Interaction of β‐cyclodextrin‐capped CdSe quantum dots with inorganic anions and cations

Abstract

A facile method was developed for the preparation of water soluble β-Cyclodextrin (β-CD)-modified CdSe quantum dots (QDs) (β-CD-QDs) by directly replacing the oleic acid ligands on the QDs surface with β-CD in an alkaline aqueous solution. The as-prepared QDs show good stability in aqueous solution for several months. Oxoanions, including phosphoric acid ion, sulphite acid ion and carbonic acid ion, affect the fluorescence of β-CD-QDs. Among them, H(2)PO(4)(-) exhibited the largest quenching effect. For the polyprotic acids (HO)(3)AO, the effect of acidic anions on the fluorescence of β-CD-QDs was in the order: monoanion (HO)(2)AO(2)(-) > dianion (HO)AO(3)(2-) >> trianion AO(4)(3-). After photoactivation for several days in the presence of anions at alkaline pH, the β-CD-QDs exhibited strong fluorescence emission. The effect of various heavy and transition metal ions on the fluorescence properties of the β-CD-QDs was investigated further. It was found that Ag(+), Hg(2+) and Co(2+) have significant quenching effect on the fluorescence of the β-CD-QDs. The Stern-Volmer quenching constants increased in the order: Hg(2+) < Co(2+) <Ag(+). The adsorption model of metal ions on β-CD-QDs was explored.

Synthesis of carbon‐based quantum dots from starch extracts: Optical investigations

“…C‐QDs have emerged as a new class of material due to their good solubility and unique optical properties, easy functionalization and their potential use in drug delivery . This gives C‐QDs the advantage over semiconductor Q‐dots such as CdTe, CdS and PbS . A synthetic strategy to obtain C‐dot nanoparticles may include ‘top‐down’ like laser ablation or ‘bottom‐up’ approaches such as hydrothermal synthesis, pyrolysis, and microwave carbonization .…”

“…[6] This gives C-QDs the advantage over semiconductor Q-dots such as CdTe, CdS and PbS. [7][8][9][10][11][12] A synthetic strategy to obtain C-dot nanoparticles may include 'top-down' like laser ablation [13][14][15][16] or 'bottom-up' approaches such as hydrothermal synthesis [17] , pyrolysis [18] , and microwave carbonization. [19,20] Recent studies of synthesis, analysis and characterization of C-QDbased biogenic applications have been highlighted due to its important prediction for use in future technologies.…”

Sensitive detection of sodium cromoglycate with glutathione‐capped CdTe quantum dots as a novel fluorescence probe

“…Semiconductor quantum dots (QDs), a particularly interesting class of emerging nanomaterials, exhibit unique optical and photophysical properties, such as a broad excitation spectrum, readily size‐tunable narrow emission spectrum, high fluorescence quantum efficiency and long‐term photostability, as well as resistance to photobleaching . In addition, the luminescence of QDs is extremely sensitive to the surface state.…”

Glutathione modified CdTe quantum dots as a label for studying DNA interactions with platinum based cytostatics

“…Nanomaterials including quantum dots (QDs) as progressively developing branch, can offer a way how to investigate interactions of drugs with DNA in real time. Numerous studies investigating the fluorescence quenching caused by metal ions have been carried out , which could be used for sensing a metal‐containing compounds. Based on this fact the aim of this study was to determine binding of platinum based cytostatics (cisplatin, carboplatin and oxaliplatin) by CdTe QDs.…”