Biotin-modified glutathione as a functionalized coating for bioconjugation of CdTe-based quantum dots

In this study, biotin-conjugated glutathione was synthesized using peptide bonding of the biotin carboxy group and amino group of the γ-glutamic acid to prepare an alternative coating for CdTe quantum dots (QDs). This type of coating combines the functionality of the biotin with the fluorescent properties of the QDs to create a specific, high-affinity fluorescent probe able to react with avidin, streptavidin and/or neutravidin. Biotin-functionalized glutathione-coated CdTe QDs were prepared by a simple one-step method using Na₂ TeO₃ and CdCl₂. Obtained QDs were separated from the excess of the biotin-conjugated glutathione by CE employing 300 mM borate buffer with pH 7.8 as a background electrolyte. The detection of sample components was performed by the photometric detection at 214 nm and LIF employing Ar⁺ ion laser (488 nm).