Synthesis of carbon nanodots from caramelized glucose solutions

Carbon nanodots are a class of zero-dimensional carbon-based nanoparticles that have been used increasingly in the fields of bioimaging, drug delivery, and optronics. Despite their popularity, carbon nanodots remain difficult to isolate when synthesized by a bottom-up approach, especially through the thermal treatment of carbohydrate solutions due to the presence of many molecular byproducts which result from the Maillard reaction [1].
We investigated multiple possible methods of purification of glucose solutions [2]. Glucose solutions were heated at 120 °C for a period of 48 hours to produce carbon nanodots. We found that dialysis combined with solid phase extraction preserved the photoluminescent properties of dissolved carbon nanodots, while eliminating measurable traces of other chemical byproducts, as measured by Fourier-Transform IR spectroscopy, Carbon-NMR, and Hydrogen-NMR.

1. Essner, J. B., Kist, J. A., Polo-Parada, L., & Baker, G. A. (2018). Artifacts and Errors Associated with the Ubiquitous Presence of Fluorescent Impurities in Carbon Nanodots. Chemistry of Materials, 30(6), 1878–1887.
2. Obadiya, T., Uppala, H., & Sidebottom, D. (2019). Fluorescent Carbon Particles formed from Concentrated Glucose Solutions. In MRS Advances (Vol. 4, pp. 67–72).