Enhanced fluorescence from semiconductor quantum dot-labelled cells excited at 280 nm

Abstract

Semiconductor quantum dots (QDs) have significant advantages over more traditional fluorophores used in fluorescence microscopy including reduced photobleaching, long-term photostability and high quantum yields, but due to limitations in light sources and optics, are often excited far from their optimum excitation wavelengths in the deep-UV. Here, we present a quantitative comparison of the excitation of semiconductor QDs at a wavelength of 280 nm, compared to the longer wavelength of 365 nm, within a cellular environment. We report increased fluorescence intensity and enhanced image quality when using 280 nm excitation compared to 365 nm excitation for cell imaging across multiple datasets, with a highest average fluorescence intensity increase of 3.59-fold. We also find no significant photobleaching of QDs associated with 280 nm excitation and find that on average, ~80% of cells can tolerate exposure to high-intensity 280 nm irradiation over a 6-hour period.

Enhanced NIR fluorescence quantum yield of graphene quantum dots using dopants

“…The quantum confinement effects of QDs come into play when their sizes get comparable to their Bohr excitonic radius, and their properties become size-dependent. Semiconductor QDs have been studied extensively for their optical properties [1][2][3], which leads to their fruitful usage in solar cells, lasers, bioimaging, and bio-sensing. The usage of semiconductor QDS has highlighted concerns regarding their environmental contamination and renewability [4,5] due to the heavy metals used in their manufacturing and their toxicity.…”