Green Synthesis of Red‐Emitting Carbon Nanodots as a Novel “Turn‐on” Nanothermometer in Living Cells

Abstract

Temperature measurements in biology and medical diagnostics, along with sensitive temperature probing of living cells, is of great importance; however, it still faces significant challenges. Herein, a novel "turn-on" carbon-dot-based fluorescent nanothermometry device for spatially resolved temperature measurements in living cells is presented. The carbon nanodots (CNDs) are prepared by a green microwave-assisted method and exhibit red fluorescence (λem =615 nm) with high quantum yields (15 %). Then, an on-off fluorescent probe is prepared for detecting glutathione (GSH) based on aggregation-induced fluorescence quenching. Interestingly, the quenched fluorescence could be recovered by increasing temperature and the CNDs-GSH mixture could behave as an off-on fluorescent probe for temperature. Thus, red-emitting CNDs can be utilized for "turn-on" fluorescent nanothermometry through the fluorescence quenching and recovery processes, respectively. We employ MC3T3-E1 cells as an example model to demonstrate the red-emitting CNDs can function as "non-contact" tools for the accurate measurement of temperature and its gradient inside a living cell.

Solvent‐Controlled Synthesis of Highly Luminescent Carbon Dots with a Wide Color Gamut and Narrowed Emission Peak Widths

“…The Raman spectra of the four samples ( Figure ) show two peaks at 1348 and 1587 cm −1 , corresponding to the disordered structures or defects (D band) and the graphitic carbon domains (G band), respectively. The intensity ratios I D / I G are 1.18, 1.04, 0.87, and 0.73 for B‐, G‐, Y‐, and R‐CDs, respectively, suggesting a gradual increase in the size of sp 2 ‐domains, which is consistent with the above TEM and XRD results.…”

Facile and large-scale synthesis of green-emitting carbon nanodots from aspartame and the applications for ferric ions sensing and cell imaging

“…5f). Similar with previous reports [49], the fluorescent emission dispersed unevenly in each cell, mainly because the CDs without specific functionalization label the cell membrane and cytoplasm basically through passive endocytosis without entry into the nuclei [50,51]. The multicolor emissive property is preferential for a broad-spectrum FL probe could give us much space to select the wavelength for observation [52].…”

The One-Step Preparation of Green-Emissioned Carbon Dots through Hydrothermal Route and Its Application

“…Thus, researchers have developed more CDs with longwavelength emission, including green- [10][11][12][13], yellow- [14][15][16], and red-emissioned [17][18][19][20][21][22][23] CDs. Gu et al have prepared green-emissioned CDs through a microwave route with crane sugar as carbon source and diethylene glycol (DEG) as reaction media [24].…”