Carbon nanodots, a class of carbon nano-allotropes, have been synthesized through different routes and methods
from a wide range of precursors. The selected precursor, synthetic method, and conditions can strongly alter the physicochemical
properties of the resulting material and their intended applications. Herein, carbon nanodots (CNDs) have been synthesized from Dglucose
by combining pyrolysis and chemical oxidation methods. The effect of the pyrolysis temperature, equivalents of oxidizing
agent, and refluxing time were studied on the product and quantum yield. In the optimum conditions (pyrolysis temperature of 300
°C, 4.41 equiv of H2O2, 90 min of reflux) CNDs were obtained with 40% and 3.6% of product and quantum yields, respectively. The
obtained CNDs are negatively charged (ζ-potential = −32 mV), excellently dispersed in water, with average diameter of 2.2 nm.
Furthermore, ammonium hydroxide (NH4OH) was introduced as dehydrating and/or passivation agent during CNDs synthesis
resulting in significant improvement of both product and quantum yields of about 1.5 and 3.76-fold, respectively. The synthesized
CNDs showed a broad spectrum of antibacterial activities toward different Gram-positive and Gram-negative bacteria strains. Both
synthesized CNDs caused highly colony forming unit reduction (CFU), ranging from 98% to 99.99% for most of the tested bacterial
strains. However, CNDs synthesized in the absence of NH4OH, due to a negatively charged surface enriched in oxygenated groups,
performed better in zone inhibition and minimum inhibitory concentration. The elevated antibacterial activity of high-oxygencontaining
carbon nanodots is directly correlated to their ROS formation ability.

Title

ACS applied bio materials

Publisher

American chemical society

Publisher Country

United States of America

Indexing

Scopus

Impact Factor

None

Publication Type

Both (Printed and Online)

Volume

5

Year

2022

Pages

4860–4872