Biocompatible nitrogen-doped carbon dots: synthesis, characterization, and application

Park, Yoonsang; Kim, Yujin; Chang, Heemin; Won, Sungyeon; Kim, Hye Min; Kwon, Woosung

doi:10.1039/d0tb01334j

Cited by 105 publications

(55 citation statements)

References 139 publications

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“…Carbon network can easily be doped with various elements, such as N, S, Se, F, P, and B, among which nitrogen is eventually the most widely used dopant which can be incorporated in diverse forms (e.g., amine, pyridinic, pyrrolic, and graphitic N). [48] Most importantly, N doping was shown to be able to redshift the emission and improve the PL QY of CDs at the same time. In fact, among several examples which are introduced in Section 2.1, the DR/NIR emission of CDs could be ascribed to the synergistic effect of large sp 2 domains and the N doping.…”

Section: Doping Of Cds With Heteroatomsmentioning

confidence: 99%

Optical Properties of Carbon Dots in the Deep‐Red to Near‐Infrared Region Are Attractive for Biomedical Applications

Ushakova

Rogach

et al. 2021

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range (NIR-I region: 700-900 nm; NIR-II region: 1000-1700 nm). [15][16][17][18][19][20] Deep tissue penetration can be realized in this spectral range owing to the low degree level of photon absorption, scattering, and autofluorescence from tissues. [21,22] Therefore, imaging and therapeutic agents which operate in the DR to NIR region are highly desired. For CDs, strong PL in the blue and green region has been reported on numerous occasions, with PL quantum yields (QY) up to 90%, [23,24] while CDs with efficient longer wavelength emission have experienced extensive development only recently. Starting from the first report on the orange emissive CDs (PL peak at 580 nm) with a PL QY of 46%, [25] red emissive CDs with PL peak at 628 nm and PL QY of 53%, [26] and NIR emissive CDs with PL peak at 715 nm and PL QY of 43% [27] were introduced. A number of strategies, such as enlarging the π-conjugated structure, enhancing the surface oxidation, and employing proper precursors such as phenylenediamines were proved as effective for realization of such CDs. This review starts from summary of synthetic strategies toward CDs with absorption/PL at the wavelength from 650 nm and into the NIR-I and NIR-II spectral region. We then consider in detail the Stokes and anti-Stokes PL (ASPL), chemiluminescence (CL) and formation of reactive oxygen species (ROS) for the DR/NIR CDs. At the end, we provide a concise summary of already reported biomedical applications of CDs, such as in the photoacoustic (PA) imaging and photothermal therapy (PTT), photodynamic therapy (PDT), and their use as bioimaging agents and drug carriers.Carbon dots (CDs) represent a recently emerged class of luminescent materials with a great potential for biomedical theranostics, and there are a lot of efforts to shift their absorption and emission toward deep-red (DR) to near-infrared (NIR) region falling in the biological transparency window. This review offers comprehensive insights into the synthesis strategies aimed to achieve this goal, and the current approaches of modulating the optical properties of CDs over the DR to NIR region. The underlying mechanisms of their absorption, photoluminescence, and chemiluminescence, as well as the related photophysical processes of photothermal conversion and formation of reactive oxygen species are considered. The already available biomedical applications of CDs, such as in the photoacoustic imaging and photothermal therapy, photodynamic therapy, and their use as bioimaging agents and drug carriers are then shortly summarized.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/smll.202102325. Figure 12. a) In vivo NIR fluorescence images of a mouse stomach before (left) and after (right) gavage injection of CDs in PVP aqueous solution.Reproduced with permission. [46] Copyright 2018, Wiley-VCH. b) NIR fluorescence images of mouse tumor after intravenous injection of CDs at various time points. c) NIR fluorescence of H22 tumors that were dissected from mice at ...

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Section: Doping Of Cds With Heteroatomsmentioning

confidence: 99%

Optical Properties of Carbon Dots in the Deep‐Red to Near‐Infrared Region Are Attractive for Biomedical Applications

Ushakova

Rogach

et al. 2021

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120

101

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“…As a new type of luminescent nanocarbon materials, carbon dots (CDs) have attracted much attention and been widely applied in biotechnology, anti-counterfeiting, optoelectronic device, and photocatalysis areas in recent years due to possessing numerous superior features such as excellent photostability, chemical stability, biocompatibility, and cost-effective preparation [13][14][15][16][17][18][19][20]. More impressively, afterglow phenomena of CDs had also been discovered either through embedding them in certain matrices (e.g., poly(vinyl alcohol) (PVA), inorganic salts, urea/ biuret, zeolites, and silica) [21,22], or preparing specialstructured CDs by proper carbon precursors and reaction conditions [23,24].…”

Section: Introductionmentioning

confidence: 99%

Green and Near-Infrared Dual-Mode Afterglow of Carbon Dots and Their Applications for Confidential Information Readout

Wang

Jiang

et al. 2021

Nano-Micro Lett.

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Near-infrared (NIR), particularly NIR-containing dual-/multi-mode afterglow, is very attractive in many fields of application, but it is still a great challenge to achieve such property of materials. Herein, we report a facile method to prepare green and NIR dual-mode afterglow of carbon dots (CDs) through in situ embedding o-CDs (being prepared from o-phenylenediamine) into cyanuric acid (CA) matrix (named o-CDs@CA). Further studies reveal that the green and NIR afterglows of o-CDs@CA originate from thermal activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) of o-CDs, respectively. In addition, the formation of covalent bonds between o-CDs and CA, and the presence of multiple fixation and rigid effects to the triplet states of o-CDs are confirmed to be critical for activating the observed dual-mode afterglow. Due to the shorter lifetime and insensitiveness to human vision of the NIR RTP of o-CDs@CA, it is completely covered by the green TADF during directly observing. The NIR RTP signal, however, can be readily captured if an optical filter (cut-off wavelength of 600 nm) being used. By utilizing these unique features, the applications of o-CDs@CA in anti-counterfeiting and information encryption have been demonstrated with great confidentiality. Finally, the as-developed method was confirmed to be applicable to many other kinds of CDs for achieving or enhancing their afterglow performances.

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“…Generally speaking, carbon-based materials are inherently less toxic than metal- or semiconductor-based materials considering the intrinsic nature of carbon. Still, the cytotoxicity of CDs has raised much concern 404–406 since the toxicity of bare CDs is often dose and time dependent. 407 Surprisingly, there has been a report stating that CDs derived from the same precursors, but with different synthesis methods, demonstrated different cytotoxicities.…”

Section: Discussionmentioning

confidence: 99%

Carbon dot composites for bioapplications: a review

Chen

Jia

et al. 2022

J. Mater. Chem. B

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Biocompatible nitrogen-doped carbon dots: synthesis, characterization, and application

Abstract: Carbon dots (CDs) are promising materials for biomedical applications owing to their unique properties, biocompatibility, and biodegradability. The current studies on CDs are focused on improving their functionality by modulating...

Cited by 105 publications

References 139 publications

Optical Properties of Carbon Dots in the Deep‐Red to Near‐Infrared Region Are Attractive for Biomedical Applications

Optical Properties of Carbon Dots in the Deep‐Red to Near‐Infrared Region Are Attractive for Biomedical Applications

Green and Near-Infrared Dual-Mode Afterglow of Carbon Dots and Their Applications for Confidential Information Readout

Carbon dot composites for bioapplications: a review

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