots (QDs) into aqueous solutions.
- To evaluate the efficacy of synthesized in situ amino acid-dithiocarbamate derivatives as stabilizing ligands.
- To compare the performance of amino acid-DTC ligands with DHLA ligands for QD stabilization and phase transfer.
Main Methods:
- Synthesis of in situ dithiocarbamate derivatives of amino acids.
- Phase transfer of hydrophobic PbS/CdS QDs from organic to aqueous solutions using amino acid-DTC ligands.
- Characterization of QD size distribution, hydrodynamic diameter, and long-term stability in water.
- Assessment of spectroscopic property retention and cytotoxicity of the transferred QDs.
Main Results:
- Lysine dithiocarbamate demonstrated the most effective phase transfer and long-term stability for PbS/CdS QDs in water.
- Phase transfer was completed within 6-8 hours, yielding QDs with hydrodynamic diameters below 9 nm.
- The lysine-DTC-capped QDs retained spectroscopic properties for at least 48 hours and exhibited low toxicity.
Conclusions:
- Amino acid-dithiocarbamate ligands, particularly lysine-DTC, provide a reliable and efficient method for aqueous phase transfer of PbS/CdS QDs.
- The developed method ensures QD stability, preserves optical properties, and maintains low toxicity, making them suitable for biological applications.
- Lysine-DTC-capped PbS/CdS QDs can be readily modified with polyelectrolyte coatings for further functionalization.
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