Luminescent Properties of Water-Soluble Denatured Bovine Serum Albumin-Coated CdTe Quantum Dots

Abstract

Chemically reduced bovine serum albumin (BSA) has been used to modify the surface of water-soluble CdTe quantum dots (QDs). It is demonstrated that the denatured BSA (dBSA) can be conjugated to the surface of CdTe QDs and thereby efficiently improve the chemical stability and the photoluminescence quantum yield (PL QY) of the QDs. It is inferred that a shell-like complex structure CdTe(x)(dBSA)(1-x) will form on the surface of the CdTe "core", resulting in the enhancement of PL intensity and the blue shift of the PL peak. This study of the effects of pH and dBSA concentration on optical properties of dBSA-coated QDs suggests that, at pH 6-9, the solution of dBSA-coated CdTe QDs can keep substantial stability and fluorescent brightness, whereas further increase of pH value leads to a dramatic decrease in PL QY and chemical stability. On the other hand, too high or too low initial dBSA concentration in the QD solution results in a decrease of PL QY for dBSA-coated CdTe QDs. This study provides a new approach of preparing stable water-soluble QDs with high PL QY and controllable luminescent colors for biological labeling applications.

Aqueous phase synthesis of CdTe quantum dots for biophotonics

“…Several surfactants have been used for synthesizing CdTe quantum dots in the aqueous phase, namely, thioglycolic acid (TGA) [48][49][50], mercaptopropionic acid (MPA) [47], mercaptosucinnic acid (MSA) [51][52], glutathione (GSH) [53], and cysteine (Cys) [54]. TGA, MPA, and MSA are short stabilizing agents and they are commonly used to fabricate water-dispersible CdTe QDs in a one-pot synthesis.…”

Molecularly imprinted polymer anchored on the surface of denatured bovine serum albumin modified CdTe quantum dots as fluorescent artificial receptor for recognition of target protein

“…Herein, the dBSA was used not only to modify the surface of the CdTe QDs, but also as assistant monomer to create effective recognition sites (Kuo et al, 2008;Wang et al, 2006;Guo et al, 2006). Three proteins were chosen as the template molecules and then the receptors were synthesized by sol-gel process (imprinting process, see Fig.…”

Highly sensitive synchronous fluorescence determination of mercury (II) based on the denatured ovalbumin coated CdTe QDs

“…For example, with the help of 1-ethyl-3-(3-(dimethylamine)propyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS), bovine serum albumin (BSA) was conjugated to TGA-capped CdTe QDs via an amide link interacting with carboxyl of the TGAcapped CdTe, which could develop a novel fluorescent nanosensor for Sb 3 þ determination [17]. Wang et al [18] and Kuo et al [19] used NaBH 4 as reducing agents to promote the disulfide bonds in the BSA molecule being converted to sulfhydryl groups. The thiol group of denatured BSA has strong affinity to Cd atom, so the dBSA was modified to the QDs surface [18], which demonstrated a great enhancement of the fluorescence intensity and stability.…”

“…Wang et al [18] and Kuo et al [19] used NaBH 4 as reducing agents to promote the disulfide bonds in the BSA molecule being converted to sulfhydryl groups. The thiol group of denatured BSA has strong affinity to Cd atom, so the dBSA was modified to the QDs surface [18], which demonstrated a great enhancement of the fluorescence intensity and stability. Compared with the amide linking method, Huang's research was not only easy to operate, but also provided a new approach for the conjugation of QDs and proteins.…”