Colloidal Carbon Research Articles

Development and application of a colloidal carbon test strip for the detection of antibodies against Mycoplasma bovis.

Mycoplasma bovis (M. bovis) is an important bovine mycoplasma implicated in economically important clinical diseases, such as respiratory diseases, otitis media, and mastitis. The prevalence of M. bovis-associated mastitis in both cattle and buffaloes has been increasingly recognized as a global problem. High morbidity rates and consequential economic losses have been devastating to the affected cattle and buffalo farms, especially those in developing countries. Therefore, a rapid and accurate method is urgently needed to detect M. bovis. In this study, a rapid and simple lateral flow strip for detecting antibodies against M. bovis was established that used carbon nanoparticles (CNPs) as the labelled materials. The results from the test strip were highly consistent with those from ELISA. The test showed high specificity (100%) and no cross-reaction with other bovine pathogens. The detection sensitivity of the test was also relatively high (97.67%). All the results indicated that the colloidal carbon test strip could serve as a simple, rapid, sensitive, and specific diagnostic method for detecting antibodies against M. bovis at cattle farms.

Changes in splenic uptake pattern associated with X-ray irradiation

PurposeTo evaluate the splenic uptake function after irradiation with high-energy X-rays. Materials and methodsFourteen male Wistar rats were distributed into three groups. Group 1 (n = 6) – control, non-irradiated; Group 2 (n = 4) – animals that were irradiated and studied 24 h after irradiation; and Group 3 (n = 4) – animals that were irradiated and studied 48 h after irradiation. The animals were irradiated with 8 Gy X-rays in the abdominal region. According with the groups, after 24 or 48 h, 1 ml/kg of a 50% colloidal carbon solution was injected in the left internal jugular vein. After 40 min, the spleens were removed for histological studies. Macrophages containing carbon pigments in their cytoplasms were counted in 16 consecutive microscopic fields, and their means were considered as the uptake pattern of each animal. ResultsIn the control groups, carbon pigments were captured by macrophages in the red and white pulps, while in the irradiated groups, the uptake in the marginal zone, around the white pulp, was enhanced. There was no disorder on the splenic parenchyma or necrosis in histological analyzes. Qualitatively rare apoptotic events were observed, with no difference between control and irradiated animals. ConclusionThe high-energy X-ray, used in radiotherapy, modifies the splenic clearance, enhancing the amount of marginal zone macrophages containing colloid particles. This radiation was not associated with morphological changes, nor with necrosis or apoptosis of splenic tissue.

Nanomaterial Labels in Lateral Flow Immunoassays for Point-of-Care-Testing

Lateral flow immunoassays (LFIAs) have been developed rapidly in recent years and used in a wide range of application at point-of-care-testing (POCT), where small biomolecules can be conveniently examined on a test strip. Compared with other biochemical detection methods such as ELISA (enzyme linked immunosorbent assay) or mass spectrometry method, LFIAs have the advantages of low cost, easy operation and short time-consuming. However, it suffers from low sensitivity since conventional LFIA can only realize qualitative detection based on colorimetric signals. With the increasing demand for more accurate and sensitive determination, novel nanomaterials have been used as labels in LFIAs due to their unique advantages in physical and chemical properties. Colloidal gold, fluorescent nanoparticles, SERS-active nanomaterials, magnetic nanoparticles and carbon nanomaterials are utilized in LFIAs to produce different kinds of signals for quantitative or semi-quantitative detection. This review paper first gives a description of the LFIA principles, and then focuses on the state-of-the-art nanomaterial labelling technology in LFIAs. At last, the conclusion and outlook are given to inspire exploration of more advanced nanomaterials for the development of future LFIAs.

Colloidal iron and organic carbon control soil aggregate formation and stability in arable Luvisols

Several beneficial soil functions are linked to aggregates, but how the formation and stability depend on the presence of colloidal- and nanosized (1000–1 nm) bulding blocks is still understood poorly. Here, we sampled subsites from an arable toposequence with 190 and 340 g kg−1 clay, and isolated small soil microaggregates (SMA; <20 µm) from larger macroaggregate units (>250 µm) using an ultrasonic dispersion energy of 60, 250, and 440 J mL−1, respectively. We then allowed these small SMA to reaggregated after chemical removal of organic carbon (OC) as well as of Fe- and Al (hydr)oxides, respectively. The size distribution of the reaggregated small SMA and fine colloids (<0.45 µm) was analyzed via laser diffraction and asymmetric flow field-flow fractionation coupled to inductively coupled plasma mass spectrometry and organic carbon detection, respectively. We found elevated amounts of both finer colloids and stable SMA at subsites with higher clay contents. The size distribution of small SMA was composed of two distinctive fractions including colloids and larger microaggregates with an average size of 5 µm. The removal of Fe with Dithionite-Citrate-Bicarbonate (DCB) shifted the size of the small SMA to a larger equivalent diameter, while removal of OC with NaOCl reduced it. After three wetting and drying cycles, the concentration of colloids declined, whereas the small SMA without chemical pre-treatments reaggregated to particles with larger average diameters up to 10 µm, with the size depending on the clay content. Intriguingly, this gain in size was more pronounced after Fe removal, but it was not affected by OC removal. We suggest that Fe (hydr)oxides impacts the stability of small SMA primarily by being present in small-sized pores and thus cementing the aggregates to smaller size. In contrast, the effect of OC was restricted to the size of colloids, gluing them together to small SMAs within defined size ranges when OC was present but releasing these colloids when OC was absent.

Characterization of Iron and Organic Carbon Colloids in Boreal Rivers and Their Fate at High Salinity.

Riverine colloids are important carriers of macronutrients, trace metals, and pollutants into marine waters. The aim of the current study was to extend the understanding of iron (Fe) and organic carbon (OC) colloids in boreal rivers and their fate at higher salinities. X‐ray absorbance spectroscopy (XAS) and dynamic light scattering (DLS) were combined to explore Fe speciation and colloidal characteristics such as size and surface charge and how these are affected at increasing salinity. XAS confirmed the presence of two Fe phases in the river waters—Fe‐organic matter (OM) complexes and Fe(oxy)hydroxides. From DLS measurements on filtered and unfiltered samples, three particle size distributions were identified. The smallest particles (10–40 nm) were positively charged and suggested to consist of essentially bare Fe(oxy)hydroxide nanoparticles. The largest particles (300–900 nm) were dominated by Fe(oxy)hydroxides associated with chromophoric molecular matter. An intermediate size distribution (100–200 nm) with a negative surface charge was presumably dominated by OM and containing Fe‐OM complexes. Increasing the salinity resulted in a removal of the smallest distribution. Unexpectedly, both the intermediate and largest size distributions were still detected at high salinity. The collective results suggest that Fe(oxy)hydroxides and Fe‐OM complexes are both found across the wide size range studied and that colloidal size does not necessarily reflect either Fe speciation or stability toward salinity‐induced aggregation. The findings further demonstrate that also particles beyond the typically studied <0.45‐μm size range should be considered to fully understand the riverine transport and fate of macronutrients, trace metals, and pollutants.

Preparation of CoFe2O4 hollow spheres with carbon sphere templates and their wave absorption performance

In the synthesis of colloidal carbon spheres (CCSs) from glucose by hydrothermal carbonization, agglomeration and cross-linking often occur, affecting their functions as templates. In this study, the effects of various surfactants on the dispersion and particle size of CCS were investigated. The CCS synthesized with dodecyltrimethylammonium bromide was much larger than those of other groups, and the average diameter exceeded 6.4 μm. CCS with complete spherical shape and good dispersion were obtained using sodium polyacrylate, with a diameter of approximately 450 nm CoFe2O4 hollow spheres were prepared by a simple adsorption–calcination method using CCS as the templates, and the effects of different dispersions and particle sizes on the electromagnetic parameters and microwave absorption properties of hollow spheres were studied. The results show that the absorption bandwidth corresponding to reflection loss less than −7 dB widened from 2.64 GHz to 3.44 GHz with improving dispersion of hollow sphere structure. When the size of the hollow sphere increased to the micron level, the thickness required to reach the maximum bandwidth reduced by 0.5 mm. Compared to the unoptimized hollow spheres, the microwave absorption performance of the as-prepared CCCs improved effectively. The effect of surfactants on the dispersion of CCS and the effect of the dispersion and size of CoFe2O4 hollow spheres on their electromagnetic properties are discussed in detail.

In Vivo Immunomodulatory Potential of Partial Purified Lectin from the Saffron Milk Cap Mushroom, Lactarius deliciosus (Agaricomycetes), against Colloidal Carbon Particles.

Mushroom compounds and biomolecules are known for their biological beneficial effects and dietary properties. Their molecules can be used in immunology for their ability to stimulate immune cells and in biotherapy of diseases. In this study, the immunomodulatory effect using carbon clearance test in vivo of partial purified lectin of Lactarius deliciosus using DEAE-Sephacyl column, with sugar affinity against galactose, methyl-β-D-galactopyranoside and lactose, showed a significant effect on phagocytic activity and half-life of carbon particles in mice with different concentrations (5, 10, 15, and 30 mg/kg). The results showed that the immunomodulatory effect increased in low doses and decreased in high doses compared with the control group p < 0.0001. L. deliciosus lectin exerted a dose-dependent immunostimulant activity toward the reticulo-endothelial system, and phagocytic activity toward macrophages and neutrophils in spleen and liver against the colloidal carbon.

Antigen trapping in the reticuloendothelial system of Schizothorax niger Haeckel

By injecting the colloidal carbon particles, the mononuclear phagocyte system in Schizothorax niger was studied in vivo. As per results the major organs of carbon particle localization in Schizothorax niger after studying histology of organs from 2 hours to day 8 were kidney, spleen, thymus and heart. Spleen was seen with highest density of carbon particles followed by the kidney. The medulla of the thymus was seen first with antigen trapping ability followed by the cortex after day 4. The ventricular endocardial cells of heart were seen as Immunocompetent. Uptake of carbon particles by the monocytes was seen upto day 2.

Performance improvement of oxygen on the carbon substrate surface for dispersion of cobalt nanoparticles and its effect on hydrogen generation rate via NaBH4 hydrolysis

Carbon substrates, as previously reported, are colloidal carbon spheres (CCS) that contain oxygen-rich functional groups on the surface could that provide a suitable support for Co catalysts used for the hydrolysis of NaBH4. Our results show that the unmodified CCS substrate does not adequately interact with the Co2+ precursor to decrease the cobalt ion concentration in solution. However, after successful modification of the oxygen groups on the CCS substrate's surface, the Co ion concentration in solution decreased by 30% indicating interaction of the Co ions with the substrate surface. Also the cobalt dispersion and the hydrogen generation rate (HGR) for the catalysts supported on the modified substrate is much better than for the Co catalyst supported on the unmodified substrate. Therefore, the presence of oxygen on the substrate surface is not sufficient to provide a suitable dispersion and performance for nanocatalysts and modification of the surface leads to an improved catalyst.

Amorphous Photonic Structures with Brilliant and Noniridescent Colors via Polymer-Assisted Colloidal Assembly.

Efficient and large area fabrication of amorphous photonic crystals (APCs) with multicolor, angle independency, and fine resolution is always desired owing to their application in color displays, sensors, and pigments. Here, we report a polymer-assisted colloidal assembly (PACA) method to fabricate APCs with brilliant structural colors by the co-assembly of silica colloidal particles, polyvinylpyrrolidone (PVP), and carbon black (CB). PVP is the key to enable the amorphous aggregations of the particles, the uniform and noniridescent structural colors of the APCs. Moreover, multicolor and high-resolution patterns can be prepared through the mask-based brush printing with colloids–PVP–CB precursor solution as ink (named as APCs-ink). The developed printing method can be applied to various substrates with different roughness, curvature, and flexibility such as papers, metals, plastic films, stones, and even curved glasses. PACA is efficient and straightforward for the fabrication of APCs and high-resolution patterns with large area, low cost, and easy operation, which will facilitate their practical applications in the fields of color-related display, green painting, anticounterfeiting, and so on.

Free and conjugated estrogens detections in drainage tiles and wells beneath fields receiving swine manure slurry

Although livestock manure, such as from swine (Sus scrofa domestica), have high capacity to introduce endocrine-disrupting free estrogens into the environment, the frequency of estrogen detections from reconnaissance studies suggest that these compounds are ubiquitous in the environment, perhaps resulting from historic manure inputs (e.g. cattle grazing residues, undocumented historic manure applications) or uncontrolled natural sources. Compared to free estrogens, conjugates of estrogens are innocuous but have greater mobility in the environment. Estrogen conjugates can also hydrolyze to re-form the potent free estrogens. The objective of this study was to identify the transport of free and conjugated estrogens to subsurface tile drains and groundwater beneath fields treated with swine manure slurry. Three field treatments were established, two receiving swine lagoon manure slurry and one with none. Manure slurry was injected into soils at a shallow depth (∼8 cm) and water samples from tile drains and shallow wells were sampled periodically for three years. Glucuronide and sulfate conjugates of 17β-estradiol (E2) and estrone (E1) were the only estrogen compounds detected in the tile drains (total detects = 31; 5% detection frequency; conc. range = 3.9–23.1 ng L−1), indicating the important role conjugates played in the mobility of estrogens. Free estrogens and estrogen conjugates were more frequently detected in the wells compared to the tile drains (total detects = 70; 11% detection frequency; conc. range = 4.0–1.6 × 103 ng L−1). No correlations were found between estrogen compound detections and dissolved or colloidal organic carbon (OC) fractions or other water quality parameters. Estrogenic compounds were detected beneath both manure treated and non-treated plots; furthermore, the total potential estrogenic equivalents (i.e. estrogenicity of hydrolyzed conjugates + free estrogens) were similar between treated and non-treated plots.

Nanoengineering Carbon Spheres as Nanoreactors for Sustainable Energy Applications.

Colloidal carbon sphere nanoreactors have been explored extensively as a class of versatile materials for various applications in energy storage, electrochemical conversion, and catalysis, due to their unique properties such as excellent electrical conductivity, high specific surface area, controlled porosity and permeability, and surface functionality. Here, the latest updated research on colloidal carbon sphere nanoreactor, in terms of both their synthesis and applications, is summarized. Various synthetic strategies are first discussed, including the hard template method, the soft template method, hydrothermal carbonization, the microemulsion polymerization method, and extension of the Stöber method. Then, the functionalization of colloidal carbon sphere nanoreactors, including the nanoengineering of compositions and the surface features, is discussed. Afterward, recent progress in the major applications of colloidal carbon sphere nanoreactors, in the areas of energy storage, electrochemical conversion, and catalysis, is presented. Finally, the perspectives and challenges for future developments are discussed in terms of controlled synthesis and functionalization of the colloidal carbon sphere nanoreactors with tunable structure, and the composition and properties that are desirable for practical applications.

Synthesis of Well-Defined Internal-Space-Controllable UiO-66 Spherical Nanostructures Used as Advanced Nanoreactor.

Controllable well-defined metal-organic frameworks (MOFs) spherical structures are expected to be potential good platforms for the heterogeneous catalysis, guest storage, and drug delivery. However, the synthesis faces a challenge. In this paper, a series of well-defined MOFs spherical structures including core-shell, yolk-shell, and hollow spheres were successfully constructed with colloidal carbon as template. Meanwhile, the shapes of MOFs unit (bricklike or octahedral) and sizes of the formed internal space can be controlled simultaneously by rationally changing the modulator and removing template in a good manner. The as-prepared structures could not only keep intact crystal textures but also be used as advanced nanoreactors for enhancing raw materials conversion in the heterogeneous reaction of synthesizing benzoin ethyl ether. Particularly, by our internal-space-controllable nanoreactors, for the first time, the quantifiable relation between nanoreactors' internal space sizes and raw material conversion was revealed.

Uniform, Scalable, High-Temperature Microwave Shock for Nanoparticle Synthesis through Defect Engineering

Summary Here we demonstrate a thermal shock synthesis method triggered by microwave irradiation for the rapid synthesis of nanoparticles on reduced graphene oxide (RGO) substrate. With properly controlled reduction, RGO has high electrical conductivity while maintaining functional groups, leading to an extremely efficient microwave absorption of ∼70%. The high utilization of microwaves results in the ability to raise the temperature to 1,600 K in just 100 ms, which is followed by rapid quenching to room temperature. The defects on the RGO are crucial for achieving this record-high microwave-induced temperature as these defects play a fundamental role in absorbing the radiation as well as the self-quenching mechanism. By loading precursors onto RGO, we can utilize rapid temperature change to synthesize nanoparticles. The nanoparticles are ∼10 nm with uniform distribution. This facile, rapid, and universal synthesis technique has the potential to be employed in large-scale production of nanomaterials and suggests a new direction for nanosynthesis.

Field emission enhancement of PbS colloidal quantum dot-decorated single-walled carbon nanotubes

Herein, a simple and effective PbS colloidal quantum dot (CQD) decoration method for single-walled carbon nanotube (SWNT) is demonstrated. By dipping the SWNT film into a CQD dispersion followed by a solid-state ligand exchange, CQDs were successfully decorated onto the wall of SWNT without compromising a narrow size distribution. Spectroscopic studies suggested that (1) the CQD decoration and subsequent ligand exchange process did not alter the chemical nature of the SWNT framework and (2) there was a charge (electron) transfer process from the PbS CQD to the SWNT. Field emission (FE) characteristics of the CQD-decorated SWNT films revealed that FE enhancement was indeed established from SWNTs with a moderate degree of CQD decoration, while those with excessive decoration (coating) exhibited notable FE suppression. Horizontal current-voltage measurements with perpendicular-directional external electric field modulation suggested that electron supplement of SWNT from PbS CQD was pronounced as the amount of decorated CQDs increased. Based on the experimental results, we proposed a new mechanism demonstrating FE enhancement of a CQD/SWNT heterostructure.

Heterogeneous Contraction-Mediated Asymmetric Carbon Colloids

Introducing asymmetry in carbon colloids can enrich their already broad merits; however, the tailored synthesis of asymmetric carbon colloids remains a great challenge. Herein, we report the synthesis of asymmetric semi-yolk–shell carbon spheres (semi-YSCS) with rich N-doping (3.9 at%), raspberry-like rough surface, abundant mesopores, and uniform particle size (∼600 nm). An interface-induced heterogeneous contraction mechanism is proposed. The unique structural features endow the semi-YSCS a high specific capacitance (283 F g–1 at 1 A g–1), favorable cycling stability, and superior rate performance in aqueous supercapacitors. This work provides new insights into the rational design of asymmetric carbon colloids.

Smurfs: Forensic aspects

The Smurfs (French: Les Schtroumpfs; Dutch: De Smurfen) is a Belgian comic centered on a fictional colony of small, blue and human-like creatures that live in mushroom-shaped houses in the forest. Sometimes, in the course of forensic activity, some cases sound like this comic when patients or victims exhibit a spectacular blue appearance. We report two cases of such situation. (1) The corpse aspect of a 52-year-old dead man displays a impressive intense blue color, including mucosa and conjunctiva. A bottle containing a blue liquid is found close to the corpse. At the autopsy, all fluids and organs are of the same spectacular blue color. (2) A 62-year-old alive woman displays an inhomogeneous blue aspect on several body areas. Her medical history includes breast cancer, bipolar disease and anorexia. Blue spots appeared 10 years ago after a coccyx trauma with an upward progress on the body. Genital and oral mucosa are affected while several areas remain healthy. Methods Toxicological investigations, including screening for organic and mineral substances, are performed in biological samples (postmortem samples in case 1, blood and urine in case 2) using GC-MS, LC-MS/MS, LC-HRMS and ICP-MS. In case 2, a biological check-up and a skin biopsy are performed. (1) Positive results consist in therapeutic or infratherapeutic blood levels of codeine (109 μg/L), morphine (1 μg/L), meprobamate (1 mg/L) and pregabaline (3.8 mg/L). The blue liquid in the bottle is identified as acid blue 9 dye (or brilliant Blue FCF) that is used as a food coloring (E133). Additional Results from the police investigation include the discovery of a Compo bleu™ container. This acid blue 9 dye highly concentrated solution (500 g/L) is usually intended to be added to herbicide/pesticide liquid preparations in order to spot temporarily treated areas. The cause of death remains finally unclear, but could be related to a massive ingestion of this (although reputed non-toxic) concentrated substance. (2) Biological check-up (comprising liver and renal parameters, calcium and phosphorus homeostasis, ceruloplasmin level…) reveals no abnormality. Toxicological analyses reveal numerous psychoactive drug intakes (zolpidem, clonazepam, hydroxyzine, gabapentine). Skin biopsy discloses abundant black pigment phagocyted by histiocytes at the dermo-hypodermic level, without any inflammatory infiltrate. Electronic microscopy of skin biopsy reveals a heterogeneous intracellular material with clear vacuoles bordered with granulation (carbon was identified in this granulations using X-ray) [1] . Final diagnostic concludes in self-tatoo practices using a colloidal carbon solution in a psychiatric context. Such product (colloidal carbon 10% water solution, Sterimark™), which is easily accessible on Internet, is medically used to spot mammary tumors before radiotherapy. Smurfs do not exist in real life and our small experience illustrated by these two cases strongly suggests that those who want to look like Smurfs are cheaters.

Colloidal carbon interference in the treatability of pulp and paper wastewater by MBR

Pulp and paper wastewaters are challenging to treat due to their variability, complexity and toxicity. Membrane Bioreactor’s (MBR’s) provide high-quality filtrates but are subject to periods of low filterability / high capillary suction time (CST) which potentially limit their use in this application. There is a paucity of published literature concerning long-term operational issues in full-scale, industrial MBR’s. We hypothesised that either changes of bacterial population, alteration/reduction of bacterial metabolism or bacterial production of extra-cellular polymers (ESPs) increased CST and reduced filterability. This study, conducted over two years at the 16.4MLD Gippsland Water Factory, was structured to inform this bacterial centric hypothesis. However, no shifts in bacterial population were seen as causative of high CST and microbial stress levels and biological activity were observed to be low during high CST and no sign of toxicity was found. The strongest correlator with CST was the concentration of colloidal Total Organic Carbon of the mixed liquor suspended solids (MLSS) supernatant (following centrifugation). The carbonaceous colloids accumulated in the supernatant were named ‘Non-Centrifugable Total Organic Carbon’ (NCTOC). Their accumulation in the MLSS was found be due to their biologically refractory nature and their retention by the MBR membrane. The accumulation of NCTOC typically followed a period where the influent had a high colour and a high sodium to calcium ratio, which is consistent with a pulping by-product called ‘Black Liquor’. Additional experiments with Black Liquor allowed us to conclude that high CST can be produced by addition of Black Liquor.

Bioinspired Carbon Quantum Dots: An Antibiofilm Agents.

Carbon dots, very tiny carbon material with various surface passivations, have emerged as a new class of nanomaterials for various applications. Herein, we describe a simple, economical, and green approach for the synthesis of colloidal luminescent carbon dots (C-dots) by solvothermal method from fruit juice of Citrus limetta, an abundantly available plant in Asian countries. The existence of C-dots was confirmed by X-ray Diffraction and High Resolution Transmission Electron Microscopy studies. The C-dots size was observed to be 2-4 nm. We further evaluated the efficacy of C-dots to inhibit the attachment of Candida albicans MTCC 227, and biofilm formation on the polystyrene surfaces. The C-dots have effectively inhibited the attachment and formation of biofilm in Candida albicans at very low concentrations, which is hitherto unattempted. The ability of C-dots to inhibit biofilm formation may contribute to diverse applications of C-dots in biomedical field.

Refractive index dependent optical property of carbon dots integrated luminescent solar concentrators

Abstract Colloidal Carbon dots (C-dots) have been used as promising emitters for luminescent solar concentrators (LSCs) due to its high quantum yield, low-cost, non-toxic and simple synthetic method. While it is still very challenging to fabricate high-efficiency LSCs based on C-dots because of strong spectral overlap between the absorption and emission. It is still unclear how the refractive index of the C-dots layer affects the optical properties of LSCs. Here we used liquid junction LSCs as an example to investigate the refractive index effect. A large-area (∼100 cm2) LSC was fabricated by injecting C-dots/polyvinylpyrrolidone solution into a glass mold. The refractive index of the polymer solution can be well controlled in the range of 1.33–1.44 by simply enhancing the polymer concentration. The reabsorption energy loss and the optical efficiency of the LSCs are strongly dependent on the refractive index of the polymer solution. The LSC based on C-dots/polymer exhibits refractive index dependent optical efficiency, as high as ∼0.92% under sunlight illumination, which is 27% enhancement in efficiency over the LSC based on C-dots dispersed in methanol.