Carbon Dot Nanoparticles Research Articles

POS-220 DEVELOPING RENAL CLEARABLE NANOPARTICLES FOR THE TREATMENT OF RENAL CELL CARCINOMA

Nanoparticles (NPs) have been anticipated to revolutionise health care based on their potential to improve drug delivery. However, the design of effective cancer nano-therapeutics remains a challenge, and only a few nanoparticles have entered clinical trial. The majority of current NPs when administered intravenously are known to accumulate in lungs, liver, spleen & kidney and cause organ damage. Metastatic Renal Cell Carcinoma (RCC) is incurable, with median survival time of only 18 months, and currently there are no effective NP-based therapeutics. To effectively treat RCC and eliminate the side effects caused by NP organ accumulation, we have developed renal clearable NPs based on carbon material (Carbon Dots, CD). The aim of this project is to develop novel NPs with size less than 5.5nm as a vehicle to carry chemotherapeutic drugs such as Doxorubicin (DOX). The nanoparticles should possess renal clearable properties to target RCC and avoid non-specific distribution of drug causing adverse side effects. The study includes NP design and characterisation, drug conjugation, uptake of NPs and outcome measures. The properties of NPs were characterised, and the drug loading capacity was determined. The effect of drug and its conjugates were assessed initially in vitro. The pH difference between cancer cells and normal cells has been used as the triggering mechanism for DOX release. The cell viability of CD NPs, free DOX and CD-DOX conjugate were investigated in Renca and Hela cells by the MTT assay after 24 and 48 hr treatment. The development of an in vivo tumour model is in progress. We have successfully developed a novel type CD Nanoparticles by one-step synthesis. The Transmission Electron microscopy images revealed the CDs are spherical with an average diameter of 4nm. These CDs were shown to have low cytotoxicity with cell viability of higher than 90% at concentrations up to 200ug/ml; possess high quantum yield (58%) with bright blue fluoresce observed under UV light; very high drug loading capacity (93%). The maximum emission wavelength is at 440 nm upon excitation at 340 nm. The excitation-dependent photoluminescence properties allowed visual monitoring of the cells in blue, green and red fluorescence channels. The effective delivery and uptake of CDs into the cell’s cytoplasm was observed within 2 hrs by confocal microscopy. The cell viability assay demonstrated that CD-DOX significantly reduced the viability of the Renca cells by 2-fold compared to free DOX (24% vs 50% respectively, P value=0.0167). In Hela cells, the cell viability was furthermore reduced by 10-fold with CD-DOX compared to free DOX (5.5% vs 57.5% respectively, P value=0.0001). We have developed Carbon Dot nanoparticles with size <5.5nm with low cytotoxicity. The carbon dots have high drug loading capacity and show better inhibition of growth in cancer cell lines compared to unbound chemotherapeutics, suggesting that these nanoparticles have therapeutic potential in renal cell carcinoma.

A hybrid imprinted polymer based on magnetic graphene oxide and carbon dots for ultrasonic assisted dispersive solid-phase microextraction of oxycodone

To promote the development of molecular imprinting technique in the separation and analysis of oxycodone, molecularly imprinted polymer based on the magnetic graphene oxide and carbon dots nanoparticles (MIP@MGO/CDs NPs) was developed using ultrasonic-assisted dispersive solid-phase microextraction (UA-DSPME) and high performance liquid chromatography (HPLC). The morphology and structure characterization of synthesized nanoparticles are assessed by scanning electron microscope (SEM), Brunauer-Emmett-Teller analysis (BET), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and thermogravimetric analysis (TGA). The adsorption isotherms of MIPs followed the Langmuir model with the maximum adsorption capacity of 99 mg/g and imprinting factor of 3.39. Under optimized conditions, which achieved by central composite design under response surface methodology, the detection limit (S/N = 3) was obtained 0.80 ng/mL in the linear range of 1–2000 ng/mL. The average recoveries of oxycodone were calculated from 92.50 to 103.20% in human urine samples with RSD less than 3.65%.

Nanotheranostic Carbon Dots as an Emerging Platform for Cancer Therapy

Cancer remains one of the most deadly diseases globally, but carbon-based nanomaterials have the potential to revolutionize cancer diagnosis and therapy. Advances in nanotechnology and a better understanding of tumor microenvironments have contributed to novel nanotargeting routes that may bring new hope to cancer patients. Several low-dimensional carbon-based nanomaterials have shown promising preclinical results; as such, low-dimensional carbon dots (CDs) and their derivatives are considered up-and-coming candidates for cancer treatment. The unique properties of carbon-based nanomaterials are high surface area to volume ratio, chemical inertness, biocompatibility, and low cytotoxicity. It makes them well suited for delivering chemotherapeutics in cancer treatment and diagnosis. Recent studies have shown that the CDs are potential applicants in biomedical sciences, both as nanocarriers and nanotransducers. This review covers the most commonly used CD nanoparticles in nanomedicines intended for the early diagnosis and therapy of cancer.

Zinc Oxide Coated Carbon Dot Nanoparticles as Electron Transport Layer for Inverted Polymer Solar Cells

Interface engineering is a powerful tool to improve the performance of polymer solar cells (PSCs), and zinc oxide (ZnO) is a significant interfacial material for PSCs. However, ZnO is easy to agglo...

Functionalized carbon dot nanoparticles reinforced soy protein isolate biopolymeric film

Functionalized carbon dot nanoparticles reinforced soy protein isolate biopolymeric film

Contribution of Carbon Dot Nanoparticles in Electrocatalysis: Development in Energy Conversion Process

Contribution of Carbon Dot Nanoparticles in Electrocatalysis: Development in Energy Conversion Process

Carbon Dot Nanoparticles Exert Inhibitory Effects on Human Platelets and Reduce Mortality in Mice with Acute Pulmonary Thromboembolism.

The inhibition of platelet activation is considered a potential therapeutic strategy for the treatment of arterial thrombotic diseases; therefore, maintaining platelets in their inactive state has garnered much attention. In recent years, nanoparticles have emerged as important players in modern medicine, but potential interactions between them and platelets remain to be extensively investigated. Herein, we synthesized a new type of carbon dot (CDOT) nanoparticle and investigated its potential as a new antiplatelet agent. This nanoparticle exerted a potent inhibitory effect in collagen-stimulated human platelet aggregation. Further, it did not induce cytotoxic effects, as evidenced in a lactate dehydrogenase assay, and inhibited collagen-activated protein kinase C (PKC) activation and Akt (protein kinase B), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) phosphorylation. The bleeding time, a major side-effect of using antiplatelet agents, was unaffected in CDOT-treated mice. Moreover, our CDOT could reduce mortality in mice with ADP-induced acute pulmonary thromboembolism. Overall, CDOT is effective against platelet activation in vitro via reduction of the phospholipase C/PKC cascade, consequently suppressing the activation of MAPK. Accordingly, this study affords the validation that CDOT has the potential to serve as a therapeutic agent for the treatment of arterial thromboembolic disorders

Green Synthesis of Carbon Dots and Evaluation of Its Pharmacological Activities

In this study, an eco-friendly, cost-effective and fast microwave method of preparation of carbon dots was employed. The antimicrobial and cytotoxic activities of metal-based nanoparticles are well known, but the effects of carbon dot nanoparticles (C-dot NPs) are less explored. Stable C-dot NPs were prepared from organic waste of pomegranate and watermelon peels and characterized by UV-visible spectrophotometer, fluorescent spectroscopy, Fourier transform infrared (FTIR) spectra, high-resolution transmission electron microscopy (HRTEM) and Raman’s spectroscopic techniques. The different biological applications of C-dots such as anti-microbial activity against Fusarium oxysporum, Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis and Escherichia coli and the cytotoxic activity against MCF-7 and HepG2 cell lines were evaluated. The study revealed that the C-dots synthesized from pomegranate peel (P-C dots) have larger effect than those synthesized from the watermelon peel (W-C dots) on therapeutic properties. C-dots synthesized by pomegranate peel extract and watermelon peel extract have shown the anti-bacterial activity at the concentration of 80 μL (19.67 ± 0.37) on bacterial strains versus ciprofloxacin at 10 μg/mL (19.67 ± 0.40) which was used as control. P-C dots (61.00 ± 1.90) have shown significant antifungal activity when compared with the fluconazole (85 ± 0.90) and the W-C dots did not show any activity. Further, P-C dots and W-C dots were evaluated for cytotoxic activity. Both P-C dots and W-C dots have shown strong anti-cancer effects for cell lines; for MCF-7, P-C dots have shown significant effect when compared with W-C dots, whereas for HepG2 cell lines, both the C-dots are showing almost equal range of effects. This study reveals that the C-dots synthesized from organic wastes can be used as a therapeutic agent to treat human microbial infections.

One‐pot synthesis of carbon dots@ZrO2 nanoparticles with tunable solid‐state fluorescence

In recent years, fluorescent carbon dots (CDs) have been developed and showed potential applications in biomedical imaging and light‐emitting diodes (LEDs) for their excellent fluorescent properties. However, it still remains a challenge to incorporate fluorescent CDs into the host matrix in situ to overcome their serious self‐quenching. Herein, a one‐pot hydrothermal method is used to prepare nano‐zirconia with CDs (CDs@ZrO2) nanoparticles. During the reaction, CDs and nano‐zirconia are generated simultaneously and connected with silane coupling agent. The CDs@ZrO2 nanoparticles exhibit tunable emission wavelength from 450 to 535 nm emission by regulating the content of citric acid in the feed. The quantum yield of the CDs@ZrO2 is up to 23.8%. Furthermore, the CDs@ZrO2 nanoparticles with regulable fluorescence emission can be used for the fluorescent material to prepare white LEDs. The prepared LED has significant white light emission with color coordinates of (0.30, 0.37) and its color rendering index (CRI) is 67.1. In summary, we have developed the solid‐state CDs@ZrO2 nanoparticles with tunable emission by a valuable strategy, that is, one‐pot method, for white LEDs.

Improving visible-light-induced photocatalytic ability of TiO2 through coupling with Bi3O4Cl and carbon dot nanoparticles

The fabrication of photocatalysts with considerable photocatalytic performance can be the main purpose for the researchers to substitute the traditional wastewater treatment processes. Accordingly, in this work, visible-light-responsive TiO2/Bi3O4Cl/carbon dots (denoted as TO/BOC/CD) photocatalysts were synthesized via simple strategy. Multiple techniques including EIS, photocurrent, XPS, PL, UV–vis DRS, BET, FT-IR, EDX, XRD, HRTEM, and SEM were employed to explore electrochemical, chemical, and physical features of the nanocomposites. The photocatalytic ability of the samples for Cr (VI), methylene blue, fuchsine, and rhodamine B removals was examined to display their widespread capability in removing different pollutants. The optimal photocatalytic performance related to the nanocomposite with 20% of BOC and 1 mL of CD solution (TO/BOC/CD (1 mL) photocatalyst), which was 13.8, 25.9, 14.2, and 52.3-folds as high as the TiO2 and 2.84, 2.26, 2.57, and 5.25-times higher than the TO/BOC (20%) nanocomposite in removals of Cr (VI), methylene blue, fuchsine, and rhodamine B, respectively. The impressive photocatalytic activity of the TO/BOC/CD photocatalysts is ascribed to the betterment of the optical property of the fabricated photocatalysts. With the enhancement CD content, the respective ternary nanocomposites displayed the highest optical absorption in the visible region. The other reasons in improving the photocatalytic activity are related to increased e−/h+ separation capability, and better textural properties. Additionally, trapping experiments demonstrated that the holes and superoxide anion radicals possess a substantial role during the photocatalytic reaction. Thus, this work could promote the potential utilization of TiO2-based photocatalysts for removal of hazardous contaminants under visible light.

ZnO-Associated Carbon Dot-Based Fluorescent Assay for Sensitive and Selective Dopamine Detection.

This paper presents a simple and highly efficient method for dopamine detection using water-soluble carbon dot nanoparticles. The ZnO-associated carbon dots (CDZs) were synthesized using a green chemical strategy. An examination of the effects of biomolecules on the fluorescence of CDZs revealed selective dopamine-induced quenching. In a phosphate buffer (pH = 7.4) medium, a detection limit of 1.06 nM was obtained. This “turn off” phenomenon was attributed to the electronic interaction between CDZs and dopamine, during the oxidation of dopamine. At lower pH, however, the effects of dopamine on the fluorescence of CDZs were insignificant as the oxidation of dopamine was hindered when the proton concentration was increased. This method was found to be free from the interference of coexisting molecules, that is, ascorbic acid and uric acid. This sensing platform was applied successfully in biological fluids to confirm the practical significance of the as-designed sensor.

Evaluation of antibacterial and in vivo wound healing activity of carbon dot nanoparticles

&#x0D; &#x0D; &#x0D; Treating post-surgical wound is one of the major challenges in the field of medical Science due to the several disadvantages posed by the antibiotics. The antimicrobial and Wound healing activity of metal based nanoparticles were well known, but the effects of carbon dot nanoparticles (C-Dots) are less explored. In the present study a wet chemical method for the synthesis of C-Dots from sucrose, glucose and fructose was developed and they were characterized by UV-Visible, Fluorescent spectroscopic techniques and the pharmaceutical applications such as antibacterial and the wound healing activities were evaluated. The study revealed that the C-Dots synthesized from Sucrose (SCD) and Glucose (GCD) showed potent antibacterial activity against both positive and negative bacterial strains at 12.5µl/ml (0.1 ± 0.003) and Fructose (FCD) at 50 µl/ml (0.1 ± 0.01) compared to the vehicle Control (0.61 ± 0.06). The wound healing of SCD (367.8 ± 15.2) was observed better than the Control (280.8 ± 10.72) and FCD (326.8 ± 9.41). GCD (166.8 ± 10.83) skin tissues indicated best healing as compared to FCD (135.8 ± 8.29), SCD (157.3 ± 16.97) and Control (135.8 ± 8.29). The results suggest that C-Dots applied topically possess wound healing activity and have potential applications as a bacteriostatic agent.&#x0D; &#x0D; &#x0D;

An injectable collagen-genipin-carbon dot hydrogel combined with photodynamic therapy to enhance chondrogenesis

Collagen has been widely used for cartilage repair, but its low stiffness and rapid degradation disfavor chondrogenesis. Here we conjugated biocompatible carbon dot nanoparticles (CD NPs) onto collagen through a natural product crosslinker (genipin) to prepare an injectable hydrogel (termed collagen-genipin-CD nanoparticles, CGN). The CGN hydrogel showed increased stiffness due to the cross-linking effect of genipin and the presence of CD NPs, and could produce a moderate amount of reactive oxygen species (ROS) by photodynamic therapy (PDT). Both the stiffness enhancement and ROS generation resulted in improved chondrogenic differentiation of bone marrow-derived stem cells (BMSCs) and the subsequent enhanced cartilage regeneration for cartilage defect repair. Specifically, the CGN hydrogel presented a 21-fold higher compression modulus and a 39.3% lower degradation rate than the pure collagen hydrogel. A combination of both PDT and CGN hydrogel increased the BMSCs proliferation by 50.3%, upregulated their expression of cartilage-specific genes by multiple folds, and enhanced GAG secretion by 205.1% on day 21. This combination also accelerated the cartilage regeneration within as short as 8 weeks. The stiffness enhancement and ROS generation synergistically contributed to chondrogenic differentiation by regulating the TGF-β/SMAD and mTOR signaling pathway, respectively. The combination of CD-modified hydrogel injection and PDT treatment represents a new strategy for minimally invasive repair of cartilage defects.

Photoluminescent Carbon Dots: A Mixture of Heterogeneous Fractions.

Photoluminescent carbon dots (CDs) fractions have been isolated from a gel-like material (GM), which was synthesized using a convenient one-step solvothermal route. In terms of purification, size exclusion chromatography (SEC) and dialysis were compared with acetone wash, which revealed the advantage of acetone wash. The pre-purified GM with acetone wash (A-GM) was further isolated by the reversed-phase preparative thin layer chromatography (TLC) with acetonitrile-water mixture (7 : 3; va /vw ) as the developing solvent. As a result, there were four photoluminescent bands on the TLC plate, which indicated the presence of four photoluminescent fractions. Detailed characterization measurements such as UV/Vis absorption, fluorescence emission, attenuated total reflection Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, zeta potential, dynamic light scattering, atomic force microscopy, and TEM measurements were performed on all fractions to analyze their heterogeneous optical, structural, electrical, and morphological properties. Considering the comprehensive analysis, all isolated fractions were CDs. In addition, excitation wavelength-independent CDs were obtained with a mean size of 2.5 nm and high quantum yield (55 %). Furthermore, the study demonstrates that the excitation wavelength-dependent photoluminescence of GM could result from the mixture of different surface states of each CD fraction rather than multiple surface states of uniform CDs nanoparticles.

A Carbon-Dot-Based Fluorescent Nanosensor for Simple Visualization of Bacterial Nucleic Acids.

A simple and facile method for sensing of nucleic acids is in great need for disease biomarker detection and diagnosis. Herein, a fluorescent nanosensor utilizing carbon dot nanoparticles is introduced that form visible precipitates in the presence of target DNA. Carbon dot nanoparticles are fabricated by microwave pyrolysis of polyethylenimine, which emits strong photoluminescence and can form precipitates when added to target DNA oligonucleotides. The precipitates can be easily visualized by UV illumination, and data can be acquired as images using a smartphone, which are analyzed for quantification. This carbon-dot-based assay allowed fluorescent sensing of target oligonucleotides with various sizes and visualization even with minimal amount of DNA (≈100 pmol). Finally, the assay can be applied as a nanosensor platform for detecting bacterial DNA for the antibiotic-resistance gene KPC-2 from Klebsiella pneumoniae. This method provides a simple technique for detecting molecular targets, showing wide applicability for diagnostics on the bedside or point-of-care testing.

Influence of hydrophilic carbon dots on polyamide thin film nanocomposite reverse osmosis membranes

There is critical to fabricate reverse osmosis (RO) membranes with high water-solute selectivity, thereby decreasing the energy input required in desalination processes. To achieve this, a super hydrophilic nano Carbon Dots (CDs) with quantum size of 6.8nm was self-synthesized and successfully incorporated into the selective layer of polyamide (PA) thin-film nanocomposite (TFN) RO membrane. The novel CDs-TFN RO membrane was fabricated by dispersing the CDs nanoparticles at varying quantities into aqueous solution through interfacial polymerization (IP) of monomers of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). Using Excitation and emission matrix (EEM) to explore the incorporation of CDs into the membrane skin layer, we observe that the fluorescence properties of CDs-TFN membrane decreased in order of increasing CDs concentration in relation to the unmodified TFC RO membrane which has the highest fluorescence count. The surface morphology of all TFN membranes transform from a leaf-like structure into ridge-and-valley structure with increased roughness, which has an important implication for flux enhancement. The TFN membrane with 0.02wt% CDs incorporation exhibited promising desalination performance with water flux of 87.1L/m2/h and salt rejection of 98.8% than the control thin film composite (TFC) membrane (2000ppm NaCl solution, 25°C, 1.55MPa). The improved performances of CDs-TFN membrane were attributed to the enhanced hydrophilicity, decreased thickness as well as the increased density of the selective layer due to the incorporation of small amounts of CDs nanoparticles. By extending the deposition time of CDs on the polysulfone substrate, the membrane performance was further improved with water flux of 88.7L/m2/h and salt rejection of 99.0%.

Interaction and cellular uptake of surface-modified carbon dot nanoparticles by J774.1 macrophages.

Carbon dot (Cdot) nanoparticles are an emerging class of carbon nanomaterials with a promising potential for drug delivery and bio imaging applications. Although the interaction between Cdots and non-immune cell types has been well studied, Cdot interactions with macrophages have not been investigated. Exposure of Cdot nanoparticles to J774.1 cells, a murine macrophage cell line, resulted in minimal toxicity, where notable toxicity was only seen with Cdot concentrations higher than 0.5 mg/ml. Flow cytometric analysis revealed that Cdots prepared from citric acid were internalized at significantly higher levels by macrophages compared with those prepared from bamboo leaves. Interestingly, macrophages preferentially took up phenylboronic acid (PB)-modified nanoparticles. By fluorescence microscopy, strong blue light-specific punctate Cdot fluorescence resembling Cdot structures in the cytosolic space was mostly observed in J774.1 macrophages exposed to PB-modified nanoparticles and not unmodified Cdot nanoparticles. PB binds to sialic acid residues that are overexpressed on diseased cell surfaces. Our findings demonstrate that PB-conjugated Cdots can be taken up by macrophages with low toxicity and high efficiency. These modified Cdots can be used to deliver drugs to suppress or eliminate aberrant immune cells such as macrophages associated with tumors such as tumor-associated macrophages.

Highly efficient gene silencing and bioimaging based on fluorescent carbon dots in vitro and in vivo

Small interfering RNA (siRNA) is an attractive therapeutic candidate for sequence-specific gene silencing to treat incurable diseases using small molecule drugs. However, its efficient intracellular delivery has remained a challenge. Here, we have developed a highly biocompatible fluorescent carbon dot (CD), and demonstrate a functional siRNA delivery system that induces efficient gene knockdown in vitro and in vivo. We found that CD nanoparticles (NPs) enhance the cellular uptake of siRNA, via endocytosis in tumor cells, with low cytotoxicity and unexpected immune responses. Real-time study of fluorescence imaging in live cells shows that CD NPs favorably localize in cytoplasm and successfully release siRNA within 12 h. Moreover, we demonstrate that CD NP-mediated siRNA delivery significantly silences green fluorescence protein (GFP) expression and inhibits tumor growth in a breast cancer cell xenograft mouse model of tumor-specific therapy. We have developed a multifunctional siRNA delivery vehicle enabling simultaneous bioimaging and efficient downregulation of gene expression, that shows excellent potential for gene therapy.

Parallel factor analysis of EEM of the fluorescence of carbon dots nanoparticles

AbstractThe effect of experimental factors [pH and Hg(II)] on the fluorescence excitation emission matrices (EEMs) of nanosensor carbon dots (CDs) was analyzed by multiway decomposition methods based on parallel factor (PARAFAC) analysis. PARAFAC analysis of the EEM structures identifies three components corresponding to two different‐sized CDs with the Hg(II) and pH profiles highly correlated plus a background. Parallel profiles with Linear Dependences (PARALIND) model with three components in the excitation–emission spectral modes and two components in the Hg(II) or pH mode gave similar results as PARAFAC, but is more useful from a theoretical point of view because PARALIND shows that the two different‐sized CDs have similar chemical reactivity toward Hg(II) and pH. PARAFAC2 was used as a trilinear confirmatory test of the data structures under analysis. Copyright © 2010 John Wiley &amp; Sons, Ltd.