Effect of heteroatoms on the optical properties and enzymatic activity of N-doped carbon dots

Abstract

The characteristics of N-CDs suitable for their optical applications or for use as nanozymes were demonstrated by rationalizing the relationship between the dopant content (e.g., the amount of doped N and types of chemical bonding) and physicochemical properties.

Highly Enhanced Enzymatic Activity of Mn-Induced Carbon Dots and Their Application as Colorimetric Sensor Probes

“…Next, the enzyme-like activity of Mn:N-CDs is explored. In our previous study [22], N-CDs were confirmed to show peroxidase-mimicking activity; thus, the peroxidase-like activities of Mn:N-CDs are examined here by monitoring the change in the color of a mixed solution of TMB (10 mM) and H2O2 (100 mM) at pH 2 (Figure 3a). With the addition of Mn:N-CDs, the color of the TMB solution changes from pale yellow to blue owing to the oxidation of TMB (Figure 3b), whereas N-CDs cause a negligible change in the color Next, the enzyme-like activity of Mn:N-CDs is explored.…”

“…With the addition of Mn:N-CDs, the color of the TMB solution changes from pale yellow to blue owing to the oxidation of TMB (Figure 3b), whereas N-CDs cause a negligible change in the color Next, the enzyme-like activity of Mn:N-CDs is explored. In our previous study [22], N-CDs were confirmed to show peroxidase-mimicking activity; thus, the peroxidase-like activities of Mn:N-CDs are examined here by monitoring the change in the color of a mixed solution of TMB (10 mM) and H 2 O 2 (100 mM) at pH 2 (Figure 3a). With the addition of Mn:N-CDs, the color of the TMB solution changes from pale yellow to blue owing to the oxidation of TMB (Figure 3b), whereas N-CDs cause a negligible change in the color of the TMB solution under the same experimental conditions.…”

“…Mn:N-CDs were obtained using the previously reported hydrothermal method [22]. Citric acid and ethylenediamine were the sources of carbon, and their reaction molar ratio was 1:0.5.…”

“…Mn:N-CDs were prepared by employing a hydrothermal method that is a modified synthetic method reported in our previous work [22]. In a typical synthesis procedure, citric acid (10 µmol), ethylenediamine (5 µmol), and Mn(acetate) 2 (4.15 µmol) were dissolved in deionized (DI) water (15 mL).…”

“…Numerous researchers have investigated not only the enzymatic properties of CDs but also methods to improve these properties. For example, CDs that were doped with hetero ions such as S or P could easily catalyze 3,3 ,5,5 -tetramethylbenzidine (TMB) to produce oxidized TMB in the presence of H 2 O 2 [22,23]. The enzymatic properties of CDs are considerably improved through the formation of hybrids with other materials (e.g., Au, Pd, Fe 3 O 4 , Mn 3 O 4 , and CeO 2 ) [24][25][26][27].…”