Dynamic Visualization of Endoplasmic Reticulum Stress in Living Cells via a Two-Stage Cascade Recognition Process

Abstract

The endoplasmic reticulum (ER) is crucial for the regulation of multiple cellular processes, such as cellular responses to stress and protein synthesis, folding, and posttranslational modification. Nevertheless, monitoring ER physiological activity remains challenging due to the lack of powerful detection methods. Herein, we built a two-stage cascade recognition process to achieve dynamic visualization of ER stress in living cells based on a fluorescent carbon dot (CD) probe, which is synthesized by a facile one-pot hydrothermal method without additional modification. The fluorescent CD probe enables two-stage cascade ER recognition by first accumulating in the ER as the positively charged and lipophilic surface of the CD probe allows its fast crossing of multiple membrane barriers. Next, the CD probe can specifically anchor on the ER membrane via recognition between boronic acids and o-dihydroxy groups of mannose in the ER lumen. The two-stage cascade recognition process significantly increases the ER affinity of the CD probe, thus allowing the following evaluation of ER stress by tracking autophagy-induced mannose transfer from the ER to the cytoplasm. Thus, the boronic acid-functionalized cationic CD probe represents an attractive tool for targeted ER imaging and dynamic tracking of ER stress in living cells.

Engineered Extracellular Vesicle-Encapsuled Nanoreactors for Effective Targeting and Cascade Killing of Cancer Cells

“…From Figure d, the FL intensity of Dox increased with the incubation time, while the FL intensity of FAM reached the maximum value after 2 h but decreased afterward. This could be attributed to the increased cell membrane permeability upon the treatment of nanoreactors, which lead to the effusion of FAM . Thus, the incubation time was optimized to be 2 h for the following cell experiments.…”

“…This could be attributed to the increased cell membrane permeability upon the treatment of nanoreactors, which lead to the effusion of FAM. 31 Thus, the incubation time was optimized to be 2 h for the following cell experiments. From the above results, the release speed of Dox was accelerated under an acidic tumor microenvironment (TME), which could be attributed to two reasons: one is the enhanced solubility of Dox in acidic pH, and the other is the shedding of the PDA shell, which enables the exposure of embedded Dox (Figure 2e−g).…”

One-step synthesized amphiphilic carbon dots for the super-resolution imaging of endoplasmic reticulum in live cells

“…Because the cellular uptake pathway of nanomaterials may play a predominate role in their subcellular localization. 32,33 We have further investigated the Phe-CDs cellular uptake mechanism. The low temperature (4 °C) and different biochemical inhibitors (chloroquine, chlorpromazine, 2-deoxy- d -glucose, NH 4 Cl) were used to estimate the cellular uptake pathway of Phe-CDs.…”

Carbon Dots for Intracellular Sensing

“…Only several CDs have been reported for ER imaging. [ 89,106,107 ] Shuang et al prepared laurylamine‐modified CDs (LCDs) through linking laurylamine with amine‐functionalized CDs (ACDs) that were first synthesized from urea and CA via a hydrothermal method ( Figure A). [ 89 ] The hydrophobic alkyl groups on the LCD surface enabled the CDs to be internalized by cells and then localized in ER by endocytosis mediated by lipid raft, realizing ER imaging in MCF‐7 cells.…”