Photostability of quantum dot micelles under ultraviolet irradiation

Abstract

Phospholipid quantum dot micelles are useful for bio-applications because of their amphiphilicity and exceptional biocompatibilities. We investigated the uptake of phospholipid [polyethylene glycol (PEG), biotin, and folic acid terminated] modified CdSe/ZnS quantum dot micelles by cancer cells and its photostability under ultrviolet light in the C spectrum (UV-C) (254 nm) or UV-A (365 nm) light irradiation. The stability of micelles to the exposure of UV-C and UV-A light was assessed. Biotinmodified quantum dot micelles give photoluminescence enhancement under UV-C light irradiation. Folate modified micelle under UV-C and UV-A results show considerable photoluminescence enhancement. Photoluminescence lifetime measurements showed 7.04, 8.11 and 11.42 ns for PEG, folate, and biotin terminated phospholipid micelles, respectively. Folate and biotin-modified quantum dot micelles showed excellent uptake by HeLa cells under fluorescence confocal microscopy. Phospholipid CdSe/ZnS quantum dot micelles can be potentially used for diagnosis and treatment of cancer in the future.

Nano–bio interaction between human immunoglobulin G and nontoxic, near-infrared emitting water-borne silicon quantum dot micelles

“…5,6 Compared to commercial uorescent probes, QD probes exhibit better stability against photobleaching, high quantum yield, tunable emission, and broad absorption spectral ranges. 7,8 However, it is difficult to dissolve semiconductor QDs in water; hence, it is necessary need to functionalize the surface of the QD probes with water-soluble materials. 9 While extensive studies have been focused on the imaging efficacy of functionalized QD probes, only a few studies have been conducted on their interaction with biomacromolecules.…”

Quantum Dots for Improved Single-Molecule Localization Microscopy

“…Recent studies have validated the applications of upconverting nanoparticles, , nitrogen-vacancy color centers in nanodiamonds, , and aggregation-induced emission , for patterned illumination methods such as stimulated emission depletion. For localization-based methods, colloidal semiconductor quantum dots (QDs), as well as similar carbon- and polymer-based nanodots, are expected to achieve similar enhancements in resolution. ,,− Like the aforementioned nanoparticles, QDs are extremely photostable and very bright emitters, allowing for the observance of fluorescence from individual QDs with a high signal-to-noise ratio (SNR) from tens of minutes to hours. ,− Also, broad absorption spectra coupled with narrow emission spectra allow for simpler spectral multiplexing using a single excitation source. ,, Additionally, QDs naturally exhibit inherent fluorescence blinking, which eliminates the need for multiple photoactivation lasers or oxygen-reducing buffers in order to enable the fluorescence intensity blinking required for super-resolution imaging applications . QDs have also been proven to be viable fluorescent labels in many biological imaging applications including cancer cell detection, tumor drug delivery, cellular sensing, and molecular tracking. − …”