Ratiometric Fluorescent Silicon Quantum Dots–Ce6 Complex Probe for the Live Cell Imaging of Highly Reactive Oxygen Species

Abstract

The monitoring of reactive oxygen species (ROS) in living cells remains challenging because of the complexity, short half-life, and autofluorescence of biological samples. In this work, we designed a ratiometric fluorescent probe for the detection and imaging of ROS, which was constructed from silicon quantum dots (Si QDs) with chlorin e6 (Ce6) through electrostatic attraction and showed well-resolved dual fluorescence emission signals (490 and 660 nm). Sensitive and selective biosensing of hydroxyl radical (OH) was demonstrated on the basis of fluorescence quenching of the Si QDs and Ce6 as an internal reference to avoid environmental interference, with a detection limit of ∼0.97 μM. The endogenous release of OH was also monitored and imaged in living cells.

Free radical sensors based on inner-cutting graphene field-effect transistors

“…17) shows that the FET sensor (modified by 10 −5 M Zn 2+ ) has a small change of I ds when exposing in 10 −7 M •OH, while no response is observed in the case of the FET sensor modified by 10 −6 M Zn 2+ . According to this result, the current response of different FET sensors upon the addition of 10 μg mL −1 LPS indicates the extracellular •OH concentration is at a level of ~10 −7 M. This amount is lower than the intracellular concentration (10 −6 M) measured by other methods 9–11 , in correspondence with the fact that the extracellular •OH originates from other ROS released from the cells and the production of •OH is relatively low (i.e., the rate constant of H 2 O 2 + •O 2 − → •OH + OH − + O 2 is around 1.3 M −1 s −1 , <40–80 M −1 s −1 of Fenton reaction) 55,56 .…”

“…In order to understand the role that free radical plays in biological and pathological events, much attention has been paid on monitoring the free radicals in living systems. Traditionally, the free radical is detected by electron spin resonance (ESR) spectroscopy 8 , fluorescence spectroscopy 9–11 , chromatography 12,13 , and electrochemical approaches 14 . However, these techniques suffer from some of the disadvantages such as costly instrumentation, low throughput, complicated sample preparation, need for well-trained operators, or lack of portability.…”

“…The spin traps or fluorescent probes determine the detection limit and selectivity. In some cases, the detection limit of •OH is only 10 −6 M (fluorescence) 9,11 , while ROS such as •O 2 − and •HO 2 can also induce a response in the fluorescence or ESR signal 10,15 . Therefore, it is still a challenge to real-time monitor the free radicals with high sensitivity and selectivity by a low-cost, portable, and user-friendly analytical platform.…”

Reactive oxygen species in photodynamic therapy

“…Kong课题组 [5] [112,113] . Peng课题组 [6] 合成了一种基于杂环 吩噻嗪(phenothiazine-cyanine, PTZ-Cy2)的新花青染 .5~0.9 [94,114] .…”

One-pot hydrothermal synthesis of luminescent silicon-based nanoparticles for highly specific detection of oxytetracyclineviaratiometric fluorescent strategy

“…There is almost no characteristic peak toward zero valence silicon (Si 0 ) observed in XPS measurement, suggesting Si-O bonds are mainly exists in the SiNPs. 35,36 Furthermore, XRD pattern ( Fig. 1c) of SiNPs represents one single diffraction peak at about 2q ¼ 22 , assigned to the (101) planes of silicon oxide (ICDD 39-1426).…”