An efficient method to prepare supported bismuth nanoparticles as highly selective electrocatalyst for the conversion of CO2 into formate

We report a cost-effective, straightforward synthesis of a novel electrocatalyst for the reduction of CO2 to formate, which achieves nearly complete Faradaic efficiency (FE) at an overpotential (η) of 0.88 V under ambient conditions. The electrocatalyst was prepared using bismuth subsalicylate as precursor and consists of bismuth nanoparticles (Bi NPs) with an average diameter of 5.5 nm supported on activated carbon. This journal is</p

PMMA-based bone cements and the problem of joint arthroplasty infections: Status and new perspectives

Polymethyl methacrylate (PMMA)-based bone cement is a biomaterial that has been used over the last 50 years to stabilize hip and knee implants or as a bone filler. Although PMMA-based bone cement is widely used and allows a fast-primary fixation to the bone, it does not guarantee a mechanically and biologically stable interface with bone, and most of all it is prone to bacteria adhesion and infection development. In the 1970s, antibiotic-loaded bone cements were introduced to reduce the infection rate in arthroplasty; however, the eciency of antibiotic-containing bone cement is still a debated issue. For these reasons, in recent years, the scientific community has investigated new approaches to impart antibacterial properties to PMMA bone cement. The aim of this review is to summarize the current status regarding antibiotic-loaded PMMA-based bone cements, fill the gap regarding the lack of data on antibacterial bone cement, and explore the progress of antibacterial bone cement formulations, focusing attention on the new perspectives. In particular, this review highlights the innovative study of composite bone cements containing inorganic antibacterial and bioactive phases, which are a fascinating alternative that can impart both osteointegration and antibacterial properties to PMMA-based bone cement

Synthesis and characterization of magnetic and antibacterial nanoparticles as filler in acrylic cements for bone cancer and comorbidities therapy

In this work an innovative formulation of bone cement for the treatment of bone tumor and its associated complications has been designed by preparing a new class of Fe3O4–Ag nanostructures, using gallic acid as a reducing agent. The obtained nanoparticles have been introduced in polymethyl methacrylate (PMMA)-based composite cement evaluating the insertion of different amounts and the use of different mixing methods. The morphology, the composition and the antibacterial effect of Fe3O4–Ag nanostructures have been investigated together with the morphology, the composition, the mechanical properties of the nanoparticles-containing composite cements as well as their antibacterial effect. The obtained results revealed a good antimicrobial effect of Fe3O4–Ag nanostructures, a significant influence of their amount and of the used mixing method on the particles dispersion and agglomeration in the PMMA matrix and, as a result, on the mechanical properties. In particular, a better dispersion of nanoparticles was obtained by using the mechanical mixing, reducing the tendency to agglomerate. The increase of nanoparticles amount induced a slight decrease of the mechanical properties; however, the introduction of 10% w/w of Fe3O4–Ag allowed to improve the composites ability to reduce the bacteria adhesion

Electrophoretic deposition of composite coatings based on alginate matrix/45S5 bioactive glass particles doped with B, Zn or Sr

In this research work composite coatings made of alginate and 45S5 bioactive glass particles doped with B, Zn or Sr were synthesized by means of electrophoretic deposition and characterized from morphological, compositional, thermogravimetric, mechanical and electrochemical points of view. The developed coatings were also subjected to in vitro test in SBF solution to evaluate their ability to induce hydroxyapatite precipitation and cytocompatibility evaluation using human primary fibroblasts. The obtained results demonstrated a good homogeneity of the coatings, high adhesion and a protective behavior towards the substrate. The thermogravimetric analysis proved that the glass amount was constant before and after the deposition and all the investigated coatings promoted the deposition of hydroxyapatite but with different kinetics. Since the Zn containing coating showed the best bioactive behavior it was subjected to cytocompatibility test, which demonstrated, after an initial reduction of cell viability, a good cell proliferation and the production of collagen from the ECM. These findings suggest that the obtained coatings are promising materials to coat metallic prosthetic devices

Competitive surface colonization of antibacterial and bioactive materials doped with strontium and/or silver ions

Nowadays, there is a large amount of research aimed at improving the multifunctional behavior of the biomaterials for bone contact, including the concomitant ability to induce apatite formation (bioactivity), fast and effective osteoblasts colonization, and antibacterial activity. The aim of this study is to develop antibacterial and bioactive surfaces (Ti6Al4V alloy and a silica-based bioactive glass) by chemical doping with strontium and/or silver ions. The surfaces were characterized by Scanning Electron Microscopy equipped with Energy Dispersive X ray Spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), and Transmission Electron Microscopy (TEM). To better focus on the cells–bacteria competition for the implant surface, in addition to the standard assays for the evaluation of the bacteria adhesion (ISO22196) and for single-cell cultures or biofilm formation, an innovative set of co-cultures of cells and bacteria is here proposed to simulate a competitive surface colonization. The results suggest that all the bioactive tested materials were cytocompatible toward the bone progenitor cells representative for the self-healing process, and that the doped ones were effective in reducing the surface colonization from a pathogenic drug-resistant strain of Staphylococcus aureus. The co-cultures experiments demonstrated that the doped surfaces were able to protect the adhered osteoblasts from the bacteria colonization as well as prevent the infection prior to the surface colonization by the osteoblasts

The effect of magnesium on bioactivity, rheology and biology behaviors of injectable bioactive glass-gelatin-3-glycidyloxypropyl trimethoxysilane nanocomposite-paste for small bone defects repair

Injectable bioactive glass-based pastes represent promising biomaterials to fill small bone defects thus improving and speed up the self-healing process. Accordingly, injectable nanocomposite pastes based on bioactive glass-gelatin-3-glycidyloxypropyl trimethoxysilane (GPTMS) were here synthesized via two different glasses 64SiO2. 27CaO. 4MgO. 5P2O5 (mol.%) and 64SiO2.31CaO. 5P2O5 (mol.%). In particular, the effects of MgO on bioactivity, rheology, injectability, disintegration resistance, compressive strength and cellular behaviors were investigated. The results showed that the disintegration resistance and compressive strength of the composite were improved by the replacement of MgO; thus, leading to an increase in the amount of storage modulus (G′) from 26800 to 43400 Pa, equal to an increase in the viscosity of the paste from 136 × 103 to 219 × 103 Pa s. Since the release rate of ions became more controllable, the formation of calcite was decreased after immersion of the Mg bearing samples in the SBF solution. Specimens’ cytocompatibility was firstly verified towards human osteoblasts by metabolic assay as well as visually confirmed by the fluorescent live/dead staining; finally, the ability of human fibroblasts to penetrate within the pores of 3D composites was verified by a migration assay simulating the devices repopulation upon injection in the injured site

Anterior cruciate ligament recostruction with bone-patellar tendon-bone autograft in Tanner 3 stage patients with open physes

Ten skeletally immature patients were treated with an arthroscopic-assisted anterior cruciate ligament reconstruction with bone-patellar tendon bone autograft (compass, 50\u2013558; holes, 7\u20139 mm). Radiological assessments (standard radiograph), Orthopa\ua8 dische Arbeitsgruppe Knie (OAK) score and KT 1000, were conducted on all patients, 1 year after surgery. Skeletal maturity had been reached by all patients and no complications were observed. All patients returned to their preinjury sport level. Drilling more vertical tunnels when bone-tendon-bone autograft was chosen to avoid partial epiphysiodesis and offers good functional and isometric results

Structure optimisation and biological evaluation of bone scaffolds prepared by co-sintering of silicate and phosphate glasses

A degradable phosphate glass (ICEL) and a bioactive silicate glass (CEL2) were mixed in different ratios (wt-%: 100%ICEL, 70%ICEL-30%CEL2, 30%ICEL-70%CEL2, 100%CEL2; codes 100-0, 70-30, 30-70, 0-100) and then co-sintered to obtain three-dimensional porous scaffolds by gel casting foaming. Thermal analyses were carried out on the glass mixtures and were used as a starting point for the optimisation of the scaffold sintering treatment. The microcomputed tomography and field emission scanning electron microscope analyses allowed the selection of the optimal sintering temperature to obtain an adequate structure in terms of total and open porosity. The scaffolds showed an increasing solubility with increasing ICEL glass content, and for 30-70 and 0-100, the precipitation of hydroxyapatite in simulated body fluid was observed. In vitro tests indicated that all the scaffolds showed no cytotoxic effect. The co-sintering of silicate and phosphate glasses showed to be a promising strategy to tailor the scaffold osteoconductivity, degradation and bioactivit

Indicatori microscopici di pascolo per ricostruzioni di paleoeconomia e paleoambiente: polline, spore di funghi coprofili e uova di parassiti

The paper reports two study cases showing integrated analyses of microscopic records (pollen, coprophilous fungi and parasites remains) which are of basic importance to reconstruct past breeding and pastoral activities in Italy. The sites are located at Piano Locce (1225 m a.s.l., Barisciano, L’Aquila) in a depression in a mountain area and in the Bradano Valley (about 150-500 m a.s.l., Basilicata) in a hilly area rich in archaeological sites. The pollen-based palaeoenvironmental reconstruction of Piano Locce provided the history of plants landscape from around 36.000 years BP. Before the Holocene, a steppe vegetation and a grassland characterized the area where wild animals freely browsed. This assumption is strongly supported by the association of spores of coprophilous fungi with intestinal parasites eggs (Dicrocoelium) and pollen clumps. The trend of coprophilous fungi and pollen assemblages including Anthropogenic Indicators shows that, after the wild animals browsing, a fairly continuous presence of domesticated animals, prevalently ovicaprines, interested the area in the Holocene. The archaeological sites of Difesa San Biagio and Altojanni in Bradano Valley showed evidences of ovicaprine-farming and cattle breeding during Hellenistic and Mediaeval periods. In particular, Cichorioideae, Chenopodiaceae and Brassicaceae pollen and spores of coprophilous fungi (such as Sordaria type, Sporormiella and Podospora type) attest the predominance of pastoral activities during the Hellenistic period at San Biagio. A greater pollen biodiversity characterizes Altojanni, where spores of the coprophilous fungi were associated with spores of fungi with a different ecology as Chaetomium and Valsaria variospora type. The environmental and microarchaeobotanical contexts are in agreement with archaeological evidences that attest the presence of domestic animals, probably cattle, maintained in this site during Middle Ages