Peptide-coated semiconductor nanocrystals for biomedical applications

Abstract

We have developed a new functionalization approach for semiconductor nanocrystals based on a single-step exchange of surface ligands with custom-designed peptides. This peptide-coating technique yield small, monodisperse and very stable water-soluble NCs that remain bright and photostable. We have used this approach on several types of core and core-shell NCs in the visible and near-infrared spectrum range and used fluorescence correlation spectroscopy for rapid assessment of the colloidal and photophysical properties of the resulting particles. This peptide coating strategy has several advantages: it yields probes that are immediately biocompatible; it is amenable to improvements of the different properties (solubilization, functionalization, etc) via rational design, parallel synthesis, or molecular evolution; it permits the combination of several functions on individual NCs. These functionalized NCs have been used for diverse biomedical applications. Two are discussed here: single-particle tracking of membrane receptor in live cells and combined fluorescence and PET imaging of targeted delivery in live animals.

Synthesis, structural and optical properties of pure ZnO and Co doped ZnO nanoparticles prepared by the co-precipitation method

“…Among them, the widely accepted method to modify the electrical and optical properties of a semiconductor is the addition of impurity atoms, or doping [3][4][5]. The different type of shapes, such as nanorods, tetrapods and nanowire [6] formed by adding dopants insulating material begun to work as semiconductors and such semiconducting nanomaterials can be used for wavelengthtunable lasers [7], bio-imaging [8] and solar cells [9]. There are several methods reported in the literature for the synthesis of undoped, doped ZnO NPs and its derivatives which can be categorized into either (Chemical or Physical, co-precipitation, hydrothermal, solvothermal, emulsion and microemulsion methods etc.)…”

Fabrication of fluorescent composite with ultrafast aqueous synthesized high luminescent CdTe quantum dots

“…Due to the excellent photoluminescence (PL) properties, broad absorption spectrum, narrow emission FWHM (full width at half mount), high quantum yield (QY) and outstanding emission stability, QDs have been heavily investigated during the past two decades [2] for the expectation of the potential application in solar cells [3], biological sensors [4] and light emitting devices [5]. Meanwhile, accompanied with the robust progress in various promising products, synthetic methodologies have been well developed as a guarantee of the applications.…”

The Applications of Metallic Nanowires for Live Cell Studies

“…Nanoparticles, such as quantum dots or metallic nanoparticles, have been shown to exhibit superior performance to the conventional techniques in biosensing (Nam et al, 2003;Xiao et al, 2003) and biolabeling (Michalet et al, 2005;Medintz et al, 2005). However, the applications of nanoparticles for the studies of living cells are less explored due to the issues of biocompatibility and cytotoxicity (Derfus et al, 2004;Goodman et al, 2004;Chithrani et al, 2006).…”