Scaling-up of carbon dots hydrothermal synthesis from sugars in a continuous flow microreactor system for biomedical application as in vitro antimicrobial drug nanocarrier

Abstract

Carbon dots (CDs) are a new class of nanomaterials exhibiting high biocompatibility, water solubility, functionality, and tunable fluorescence (FL) property. Due to the limitations of batch hydrothermal synthesis in terms of low CDs yield and long synthesis duration, this work aimed to increase its production capacity through a continuous flow reactor system. The influence of temperature and time was first studied in a batch reactor for glucose, xylose, sucrose and table sugar precursors. CDs synthesized from sucrose precursor exhibited the highest quantum yield (QY) (175.48%) and the average diameter less than 10 nm (~6.8 ± 1.1 nm) when synthesized at 220°C for 9 h. For a flow reactor system, the best condition for CDs production from sucrose was 1 mL min −1 flow rate at 280°C, and 0.2 MPa pressure yielding 53.03% QY and ~ 6.5 ± 0.6 nm average diameter (6.6 mg min −1 of CDs productivity). CDs were successfully used as ciprofloxacin (CP) nanocarrier for antimicrobial activity study. The cytotoxicity study showed that no effect of CDs on viability of L-929 fibroblast cells was detected until 1000 µg mL −1 CDs concentration. This finding demonstrates that CDs synthesized via a flow reactor system have a high zeta potential and suitable surface properties for nano-theranostic applications.

Carbon Dots: Synthesis, Characterizations, and Recent Advancements in Biomedical, Optoelectronics, Sensing, and Catalysis Applications

“…According to the cytotoxicity investigation, CNDs had no influence on the viability of L-929 fibroblast cells until a concentration of 1000 μg mL –1 of CNDs was reached. This result shows that CNDs produced using a flow reactor method have a high zeta potential and appropriate surface characteristics for use in nanotechnology . Different hetero atoms were doped into virgin CNDs structures by Girum Getachew et al They used simple and quick microwave heating to create N, Cl, and S-doped CNDs (NClS/CNDs) and Se, N, and Cl-doped CNDs (NClSe/CNDs) with exceptional optoelectronic capabilities.…”

“…This result shows that CNDs produced using a flow reactor method have a high zeta potential and appropriate surface characteristics for use in nanotechnology. 164 When compared to undoped CNDs (0.66%), the quantum efficiencies of these NClS/CNDs and NClSe/CNDs were increased to 30.7% and 42.9%, respectively. Under 532 nm laser irradiation, NClS/CNDs efficiently generated reactive oxygen species (ROS) for photodynamic treatment (PDT) because of their superior light absorption characteristics.…”