Aluminum doped carbon nanodots as potent adjuvants on the mammalian macrophages

In this manuscript, we aimed to report the synthesis of aluminum (Al) incorporated carbon nanodots (CD) and their activities on the immune cells. A green synthesis method involving the in situ doping of the nanodot was conducted. Synthesized nanodots immunomodulatory and immunostimulatory activities were tested in vitro on the macrophages. The produced carbon dots were water-soluble, fluorescent and monodispersed, with an average diameter of around 10-20 nm. After Al-doping, their surface properties, stability, crystallinity, as well as their fluorescent and optical properties were evaluated. These Al-CDs displayed no cytotoxicity and enhanced the pro-inflammatory activities of the mammalian macrophages with much lower aluminum concentrations (‰ 20) compared to that of conventional aluminum salt, by virtue of which they have the potential to serve as safe and effective adjuvant carrier. The stability of the nanocarriers was found to be persistent for over 3 months at room temperature with no significant formation of the aggregates. These results support the promise of such nanodots as the new generation non-toxic adjuvant candidates. Al incorporation changed the activity of carbon nanodot (CD). Plain CD did not have major affect on the inflammatory function of macrophages. Al incorporated CD was able to stimulate the macrophages in the absence of danger stimulus which supports its adjuvant potential. Compared to the Al salt as a control Al-CD was more potent even with ‰ 20 Al concentration on the inflammatory activity of the macropahges in vitro.