Multi‐spectroscopic Study on the Interaction between CdTe Quantum Dots and Bovine Serum Albumin

Abstract

The interaction between CdTe quantum dots (QDs) and bovine serum albumin (BSA) was systematically investigated by fluorescence, UV-vis absorption and circular dichroism (CD) spectroscopy under physiological conditions. The experimental results showed that the fluorescence of BSA could be quenched by CdTe QDs with a static quenching mechanism, indicating that CdTe QDs could react with BSA. The quenching constants according to the modified Stern-Volmer equation were obtained as 1.

Multi-spectroscopic techniques to evaluate the toxicity of alloyed CdSeS quantum dots

“…This result agrees well with the conclusion that larger sized QDs show stronger binding force upon interaction with BSA, as the alloyed CdSeS QDs (2.1 nm) are smaller than the green CdTe QDs (2.5 nm) [27,35]. Synchronous fluorescence spectroscopy is a useful technique to separate the overlapped excitation peaks of aromatic amino acid residues of protein, which offers the information on the microenvironment changes of the residues by measuring the possible shift in wavelength emission maximum [33,35]. The synchronous fluorescence spectra of BSA contributing to tyrosine and tryptophan residues were recorded by a simultaneous scanning of the excitation and emission wavelengths in the 15-and 60-nm wavelength intervals and the data are presented in Fig.…”

“…With the addition of CdSeS QDs, the absorption intensity of BSA increased gradually along with a slight blueshift from 278 nm to 276 nm, reconfirming that there is the ground state complex formation between BSA and CdSeS QDs because dynamic quenching does not change the absorption spectra while the formation of ground state complex, that is, static quenching often leads to a change in the absorption spectra [22]. Similar results were also observed in the study of L-cysteine capped CdSe/CdS QDs and thioglycolic acid capped CdTe QDs on BSA [13,33]. The blue shift of absorption peaks showed the peptide strands of BSA molecules extended more and the hydrophobicity was decreased [12][13]31].…”

“…6B shows that binding of CdSeS QDs probably induces the tertiary structural changes of the adsorbed BSA, and increased the polarity around the tryptophan residues. Similar observation was reported when mercaptoacetic acid capped CdTe QDs (3.0 nm) were adopted to bind with BSA [33]. However, a blueshift was obtained when starch capped CdS nanoparticles were used [37], implying that the functional group on the surface of QDs and the size of QDs played an important role in the interactions between QDs and BSA [30].…”

Interaction of CdTe Quantum Dots with 2,2-Diphenyl-1-Picrylhydrazyl Free Radical: A Spectroscopic, Fluorimetric and Kinetic Study

“…The preparation of NaHTe was via a method described previously in literature but with some modifications [4]. Briefly, 1.0 mmol of tellurium powder and 2.6 mmol of sodium borohydride (molar ratio of Te to NaBH 4 is 1:2.6) were loaded into a 25 ml 3-necked flask and 10 ml of Millipore water was added.…”

“…They exhibit tunable and intense fluorescence spectra [1][2][3][4][5], broad excitation spectra and favourable photostability [6][7][8][9]. Imaging and sensing applications have been proposed for QDs [7,[10][11][12].…”