Nonblinking carbon dots for imaging and tracking receptors on a live cell membrane

Guo

Advanced Optical Materials

et al. 2022

Despite of these marvelous achievements, the exact photoluminescence processes of C-dots, one of fundamental and pivotal concerns, has remained an open challenge. To date, considerable efforts have been put into such intricate but fascinating scientific issue, and obtained a few valuable results and insightful perceptions. [19][20][21][22][23][24][25][26] These studies undoubtedly help us to understand their photoluminescence properties indeed. However, there still has an obvious gap between the present cognition and a clear photophysical picture on C-dots' photoluminescence mechanism. For example, where does the photoluminescence of C-dots come from, particles' surface or cores? Do C-dots have quantum confinement effects and sizedependent emission? Whether and how do heteroatoms (O, N, S, P, etc.) affect the emission behaviors of C-dots? To date, these critical problems on C-dots' photoluminescence are still far from resolved. What's more, in terms of a few published reports, different and even completely contradictory conclusions are often obtained, causing longstanding confusion about the origin of C-dots' photoluminescence.The barriers to understanding C-dots' photoluminescence processes are the indeterminate constitution and complicated composition/structure of the samples. First, C-dots are often highly heterogenetic. For a long time, exploring the separation and purification of C-dots has been substantially neglected. To date, the most popular and frequently used purification method is dialysis. [4,27] Due to limited separation capacity, the obtained products usually are mixture containing particles, oligomeric and/or polymeric like molecules, etc. With the employment of various column separation techniques, this situation has been improved to some extent. [20,28,29] However, new separation approaches for highly purified C-dots are still sought after. Second, C-dots often possess complex chemical compositions and/or surface structures, whether they are fabricated by bottom-up or top-down methods. Generally, almost all C-dots contain lots of oxygen-containing functional (−OH and −COOH) groups. [6,8,10,13,15,16,21] Furthermore, if a few heteroatoms (N, B, S, P, etc.) are intentionally incorporated, [7,8,12,29,30] the corresponding products would be more complicated. Even more unfortunately, the above two situations often closely interweave with each other, which causes not only the uncertainty of their composition/structure, but the lack of suitable samples for contrastive analysis. As a result, it is nearly impossible to Understanding the photoluminescence mechanism of carbon dots (C-dots) is both of fundamental and technical significance. However, it has remained an extreme challenge due to C-dots' indeterminate constitution and complicated composition/structure. Herein, a combined processing system, namely extraction and subsequent preparative thin layer chromatography for C-dots separation is presented. Benefiting from its powerful separation performances, two minimalistic C-dots with almost identical st...

Section: Introductionmentioning

confidence: 99%

Twins of Minimalistic Carbon Dots: Uniform Emitting‐Units and Molecular Level Repeatable Photoluminescence

Guo

Advanced Optical Materials

et al. 2022

“…Chemokine receptors CXCR4 and CCR3 tagged with EGFP were found to dimerize on T-REx-293 cell membranes in our previous work. − In this study, we further optimized the experimental details and improved the imaging quality to investigate the oligomeric status of CCR5 receptors. The EGFP tag was replaced by mNeonGreen since it is monomeric, about 3-fold brighter, and 3-fold shorter maturation time than that of EGFP. , T-REx-293 cells were replaced by CHO-K1 (hereinafter referred to as CHO) cells as we found that CHO cells have higher adherent growth ability and are more suitable for TIRFM imaging.…”

mentioning

confidence: 99%

Oligomerization-Enhanced Receptor–Ligand Binding Revealed by Dual-Color Simultaneous Tracking on Living Cell Membranes

Ding

Liu

et al. 2021

J. Phys. Chem. Lett.

Self Cite

GPCR oligomerization plays a critical role in cellular signaling, yet the stoichiometry of the interactions between oligomers and binding ligands in living cells remains a longstanding challenge. Here, by developing a dual-color simultaneous tracking system based on a total internal reflection fluorescence microscope (TIRFM), the CCR5-CCL5 interactions are visualized and quantitatively assessed in real time. Results show that each oligomeric state of CCR5 could bind with CCL5 but with different binding affinities; CCR5 dimers have a 3.5-fold higher binding affinity than the monomers. The dimerization may cause an asymmetric conformational change which makes the first binding pocket have a 3.5-fold higher binding affinity and the second have only a half compared with the monomeric CCR5. This study is the first example to directly scrutinize the CCR5-CCL5 interactions at the single-molecule level on living cell membranes and will offer great potential for the interaction stoichiometry study of diverse surface proteins.

“…3 Currently, extensive attention has been paid to CDs owing to their several advantages, such as abundant carbon source, low cost, excellent biocompatibility, 4,5 water solubility, [6][7][8] and fascinating fluorescent properties. [9][10][11] Additionally, CDs are widely applied for bioimaging, [12][13][14][15] sensing, [16][17][18][19] lubrication, 20 solar cells, [21][22][23] catalysis, [24][25][26][27] batteries, 28,29 etc. Various carbon materials can be adopted to prepare CDs, such as graphite, 30 graphene, 31 glucose, 32 carbon nanotubes and carbon fibers, 33,34 and citric acid, 35,36 and even biomass like the leaves 37,38 and fruits of plants.…”

Section: Introductionmentioning

confidence: 99%

Application of coal-based carbon dots for photocatalysis and energy storage: a minireview

et al. 2022