Regulating photochemical properties of carbon dots for theranostic applications

Abstract

As a new zero‐dimensional carbon‐based material, carbon dots (CDs) have attracted extensive attention owing to their advantages such as easy preparation and surface modification, good biocompatibility and water solubility, and tunable photochemical properties. CDs have become one of the most promising nanomaterials in the field of fluorescent sensing, bioimaging, and cancer therapy. How to precisely regulate the photochemical properties, especially the absorption, fluorescence, phosphorescence, reactive oxygen species generation, and photothermal conversion of the CDs, is the key to developing highly efficient phototheranostics for cancer treatment. Although many studies on cancer therapy using CDs have been published, no review has focused on the regulation of photochemical properties of CDs for phototheranostic applications. In this review, we summarized the strategies such as the selection of suitable carbon source, heteroatomic doping, optimum reaction conditions, surface modification, and assembly strategy to efficiently regulate the photochemical properties of the CDs to meet the requirements of different practical applications. This review might provide some valuable insight and new ideas for the development of CDs with excellent phototheranostic performance. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > In Vivo Nanodiagnostics and Imaging

Zero-Dimensional Carbon Nanomaterials for Fluorescent Sensing and Imaging

“…In contrast, nonmetal doping is more advantageous than metal doping. In nonmetal doping, carbon atoms in the sp 2 - and sp 3 -hybridized network of 0D CNMs are replaced with N, B, S, P, Si, or halogen atoms, ,− which extends the π–electron conjugation, changes the 0D CNMs aggregation state, generates additional energy levels, and promotes radiative combination, therefore, improves the optical properties. , Among these methods, nitrogen doping is used the most often because nitrogen is the closest to carbon in the periodic table. , N doping injects electrons into 0D CNMs to form surface states and trap excited electrons, which can increase the electronic density and, thus, substantially enhance the QY. , …”

“…288,289 Among these methods, nitrogen doping is used the most often because nitrogen is the closest to carbon in the periodic table. 290,291 N doping injects electrons into 0D CNMs to form surface states and trap excited electrons, which can increase the electronic density and, thus, substantially enhance the QY. 292,293…”

Fluorescent Silk Obtained by Feeding Silkworms with Fluorescent Materials†

“…[ 83‐86 ] On the other hand, the properties of CDs are easily adjustable. The solvents, [ 87‐90 ] reactant ratios, [ 91‐93 ] reaction temperature, [ 94‐95 ] precursors, [ 69,96‐97 ] and time, [ 98‐100 ] can be finely adjusted to regulate the fluorescent emission, quantum yield, size, chemical reactivity of CDs. Flexible tuning methods and various tunable items make it possible to precisely and rationally design CDs according to the required functionality.…”

Enhancing catalytic efficiency of carbon dots by modulating their Mn doping and chemical structure with metal salts

“…Nanozymes, nanoparticle-based articial enzymes, have been actively investigated owing to their advantages over natural enzymes; their advantages include controllable and facile synthesis, tunability in catalytic activities, cost-effectiveness, and high stability against stringent conditions. [1][2][3][4][5][6] Owing to these advantages, they are widely applied in various elds, including H 2 generation, CO 2 reduction, wastewater treatment, organic reactions, biosensors, cancer therapy, energy transfer, and pollutant removal. 4,[7][8][9][10][11][12][13] Representative nanozymes include metal oxide-or sulde-based materials (e.g., Fe 3 O 4 , CeO 2 , Co 9 S 8 , CuO, MnO 2 ); metal-based materials (e.g., Au, Ag, Pt, and Ir); and carbon-based materials (e.g., carbon dots (CDs), g-C 3 N 4 , graphene, CNT).…”