Facile synthesis of highly emissive carbon dots from pyrolysis of glycerol; gram scale production of carbon dots/mSiO2 for cell imaging and drug release

Abstract

We report on a facile method to synthesize carbon dots (CDs) using glycerol solvent as a single precursor via a pyrolysis process free from catalysts. This method is extremely simple and economical, and provides a feasible route for mass production of highly emissive CDs. For rationalization, a mechanism incorporating dehydration of glycerol, followed by acrylaldehyde formation is tentatively proposed for CD production. Further systematic improvement of particle homogeneity is made by harnessing the growth of CDs inside the mesoporous silica nanoparticles that act as a nano-reactor to regulate the size distribution. Simultaneously capping a polyethylene glycol (PEG)-derived reactant onto the CDs@SiO 2 enhances their luminescence, stability and bio-compatibility. The as-prepared CDs@mSiO 2 -PEG nanocomposites are then loaded with the anti-cancer drug doxorubicin (DOX), so that the controlled release of DOX could be monitored by both time-dependent and spatially resolved ratiometric fluorescence intensity for CDs versus DOX in HeLa cells, successfully demonstrating that the CDs@mSiO 2 -PEG nanocomposites are suitable for cell imaging and drug release.

Carbon Quantum Dots: Synthesis, Characterization and Biomedical Applications

“…After template removal, passivation, and carbonization, the obtained C-dots' compositions, tunable sizes, and crystalline degrees had additional high stability properties, up-conversion PL and PL effectiveness as high as 3.3-4.7%. The difficulty of aggregate formation was successfully eliminated 25 developed C-dots in the NPs of mesoporous silica, which served as a nanoreactor to control the size distribution. Initially the authors developed mesoporous silica NPs (mSiO 2 ); the mSiO 2 NPs were blended with PEG-NH 2 and glycerol, then heated to 30 min at 230 °C.…”

Progress of Luminescent Carbon Dots in Biomedicine Engineering

“…The introduction of heteroatoms has been studied to tune the conduction/valence band position of C-dots, which confers additional functions [27][28][29]. For example, the quantum yield (QY) of C-dots could be significantly improved by incorporating the N element while C-dots with a wide band gap could be synthesized by incorporating the S element [30][31][32][33][34].…”

Photoluminescent nanoplatforms in biomedical applications

“…Heating the precursors above their melting point using simple combustion, plasma, or microwave irradiation leads to the formation of the C-dots, localizing the growth of the nanodots and blocking their agglomeration during the high-temperature treatment [59]. Some of the precursors for this synthetic method include ammonium citrate salts [69], glycerol [70], saccharides [71], and ascorbic acid [72]. These methods constitute an effective and simple alternative for the synthesis of the C-dots and allow the introduction of desirable heteroatoms from the precursors into the nanoparticles.…”