Peptide Facilitated Intracellular Delivery of Quantum Dots for Live‐Cell Imaging

Abstract

Semiconductor Quantum Dots (QDs) are luminescent colloidal nanocrystals that display unique optical properties resulting from a combination of their core semiconductor materials and their nanometer‐sized quantum confined effects. QDs are composed of semiconductor cores, which are often coated with one or more shell(s) consisting of another semi‐conductor material with suitable lattice parameters and higher band gap energy (for type I QDs; e.g., CdSe/ZnS core/shell or CdSe/CdS/ZnS core/shell/shell QDs). The photophysical properties of QDs can be controlled by their core sizes, the shell thickness, the composition of the cores/shell(s), and partly by their surface ligands. Thus, the final absorption and emission features of QDs can be tuned from the UV to the near‐IR to fit the desired spectral characteristics, making them ideally suited for many spectroscopic and imaging applications. Due to their outstanding photophysical properties, QDs are suited for a wide range of applications as labels and sensors in biochemistry, biotechnology and medicine (e.g. fluorescence spectroscopy and microscopy as well as FRET‐based assays and diagnostics).In order to create stable, bio‐functional QDs, hydrophobic surface capping ligands are either exchanged with or converted to hydrophilic ligands that interact with the QD shell surface (e.g., amphiphilic polymers, dithiols) and provide a surface layer that affords aqueous solubility and allows further conjugation to proteins, DNA or other biomolecules, for example, The Medintz group at Naval Research Laboratories (NRL) has developed several types of QD‐functionalizing ligands that offer a variety of chemistries for bioconjugation.In this study we aim to passively deliver QDs‐bioconjugates to the cytosol of cells for subsequent live cell imaging experiments, the results will be discussed.Support or Funding InformationNSF