Fabrication of hierarchical multilayer poly(glycerol sebacate urethane) scaffolds based on ice-templating

In this study, it was demonstrated that ice-templating via freeze drying with custom-made moulds, in combination with air brushing, allows for the fabrication of poly(glycerol sebacate urethane) (PGSU) scaffolds with hierarchical multilayer microstructures to replicate various native soft tissues. The PGSU scaffolds were either monolayered but exhibited an anisotropic microstructure, or bilayered and trilayered, with each layer showing different microstructures. By using freeze drying with custom-made moulds, the ice crystals of the solvent were grown unidirectionally, and after freeze-drying, the scaffolds had an anisotropic microstructure, mimicking tissues such as tendon and skeletal muscle. The anisotropic PGSU scaffolds were also examined for their tensile strength, and a range of mechanical properties were obtained by altering the reactants’ molar ratio and polymer concentration. This is of importance, since soft tissues exhibit different mechanical properties depending on their native location and functionality. By combining freeze drying with airbrushing, scaffolds were fabricated with a thin, non-porous layer on top of the porous layers to allow three-dimensional cell co-culture for tissues such as skin and oral mucosa. These results show that fabrication techniques can be combined to produce PGSU scaffolds with tailored hierarchical microstructures and mechanical properties for multiple tissue engineering applications

A generalised porous medium approach to study thermo-fluid dynamics in human eyes

The present work describes the application of the generalised porous medium model to study heat and fluid flow in healthy and glaucomatous eyes of different subject specimens, considering the presence of ocular cavities and porous tissues. The 2D computational model, implemented into the open-source software OpenFOAM, has been verified against benchmark data for mixed convection in domains partially filled with a porous medium. The verified model has been employed to simulate the thermo-fluid dynamic phenomena occurring in the anterior section of four patient-specific human eyes, considering the presence of anterior chamber (AC), trabecular meshwork (TM), Schlemm’s canal (SC), and collector channels (CC). The computational domains of the eye are extracted from tomographic images. The dependence of TM porosity and permeability on intraocular pressure (IOP) has been analysed in detail, and the differences between healthy and glaucomatous eye conditions have been highlighted, proving that the different physiological conditions of patients have a significant influence on the thermo-fluid dynamic phenomena. The influence of different eye positions (supine and standing) on thermo-fluid dynamic variables has been also investigated: results are presented in terms of velocity, pressure, temperature, friction coefficient and local Nusselt number. The results clearly indicate that porosity and permeability of TM are two important parameters that affect eye pressure distribution

Regulating the catalytic properties of Pt/Al2O3 through nanoscale inkjet printing

For the first time ever, a 0.1 wt% Pt/Al2O3 catalyst was prepared by novel inkjet printing and compared against two catalysts prepared by a standard and modified wet impregnation method. The printed catalyst was found to present excellent activity and wide operating temperature window on the selective catalytic reduction of NO by H2 under strongly oxidizing conditions (H2-SCR) in the very low-temperature range of 100–200 °C. The transient studies performed in the present work indicated that the printing process followed led to a unique surface structure of the printed catalyst that probably favors the formation of different active intermediate NOx species, which are active at very low reaction temperatures. Moreover, it was found that the inkjet printing protocol followed resulted in a relatively uniform nano-spherical structure of the developed catalyst

New insights into the antimicrobial treatment of water on Ag‐supported solids

BACKGROUND: Silver (Ag) has been long known to be a strong antimicrobial agent and has been used as such either as AgNO3 or in the form of nanoparticles. The antimicrobial activity of nanosilver is believed to be due to free metal ion toxicity, the consequent generation of excess reactive oxygen species and inhibition of gene expression in several cells. RESULTS: The antimicrobial activity of Ag/Al2O3 spheres was studied after suppression of free Ag ions by using a suitable complexing agent (Ag+ scavenger). It was found that Ag/Al2O3 retained its antimicrobial activity even after the addition of the Ag+ complexing agent, which is in contrast to the behaviour of an AgNO3 solution which became completely inactive. Initial/preliminary transmission electron microscopy and Fourier transform infrared studies indicate possible phospholipid residues on the Ag-supported solid surface. •OH radicals were confirmed to be formed during the antimicrobial process. CONCLUSIONS: The present work provides strong evidence that the antimicrobial property of Ag-supported solids is not exclusively due to the dissolution of surface silver (free Ag+). A possible simplified mechanism is proposed in which the initiation of the antimicrobial reaction is proposed to be a heterogeneous intersurface process, which might include the interaction between the partially positively charged, surface silver atoms and the negatively charged outer membrane (OM) of microbes, and the subsequent activation of a free radical mechanism. Further study and confirmation of the above findings might be decisive for the development of novel Ag-supported solids with limited metal surface dissolution but strong antimicrobial activity useful for the confrontation of particular environmental challenges

Identification of exosomal muscle-specific miRNAs in serum of myotonic dystrophy patients relating to muscle disease progress

Myotonic dystrophy type 1 (DM1) is the most common form of adult-onset muscular dystrophy, which is characterised by progressive muscle wasting and the discovery of reliable blood-based biomarkers could be useful for the disease progress monitoring. There have been some reports showing that the presence of specific miRNAs in blood correlates with DM1. In one of these, our group identified four muscle-specific miRNAs, miR-1, miR-133a, miR-133b and miR-206, which correlated with the progression of muscle wasting observed in DM1 patients. The levels of the four muscle-specific miRNAs were elevated in the serum of DM1 patients compared to healthy participants and were also elevated in the serum of progressive muscle wasting DM1 patients compared to disease-stable DM1 patients. The aim of this work was to characterise the ontology of these four muscle-specific miRNAs in the blood circulation of DM1 patients. Here we show that the four muscle-specific miRNAs are encapsulated within exosomes isolated from DM1 patients. Our results show for the first time, the presence of miRNAs encapsulated within exosomes in blood circulation of DM1 patients. More interestingly, the levels of the four exosomal muscle-specific miRNAs are associated with the progression of muscle wasting in DM1 patients. We propose that exosomal muscle-specific miRNAs may be useful molecular biomarkers for monitoring the progress of muscle wasting in DM1 patients. There has been a growing interest regarding the clinical applications of exosomes and their role in prognosis and therapy of various diseases and the above results contribute towards this way

Identification of exosomal muscle-specific miRNAs in serum of myotonic dystrophy patients relating to muscle disease progress

Myotonic dystrophy type 1 (DM1) is the most common form of adult-onset muscular dystrophy, which is characterised by progressive muscle wasting and the discovery of reliable blood-based biomarkers could be useful for the disease progress monitoring. There have been some reports showing that the presence of specific miRNAs in blood correlates with DM1. In one of these, our group identified four muscle-specific miRNAs, miR-1, miR-133a, miR-133b and miR-206, which correlated with the progression of muscle wasting observed in DM1 patients. The levels of the four muscle-specific miRNAs were elevated in the serum of DM1 patients compared to healthy participants and were also elevated in the serum of progressive muscle wasting DM1 patients compared to disease-stable DM1 patients. The aim of this work was to characterise the ontology of these four muscle-specific miRNAs in the blood circulation of DM1 patients. Here we show that the four muscle-specific miRNAs are encapsulated within exosomes isolated from DM1 patients. Our results show for the first time, the presence of miRNAs encapsulated within exosomes in blood circulation of DM1 patients. More interestingly, the levels of the four exosomal muscle-specific miRNAs are associated with the progression of muscle wasting in DM1 patients. We propose that exosomal muscle-specific miRNAs may be useful molecular biomarkers for monitoring the progress of muscle wasting in DM1 patients. There has been a growing interest regarding the clinical applications of exosomes and their role in prognosis and therapy of various diseases and the above results contribute towards this way

Fretting corrosion of CoCr alloy: Effect of load and displacement on the degradation mechanisms

Fretting corrosion of medical devices is of growing concern, yet, the interactions between tribological and electrochemical parameters are not fully understood. Fretting corrosion of CoCr alloy was simulated, and the components of damage were monitored as a function of displacement and contact pressure. Free corrosion potential (Ecorr), intermittent linear polarisation resistance and cathodic potentiostatic methods were used to characterise the system. Interferometry was used to estimate material loss post rubbing. The fretting regime influenced the total material lost and the dominant degradation mechanism. At high contact pressures and low displacements, pure corrosion was dominant with wear and its synergies becoming more important as the contact pressure and displacement decreased and increased, respectively. In some cases, an antagonistic effect from the corrosion-enhanced wear contributor was observed suggesting that film formation and removal may be present. The relationship between slip mechanism and the contributors to tribocorrosion degradation is presented

miR-223-3p and miR-24-3p as novel serum-based biomarkers for myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is the most common adult-onset muscular dystrophy, primarily characterized by muscle wasting and weakness. Many biomarkers already exist in the rapidly developing biomarker research field that aim to improve patients’ care. Limited work, however, has been performed on rare diseases, including DM1. We have previously shown that specific microRNAs (miRNAs) can be used as potential biomarkers for DM1 progression. In this report, we aimed to identify novel serum-based biomarkers for DM1 through high-throughput next-generation sequencing. A number of miRNAs were identified that are able to distinguish DM1 patients from healthy individuals. Two miRNAs were selected, and their association with the disease was validated in a larger panel of patients. Further investigation of miR-223-3p, miR-24-3p, and the four previously identified miRNAs, miR-1-3p, miR-133a-3p, miR-133b-3p, and miR-206-3p, showed elevated levels in a DM1 mouse model for all six miRNAs circulating in the serum compared to healthy controls. Importantly, the levels of miR-223-3p, but not the other five miRNAs, were found to be significantly downregulated in five skeletal muscles and heart tissues of DM1 mice compared to controls. This result provides significant evidence for its involvement in disease manifestation