Rapid solid-phase microwave synthesis of highly photoluminescent nitrogen-doped carbon dots for Fe³⁺detection and cellular bioimaging

Abstract

Recently, carbon dots (CDs) have been playing an increasingly important role in industrial production and biomedical field because of their excellent properties. As such, finding an efficient method to quickly synthesize a large scale of relatively high purity CDs is of great interest. Herein, a facile and novel microwave method has been applied to prepare nitrogen doped CDs (N-doped CDs) within 8 min using L-glutamic acid as the sole reaction precursor in the solid phase condition. The as-prepared N-doped CDs with an average size of 1.64 nm are well dispersed in aqueous solution. The photoluminescence of N-doped CDs is pH-sensitive and excitation-dependent. The N-doped CDs show a strong blue fluorescence with relatively high fluorescent quantum yield of 41.2%, which remains stable even under high ionic strength. Since the surface is rich in oxygen-containing functional groups, N-doped CDs can be applied to selectively detect Fe(3+) with the limit of detection of 10(-5) M. In addition, they are also used for cellular bioimaging because of their high fluorescent intensity and nearly zero cytotoxicity. The solid-phase microwave method seems to be an effective strategy to rapidly obtain high quality N-doped CDs and expands their applications in ion detection and cellular bioimaging.

Blue light-emitting carbon dots (CDs) from a milk protein and their interaction with Spinacia oleracea leaf cells

“…Similarly, in an interesting work by He et al, nitrogen-doped CDs (N-doped CDs) were synthesized by microwaves exposure of l-glutamic acid as the sole reaction precursor in the solid-phase condition. The N-doped CDs, prepared within 8 min, had an average size of 1.64 nm [25]. It is worth mentioning here that a proper selection of microwave power and exposure time plays a significant role in inducing photoluminescence in carbon dots and in controlling their size as well.…”

Hemostatic bioactivity of novel Pollen Typhae Carbonisata-derived carbon quantum dots

“…As another important type of nanomaterial emerging recently, CQDs have superior properties compared with those of other nanomaterials in terms of high aqueous solubility, low toxicity, and good biocompatibility [ 10 ]. However, the application of CDs in the biomedical domain was mainly focused on drug delivery [ 11 , 12 ], bio-imaging [ 13 , 14 ], and optical imaging and sensing [ 15 , 16 ]. The intrinsic bioactivity and potential pharmacological effects of CQDs have not attracted adequate attention, and has become a ‘blind spot’ in research.…”

Fluorescent Nitrogen-Doped Carbon Dots via Single-Step Synthesis Applied as Fluorescent Probe for the Detection of Fe3+ Ions and Anti-Counterfeiting Inks

“…These unique characteristics have resulted in CNPs with a wide scope of applications, such as biological labeling, light conversion materials and invisible ink for anti-counterfeiting. 17,18 Several synthetic methods to prepare carbon dots (CDs) have been reported, such as laser ablation of graphite, 19 electrochemical oxidation of multiwalled carbon nanotubes, 20,21 arc-discharge and chemical oxidation of graphene. 22 However, most of these methods require complex procedures, strong acid, and further modi¯cation to enhance photostability and solubility in relevant solvents.…”