Fluorescent Carbon Nanoparticles Research Articles

Carbon quantum dots for efficient hydrogen production: A critical review

Fluorescent carbon nanoparticles, also known as carbon quantum dots (CQDs), have piqued the interest of researchers due to their numerous uses in chemical sensing, biomedical imaging, nanotechnology, photovoltaics, LEDs, and hydrogen generation. Aside from their optical brilliance, CQDs have benefits like low toxicity, environmental friendliness, cost‐effectiveness, and ease of manufacture, with adjustable properties via surface passivation and functionalization. This review article goes over CQDs in depth, addressing synthesis advances, benefits, limits, various synthesis processes, and prospective hydrogen generation applications. While CQDs have photocatalytic properties, they confront a few challenges, including low quantum yields, spectrum limitations, photostability limitations, limited catalytic activity, scaling difficulties, and environmental issues. Thorough research is required to use CQDs in sustainable hydrogen generation. Despite obstacles, CQD research remains appealing, with transformational promise for a cleaner and more sustainable energy future through controlled synthesis approaches displaying CQDs' many uses.

Hydrogen peroxide assisted synthesis of fluorescent carbon nanoparticles from teak leaves for dye-sensitized solar cells

Fluorescent carbon nanoparticles (FCNs) have emerged as promising sensitizers for dye-sensitized solar cells (DSSCs) owing to their unique optical properties and low-cost fabrication.

Dopamine sensing by fluorescent carbon nanoparticles synthesized using artichoke extract.

The practical and easy detection of dopamine levels in human fluids, such as urine and saliva, is of great interest due to the correlation of dopamine concentration with several diseases. In this work, the one-step synthesis of water-soluble carbon nanoparticles (CNPs), starting from artichoke extract, containing catechol groups, for the fluorescence sensing of dopamine is reported. Size, morphology, chemical composition and electronic structure of CNPs were elucidated by DLS, AFM, XPS, FT-IR, EDX and TEM analyses. Their optical properties were then explored by UV-vis and fluorescence measurements in water. The dopamine recognition properties of these CNPs were investigated in water through fluorescence measurements and we observed the progressive enhancement of the CNP emission intensity upon the progressive addition of dopamine, with a binding affinity value of log K = 5.76 and a detection limit of 0.81 nM. Selectivity towards dopamine was tested over other interfering analytes commonly present in human saliva. Finally, in order to perform a solid point of care test, CNPs were adsorbed on a solid support and exposed to different concentrations of dopamine, thus observing a pseudo-linear response, using a smartphone as a detector. Therefore, the detection of dopamine in simulated human saliva was performed with excellent results, in terms of selectivity and a detection limit of 100 pM.

Dopamine sensing by fluorescent carbon nanoparticles synthetized by artichoke extract

The practical and easy detection of Dopamine levels in human fluids, such as urine and saliva, is of great interest due to the correlation of Dopamine concentration with several diseases....

Effects of different roasting temperatures on rabbit meat protein oxidation and fluorescent carbon nanoparticle formation

This study explores the oxidation of rabbit meat proteins and the physicochemical properties of the resulting fluorescent carbon nanoparticles (CNPs) under various roasting temperatures (180, 210, 240, 270, and 300 °C). The determination of sulfhydryl content, along with the results from UV and fluorescence spectroscopy, indicates that the protein structure undergoes changes during the roasting process, and the degree of oxidation shows an increasing trend with rising roasting temperatures. The CNP solution obtained exhibits a typical blue fluorescence. Moreover, as the roasting temperature increases from 180 °C to 300 °C, the relative content of the three elements in CNPs, namely C, N, and O, increases by 12 %, −3%, and −9 %, respectively. The surface of the obtained rabbit meat CNPs contains hydrophilic and polycyclic groups, such as carbonyl, hydroxyl, and amide bonds. Correlation analysis reveals a significant positive correlation between the degree of protein oxidation and the fluorescence intensities of CNPs.

Shape Control of Carbon Nanoparticles via a Simple Anion‐Directed Strategy for Precise Endoplasmic Reticulum‐Targeted Imaging

AbstractHerein, small‐sized fluorescent carbon nanoparticles (CNs) with tunable shapes ranging from spheres to various rods with aspect ratios (ARs) of 1.00, 1.51, 1.89, and 2.85 are prepared using a simple anion‐directed strategy for the first time. Based on comprehensive morphological and structural characteristics of CNs, along with theoretical calculations of density functional theory and molecular dynamics simulations, their shape‐control mechanism is attributed to interionic interactions‐induced self‐assembly, followed by carbonization. The endoplasmic reticulum‐targeting accuracy of CNs is gradually enhanced as their shape changes from spherical to higher‐AR rods, accompanied by a Pearson's correlation coefficient up to 0.90. This work presents a facile approach to control the shape of CNs and reveals the relationship between the shape and organelle‐targeting abilities of CNs, thereby providing a novel idea to synthesize CNs that serve as precise organelle‐targeted fluorescent probes.

Shape Control of Carbon Nanoparticles via a Simple Anion-Directed Strategy for Precise Endoplasmic Reticulum-Targeted Imaging.

Herein, small-sized fluorescent carbon nanoparticles (CNs) with tunable shapes ranging from spheres to various rods with aspect ratios (ARs) of 1.00, 1.51, 1.89, and 2.85 are prepared using a simple anion-directed strategy for the first time. Based on comprehensive morphological and structural characteristics of CNs, along with theoretical calculations of density functional theory and molecular dynamics simulations, their shape-control mechanism is attributed to interionic interactions-induced self-assembly, followed by carbonization. The endoplasmic reticulum-targeting accuracy of CNs is gradually enhanced as their shape changes from spherical to higher-AR rods, accompanied by a Pearson's correlation coefficient up to 0.90. This work presents a facile approach to control the shape of CNs and reveals the relationship between the shape and organelle-targeting abilities of CNs, thereby providing a novel idea to synthesize CNs that serve as precise organelle-targeted fluorescent probes.

(Digital Presentation) Hydrogen Peroxide Assisted Fluorescent Carbon Nanoparticles from Teak Leaves

H2O2supported carbon nanoparticles were synthesized through hydrothermal treatment. The Fluorescent Carbon Nanoparticles (FCNs) could be easily functionalized with H2O2 and showed blue emission fluorescence with higher stability in aqueous solution. The FCNs were characterized using absorption spectroscopy, Fluorescence spectroscopy, Fourier-transformed Infrared spectroscopy, Field Emission Scanning Microscopy, and Transmission Electron Microscopy. The synthesized FCNs were subsequently applied in dye sensitized solar cells to enhance the efficiency of the solar cells. The essential photovoltaic parameters, such as open circuit voltage (VOC), short circuit current density (ISC), fill factor (FF), and the overall conversion efficiency (η), were evaluated. The solar-to-electric efficiency of the fabricated dye sensitized solar cell was 0.10%. Furthermore, electrochemical impedance spectroscopy (EIS) was performed to elucidate the charge transfer and transport processes that occur in the fabricated DSSC.

Extraction, characterization and toxicity evaluation of fluorescent carbon nanoparticles in bamboo charcoal peanut

Extraction, characterization and toxicity evaluation of fluorescent carbon nanoparticles in bamboo charcoal peanut

Single-port endoscopic-sentinel lymph node biopsy combined with indocyanine green and carbon nanoparticles in breast cancer

BackgroundIn order to explore the surgical safety and the reliability of axillary staging of single-port endoscopic-sentinel lymph node biopsy, we combined it with indocyanine green that was excited by near-infrared fluorescence endoscopy and carbon nanoparticles as a tracer and compared this method to conventional open sentinel lymph node biopsy.MethodsThis is a retrospective and observational study, there were 20 patients in each group and the total sample size was 60: Group 1, single-port endoscopic-sentinel lymph node biopsy combined with indocyanine green and carbon nanoparticles; Group 2, single-port endoscopic-sentinel lymph node biopsy with carbon nanoparticles only; Group 3, conventional sentinel lymph node biopsy with indocyanine green and carbon nanoparticles. Sentinel lymph node detection and upper extremity function were determined to measure the safety and efficacy of the novel single-port endoscopic-sentinel lymph node biopsy (SPE-SLNB) technique to the standard conventional sentinel lymph node biopsy technique.ResultsThe detection rate of sentinel lymph nodes was 100% in Group 1, 100% in Group 2, and 95% in Group 3. There were no significant differences in upper arm function and pain scores between the three groups.ConclusionThe novel technique of combining indocyanine green and carbon nanoparticles with single-port endoscopic-sentinel lymph node biopsy achieved a similar detection rate and mean number of sentinel lymph nodes as conventional sentinel lymph node biopsy. Traditional open surgery requires two different incisions for breast surgery and SLNB. While the most important advantage of SPE-SLNB is that two procedures can be effectively performed through a single-port in the axilla Therefore, for patients who meet the indications, single-port endoscopic-sentinel lymph node biopsy is as safe and reliable as conventional sentinel lymph node biopsy but has the aesthetic advantage of only one incision.

OPTICAL PROPERTIES OF COLLOIDAL SOLUTIONS OF CARBON DOTS

In this work, optical properties of carbon dots (CDs) chemically synthesized by solvothermal carbonization of a mixture of urea and anhydrous citric acid were studied. Size distribution of CDs with a typical chemical structure was estimated from dynamic light scattering. Absorption, fluorescence excitation/emission spectra as well as characteristic fluorescence lifetimes were measured. An energy diagram of photostimulated electronic transitions in this type of multicolor fluorescent carbon nanoparticles was also proposed. Temperature dependence of the PL/PLE-maps of CDs colloids in the range of 5‒75 ° C was measured and it demonstrates the possibility of their use for thermometry purposes. We also showed a possibility of CDs using for multicolor cell fluorescence imaging.

Effect of Hydrophobicity of Fluorescent Carbon Nanoparticles on Transport in Porous Media: Column Experiments and Modeling

AbstractEngineered carbon‐based nanoparticles are increasingly used for environmental, industrial, and medical purposes. Thus, understanding their interaction with and transport through materials is important. We examine the impact of nanoparticle hydrophobicity and porous medium surface area on the transport of carbon nanoparticles through sand‐packed columns under saturated and unsaturated conditions. The fluorescent carbon nanoparticles (FCNs) used in this study, synthesized from citric acid and ethanolamine, exhibit synthesis‐temperature‐dependent hydrophobicity. To quantify the impact of hydrophobicity on retention, we use FCNs synthesized at four temperatures: 190°C (FCN190), 210°C (FCN210), 230°C (FCN230), and 250°C (FCN250). Several observations are noted. First, the more hydrophobic particles (FCN230 and FCN250) attain lower outlet concentrations and mass recovery than more hydrophilic particles (FCN190 and FCN210). For instance, while 77% of the FCN190 was recovered after passing through a fine‐sand‐packed column, only 23% of the FCN250 was recovered. Second, sand surface area significantly impacts FCN recovery. A 17‐fold increase in sand surface area yields a 30% decrease in the recovery of FCN210. Third, no significant difference in the mass recovery of the FCNs was observed between the unsaturated and saturated conditions, which is attributed to the small size of the FCNs relative to the water film thickness surrounding sand grains. Fourth, the particle transport model in HYDRUS‐1D successfully simulated FCN transport, showing approximately a tenfold increase in the attachment coefficient for hydrophobic FCNs. In summary, through experiments and modeling, we show that hydrophobicity is a major factor impacting FCN transport.

Red emitting fluorescent carbon nanoparticles to track spatio-temporal dynamics of endocytic pathways in model neuroblastoma neurons.

One of the biggest challenges limiting the biological applications of fluorescent carbon-based nanoparticles is their capacity to emit in the red region of the spectrum and simultaneously maintaining the smaller size. These two parameters always go in inverse proportion, thus lagging their applications in biological imaging. Endocytic pathways play important roles in regulating major cellular functions such as cellular differentiation. The Spatio-temporal dynamics of endocytic pathways adopted by various ligands (including nanoparticles) over longer durations in cellular differentiation remain unstudied. Here we have used red-emitting fluorescent carbon nanoparticles to study the endocytic pathways in neuronal cells at different stages of differentiation. These small-sized, bright, red-emitting carbon nanoparticles (CNPs) can be internalized by live cells and imaged for extended periods, thus capturing the Spatio-temporal dynamics of endocytic pathways in model SH-SY5Y derived neuroblastoma neurons. We find that these nanoparticles are preferably taken up via clathrin-mediated endocytosis and follow the classical recycling pathways at all the stages of neuronal differentiation. These nanoparticles hold immense potential for their size, composition, surface and fluorescence tunability, thus maximizing their applications in spatio-temporally tracking multiple cellular pathways in cells and tissues simultaneously.

Synthesis of fluorescent carbon nanoparticles by dispersion polymerization of acetylene.

Carbon nanoparticles (CNPs) are of interest due to their distinct optoelectronic properties for a diverse range of applications and their functions and properties can be changed by varying their shape, size and dimensionality. The current synthetic methods reported often result in uncontrolled shape, size and polydispersity. In this work, we focus on developing a low-temperature synthetic method for preparing fluorescent carbon nanoparticles and modulation of properties. Our method, based on the dispersion Glaser-Hay polymerization of acetylene followed by decomposition into a carbonaceous material, yields CNPs with sizes varying from 30 nm to 60 nm. The change in reaction parameters influences the shape and size of CNPs, yielding spherical CNPs. The residual alkynes were exploited further for post-functionalization/graphitization by UV irradiation to yield multifunctional CNPs, which were fluorescent in the blue region. The CNPs were characterized with microscopy and spectroscopy techniques after synthesis and after UV-irradiation to study the morphological, chemical, physical and optical properties. This allowed us to understand the influence of parameter variation on the properties and to attempt to establish the structure-property relationship.

Development of fluorescent carbon nanoparticles from Madhuca longifolia flower for the sensitive and selective detection of Cr6+: a collective experimental-computational approach.

Herein, blue-emitting carbon nanoparticles (CNPs) were synthesized using the Madhuca longifolia flower for the highly selective and sensitive detection of Cr6+ ions in aqueous media using a simple, green, and cost-effective approach, and computational experiments were also performed. The prepared CNPs were well-dispersed in water with an average diameter of 12 nm and functionalized with carbonyl, hydroxyl and carboxylic acid groups. The decrease in the fluorescence intensity of the CNPs with an increase in the content of Cr6+ provided an important signal for the sensitive and selective detection of Cr6+ in aqueous media. The limit of detection for Cr6+ in an aqueous medium was found to be 103 ppb, which is more sensitive in comparison with the previously reported study. Furthermore, the validation of the proposed higher sensing feature and more selective nature of the CNPs towards Cr6+ was also explained using an in silico approach. The results from the theoretical calculations based on the DFT approach demonstrated that the binding energy (BE) of the CNPs with three transition metal (TM) cations (Cr6+, Fe3+, and Hg2+) follows the order of Cr6+ > Fe3+ > Hg2+, where the Cr6+ TM cation associated with the CNPs possesses the highest valence state, showing the highest sensing feature and highest selectivity among the investigated ions, as expected. The metal ions associated with the CNPs having a higher charge and a smaller radius indicated a higher BE and larger degree of deformation of the CNPs. Moreover, to achieve new insights into the structural, stability/energetics, and electronic features, some useful tools, such as NCI-plot, HOMO-LUMO gap, MESP, and QTAIM analysis were employed, which facilitated noteworthy outcomes.

Facile Access to Fabricate Carbon Dots and Perspective of Large-Scale Applications.

Carbon dots (CDs), fluorescent carbon nanoparticles with particle sizes < 10nm, are constantly being developed for potential large-scale applications. Recently, methods allow CD synthesis to be carried out on large-scale preparation in a controlled fashion are potentially important for multiple disciplines, including bottom-up strategy, top-down method. In this review, the recent progresses in the research of the methods for large-scale production of CDs and their functionalization are summarized. Especially, the methods of CD synthesis, such as large-scale preparation, hydrothermal/solvothermal, microwave-assisted, magnetic hyperthermia microfluidic and other methods, along with functionalization of CDs, are summarized in detail. By promising applications of CDs, there are three aspects have been already reported, such as enhancing mechanical properties, flame retardancy, and energy storage. Also, future development of CDs is prospected.

Carbon Nanoparticles Extracted from Date Palm Fronds for Fluorescence Bioimaging: In Vitro Study.

Numerous studies have been reported on single- and multicolored highly fluorescent carbon nanoparticles (FCNPs) originating from various sources and their potential applications in bioimaging. Herein, multicolored biocompatible carbon nanoparticles (CNPs) unsheathed from date palm fronds were studied. The extracted CNPs were characterized via several microscopic and spectroscopic techniques. The results revealed that the CNPs were crystalline graphitic and hydrophilic in nature with sizes ranging from 4 to 20 nm. The unsheathed CNPs showed exemplary photoluminescent (PL) properties. They also emitted bright blue colors when exposed to ultraviolet (UV) light. Furthermore, in vitro cellular uptake and cell viability in the presence of CNPs were also investigated. The cell viability of human colon cancer (HCT-116) and breast adenocarcinoma (MCF-7) cell lines with aqueous CNPs at different concentrations was assessed by a cell metabolic activity assay (MTT) for 24 and 48 h incubations. The results were combined to generate dose-response curves for the CNPs and evaluate the severity of their toxicity. The CNPs showed adequate fluorescence with high cell viability for in vitro cell imaging. Under the laser-scanning confocal microscope, the CNPs with HCT-116 and MCF-7 cell lines showed multicolor fluorescence emissions, including blue, green, and red colors when excited at 405, 458, and 561 nm, respectively. These results prove that unsheathed CNPs from date palm fronds can be used in diverse biomedical applications because of their low cytotoxicity, adequate fluorescence, eco-friendly nature, and cheap production.

One-pot room-temperature direct synthesis of bovine serum albumin-based fluorescent carbon nanoparticles

Fluorescent carbon nanoparticles (FC-NPs) with a mean size of 5.5 nm were fabricated at room temperature by means of a novel one-pot direct synthesis method, using bovine serum albumin (BSA), as a biomass-based precursor, and glutaraldehyde in a mixture of water/ethanol (1:4 v/v) under alkali conditions. This novel method shortens the times of synthesis and purification of the nanoparticles, and does not require thermal energy, since no calcination is needed for the nanoparticles production, and the waste of reactants and solvents is minor. The FC-NPs displayed two emission peaks: one around 450 nm, and the second at 555 nm, being the later the most intense for wavelength excitations from 450 nm; fluorescence quantum yields values varied from 11.6 to 27 %, depending on their synthesis conditions, and in fact, the solutions emit a strong green-yellow fluorescence when excited with 532 nm. The FTIR spectra indicated that the main functional groups present were -NH2 and -COOH. XPS analysis confirmed the FTIR results and showed that carbon dots were composed mainly of C, N, O and Na. Finally, we tested the fluorescent carbon nanoparticles as cell biomarkers in human, plant cell lines and microbial cultures, achieving good results for this application.

(Digital Presentation) Synthesis of Fluorescent Carbon Nanoparticles By Dispersion Polymerization of Acetylene

Carbon nanoparticles (CNPs) have emerged as one of the most promising nanomaterials due to their distinct optoelectronic properties for a diverse range of applications in the area of electronics, energy conversion/ storage, and bio-imaging. The uniqueness in terms of functions and properties of the CNPs gets more interesting as it changes distinctly with a change in the shape, size, and dimensionality of these nanoparticles. The synthetic methods reported until now involves high-temperature (>100 °C) processes, which often results in uncontrolled shape, size, and polydispersity. In this work, we focus on the development of a low-temperature synthetic method for the preparation of fluorescent carbon nanoparticles allowing precise control over the shape, size, and properties by dispersion polymerization of acetylene as a precursor. The shape- and size-tunable nanoparticles were synthesized in a single step with dispersion polymerization by Glaser-Hay coupling. The shape and size of the resulting carbon nanoparticles are controlled by changing different reaction parameters such as temperature, reaction time and pressure. The control over the different reaction parameters allows us to obtain monodisperse CNPs in spherical (and tubular) shape with a size in the range of 25 nm to 250 nm. The use of low-temperature methods (RT < T < 70 °C) also allows us to overcome the limitations associated with current methods. After isolation, CNPs were characterized by microscopy techniques to analyze their shape and size. The nanoparticles were further characterized to by various techniques for chemical composition, structure, morphology, and optical properties. The residual alkynes in the CNPs' structure were exploited for further post-functionalization/graphitization to yield multifunctional CNPs, which were fluorescent in the blue region.

(Digital Presentation) Synthesis of Fluorescent Carbon Nanoparticles (CNPs) By Microwave-Assisted Polymerization of Sp-Carbon Rich Precursors

Carbon nanoparticles (CNPs) have emerged as one of the most promising nanomaterials due to their distinct optoelectronic properties for a diverse range of applications. These unique properties arise from the network of hybridized sp2 carbon atoms as it allows delocalization of the electrons over the entire surface of the molecule. These surface groups help CNPs emit strong fluorescence in visible region. The significant fluorescence of CNPs combined with low toxicity, and photostability makes them suitable for various applications in biosensing, bio-imaging, and OLEDs. Despite several advantages and unique properties, the transformation from laboratory to industrial products has been slow for carbon nanoparticles. The synthetic methods reported until now chemically inert nanoparticles, increasing the difficulty to modulate their morphological, optical, and electronic properties. The organic synthesis methods for synthesizing CNPs often involve several synthesis steps, long reaction time, low yield, non-scalable and inefficient purification methods. Most of these synthesis methods involve several catalysts and removal of catalysts is always a challenge. Resulting nanoparticles also need functionalization using another synthesis step to give them properties such as fluorescence and making them soluble. Therefore, a synthesis method with minimum steps, minimum catalysts which could result in soluble and fluorescence nanoparticles is desired.This work investigates the use of highly reactive sp-carbon rich precursors for polymerization with microwave heating with minimum use of catalysts resulting in fluorescent CNPs. The sp-carbon rich precursors such as TMS-Benzene, butadiyne and acetylene were used as starting material. These alkynes are highly reactive and reacts to other alkynes present in the system in the presence of heat and form polyyne intermediates which are thermodynamically unstable in the form of long chains and decompose to provide us with CNPs. The plan is to use the high reactivity with microwave heating for polymerization without catalysts and further investigate the use of oxidants or minimum catalysts to increase the rate of polymerization and conversion into CNPs. The resulting nanoparticles required minimum purification in centrifuge and were isolated easily as there were no catalysts involved. The resulting nanoparticles were characterized with various techniques to study the morphology, structure, composition, and optical properties of CNPs. The resulting nanoparticles had blue fluorescence under the UV lamp. The single step synthesis of blue fluorescence CNPs was performed with microwave assisted polymerization of sp-carbon rich precursors without any catalysts. Further investigation of this method will provide a single step synthesis method for fluorescent CNPs which would be suitable for application in sensing and OLEDs.