Ratiometric Fluorescent Detection of Intracellular Singlet Oxygen by Semiconducting Polymer Dots

Abstract

Singlet oxygen ( 1 O 2 ) plays important roles in many biological processes. However, it is very difficult to detect 1 O 2 in the intracellular environment because of its relatively low concentration and short lifetime. Here, we developed a ratiometric probe based on semiconducting polymer dots (Pdots) that can sensitively detect 1 O 2 in live cells. An organic dye, singlet oxygen sensor green (SOSG), was doped in polyfluorene Pdots, and excitation energy was efficiently transferred from the polymer to the SOSG dye. Accordingly, the Pdots showed constant blue fluorescence as a reference, and increased green fluorescence upon singlet oxygen generation. The ratiometric response of Pdots was examined in the intracellular environment by in situ 1 O 2 generation with a photosensitizer and light irradiation. Both spectroscopic measurements and confocal imaging were performed to monitor intracellular 1 O 2 generation during photodynamic therapy using the Pdot probe. Our results indicate that the SOSG-doped Pdots are promising for intracellular 1 O 2 detection.

Measuring Cellular Uptake of Polymer Dots for Quantitative Imaging and Photodynamic Therapy

“…Upconversion nanoparticles are developed based on their deep tissue penetration and weak background interference, yet complex mechanisms associated with a nonlinear photon upconversion impede quantification by means of fluorescence intensity. Semiconducting polymer dots (Pdots) have received considerable attention in biology and medicine. − Various Pdots have been demonstrated in applications such as optical imaging, photoacoustic imaging, biosensing, phototherapy, and drug delivery. − Pdots exhibit stable fluorescence intensity in a physiological environment comprising biologically relevant ions and ROS . The Pdots also remain highly dispersed without a sign of aggregation in a biological medium.…”

Luminescent lanthanide complexes for reactive oxygen species biosensing and possible application in Alzheimer’s diseases

“…SOSG penetration and behavior in cells are influenced by proteins and therefore may be unequal between cell models. SOSG-loaded polymer dots may overcome this problem, and such a ratiometric probe could be a promising way for intracellular monitoring of 1 O 2 [65].…”

General Strategy to Achieve Color-Tunable Ratiometric Two-Photon Integrated Single Semiconducting Polymer Dot for Imaging Hypochlorous Acid

“…There is initiative to expand Pdot-based fluorescent probes for different bioapplications. However, the construction of Pdot-based nanoprobes is mainly through postmodification strategies including in situ doping, − in situ embedding, surface modification, , and integrated functionalization to engineer bare Pdot to achieve desired applications. − These modified Pdots inevitably encounter the above-mentioned drawbacks such as limited content of functional groups, leakage, and photobleaching. In order to overcome these issues, it is an alternative strategy to prepare integrative Pdot with desired performances without any postmodification procedures, primarily composed of all-in-one polymer through molecular engineering, for sensing applications.…”