Carbon-Dot-Based Ratiometric Fluorescent Probe for Imaging and Biosensing of Superoxide Anion in Live Cells

Abstract

In this article, a ratiometric fluorescent biosensor for O2(•-) was developed, by employing carbon dots (C-Dots) as the reference fluorophore and hydroethidine (HE), a specific organic molecule toward O2(•-), playing the role as both specific recognition element and response signal. The hybrid fluorescent probe CD-HE only emitted at 525 nm is ascribed to C-Dots, while HE was almost nonfluorescent, upon excitation at 488 nm. However, after reaction with O2(•-), a new emission peak ascribed to the reaction products of HE and O2(•-) was clearly observed at 610 nm. Meanwhile, this peak gradually increased with the increasing concentration of O2(•-) but the emission peak at 525 nm stayed constant, leading to a ratiometric detection of O2(•-). The inorganic-organic fluorescent sensor exhibited high sensitivity, a broad dynamic linear range of ~5 × 10(-7)-1.4 × 10(-4) M, and low detection limit down to 100 nM. The present probe also showed high accuracy and excellent selectivity for O2(•-) over other reactive oxygen species (ROS), metal ions, and so on. Moreover, the C-Dot-based inorganic-organic probe demonstrated long-term stability against pH changes and continuous light illumination, good cell-permeability, and low cytotoxicity. Accordingly, the developed fluorescent biosensor was eventually applied for intracellular bioimaging and biosensing of O2(•-) changes upon oxidative stress.

Characterization and Analytical Separation of Fluorescent Carbon Nanodots

“…AFM is a high-resolution scanning probe microscopy which provides dimensional surface images of C-dots at resolution lower than 1 nm [85,[125][126][127][128]. Compared to SEM and TEM techniques, AFM not only produces two-dimensional (2D) images of C-dots from which the C-dots dimension can be determined by randomly counting the height of particles on the images but also provides three-dimensional (3D) information about the surface morphology of C-dots.…”

Gold nanocluster-based fluorescence biosensor for targeted imaging in cancer cells and ratiometric determination of intracellular pH

“…To solve these two problems, we designed a ratiometric fluorescent biosensor with targeted marker for imaging and biosensing of pH in cancer cells. Ratiometric fluorescence measurements can eliminate the influence of variations in the local probe concentration and distribution, thus enhancing the accuracy of measurements (Du et al, 2013;Fu et al, 2013;Gao et al, 2014;Miao et al, 2013; Zhu et al, 2012). Silica nanoparticals and polymer gel coating with different dyes and quantum dots (QDs) were widely used as the reference fluorescences for construction of raiometric fluorescence probes (Dennis et al, 2012;Peng et al, 2010;Tsou et al, 2014).…”

Highly fluorescent carbon dots for visible sensing of doxorubicin release based on efficient nanosurface energy transfer

“…Numerous natural and synthetic, graphite and organic substances have been explored for the fabrication of CDs with various routes, such as oxidization by-products of carbon nanotubes and graphite (Tao et al 2011) and candle soot (Liu et al 2007), hydrothermal cracking or microwave assisted synthesis of organic compounds (Sahu et al 2012;Yang et al 2012). Due to their unique properties, CDs have increasingly shown potential in broad applications including energy conversion , environmental analysis and bioanalysis (Costas-Mora et al 2014;Liu et al 2012), sensors (Gao et al 2014), diagnostics (Posthuma-Trumpie et al 2012) and bioimaging (Wang et al 2014a, b).…”