Conjugating Luminescent CdTe Quantum Dots with Biomolecules

Abstract

Newly prepared CdTe quantum dots ( QD) bearing shells of water solubility providing capping agents (i.e., thioglycolic acid ( TGA) and 2-(dimethylamino)ethanethiol hydrochloride (DMAET) were subjected to electrostatic assays with several proteins (i.e., cytochrome c (cyt c) and human serum albumin (HSA). In particular, we employed absorption, emission, transient absorption and time-resolved emission spectroscopic means to test their response to light. Only for negatively capped QDs spectroscopic and kinetic evidence were gathered that corroborate the successful bioconjugation of QDs with cyt c to yield QD- cyt c bioconjugates. In fact, photoexcitation of QD-cyt c leads to a fast deactivation of the QD band gap emission and of the QD excited state. Notably, these interactions depend on the size of the QDs. Repulsive forces, on the other hand, are operative between the positively capped QDs and cyt c, hampering any bioconjugation.

Composite of CdTe quantum dots and molecularly imprinted polymer as a sensing material for cytochrome c

“…Generally, the approaches for linking antibody or aptamer to QDs can be classified into two categories, covalent and non-covalent bindings. Functional reagents like gultaraldehyde or NHS/EDC can form coupling products through covalent approaches, while the noncovalent bindings were often through the electrostatic interaction, hydrogen bonding interactions and hydrophobic force (Gerhards et al, 2008). Based on the fact that the products through noncovalent interaction not only can maintain the native conformation of the protein, but also can make the removal of the template protein from the copolymers easily, the coupling products in this work were chosen to be formed through noncovalent approaches.…”

“…This is mainly due to a photo-induced electron transfer process. Under photo-irradiation, hemeproteins (III) can directly intercept one of the charge carriers and be reduced to hemeproteins (II), which disrupts the radiative recombination of the holes and the excited electrons, causing the fluorescence quenching of the QDs (Cao et al, 2009;Gerhards et al, 2008). Therefore, the Cyt was chosen as template for further studies.…”

“…Recently, QDs as sensing and recognizing element have been widely applied in the biomolecule detections (Han et al, 2009;Cao et al, 2009). Because QDs not only have good photostability, high luminescence efficiency and size-dependent emission wavelengths, but also have ability to form coupling complexes with biomolecule of interest (Gerhards et al, 2008;Jiang et al, 2006;Van Tilborg et al, 2006;Jin et al, 2004;Lagerholm et al, 2004). Furthermore, QDs offer the potential for performing multiple targets on a single sample simultaneously (Lin et al, 2004a).…”

ONE-POT SYNTHESIS OF HIGHLY LUMINESCENT CdTe QUANTUM DOTS USING SODIUM TELLURITE AS TELLURIUM SOURCE IN AQUEOUS SOLUTION

“…Because of their unique optical and electrical properties, CdTe QDs are of great interest in for both fundamental research and technical applications [1][2][3][4] . Up to now, many approaches, including organic synthesis 5,6 and aqueous synthesis [7][8][9][10] , have been developed for the preparation of CdTe QDs.…”

Luminescent properties dependence of water-soluble CdTe quantum dots on stabilizing agents and reaction time

“…In addition, it is generally believed that CdTe QDs with different emission wavelengthes could be prepared at different reaction time [7,23]. However, there is not a special report to describe various luminescent properties of CdTe QDs synthesized in water-phase system at different reaction time systematically.…”