Hydrogels for biomedical applications.

Despite the various synthesis methods to obtain carbon dots (CDs), the bottom-up methods are still the most widely administrated route to afford large-scale and low-cost synthesis. However, as CDs are developed with increasing reports involved in producing many CDs, the structure and property features have changed enormously compared with the first generation of CDs, raising classification concerns. To this end, a new classification of CDs, named carbonized polymer dots (CPDs), is summarized according to the analysis of structure and property features. Here, CPDs are revealed as an emerging class of CDs with distinctive polymer/carbon hybrid structures and properties. Furthermore, deep insights into the effects of synthesis on the structure/property features of CDs are provided. Herein, the synthesis methods of CDs are also summarized in detail, and the effects of synthesis conditions of the bottom-up methods in terms of the structures and properties of CPDs are discussed and analyzed comprehensively. Insights into formation process and nucleation mechanism of CPDs are also offered. Finally, a perspective of the future development of CDs is proposed with critical insights into facilitating their potential in various application fields.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/advs.201901316

Evolution and Synthesis of Carbon Dots: From Carbon Dots to Carbonized Polymer Dots

Carbon dots (CDs) are potentially useful in many areas such as bioimaging, light-emitting diodes, and sensing because of their excellent optical properties, high biocompatibility, and low toxicity. Knowledge of their photoluminescence (PL) mechanisms, which have been widely studied, is of significance in guiding the synthesis and promoting applications of CDs with tunable PL emissions. However, the intrinsic mechanism of PL emission remains unclear, and a unified mechanism has not been found because of differences in particle structures. This review generalizes the categories of CDs, noting their structural diversity. Three types of PL mechanism pertaining to structural differences are outlined: internal factors dominated emission (including the conjugation effect, the surface state, and the synergistic effect), external factors dominated emission (including the molecular state and the environment effect), and crosslink-enhanced emission. Optical applications of CDs are also briefly mentioned. Finally, the prospects for research into PL mechanisms are discussed, noting the remaining challenges and directions for future work.

Insights into photoluminescence mechanisms of carbon dots: advances and perspectives

Influence of molecular fluorophores on the research field of chemically synthesized carbon dots

Carbon dots (CDs) with incomparable optical properties have attracted extensive attention. However, some unclear issues remain, which has impeded the basic understanding and practical application of CDs. The formation process and chemical structure of CDs are critical factors for understanding their optical properties. In this review, recent progress in the formation and fluorophores of CDs is summarized and discussed, which draws a clear picture of related research and indicates a promising future for further studies.

The formation mechanism and fluorophores of carbon dots synthesized via a bottom-up route

In this report, we present the results of our investigations into the elucidation of the chemical structure of moieties responsible for the blue and green luminescence of CDs derived from the microwave-assisted pyrolysis of citric acid in the presence of urea. The molecular fluorophore that forms during the synthesis of green fluorescing CDs is 4-hydroxy-1H-pyrrolo[3,4-c]pyridine-1,3,6(2H,5H)-trione (HPPT).

Luminescence phenomena of carbon dots derived from citric acid and urea – a molecular insight

Persulfate initiated free-radical polymerization of itaconic acid: Kinetics, end-groups and side products

Multi-colored shades of betalains: recent advances in betacyanin chemistry.

https://pubs.rsc.org/en/content/articlepdf/2021/py/d1py00228g

New horizons for carbon dots: quantum nano-photoinitiating catalysts for cationic photopolymerization and three-dimensional (3D) printing under visible light

The anti-hypochlorite activity of acai (Euterpe oleracea Mart.), goji (Lycium barbarum L.) and schisandra (Schisandra chinensis) fruit extracts were assessed by determining the reactive chlorine species (RCS)-scavenging ability of these three “super-food” berries. In addition, the aqueous extracts obtained were employed as both the media and the catalyst in a green chemistry approach to the synthesis of a coumarin-based fluorescence turn-off sensor, which was then used for anti-hypochlorite activity testing. The aqueous extracts were also assessed for total phenolic content (TPC), using the Folin–Ciocalteu method, and the antioxidant activity using the ABTS+• assay. Moreover, the main water-soluble polyphenolic constituents of the extracts were identified by the HPLC-PDA-ESI-MS technique. Among the extracts tested, acai demonstrated the highest anti-hypochlorite and antioxidant activities, while the highest TPC value was found for the goji extract. All extracts demonstrated modest catalytic activity as Knoevenagel condensation catalysts.

/pdf/anti-hypochlorite-antioxidant-and-catalytic-activity-of-99k9a1ew4n.pdf

Tomasz Świergosz

Papers

Luminescence phenomena of carbon dots derived from citric acid and urea – a molecular insight

Persulfate initiated free-radical polymerization of itaconic acid: Kinetics, end-groups and side products

Multi-colored shades of betalains: recent advances in betacyanin chemistry.

New horizons for carbon dots: quantum nano-photoinitiating catalysts for cationic photopolymerization and three-dimensional (3D) printing under visible light

Anti-Hypochlorite, Antioxidant, and Catalytic Activity of Three Polyphenol-Rich Super-Foods Investigated with the Use of Coumarin-Based Sensors.