Multifunctional Sr,Mg-Doped Mesoporous Bioactive Glass Nanoparticles for Simultaneous Bone Regeneration and Drug Delivery.

Mesoporous bioactive glass nanoparticles (MBGNs) doped with therapeutical ions present multifunctional systems that enable a synergistic outcome through the dual delivery of drugs and ions. The aim of this study was to evaluate influence of co-doping with strontium and magnesium ions (SrMg-MBGNs) on the properties of MBGNs. A modified microemulsion-assisted sol-gel synthesis was used to obtain particles, and their physicochemical properties, bioactivity, and drug-loading/release ability were evaluated. Indirect biological assays using 2D and 3D cell culture models on human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and endothelial EA.hy926 cells, respectively, were used to determine biocompatibility of MBGNs, their influence on alkaline phosphatase (ALP) production, calcium deposition, and cytoskeletal organization. Results showed that Sr,Mg-doping increased pore volume and solubility, and changed the mesoporous structure from worm-like to radial-dendritic, which led to a slightly accelerated drug release compared to pristine MBGNs. Biological assays confirmed that particles are biocompatible, and have ability to slightly induce ALP production and calcium deposition of hBM-MSCs, as well as to significantly improve the proliferation of EA.hy926 compared to biochemical stimulation via vascular endothelial growth factor (VEGF) administration or regular media. Fluorescence staining revealed that SrMg-MBGNs had a similar effect on EA.hy926 cytoskeletal organization to the VEGF group. In conclusion, Sr,Mg-MBGNs might be considered promising biomaterial for biomedical applications.

Real-time application and modelling of the NOx-sorption reaction on a particulate calcium carbonate surface-flow filter exposed to combustion exhaust.

Of major interest, especially in city environments, and increasingly inside vehicles or industrial plants, is the drive to reduce human exposure to nitrogen oxides (NOx). This trend has drawn increasing attention to filtration, which has developed remarkably owing to the capabilities of recently developed mathematical models and novel filter concepts. This paper reports on the study of the kinetic modelling of adsorption of nitrogen dioxide (NO2), collected from the tailpipe of a diesel engine, reacting to calcium nitrate salt (Ca(NO3)2) on a surface flow filter consisting of a coating of fine ground limestone or marble (CaCO3) in combination with micro-nanofibrillated cellulose (MNFC) acting as binder and humectant applied onto a multiply recycled newsprint substrate. The coating and substrate are both porous, but on different pore size scales, with the coating having significantly lower permeability. To maximise gas-coating contact, therefore, the coating deposition is pixelated, achieved by pin coating. An axially dispersed gaseous plug flow model (dispersion model) was used to simulate the transport within the coating pore network structure, following earlier flow modelling studies, and a kinetic reaction model was used to examine NO2 to NO3- conversion in correlation with experimental results. Modelling results indicate a 60.38% conversion of exposed NO2 gas to Ca(NO3)2 under the specific conditions applied, with an absolute relative error between the predicted and experimentally estimated value being 0.81%. The model additionally enabled a prediction of effects of changing parameters over a limited perturbation range, thus assisting in predicting filter element consumption, with attention given to the active component CaCO3 surface as a function of particle size in relation to the gas contact exchange, promoting the reaction over time. It is intended that the Ca(NO3)2 formed from the reaction can go on to be used as a value-added fertiliser, thus contributing to circular economy.

Biodegradable Cellulose/Polycaprolactone/Keratin/Calcium Carbonate Mulch Films Prepared in Imidazolium-Based Ionic Liquid.

Ionic liquid 1-butyl-3-methylimidazolium chloride [BMIM][Cl] was used to prepare cellulose (CELL), cellulose/polycaprolactone (CELL/PCL), cellulose/polycaprolactone/keratin (CELL/PCL/KER), and cellulose/polycaprolactone/keratin/ground calcium carbonate (CELL/PCL/KER/GCC) biodegradable mulch films. Attenuated Total Reflectance Fourier-Transform Infrared (ATR-FTIR) spectroscopy, optical microscopy, and Field-Emission Scanning Electron Microscopy (FE-SEM) were used to verify the films' surface chemistry and morphology. Mulch film made of only cellulose regenerated from ionic liquid solution exhibited the highest tensile strength (75.3 ± 2.1 MPa) and modulus of elasticity of 944.4 ± 2.0 MPa. Among samples containing PCL, CELL/PCL/KER/GCC is characterized by the highest tensile strength (15.8 ± 0.4 MPa) and modulus of elasticity (687.5 ± 16.6 MPa). The film's breaking strain decreased for all samples containing PCL upon the addition of KER and KER/GCC. The melting temperature of pure PCL is 62.3 °C, whereas that of CELL/PCL film has a slight tendency for melting point depression (61.0 °C), which is a characteristic of partially miscible polymer blends. Furthermore, Differential Scanning Calorimetry (DSC) analysis revealed that the addition of KER or KER/GCC to CELL/PCL films resulted in an increment in melting temperature from 61.0 to 62.6 and 68.9 °C and an improvement in sample crystallinity by 2.2 and 3.0 times, respectively. The light transmittance of all studied samples was greater than 60%. The reported method for mulch film preparation is green and recyclable ([BMIM][Cl] can be recovered), and the inclusion of KER derived by extraction from waste chicken feathers enables conversion to organic biofertilizer. The findings of this study contribute to sustainable agriculture by providing nutrients that enhance the growth rate of plants, and hence food production, while reducing environmental pressure. The addition of GCC furthermore provides a source of Ca2+ for plant micronutrition and a supplementary control of soil pH.

Micro Nanofibrillated Cellulose as Functional Additive Supporting Processability of Surface-Active Mineral Suspensions: Exemplified by Pixel Coating of an NOx-Sorbent Layer.

Unlike established coating formulations, functional particulate coatings often demand the omission of polymer dispersant so as to retain surface functionality. This results in heterogeneous complex rheology. We take an example from a novel development for an NOx mitigation surface flow filter system, in which ground calcium carbonate (GCC), applied in a coating, reacts with NO2 releasing CO2. Inclusion of mesoporous ancillary mineral acts to capture the CO2. The coating is applied as droplets to maximize gas-contact dynamic by forming a pixelated 2D array using a coating device consisting of protruding pins, which are loaded by submersion in the aqueous coating color such that the adhering droplets are transferred onto the substrate. The flow is driven by surface meniscus wetting causing lateral spread and bulk pore permeation. Filamentation occurs during the retraction of the pins. Stress-related viscoelastic and induced dilatancy in the suspension containing the ancillary mesoporous mineral disrupts processability. Adopting shear, oscillation and extensional rheometric methods, we show that the inclusion of an ancillary mineral that alone absorbs water, e.g., perlite (a naturally occurring porous volcanic glass), is rheologically preferable to one that in addition to absorbing water also immobilizes it on the mineral surface, e.g., sepiolite. When including micro-nanofibrillated cellulose (MNFC), critical for maintaining moisture to support NO2 sorption, it is observed that it acts also as a flow modifier, enabling uniform coating transfer to be achieved, thus eliminating any possible detrimental effect on mineral surface activity by avoiding the use of soluble polymeric dispersant.

Modification of CaCO3 and CaCO3 pin-coated cellulose paper under supercritical carbon dioxide-ethanol mixture for enhanced NO2 capture.

In this work, we examine two modifications of fine-ground calcium carbonate material (GCC) in order to enhanced sorption of NO2 and subsequent reaction properties toward NO2-/NO3- formation by firstly exposing the GCC to supercritical (sc) CO2 in order to increase particle surface area, a choice specifically made to avoid altering the surface chemistry, and secondly considering the potential advantage of using a surface coupling agent toward NO2. The modification by the coupling agent amino silane (AMEO silane) was applied in a supercritical CO2-ethanol mixture. The samples were characterised before and after modification by field emission scanning electron microscopy (FESEM), specific surface area determination (BET nitrogen adsorption), ATR-FTIR spectroscopy and ion chromatography to reveal the effects of the surface modification(s) on the morphology, surface textural properties and sorption versus reaction properties with NO2. The performance of the treated sorbents for NO2 capture was evaluated at room temperature. Results show that reactivity of NO2 with GCC was observed to increase as a function of increased surface area resulting from scCO2 exposure, but that the presence of AMEO silane on the surface, while enhancing initial adsorption of NO2 was seen subsequently to act to block reactivity. Thus, judicious use of coupling agent can provide desired rapid initial adsorption of the gas, but the goal of long-term CaCO3-consuming reactivity, so as to prolong the uptake of NO2 beyond surface saturation alone, is achieved by increasing surface area while retaining chemical-free exposed CaCO3 surface.

Distribution and mobility of heavy elements in floodplain agricultural soils along the Ibar River (Southern Serbia and Northern Kosovo). Chemometric investigation of pollutant sources and ecological risk assessment.

This work investigates the influence of a high-magnitude flood event on heavy elements (HEs) pollution and mobility in the agricultural soils along Ibar River in Southern Serbia and Northern Kosovo. The study area was one of the most important Pb/Zn industrial regions in Europe. Soil samples (n = 50) collected before and after the floods in May 2014 were subjected to the sequential extraction procedure proposed by the Community Bureau of Reference (BCR). The results indicated that the floods significantly increased not only the pseudo total concentrations of HEs in the soil but also their mobile and potentially bioavailable amounts. Moreover, higher concentrations (both pseudo total and potentially bioavailable) were found in the agricultural soils closer to the industrial hotspots. Principal component analysis and hierarchical cluster analysis successfully grouped the analyzed elements according to their anthropogenic or natural origin. The floods significantly increased the potential ecological risk of HEs associated with Pb/Zn industrial activities in the study area. The potential ecological risk of Cd after the floods was highest and should be of special concern.