Search

Sepsis-induced acute kidney injury (AKI) is a common in clinic. Circular RNAs (circRNAs) play significant roles in ameliorating AKI. The purpose of this study was aimed to identify the role of circ_0074371 and the potential action mechanism in sepsis-induced AKI.AKI patients and healthy individual serum samples were collected and the relative expression of circ_0074371 was measured by real-time polymerase chain reaction (RT-PCR). HK2 cells were treated with different dose (0, 2.5, 5 and 10 μg/ml) lipopolysaccharide (LPS) to establish the AKI cell model. The cell viability and apoptosis of HK2 cells were detected using cell counting kit-8 (CCK-8) and flow cytometry, respectively. The contents of malondialdehyde (MDA), and superoxide dismutase (SOD) were evaluated using the relative commercial kits. The IL-1β and TNF-α levels in cell culture supernatants were measured by ELISA. The interaction relationship between miR-330-5p and circ_0074371 or ELK1 was predicted by Targetscan database and further confirmed by the dual-luciferase reporter assay system.The circ_0074371 expression was up-regulated in sepsis patients and LPS-induced HK2 cells. Silencing circ_0074371 promoted HK2 cells viability and inhibited the HK2 cells apoptosis. miR-330-5p inhibitor weakened circ_0074371 inhibitor-induced cell viability, apoptosis and oxidative stress. Further mechanism analysis showed that circ_0074371 acted as a sponge for miR-330-5p to increase ELK1 expression level. Importantly, miR-330-5p downregulation or ELK1 upregulation reversed the action of circ_0074371 knockdown on LPS-induced HK2 cells.Knockdown of circ_0074371 ameliorated LPS-induced HK2 cells apoptosis, inflammation and oxidative stress via regulating miR-330-5p/ELK1, opening a new window into the pathogenesis AKI.

Carbon dots (CDots) coupled with visible light exposure were found highly effective in the inactivation of bacterial pathogens.

A filamentous cell-shaped halophilic archaeon (strain AD-1T) was isolated from Aiding Salt Lake, PR China. Its colonies on HCM7 agar plates were pinkish white, 1–4 mm (diameter), elevated and round. The optimum conditions for growth were observed at 42 °C, 4.3 M NaCl, 0.01 M MgCl2 and pH 7. Strain AD-1T could hydrolyse Tween 60, Tween 80, starch and gelatin. Phylogenetic analysis based on 16S rRNA gene, rpoB′ and the concatenated 484 single-copy orthologous proteins revealed that strain AD-1T formed a clade with Halocatena pleomorpha SPP-AMP-1T. The average nucleotide identity and in silico DNA–DNA hybridization values between strain AD-1T and Halocatena pleomorpha SPP-AMP-1T were both below the species delineation thresholds (95~96 and 70 %, respectively). The major phospholipids of strain AD-1T were phosphatidic acid, phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester, while the major glycolipids were sulphated galactosyl mannosyl glucosyl diether, galactosyl mannosyl glucosyl diether and glucosyl mannosyl glucosyl diether. The phenotypic, phylogenetic and genome-based analyses suggested that strain AD-1T (=CGMCC 1.13724T=JCM 32960T) represents a novel species, for which the name Halocatena salina sp. nov. is proposed.

Understanding the cellular uptake and exocytosis processes of nanoparticles (NPs) is essential for developing the nanomedicines and assessing the health risk of nanomaterials. Considerable efforts have been made to reveal how physicochemical properties of NPs influence these processes. However, little attention has been paid to how cell type impacts these processes, especially exocytosis. Herein, the uptake and exocytosis of the carbon dots (CDs) obtained from the carbonization of citric acid with polyethylenimine (PEI) oligomers (CDs-PEI) in five human cell lines (HeLa, A549, BEAS-2B, A431, and MDA-MB-468) are analyzed to understand how cell type influences the fate of CDs in cells. The cell division is taken into account by the correction of cell number for accurate quantification of the uptake and exocytosis of CDs-PEI. The results indicate that the cell type significantly affects the cellular uptake, trafficking, and exocytosis of CDs-PEI. Among the cell types investigated, MDA-MB-468 cells have the greatest capacity for both uptake and exocytosis, and HeLa cells have the least capacity. The kinetics of the exocytosis largely follows a single exponential decay function, with the remaining CDs-PEI in cells reaching plateaus within 24 h. The kinetic parameters are cell-dependent but insensitive to the initial intracellular CDs-PEI content. Generally, the Golgi apparatus pathways are more important in exocytosis than the lysosomal pathway, and the locations of CDs-PEI in the beginning of exocytosis are not correlated with their exocytosis pathways. The findings on the cell type-dependent cellular uptake and exocytosis reported here may be valuable to the future design of high-performance and safe CDs and related nanomaterials in general.

Six novel halophilic archaeal strains of XZYJT10

Aim To synthesize qualitative evidence on nurses' and midwives' experiences in the provision of surgical abortion care. We address three specific questions: (a) what are the experiences of nurses and midwives in surgical abortion care? (b) what are their responses and coping strategies? (c) what are the deficiencies in surgical abortion care? Design Qualitative studies were synthesized using Thomas and Harden's qualitative thematic synthesis method. Data sources Electronic databases, including PubMed, Embase, CINAHL, PsycINFO, Scopus and Web of Science were searched. Grey literature using ProQuest was searched. The databases were searched from inception to 5 August 2020. Review methods The SPIDER (Sample, Phenomenon of Interest, Design, Evaluation and Research type) search tool was used in the literature search. Data synthesis was conducted using the three-stage thematic synthesis method described by Thomas and Harden. Results 966 studies were identified in the initial search and 18 studies were included. Four analytical themes were generated: 'Providing abortion care requires high emotional labour'; 'Professionalism of abortion care providers'; 'Initiatives in professional development' and 'Improving directions for high-quality abortion care'. Conclusion Nurses and midwives indicated that they require support to enhance psychological health and improve professional skills. Hospital managers should organize regular debriefing or structured group workshops for exchange of practical experiences and strengthening emotional support. More research is required to establish comprehensive training related to abortion care for nurses and midwives. The findings demonstrate that optimization of abortion services should start from hospital management models, pain management and bereavement care. Impact Understanding the experiences of nurses and midwives in abortion provision will inform future clinical practice in surgical abortion care, which would be helpful in improving the professionalism and confidence of abortion providers. Our findings have implications for the training, development of policies and standards for surgical abortion care for nurses and midwives.

The prevention of viral transmission is an important step to address the spread of viral infections. Using the enveloped vesicular stomatitis virus (VSV) as a model, this study explored the antiviral functions of the specifically designed and prepared carbon dots (CDots). The CDots were prepared using small carbon nanoparticles with surface functionalization-passivation by oligomeric polyethylenimine (PEI). The results indicated that the PEI-CDots were readily activated by visible light to effectively and efficiently inactivate VSVs under various combinations of experimental conditions (viral titer, dot concentration, and treatment time). The photodynamically induced viral structural protein degradation and genomic RNA degradation were observed, suggesting the mechanistic origins, leading to the inactivation of virus. The results suggested CDots as a class of promising broad-spectrum antiviral agents for disinfection of viruses.

Three halophilic archaeal strains, NEN8

Carbon dots (CDots) are defined as surface-passivated small carbon nanoparticles, with the effective passivation generally achieved by organic functionalization. Photoexcited CDots are both potent electron donors and acceptors, and their characteristic bright and colorful fluorescence emissions make them excellent fluorescence sensors for organic analytes and metal ions. For the latter extraordinarily low detection limits based on extremely efficient quenching of fluorescence intensities by the targeted metal cations have been observed and reported in the literature. However, all of the dot samples in those reported studies were made from “one-pot” carbonization of organic precursors mostly under rather mild processing conditions, unlikely to be sufficient for the required level of carbonization. Those dot samples should therefore be more appropriately considered as “nano-carbon/organic hybrids”, characterized structurally as being highly porous and spongy, which must be playing a dominating role in the reported sensing results. In this study, we compared the dot samples from carbonization syntheses under similarly mild and also more aggressive processing conditions with the classically defined and structured CDots for the fluorescence sensing of copper(II) cations in aqueous solutions. The observed dramatic decoupling between quenching results for fluorescence intensities and lifetimes of the carbonization samples, with the former being extraordinary and the latter within the diffusion controlled limit, suggested that the quenching of fluorescence intensities was greatly affected by the higher local quencher concentrations than the bulk associated with the porous and spongy sample structures, especially for the sample from carbonization under too mild processing conditions. The major differences between the classical CDots and the nano-carbon/organic hybrids are highlighted, and the tradeoffs between sensitivity and accuracy or reproducibility in the use of the latter for fluorescence sensing are discussed.

Carbon dots (CDots) are strongly absorptive over the visible spectrum, with the effective photon-harvesting driving rich excited state processes and properties. In this work, spectroscopic probing of these processes and properties is coupled with the evaluation of the photoinduced bactericidal function of CDots, aimed toward making correlations among the findings from the former and those from the latter on the inactivation of bacterial pathogens. Within the general mechanistic framework for CDots, the observed effective and efficient antibacterial activities of the CDots under visible light are attributed to major contributions by the initially photo-generated electrons and holes that are trapped at passivated surface defect sites of the dots, in addition to the traditional reactive oxygen species (ROS) produced in the emissive excited states from the recombination of the redox pairs. Such major contributions to the inactivation of the bacteria by the separated redox species in CDots can not be quenched by ROS scavengers commonly used in the study of photodynamic effects with classical molecular photosensitizers, thus making light-activated CDots uniquely potent antimicrobial agents. The characteristic features of photoexcited CDots and their related mechanistic implications are discussed in reference to the similar behaviors and mechanistic model of conventional semiconductor quantum dots.

Carbon “quantum” dots or carbon dots (CDots) exploit and enhance the intrinsic photoexcited state properties and processes of small carbon nanoparticles via effective nanoparticle surface passivation by chemical functionalization with organic species. The optical properties and photoinduced redox characteristics of CDots are competitive to those of established conventional semiconductor quantum dots and also fullerenes and other carbon nanomaterials. Highlighted here are major advances in the exploration of CDots for their serving as high-performance yet nontoxic fluorescence probes for one- and multi-photon bioimaging in vitro and in vivo, and for their uniquely potent antimicrobial function to inactivate effectively and efficiently some of the toughest bacterial pathogens and viruses under visible/natural or ambient light conditions. Opportunities and challenges in the further development of the CDots platform and related technologies are discussed.

Foodborne pathogens have long been recognized as major challenges for the food industry and repeatedly implicated in food product recalls and outbreaks of foodborne diseases. This study demonstrated the application of a recently discovered class of visible-light-activated carbon-based nanoparticles, namely, carbon dots (CDots), for photodynamic inactivation of foodborne pathogens. The results demonstrated that CDots were highly effective in the photoinactivation of Listeria monocytogenes in suspensions and on stainless steel surfaces. However, it was much less effective for Salmonella cells, but treatments with higher CDot concentrations and longer times were still able to inactivate Salmonella cells. The mechanistic implications of the observed different antibacterial effects on the two types of cells were assessed, and the associated generation of intracellular reactive oxygen species (ROS), the resulting lipid peroxidation, and the leakage of nucleic acid and proteins from the treated cells were analyzed, with the results collectively suggesting CDots as a class of promising photodynamic inactivation agents for foodborne pathogens. IMPORTANCE Foodborne infectious diseases have long been recognized as major challenges in public health. Contaminations of food processing facilities and equipment with foodborne pathogens occur often. There is a critical need for new tools/approaches to control the pathogens and prevent such contaminations in food processing facilities and other settings. This study reports a newly established antimicrobial nanomaterials platform, CDots coupled with visible/natural light, for effective and efficient inactivation of representative foodborne bacterial pathogens. The study will contribute to promoting the practical application of CDots as a new class of promising nanomaterial-based photodynamic inactivation agents for foodborne pathogens.

Hexagonal boron nitride (h-BN) and exfoliated nanosheets (BNNs) not only resemble their carbon counterparts graphite and graphene nanosheets in structural configurations and many excellent materials characteristics, especially the ultra-high thermal conductivity, but also offer other unique properties such as being electrically insulating and extreme chemical stability and oxidation resistance even at elevated temperatures. In fact, BNNs as a special class of 2-D nanomaterials have been widely pursued for technological applications that are beyond the reach of their carbon counterparts. Highlighted in this article are significant recent advances in the development of more effective and efficient exfoliation techniques for high-quality BNNs, the understanding of their characteristic properties, and the use of BNNs in polymeric nanocomposites for thermally conductive yet electrically insulating materials and systems. Major challenges and opportunities for further advances in the relevant research field are also discussed.

Foodborne pathogens have long been recognized as major challenges for the food industry and repeatedly implicated in food product recalls and outbreaks of foodborne diseases. This study demonstrated the application of a recently discovered class of visible-light-activated carbon-based nanoparticles, namely, carbon dots (CDots), for photodynamic inactivation of foodborne pathogens. The results demonstrated that CDots were highly effective in the photoinactivation of Listeria monocytogenes in suspensions and on stainless steel surfaces. However, it was much less effective for Salmonella cells, but treatments with higher CDot concentrations and longer times were still able to inactivate Salmonella cells. The mechanistic implications of the observed different antibacterial effects on the two types of cells were assessed, and the associated generation of intracellular reactive oxygen species (ROS), the resulting lipid peroxidation, and the leakage of nucleic acid and proteins from the treated cells were analyzed, with the results collectively suggesting CDots as a class of promising photodynamic inactivation agents for foodborne pathogens. IMPORTANCE Foodborne infectious diseases have long been recognized as major challenges in public health. Contaminations of food processing facilities and equipment with foodborne pathogens occur often. There is a critical need for new tools/approaches to control the pathogens and prevent such contaminations in food processing facilities and other settings. This study reports a newly established antimicrobial nanomaterials platform, CDots coupled with visible/natural light, for effective and efficient inactivation of representative foodborne bacterial pathogens. The study will contribute to promoting the practical application of CDots as a new class of promising nanomaterial-based photodynamic inactivation agents for foodborne pathogens.

Carbon dots (CDots) have emerged to represent a highly promising new platform for visible/natural light-activated microbicidal agents. In this article, the syntheses, structures, and properties of CDots are highlighted, representative studies on their activities against bacteria, fungi, and viruses reviewed, and the related mechanistic insights discussed. Also highlighted and discussed are the excellent opportunities for potentially extremely broad applications of this new platform, including theranostics uses.

For addressing the ever increasing challenge of multidrug-resistant (MDR) bacterial infections, specifically designed and prepared carbon dots (CDots) of small carbon nanoparticles with surface functionalization–passivation by oligomeric polyethylenimine were found to be readily activated by visible light to effectively and efficiently inactivate MDR bacterial strains. The inactivation was evaluated under various combinations of experimental conditions (dot concentrations, light intensities, and treatment times), with the results collectively suggesting CDots as a new class of promising agents for combating MDR bacteria. Mechanistic origins and implications of the observed strong antibacterial actions as relevant to the photoexcited state processes in CDots and the photodynamically induced cellular damages leading to the death of the bacterial cells were explored, with the results discussed.

The antiviral function of carbon dots (CDots) with visible light exposure was evaluated, for which the model bacteriophages MS2 as a surrogate of small RNA viruses were used. The results show clearly that the visible light-activated CDots are highly effective in diminishing the infectivity of MS2 in both low and high titer samples to the host E. coli cells, and the antiviral effects are dot concentration- and treatment time-dependent. The action of CDots apparently causes no significant damage to the structural integrity and morphology of the MS2 phage or the breakdown of the capsid proteins, but does result in the protein carbonylation (a commonly used indicator for protein oxidation) and the degradation of viral genomic RNA. Mechanistically the results may be understood in the framework of photodynamic effects that are associated with the unique excited state properties and processes of CDots. Opportunities for potentially broad applications of CDots coupled with visible/natural light in the prevention and control of viral transmission and spread are highlighted and discussed.

Boron nitride nanosheets (BNNs) are pursued for their high thermal conductivity yet electrical insulation and their extreme thermal and chemical stabilities for a variety of applications. For high-quality BNNs, a number of exfoliation approaches under different processing conditions were evaluated. Three more effective methods were identified, including method-A based on refluxing and vigorous sonication in isopropyl alcohol, method-B involving ball-milling in urea, and method-C with the aid of ammonia in hydrothermal processing. These methods produced BNNs of apparently different structural and morphological characteristics, with those from the first two being smaller pieces, more defective, and their polymeric nanocomposites exhibiting relatively lower thermal conductive performance. The method-C yielded BNNs of obviously better quality, as also made evident by the observed high thermal diffusivities of their corresponding polymeric nanocomposites. Correlations of exfoliation approaches and conditions w...

Carbon dots (CDots) for their excellent optical and other properties have been widely pursued for potential biomedical applications, in which a more comprehensive understanding on the cellular behaviors and mechanisms of CDots is required. For such a purpose, two kinds of CDots with surface passivation by 3-ethoxypropylamine (EPA-CDots) and oligomeric polyethylenimine (PEI-CDots) were selected for evaluations on their uptakes by human cervical carcinoma HeLa cells at three cell cycle phases (G0/G1, S and G2/M), and on their different internalization pathways and translocations in cells. The results show that HeLa cells could internalize both CDots by different pathways, with an overall slightly higher internalization efficiency for PEI-CDots. The presence of serum in culture media could have major effects, significantly enhancing the cellular uptake of EPA-CDots, yet markedly inhibiting that of PEI-CDots. The HeLa cells at different cell cycle phases have different behaviors in taking up the CDots, which are also affected by the different dot surface moieties and serum in culture media. Mechanistic implications of the results and the opportunities associated with an improved understanding on the cellular behaviors of CDots for potentially the manipulation and control of their cellular uptakes and translocations are discussed.

Carbon dots (CDots) exploit unique properties of small carbon nanoparticles, which represent the often under-appreciated zero-dimensional carbon allotrope. The carbon nanoparticles in CDots could be modified by a selected organic chromophore of desired strong red/near-IR absorption in the dot synthesis to obtain a specific type of hybrid CDots. The reported results show that these hybrid CDots derived from the modification of core carbon nanoparticles by selected dyes or other chromophoric species represent a highly versatile and effective platform for CDots of desired optical properties and photoinduced redox characteristics in a by-design fashion.

Producing carbon nanomaterials adjustably on a large scale with existing manufacturing methods is a promising direction. Here, multiwalled carbon nanotubes (MWCNTs) were grown on stainless steel substrate using a self-built V-type flame burner under atmospheric pressure. The surface structure of mirror and wiredrawing stainless steel substrates was observed by scanning electron microscopy. Carbon nanotubes only grow on calcined wiredrawing stainless steel substrate. X-ray diffraction was used to investigate the crystallinity of MWCNTs synthesized on substrates that were heated at 400 °C, 600 °C, and 800 °C, indicating that the calcining temperature of the substrate affects the properties of MWCNTs growth. Products grown on the substrate calcined at 600 °C are optimal. Scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy were employed to examine the morphology and chemical compositions of substrates calcined at different temperatures before growing carbon nanotubes. It was found that the morphology of the substrate surface is a key factor in controlling the growth of MWCNTs. Uniform particles with glossy boundaries are available for MWCNTs synthesis. Energy-dispersive spectroscopy was performed on single metallic particles found inside the nanotubes, clarifying that iron nanoparticles provide active sites for carbon nanotube growth on stainless steel instead of oxidation iron and other elements. A better understanding of the growth of carbon nanotubes on stainless steel using a V-type flame burner can help to adjust the properties of carbon nanotubes deposited on the required constructions, and provide additional insight into realization of large-scale and low-cost constructions covered with carbon nanotubes.

Background: Carbon dots (CDots) have recently been demonstrated their effective visible light-activated antimicrobial activities toward bacteria. This study was to evaluate and understand the roles of the surface functionalities in governing the antimicrobial activity of CDots. Methods: Using the laboratory model bacteria Bacillus subtilis, the photo-activated antimicrobial activities of three groups of CDots with specifically selected different surface functionalization moieties were evaluated and compared. The first group consisting of CDots with surface functionalization by 2,2-(ethylenedioxy)bis(ethylamine) (EDA) vs. 3-ethoxypropylamine (EPA), was evaluated to determine the effect of different terminal groups/charges on their photo-activated antibacterial activities. The second group consisting of CDots functionalized with oligomeric polyethylenimine (PEI) and those prepared by the carbonization of PEI – citric acid mixture, was to evaluate the effects of dot surface charges vs. fluorescent quantum yields on their antimicrobial activities. The third group consisting of CDots functionalized with PEI of 1,200 vs. 600 in average molecular weight was evaluated for the effect of molecular weight of surface passivation molecular on their antimicrobial activities. Results: The results indicated the EDA-CDots in the first group was more effective and was attributed to the positive charges from the protonation of the amino groups (–NH2) being more favorable to interactions with bacterial cells. The evaluation of the second group CDots suggested the same surface charge effect dominating the antibacterial performance over the fluorescent quantum yields. The evaluation of the third group CDots functionalized with PEI of 1,200 vs. 600 in average molecular weight, indicated the latter was significantly more effective. Conclusions: The results from this study highlighted the dominant role of surface functionalities in governing CDots’ light activated antimicrobial activity and should have significant implications to the further design and development of CDots as a new class of visible light-activated antibacterial agents.

Carbon dots were originally found and reported as surface-passivated small carbon nanoparticles, where the effective surface passivation was the chemical functionalization of the carbon nanoparticles with organic molecules. Understandably, the very broad optical absorptions of carbon dots are largely the same as those intrinsic to the carbon nanoparticles, characterized by progressively decreasing absorptivities from shorter to longer wavelengths. Thus, carbon dots are generally weak absorbers in the red/near-IR and correspondingly weak emitters with low quantum yields. Much effort has been made on enhancing the optical performance of carbon dots in the red/near-IR, but without meaningful success due to the fact that optical absorptivities defined by Mother Nature are in general rather inert to any induced alterations. Nevertheless, there were shockingly casual claims in the literature on the major success in dramatically altering the optical absorption profiles of “carbon dots” by simply manipulating the dot synthesis to produce samples of some prominent optical absorption bands in the red/near-IR. Such claims have found warm receptions in the research field with a desperate need for carbon dots of the same optical performance in the red/near-IR as that in the green and blue. However, by looking closely at the initially reported synthesis and all its copies in subsequent investigations on the “red/near-IR carbon dots”, one would find that the “success” of the synthesis by thermal or hydrothermal carbonization processing requires specific precursor mixtures of citric acid with formamide or urea. In the study reported here, the systematic investigation included precursor mixtures of citric acid with not only formamide or urea but also their partially methylated or permethylated derivatives for the carbonization processing under conditions similar to and beyond those commonly used and reported in the literature. Collectively all of the results are consistent only with the conclusion that the origins of the observed red/near-IR optical absorptions in samples from some of the precursor mixtures must be molecular chromophores from thermally induced chemical reactions, nothing to do with any nanoscale carbon entities produced by carbonization.

In the vast research field on carbon nanostructures, a seemingly broadly accepted family configuration of nanoscale carbon allotropes is such that fullerenes take the zero-dimensional dot spot, in perfect harmony with one-dimensional carbon nanotubes and two-dimensional graphene nanosheets. More recently, however, a threat to the nice “family value” has been the emergence of small carbon nanoparticles, which are carbon particles of a few nanometers in size without any defined crystal structures or largely amorphous and populated with abundant surface and other defects. The growing experimental evidence has revealed the unique and/or advantageous optical and photoexcited state properties and photoinduced redox characteristics of the small carbon nanoparticles, elevating them to the position of being able to compete with fullerenes for the title of nanoscale carbon allotrope at the zero-dimension. Moreover, a related supporting argument is that fullerenes are molecules, nanoscale in their sizes but not necessarily “nanomaterials” strictly speaking. In this presentation, relevant experimental results of the nanoparticles and fullerenes will be compared for a fair assessment and judgment of their title competition, and more importantly their shared structural features and electronic properties and also their enormous potential in the development of materials for a variety of technological applications will be highlighted.

Carbon dots (CDots) are defined as surface-passivated small carbon nanoparticles, with the effective passivation generally achieved by organic functionalization. Photoexcited CDots are both potent electron donors and acceptors, and their characteristic bright and colorful fluorescence emissions make them excellent fluorescence sensors for organic analytes and metal ions. For the latter extraordinarily low detection limits based on extremely efficient quenching of fluorescence intensities by the targeted metal cations have been observed and reported in the literature. However, all of the dot samples in those reported studies were made from "one-pot" carbonization of organic precursors mostly under rather mild processing conditions, unlikely to be sufficient for the required level of carbonization. Those dot samples should therefore be more appropriately considered as "nano-carbon/organic hybrids", characterized structurally as being highly porous and spongy, which must be playing a dominating role in the reported sensing results. In this study, we compared the dot samples from carbonization syntheses under similarly mild and also more aggressive processing conditions with the classically defined and structured CDots for the fluorescence sensing of copper(ii) cations in aqueous solutions. The observed dramatic decoupling between quenching results for fluorescence intensities and lifetimes of the carbonization samples, with the former being extraordinary and the latter within the diffusion controlled limit, suggested that the quenching of fluorescence intensities was greatly affected by the higher local quencher concentrations than the bulk associated with the porous and spongy sample structures, especially for the sample from carbonization under too mild processing conditions. The major differences between the classical CDots and the nano-carbon/organic hybrids are highlighted, and the tradeoffs between sensitivity and accuracy or reproducibility in the use of the latter for fluorescence sensing are discussed.

Carbon dots (CDots), generally small carbon nanoparticles with surface passivation by a soft corona-like layer of mostly organic species, have been actively pursued for potential applications in optoelectronics, including various functions that have been served by some popular fullerene derivatives. For the preparation of CDots, chemical functionalization of pre-processed and selected small carbon nanoparticles by organic molecules, so far mostly molecules with primary and secondary amine groups, has been an effective method. In this study, carbon nanoparticles were functionalized by N-ethylcarbazole (NEC) under microwave-assisted reaction conditions for NEC-CDots, analogous but with advantages to the CDots of surface functionalization by poly(N-vinylcarbazole) (PVK, which holds a special place in optoelectronics). NEC molecules can apparently be activated under the reaction conditions for reactive functionalities such as radicals to bind to surface carbons of the nanoparticles, consistent with the observed high stability of NEC-CDots. These dots, likely with a unique surface passivation scheme, exhibited optical properties and photoinduced redox characteristics similar to those found in other high-performance CDots. The potentially broad applicability of the new functionalization approach is discussed, so are implications of the unique surface passivation of carbon nanoparticles by the carbazole moieties.