Carbon Dots with Red Emission for Sensing of Pt²⁺, Au³⁺, and Pd²⁺ and Their Bioapplications in Vitro and in Vivo

Abstract

Red emissive carbon dots (CDs) have drawn more and more attention due to their good organ penetration depth and slight biological tissue photodamage. Herein, the fluorescent CDs with red emission were synthesized by the facile one-pot hydrothermal treatment of citric acid and neutral red and they show red fluorescence both in aqueous solution and solid state. The solution of CDs exhibits the quantum yield of 12.1%, good stability against photobleaching, and low cytotoxicity. As-prepared CDs can be used as a fluorescent probe for peculiar detection of Pt, Au, and Pd. Furthermore, the CDs show excellent biocompatibility, which were successfully used as hopeful bioimaging and biosensing of noble metal ions in PC12 cells and zebrafish.

Multifunctional Nanohybrid of Palladium Nanoparticles Encapsulated by Carbon‐Dots for Exploiting Synergetic Applications

“…The presence of Pd in the zero‐valence oxidation state (Pd 0 ) should strengthen the formation of Pd NPs . For C 1s, four peaks were observed at 282.2, 284.8, 286.9, and 288.5 eV corresponding to CC, CC, CO, and CO components, respectively (Figure b), whereas the O 1s spectrum shows two peaks at 532.5 and 534.2 eV corresponding to CO and C=O components, respectively (Figure c) . These peaks confirm the existence of carboxylic groups, consistent with the FTIR result.…”

“…To understand the functional groups in C‐dots and Pd/C‐dots, the FTIR spectra were measured as shown in Figure b. The FTIR spectrum of C‐dots exhibits prominent peaks at ≈1720 and 1630 cm −1 , which are ascribed to the stretching vibration of CO and NH bending of primary amine, respectively . In addition, a broad peak was observed at ≈3400 cm −1 corresponding to both OH of carboxylic and NH of amine‐stretching vibrations .…”

Near-infrared emissive carbon dots with 33.96% emission in aqueous solution for cellular sensing and light-emitting diodes

“…When excited by 500 nm wavelength, the best emission intensity is obtained, and the maximum emission wavelength is 600 nm (quantum yield (QY) = 5.44%). Gao et al [52] synthesized red emissive CDs by the hydrothermal treatment of citric acid and neutral red. The solution of CDs exhibited a QY of 12.1%.…”

Novel single excitation dual-emission carbon dots for colorimetric and ratiometric fluorescent dual mode detection of Cu2+ and Al3+ ions

“…Previous reports demonstrate uorescence response of CDs to metal ions mainly involve the uorescence resonance energy transfer (FRET), inner lter effect (IFE), aggregation-induced emission quenching (ACQ) and aggregation-induced emission enhancement (AIEE). [38][39][40][41] In our case, it is impossible that there are FRET and IFE between D-CDs and Al 3+ or Cu 2+ since two kinds of metal ions have neither characteristic absorption nor spectral overlap with the excitation and emission spectra of D-CDs (Fig. S7 †).…”