Scaling-up of carbon dots hydrothermal synthesis from sugars in a continuous flow microreactor system for biomedical application as <i>in vitro</i> antimicrobial drug nanocarrier
Siriboon Supajaruwong, Sirawich Porahong, Agung Wibowo, Yu‐Sheng Yu, Mohd Jahir Khan, Pisut Pongchaikul, Pattaraporn Posoknistakul, Navadol Laosiripojana, Kevin C.‐W. Wu, Chularat Sakdaronnarong
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 firstly 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 was successfully used as ciprofloxacin nanocarrier for antimicrobial activity study. The cytotoxicity study showed 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.