Self-Targeting Carbon Quantum Dots for Peroxynitrite Detection and Imaging in Live Cells

Abstract

Peroxynitrite (ONOO − ), a highly reactive nitrogen species (RNS) generated mainly in mitochondria, has been identified to be associated with numerous pathophysiological processes, and thus accurate ONOO − imaging with superior sensitivity and selectivity is highly desirable. Herein, we prepared a new type of carbon quantum dots (CQDs) with mitochondria-targeting function without the aid of any targeting molecules via a simple one-step hydrothermal route. The as-prepared CQDs not only displayed relatively uniform size distribution, few surface defects, high photostability, and excellent biocompatibility but also exhibited good selective fluorescence turn-off response toward ONOO − , owing to the oxidation of amino groups on the surface of carbon dots. A great linear correlation between the quenching efficiency and ONOO − concentration in the range from 0.15 to 1.0 μM with a detection limit of 38.9 nM is shown. Moreover, the as-prepared CQDs acting as a functional optical probe through a self-targeting mechanism were successfully applied for in situ visualization of endogenous ONOO − generated in the mitochondria of live cells, providing great promise for elucidating the complex biological roles of ONOO − in related pathological processes.

Regulation of multi-color fluorescence of carbonized polymer dots by multiple contributions of effective conjugate size, surface state, and molecular fluorescence

“…The lattices of CDs-2, CDs-10, CDs-5, and CDs-6 all belong to the (100) plane of graphite. 13,35,36 The average particle size of the CDs-11 and CDs-12 became significantly smaller, about 1.43 and 1.44 nm, respectively, showing good dispersion. However, the CDs-11 and CDs-12 do not show an obvious lattice (see Fig.…”

Carbon Dots for Intracellular Sensing

“…CD-based fluorescent probes have been developed for intracellular ONOO À measurement. [69,279] Wu et al fabricated mitochondrion-targeting CDs for probing ONOO À in living cells (Figure 11D). [69] The CDs prepared from o-phenylenediamine and ethanol were rich in amino groups on their surface, which were utilized to be covalently coupled with a mitochondrion-targeting ligand TPP, forming a nanocomposite termed C-dots-TPP.…”

Piperazine-Based Mitochondria-Immobilized pH Fluorescent Probe for Imaging Endogenous ONOO– and Real-Time Tracking of Mitophagy

“…The imaging technology in fluorescent probes has been used to noninvasively detect and image biological species in living cells. Its high resolution and sensitivity make it an excellent detection method. − In the past few decades, fluorescent probes have been studied to detect ONOO – or mitophagy. − In 2006, Yang et al reported first an ONOO – -specific fluorescent probe via oxidation of anisole-derived ketone, which also opened a new path for detecting ONOO – in biological systems. Since then, many fluorescent probes for in-depth detection of ONOO – have been gradually developed.…”