Activated Carbon/Pectin Composite Enterosorbent for Human Protection from Intoxication with Xenobiotics Pb(II) and Sodium Diclofenac.

The use of enterosorbents-materials which can be administered orally and eliminate toxic substances from the gastrointestinal tract (GIT) by sorption-offers an attractive complementary protection of humans against acute and chronic poisoning. In this study, we report the results of developing a microgranulated binary biomedical preparation for oral use. It was designed with a core-shell structure based on pectin with low degree of esterification as the core, and nanoporous activated carbon produced from rice husk, AC-RH, as the shell, designated as AC-RH@pectin. The adsorption properties of the synthesized materials were studied in aqueous solutions for the removal of lead (II) nitrate as a representative of toxic polyvalent metals and sodium diclofenac as an example of a medicinal drug. The composite enterosorbent demonstrated high adsorption capacity for both adsorbates studied. Adsorption kinetics of lead and diclofenac adsorption by AC-RH, pectin, and AC-RH@pectin, fitted well a pseudo-second-order model. According to the Langmuir adsorption isotherm model, the best fitted isotherm model, the maximum adsorption capacity, qmax, of AC-RH@pectin for diclofenac and for lead (II) was 130.9 mg/g and 227.8 mg/g, respectively. Although qmax of AC-RH for diclofenac, 537.6 mg/g, and qmax of pectin for lead (II), 245.7 mg/g, were higher, the maximum adsorption capacity of AC-RH for lead (II), 52.7 mg/g, was much lower than that of the composite AC-RH@pectin and the adsorption capacity of pectin for diclofenac was negligible. Therefore, the composite material AC-RH@pectin demonstrated substantial efficiency of removing both species which potentially defines it as a more universal enterosorbent suitable for treating poisoning caused by substances of different chemical nature.

Surface-Functionalized Conducting Nanofibers for Electrically Stimulated Neural Cell Function.

Strategies involving the inclusion of cell-instructive chemical and topographical cues to smart biomaterials in combination with a suitable physical stimulus may be beneficial to enhance nerve-regeneration rate. In this regard, we investigated the surface functionalization of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV)-based electroconductive electrospun nanofibers coupled with externally applied electrical stimulus for accelerated neuronal growth potential. In addition, the voltage-dependent conductive mechanism of the nanofibers was studied in depth to interlink intrinsic conductive properties with electrically stimulated neuronal expressions. Surface functionalization was accomplished using 3-aminopropyltriethoxysilane (APTES) and 1,6-hexanediamine (HDA) as an alternative to costly biomolecule coating (e.g., collagen) for cell adhesion. The nanofibers were uniform, porous, electrically conductive, mechanically strong, and stable under physiological conditions. Surface amination boosted biocompatibility, 3T3 cell adhesion, and spreading, while the neuronal model rat PC12 cell line showed better differentiation on surface-functionalized mats compared to nonfunctionalized mats. When coupled with electrical stimulation (ES), these mats showed comparable or faster neurite formation and elongation than the collagen-coated mats with no-ES conditions. The findings indicate that surface amination in combination with ES may provide an improved strategy to faster nerve regeneration using MEH-PPV-based neural scaffolds.

Synthetic Amphoteric Cryogels as an Antidote against Acute Heavy Metal Poisoning.

The effectiveness of an amphoteric cryogel (AAC) as an oral sorbent (enerosorbent) for the treatment of acute poisoning of small animals (rats) with heavy metals (HMs) was studied in in vivo experiments. The morphological structure of the cryogel was examined using scanning electron microscopy/energy-dispersive X-ray analysis and confocal microscopy. The use of the cryogel in the treatment of rats administered an LD50 dose of Cd(NO3)2, CsNO3, Sr(NO3)2, or HgCl2 in aqueous solution showed their high survival rate compared to the control group, which did not receive such treatment. The histological and chemical analysis of internal tissues and the biochemical analysis of the blood of the experimental animals showed the effectiveness of the cryogel in protecting the animals against the damaging effect of HMs on the organism comparable with unithiol, a chelating agent based on 2,3-dimercapto-1-propane sulfonic acid sodium salt (DMPS) approved for the treatment of acute poisoning with some heavy metals.

Correction to: a new Rhodococcus aetherivorans strain isolated from lubricant-contaminated soil as a prospective phenol-biodegrading agent.

The published online version contains mistake in Table 3.

A new Rhodococcus aetherivorans strain isolated from lubricant-contaminated soil as a prospective phenol-biodegrading agent.

Microbe-based decontamination of phenol-polluted environments has significant advantages over physical and chemical approaches by being relatively cheaper and ensuring complete phenol degradation. There is a need to search for commercially prospective bacterial strains that are resistant to phenol and other co-pollutants, e.g. oil hydrocarbons, in contaminated environments, and able to carry out efficient phenol biodegradation at a variable range of concentrations. This research characterizes the phenol-biodegrading ability of a new actinobacteria strain isolated from a lubricant-contaminated soil environment. Phenotypic and phylogenetic analyses showed that the novel strain UCM Ac-603 belonged to the species Rhodococcus aetherivorans, and phenol degrading ability was quantitatively characterized for the first time. R. aetherivorans UCM Ac-603 tolerated and assimilated phenol (100% of supplied concentration) and various hydrocarbons (56.2-94.4%) as sole carbon sources. Additional nutrient supplementation was not required for degradation and this organism could grow at a phenol concentration of 500 mg L-1 without inhibition. Complete phenol assimilation occurred after 4 days at an initial concentration of 1750 mg L-1 for freely-suspended cells and at 2000 mg L-1 for vermiculite-immobilized cells: 99.9% assimilation of phenol was possible from a total concentration of 3000 mg L-1 supplied at daily fractional phenol additions of 750 mg L-1 over 4 days. In terms of phenol degradation rates, R. aetherivorans UCM Ac-602 showed efficient phenol degradation over a wide range of initial concentrations with the rates (e.g. 35.7 mg L-1 h-1 at 500 mg L-1 phenol, and 18.2 mg L-1 h-1 at 1750 mg L-1 phenol) significantly exceeding (1.2-5 times) reported data for almost all other phenol-assimilating bacteria. Such efficient phenol degradation ability compared to currently known strains and other beneficial characteristics of R. aetherivorans UCM Ac-602 suggest it is a promising candidate for bioremediation of phenol-contaminated environments.

Impact of electromagnetic fields on in vitro toxicity of silver and graphene nanoparticles.

The correlation between shape and concentration of silver nanoparticles (AgNPs), their cytotoxicity and formation of reactive oxygen species (ROS) in the presence of electromagnetic fields (EMFs) has been investigated. In addition, the bio-effects caused by the combination of EMFs and graphene nanoparticles (GrNPs) have been also assessed. The AgNPs of three shapes (triangular, spherical and colloidal) and GrNPs were added in high concentrations to the culture of human fibroblasts and exposed to EMF of three different frequencies: 900, 2400 and 7500 MHz. The results demonstrated the dependence of the EMF-induced cytotoxicity on the shape and concentration of AgNPs. The maximal cell killing effect was observed at 900 MHz frequency for NPs of all shapes and concentrations. The highest temperature elevation was observed for GrNPs solution irradiated by EMF of 900 MHz frequency. The exposure to EMF led to significant increase of ROS formation in triangular and colloidal AgNPs solutions. However, no impact of EMF on ROS production was detected for spherical AgNPs. GrNPs demonstrated ROS-protective activity that was dependent on their concentration. Our findings indicate the feasibility to control cytotoxicity of AgNPs by means of EMFs. The effect EMF on the biological activity of AgNPs and GrNPs is reported here for the first time.

Carbon-cryogel hierarchical composites as effective and scalable filters for removal of trace organic pollutants from water.

Effective technologies are required to remove organic micropollutants from large fluid volumes to overcome present and future challenges in water and effluent treatment. A novel hierarchical composite filter material for rapid and effective removal of polar organic contaminants from water was developed. The composite is fabricated from phenolic resin-derived carbon microbeads with controllable porous structure and specific surface area embedded in a monolithic, flow permeable, poly(vinyl alcohol) cryogel. The bead-embedded monolithic composite filter retains the bulk of the high adsorptive capacity of the carbon microbeads while improving pore diffusion rates of organic pollutants. Water spiked with organic contaminants, both at environmentally relevant concentrations and at high levels of contamination, was used to determine the purification limits of the filter. Flow through tests using water spiked with the pesticides atrazine (32 mg/L) and malathion (16 mg/L) indicated maximum adsorptive capacities of 641 and 591 mg pollutant/g carbon, respectively. Over 400 bed volumes of water contaminated with 32 mg atrazine/L, and over 27,400 bed volumes of water contaminated with 2 µg atrazine/L, were treated before pesticide guideline values of 0.1 µg/L were exceeded. High adsorptive capacity was maintained when using water with high total organic carbon (TOC) levels and high salinity. The toxicity of water filtrates was tested in vitro with human epithelial cells with no evidence of cytotoxicity after initial washing.

A Comprehensive Review of Topical Odor-Controlling Treatment Options for Chronic Wounds.

The process of wound healing is often accompanied by bacterial infection or critical colonization, resulting in protracted inflammation, delayed reepithelization, and production of pungent odors. The malodor produced by these wounds may lower health-related quality of life and produce psychological discomfort and social isolation. Current management focuses on reducing bacterial activity within the wound site and absorbing malodorous gases. For example, charcoal-based materials have been incorporated into dressing for direct adsorption of the responsible gases. In addition, multiple topical agents, including silver, iodine, honey, sugar, and essential oils, have been suggested for incorporation into dressings in an attempt to control the underlying bacterial infection. This review describes options for controlling malodor in chronic wounds, the benefits and drawbacks of each topical agent, and their mode of action. We also discuss the use of subjective odor evaluation techniques to assess the efficacy of odor-controlling therapies. The perspectives of employing novel biomaterials and technologies for wound odor management are also presented.

An adsorbent monolith device to augment the removal of uraemic toxins during haemodialysis.

Adsorbents designed with porosity which allows the removal of protein bound and high molecular weight uraemic toxins may improve the effectiveness of haemodialysis treatment of chronic kidney disease (CKD). A nanoporous activated carbon monolith prototype designed for direct blood contact was first assessed for its capacity to remove albumin bound marker toxins indoxyl sulphate (IS), p-cresyl sulphate (p-CS) and high molecular weight cytokine interleukin-6 in spiked healthy donor studies. Haemodialysis patient blood samples were then used to measure the presence of these markers in pre- and post-dialysis blood and their removal by adsorbent recirculation of post-dialysis blood samples. Nanopores (20-100 nm) were necessary for marker uraemic toxin removal during in vitro studies. Limited removal of IS and p-CS occurred during haemodialysis, whereas almost complete removal occurred following perfusion through the carbon monoliths suggesting a key role for such adsorbent therapies in CKD patient care.

Synthesis and application of hydride silica composites for rapid and facile removal of aqueous mercury.

The adsorption of ionic mercury(II) from aqueous solution on functionalized hydride silicon materials was investigated. The adsorbents were prepared by modification of mesoporous silica C-120 with triethoxysilane or by converting alkoxysilane into siloxanes by reaction with acetic acid. Mercury adsorption isotherms at 208C are reported, and maximum mercury loadings were determined by Langmuir fitting. Adsorbents exhibited efficient and rapid removal of ionic mercury from aqueous solution, with a maximum mercury loading of approximately 0.22 and 0.43 mmol of Hg g1 of silica C-120 and polyhedraloligomeric silsesquioxane (POSS) xerogel, respectively. Adsorption efficiency remained almost constant from pH 2.7 to 7. These inexpensive adsorbents exhibiting rapid assembly, low pH sensitivity, and high reactivity and capacity, are potential candidates as effective materials for mercury decontamination in natural waters and industrial effluents.

Activated carbons and carbon-containing poly(vinyl alcohol) cryogels: characterization, protein adsorption and possibility of myoglobin clearance.

Adsorption of myoglobin (Mb), bovine serum albumin (BSA) and γ-globulin (GG) onto activated carbons (ACs) with different pore size distributions, and poly(vinyl alcohol) (PVA) monolithic cryogels containing AC particles was studied. The highest initial rate of Mb adsorption was observed for AC having the largest specific surface area (1939 m(2) g(-1)) and pore volume (1.82 cm(3) g(-1)). The adsorption kinetics of proteins was characterized by a bimodal shape of the distribution f(D) function of an effective diffusion coefficient. Adsorption isotherms of Mb and GG were of Freundlich type within the studied range of equilibrium concentrations (10-150 µg mL(-1)). The distributions of free energy of protein adsorption were bimodal and reflected both interactions with carbon surfaces and self-association of proteins. Adsorbed amounts of Mb were the highest among the proteins studied (up to 700 mg g(-1) carbon), which was attributed to the higher fraction of pores accessible for Mb. Incorporation of carbon particles into PVA-based cryogel resulted in macroporous monolithic composite materials (AC-PVA) exhibiting good flow-through properties. Scanning electron microscopy of the composites showed macroporous aggregates of carbon particles held together by films and bridges of PVA. The rates of adsorption and adsorbed amounts of proteins on AC-PVA were reduced compared to the pristine carbon and depended on the carbon content in the composites. Nevertheless, adsorption of Mb on AC-PVA took place even in the presence of 500-fold higher concentration of BSA. This indicated a possibility of Mb clearance from blood plasma using the PVA-carbon monoliths.

Hyperstoichiometric interaction between silver and mercury at the nanoscale.

Breaking through the stoichiometry barrier: as the diameter of silver particles is decreased below a critical size of 32 nm, the molar ratio of aqueous Hg(II) to Ag(0) drastically increases beyond the conventional Hg/Ag ratio of 0.5:1, leading to hyperstoichiometry with a maximum ratio of 1.125:1. Therein, around 99% of the initial silver is retained to rapidly form a solid amalgam with reduced mercury.

Activation-dependent adsorption of cytokines and toxins related to liver failure to carbon beads.

In the course of severe pathological conditions, such as acute liver failure and sepsis, toxic metabolites and mediators of inflammation are released into the patient's circulation. One option for the supportive treatment of these conditions is plasmapheresis, in which plasma, after being separated from the cellular components of the blood, is cleansed by adsorption of harmful molecules on polymers or activated carbon. In this work, the adsorption characteristics of activated carbon beads with levels of activation ranging from 0 to 86% were assessed for both hydrophobic compounds accumulating in liver failure (bilirubin, cholic acid, phenol and tryptophan) and cytokines (tumor necrosis factor α and interleukin-6). Progressive activation resulted in significant gradual reduction of both bulk density and mean particle size, in an increase in the specific surface area, and to changes in pore size distribution with progressive broadening of micropores. These structural changes went hand in hand with enhanced adsorption of small adsorbates, such as IL-6 and cholic acid and, to a lesser extent, also of large molecules, such as TNF-α.

Competitive adsorption of macromolecules and real-time dynamics of Vroman-like effects.

Quasi-elastic light scattering (QELS) and quartz crystal microbalance (QCM) non-equilibrium and equilibrium studies of competitive interactions of pairs of polymers and proteins with fumed silica and ceramic coatings deposited on QCM crystals show complex interfacial behaviour. The effects observed depend on the adsorption sequence of co-adsorbates, their chemical structure and the morphology and chemical structure of the adsorbent. The equilibrium adsorption and dynamics of interactions of macromolecules with bare adsorbent surface and surface covered with pre-adsorbed polymer or protein, are compared in terms of the distribution functions of the Gibbs free energy of adsorption, which varied from -25 kJ mol(-1) on a bare surface to almost 0 kJ mol(-1) on a polymer or protein coated surface.

Real-time imaging of complex nanoscale mechanical responses of carbon nanotubes in highly compressible porous monoliths.

A facile and rapid assembly of powdered carbon nanotubes (CNTs) into compressible, porous, macroscale monoliths is reported. Despite a Poisson's ratio just above zero, we found that the sample under compression inside a scanning electron microscope (SEM) revealed CNT regions behaving in auxetic and vortex-like rotational modes as well as standard collapse responses. This method is crucial in understanding the macroscale behaviour based on the accumulation of nanoscale responses to an applied force.

Nanosized copper(ii) oxide/silica for catalytic generation of nitric oxide from S-nitrosothiols.

Nitric oxide NO, mediates inflammatory and thrombotic processes and designing biomaterials capable of releasing NO in contact with biological tissues is considered to be a major factor aimed at improving their bio- and haemocompatibility and antibacterial properties. Their NO-releasing capacity however is limited by the amount of the NO-containing substance incorporated in the bulk or immobilised on the surface of a biomaterial. An alternative approach is based on the design of a material generating nitric oxide from endogenous NO bearing metabolites by their catalytic decomposition. It offers, at least in theory, an unlimited source of NO for as long as the material remains in contact with blood and the catalyst maintains its activity. In this paper we studied the catalytic properties of novel nanostructured CuO/SiO2 catalysts in generating NO by decomposition of S-nitrosoglutathione (GSNO) in vitro. CuO/SiO2 catalysts with different CuO loadings were synthesized by chemisorption of copper(ii) acetylacetonate on fumed nanosilica followed by calcination. CuO content was controlled by a number of chemisorption-calcination cycles. Fourier-transform infrared spectroscopy and thermogravimetric analysis confirmed the formation of CuO/SiO2 nanoparticles (NPs) with particle size of CuO phase in the range from 71 to 88 nm. Scanning electron microscopy images revealed a uniform distribution of NPs without their sintering or agglomeration. All the materials of the CuO/SiO2 NP series exhibited NO-generating activity from GSNO confirmed by the Griess assay and by measuring the concentration of nitrite and nitrate anions in model solutions such as phosphate buffered saline and bovine serum. This activity is dependent on the material specific surface area and CuO exposure on the surface rather than CuO bulk content. The rate of NO production increased at higher initial concentration of the NO-bearing substrate studied in the range between 0.01 mM and 1.0 mM RSNO, which covers its physiological level. CuO/SiO2 NPs can be used to design polymers with NO generating properties at blood-biomaterial interface which are expected to have improved biocompatibility thus enhancing their potential for medical applications such as surgical tubing, peripheral venous catheters, auxiliary blood circulation devices and drug-eluting balloons.

Novel nanostructured iron oxide cryogels for arsenic (As(III)) removal.

Novel macroporous iron oxide nanocomposite cryogels were synthesized and assessed as arsenite (As(III)) adsorbents. The two-step synthesis method, by which a porous nanonetwork of iron oxide is firstly formed, allowed a homogeneous dispersion of the iron oxide in the cryogel reaction mixture, regardless of the nature of the co-polymer forming the cryogel structure. The cryogels showed excellent mechanical properties, especially the acrylamide-based cryogel. This gel showed the highest As(III) adsorption capacity, with the maximum value estimated at 118 mg/g using the Langmuir model. The immobilization of the nanostructured iron oxide gel into the cryogel matrix resulted in slower adsorption kinetics, however the cryogels offer the advantage of a stable three-dimensional structure that impedes the release of the iron oxide nanoparticles into the treated effluent. A preliminary toxicity evaluation of the cryogels did not indicate any apparent inhibition of human hepatic cells activity, which together with their mechanical stability and high adsorption capacity for As(III) make them excellent materials for the development of nanoparticle based adsorption devices for drinking water treatment.

Investigation of the adsorption capacity of the enterosorbent Enterosgel for a range of bacterial toxins, bile acids and pharmaceutical drugs.

Oral intestinal adsorbents (enterosorbents) are orally administered materials which pass through the gut where they bind (adsorb) various substances. The enterosorbent Enterosgel (Polymethylsiloxane polyhdrate) is recommended as a symptomatic treatment for acute diarrhoea and chronic diarrhoea associated with irritable bowel syndrome (IBS). Since 1980's there have been many Enterosgel clinical trials, however, the detailed mechanism of Enterosgel action towards specific toxins and interaction with concomitantly administered medications has not been fully investigated. Our in vitro study assessed the adsorption capacity of Enterosgel for bacterial enterotoxins and endotoxin, bile acids and interaction with the pharmaceutical drugs; Cetirizine and Amitriptyline hydrochloride. Our data demonstrate the good adsorption capacity of Enterosgel for bacterial toxins associated with gastrointestinal infection, with a lower than the comparator charcoal Charcodote capacity for bile acids whose levels can be raised in IBS patients. Adsorption capacity for the two drugs varied but was significantly lower than Charcodote. These findings suggest that the mechanism of Enterosgel action in the treatment of gastrointestinal infection or IBS is adsorption of target molecules followed by removal from the body. This therapy offers a drug free approach to prevention and treatment of infectious and chronic non-infectious diseases, where intestinal flora and endotoxemia play a role.

Composite Cryogel with Polyelectrolyte Complexes for Growth Factor Delivery.

Macroporous scaffolds composed of chitosan (CHI), hydroxyapatite (HA), heparin (Hep), and polyvinyl alcohol (PVA) were prepared with a glutaraldehyde (GA) cross-linker by cryogelation. Addition of PVA to the reaction mixture slowed down the formation of a polyelectrolyte complex (PEC) between CHI and Hep, which allowed more thorough mixing, and resulted in the development of the homogeneous matrix structure. Freezing of the CHI-HA-GA and PVA-Hep-GA mixture led to the formation of a non-stoichiometric PEC between oppositely charged groups of CHI and Hep, which caused further efficient immobilization of bone morphogenic protein 2 (BMP-2) possible due to electrostatic interactions. It was shown that the obtained cryogel matrix released BMP-2 and supported the differentiation of rat bone marrow mesenchymal stem cells (rat BMSCs) into the osteogenic lineage. Rat BMSCs attached to cryogel loaded with BMP-2 and expressed osteocalcin in vitro. Obtained composite cryogel with PEC may have high potential for bone regeneration and tissue engineering applications.

Inflammatory cytokine removal by an activated carbon device in a flowing system.

A prototype in-line filtration/adsorption device has been developed using novel synthetic pyrolysed carbon monoliths with controlled mesoporous domains of 2-50nm. Porosity was characterized by SEM and porosimetry. Removal of inflammatory cytokines TNF, IL-6, IL-1beta and IL-8 was assessed by filtering cytokine spiked human plasma through the walls of the carbon modules under pressure. The effect of carbon filtration on plasma clotting response and total plasma protein concentration was also assessed. Significant removal of the cytokines IL-6, IL-1beta and IL-8 was observed. Initially marked TNF removal diminished over time. The coagulation studies indicated that the carbon device does not exacerbate the propensity of blood plasma to clot. The total plasma protein concentration remained constant. The device offers a broader approach to the treatment of systemic inflammatory response syndrome (SIRS) by the removal of inflammatory mediators central to its progression.