Synthesis and DNA Functionalization of CdSe/CdS (Core/Shell) Quantum Dots

摘要

In recent years, colloidal semiconductor nanocrystals, commonly known as quantum dots, have gained much attention in fields such as materials chemistry, bioengineering, chemical and biomedical engineering. These semiconductor nanocrystals display unique optical, electrical, and chemical properties unlike any bulk material or individual molecule. Areas of particular interest in the field of quantum dots include biofunctionalization. Recently, advances in biology and medicine indicate successful bioconjugate functionalization of biomolecules such as peptides, antibodies, nucleic acids, or small-molecules for labeling and intracellular tracking.This research is focused on the multistep synthesis of CdSe/CdS core-shell nanoparticles as well as employment of two different solubilization methods—lipid encapsulation and ligand exchange with mercapto-carboxylic acids. The synthesis begins by synthesizing the CdSe core using CdO and Se as precursors. Two layers of CdS shells are then applied over the core with cadmium and sulfur. The quantum dot is then made water soluble by encapsulating the hydrophobic particle in a micelle using phospholipid encapsulation method or by using ligand-exchange method using 3-mercaptopropionic acid. Once water soluble, specific oligonucleotides (DNA) are then functionalized to the quantum dots. Optimizations of this procedure may include but are not limited to: reactant concentrations, reaction temperature, and reaction time. An optimized and streamlined synthesis for quantum dots can greatly revolutionize the field of chemistry, biomedical imaging, engineering, and the sciences collectively.