Mn3+/Mn4+ ion-doped carbon dots as fenton-like catalysts for fluorescence dual-signal detection of dopamine

Abstract

Carbon dots (CDs), a new zero-dimensional material, have ignited a revolution in the fields of sensing, bioimaging, and biomedicine. However, the difficulty of preparing CDs with Fenton-like catalytic properties has seriously hindered their application in the diagnosis of oxidation/reduction biomolecules or metal ions. Here, an innovative method was successfully established to synthesize Mn3+/Mn4+ ion-doped blue-green fluorescent CDs with Fenton-like catalytic properties using manganese acetate as the manganese source. Specifically, the CDs prepared here were equipped with functional groups of -COOH, NH2, C=O, and Mn-O, offering the possibility to function as a fluorescence sensor. More importantly, the introduction of manganese acetate resulted in the preparation of CDs with Fenton-like catalytic properties, and the dual-signal fluorescence detection of dopamine (DA) was realized with linear ranges of 100–275 nM and 325–525 nM, and the detection limits were 3 and 12 nM, respectively. In addition, due to the Fenton-like catalytic activity of Mn3+/Mn4+ ion-doped CDs, the material has broad application prospects in the detection of oxidation/reduction biomolecules or metal ions related to disease diagnosis and prevention.

Hypoxia mitigation by manganese-doped carbon dots for synergistic photodynamic therapy of oral squamous cell carcinoma

“…FT-IR spectra confirmed the existence of carboxyl and amino groups embedded in the CDs with the observation of a sharp peak at 1,610 cm-1 corresponding to the stretching vibration of C=O and a broad peak at 3,000 cm-1 with respect to N–H absorption ( Figure 1E ), respectively. A manifestation of their zwitterionic characteristics, allows them to be well dispersed in aqueous solutions ( Zhang et al, 2015 ; Zhu et al, 2022 ). In addition, the peak at 607 cm-1 corresponding to the Mn-O functional group and a new distinct peak at around 1,220 cm-1 caused by metal-ligand stretching vibrations furthermore indicates the existence of Mn ( Liu et al, 2022 ; Dong et al, 2022 ).…”

“…UV excitation causes severe photodamage to biological tissues due to the low penetration of the emitted light, which limits the application of fluorescent biosensing ( Zhu et al, 2022 ). Here, the as-prepared red-emissive Mn-CDs have better imaging contrast and can be directly used for intracellular imaging ( Zhu et al, 2022 ). Similarly, the optimal emission wavelength and emission wavelength of CDs were 610 nm and 675 nm, respectively ( Supplementary Figure S5B ), and the doping of Mn does not cause any change in the fluorescence properties of CDs ( Chen et al, 2021 ).…”

Dual-signal detection of tannic acid in red wines based on the peroxidase activity of carbon dots

“…Moreover, F-doping altered the CDs fluorescence properties and enhanced its quantum yield. Besides, the doping of metal ions like Fe, 8 Mn, 16 and Cu 17 could change the optical performance of CDs and endow CDs with new properties such as nanoenzyme-active like oxidase activity 18 and peroxidase activity, 19 providing the possibility of introducing a second kind of signal along with the fluorescent signal. The combination of two signals could form a dual-signal system like the colorimetric–fluorimetric method and the electrochemical–fluorimetric method, which could take advantage of two single-signal methods to further improve the anti-interference ability of the detection method and broaden the detection range of the analyte.…”

Utilizing machine learning to expedite the fabrication and biological application of carbon dots

“…This optical characteristic is developed so that the fluorescence probe senses the content of pH, 32 ions, 33–35 and biomolecules. 36–38 CDs possess good hydrophilicity owing to their amino, hydroxyl, and carboxyl groups, and can quickly be loaded with drugs. Thus, they have strong potential as superior therapeutic drug delivery agents.…”