Rational Design of Far-Red to Near-Infrared Emitting Carbon Dots for Ultrafast Lysosomal Polarity Imaging

Abstract

Carbon dots (CDs) have been widely studied for their excellent properties. However, most of the prepared CDs only show strong emission in the blue to green region, which greatly limits the application of CDs in the biomedical field. In this report, a new design strategy of long-wavelength CDs was reported. The orange phenyl-CDs with good optical properties and biocompatibility were successfully prepared by changing the substituted group of the o-phenylenediamine and the main emission band of phenyl-CDs was in the far-red region. With the increase of polarity, the wavelength of phenyl-CDs red-shifts and the fluorescence intensity decreases, demonstrating their sensitive polarity response function. In addition, phenyl-CDs can achieve ultrafast target imaging of lysosome within 40 s through clathrin-mediated endocytosis. Finally, phenyl-CDs were successfully applied for monitoring lysosomal polarity induced by drugs, which is helpful in getting a better understanding of the physiological and pathological processes of lysosomes. This report provides an important theoretical basis for the rational design and precise synthesis of long-wavelength fluorescent CDs.

Spying on the Polarity Dynamics during Wound Healing of Zebrafish by Using Rationally Designed Carbon Dots

“…Together, these results were consistent with an ability to achieve a redshift of the wavelength through the enhanced electron‐donation ability of the carbon source's amino group, which is consistent with our previous research. [ 28 ] Tests with various excitation light wavelengths from 360 to 560 nm (Figure 2b) showed no effect of the excitation wavelength on the PPh‐CDs emission wavelength, which remained at 620 nm. By using rhodamine 6G as reference, the quantum yield of the synthesized PPh‐CDs was determined to be 1.77%.…”

“…[29] Recently, we reported synthesizing two red-shifted CDs by simply changing the substituent on the nitrogen of the o-phenylenediamine precursor. [15,28] This small change induced a red-shifted emission that can be attributed to an enhanced ICT due, in turn to the stronger electron-donation ability of the new substituent. Meanwhile, it has been established that molecules displaying ICT could be used as fluorescent probes for monitoring cell polarity.…”

“…[ 27 ] Meanwhile, our previous work showed that enhancing the ICT effect can yield a redshift of the emission wavelength. [ 28 ] In the current work, NIR polarity‐sensitive N‐phenyl‐phenylenediamine‐CDs (PPh‐CDs) were synthesized by altering the substituent on the nitrogen of the р‐phenylenediamine ( Scheme ). This altered substituent provided for increased electron donation and a molecule with more extensive electron conjugation.…”

Fluorescent carbon dots with excellent moisture retention capability for moisturizing lipstick

“…Contrarily, carmine cochineal exhibit almost no emission in solution under UV irradiation (Additional file 1 : Figure S4). Besides, Car-CDs presented significant excitation-independent under different excitation wavelengths [ 28 , 29 ] (Additional file 1 : Figure S5), and the PL lifetime at 558 nm is calculated to be 3.86 ns (Additional file 1 : Figure S6).…”

Nano-Bio Interaction between Blood Plasma Proteins and Water-Soluble Silicon Quantum Dots with Enabled Cellular Uptake and Minimal Cytotoxicity

“…Near-infrared (NIR) fluorescence light, which is broadly utilized for monitoring and imaging in minimally invasive medicine, provides researchers and surgeons highly specific images of target tissues in the living body [ 1 , 2 , 3 , 4 , 5 ]. Although whole-body preoperative imaging of single-photon emission computed tomography (SPECT) and positron emission tomography (PET) has diagnostic utility, such imaging lacks the appropriate resolution, sensitivity, efficacy, and targeted NIR fluorophores to simultaneously facilitate real-time delineation of the target tissue while preserving vital tissues [ 6 ].…”