Multi-physics modeling of doxorubicine binding to ion-exchange resin in blood filtration devices

A group of drugs used in intra-arterial chemotherapy (IAC) have intrinsic ionic properties, which can be used for filtering excessive drugs from blood in order to reduce systemic toxicity. The ion-exchange mechanism is utilized in an endovascular Chemofilter device which can be deployed during the IAC for capturing ionic drugs after they have had their effect on the tumor. In this study, the concentrated solution theory is used to account for the effect of electrochemical forces on the drug transport and adsorption by introducing an effective diffusion coefficient in the advection–diffusion–reaction equation. Consequently, a multi-physics model coupling hemodynamic and electrochemical forces is developed and applied to simulations of the transport and binding of doxorubicine in the Chemofilter device. A comparison of drug adsorption predicted by the computations to that measured in animal studies demonstrated the benefits of using the concentrated solution theory over the Nernst–Plank relations for modeling drug binding.     

Modulators of Macrophage Polarization Influence Healing of the Infarcted Myocardium

To diminish heart failure development after acute myocardial infarction (AMI), several preclinical studies have focused on influencing the inflammatory processes in the healing response post-AMI. The initial purpose of this healing response is to clear cell debris of the injured cardiac tissue and to eventually resolve inflammation and support scar tissue formation. This is a well-balanced reaction. However, excess inflammation can lead to infarct expansion, adverse ventricular remodeling and thereby propagate heart failure development. Different macrophage subtypes are centrally involved in both the promotion and resolution phase of inflammation. Modulation of macrophage subset polarization has been described to greatly affect the quality and outcome of healing after AMI. Therefore, it is of great interest to reveal the process of macrophage polarization to support the development of therapeutic targets. The current review summarizes (pre)clinical studies that demonstrate essential molecules involved in macrophage polarization that can be modulated and influence cardiac healing after AMI.     

Electrospun Fibrous Architectures for Drug Delivery,Tissue Engineering and Cancer Therapy

The versatile electrospinning technique is recognized as an efficient strategy to deliver active pharmaceutical ingredients and has gained tremendous progress in drug delivery, tissue engineering, cancer therapy, and disease diagnosis. Numerous drug delivery systems fabricated through electrospinning regarding the carrier compositions, drug incorporation techniques, release kinetics, and the subsequent therapeutic efficacy are presented herein. Targeting for distinct applications, the composition of drug carriers vary from natural/synthetic polymers/blends, inorganic materials, and even hybrids. Various drug incorporation approaches through electrospinning are thoroughly discussed with respect to the principles, benefits, and limitations. To meet the various requirements in actual sophisticated in vivo environments and to overcome the limitations of a single carrier system, feasible combinations of multiple drug‐inclusion processes via electrospinning could be employed to achieve programmed, multi‐staged, or stimuli‐triggered release of multiple drugs. The therapeutic efficacy of the designed electrospun drug‐eluting systems is further verified in multiple biomedical applications and is comprehensively overviewed, demonstrating promising potential to address a variety of clinical challenges.     

Electrospun polyvinylidene pyrolidone/gelatin membrane impregnated with silver sulfadiazine as wound dressing for burn treatment

Nanofibrous membranes used for burn treatment have become widely popular due to their large surface area and high porous structure. In this study, electrospinning was used to fabricate a blended nanofibrous membrane of polyvinylidene pyrolidone (PVP) and gelatin, to use as wound dressing. The physical and mechanical properties of this novel membrane were investigated using SEM, FTIR and tensile tests. Results showed that poor mechanical properties of gelatin, which are preferred in medical applications for curing burns as they allow for antigen activity and skin repair, can be enhanced by adding PVP in the solution. Silver sulfadiazine (AgSD), an antibacterial agent, was also impregnated into the PVP/gelatin nanofibrous structure during electrospinning. The membrane thus fabricated showed antibacterial activities against both the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. AgSD release behaviour of fabricated samples indicated short-term drug delivery. It was concluded that the proposed drug-loaded membrane can be used as wound dressing, specifically, in treating skin burns.     

Effects of microstructure on electrochemical reactivity and conductivity in nanostructured ceria thin films

The proton conductivity in functional oxides is crucial in determining electrochemistry and transport phenomena in a number of applications such as catalytic devices and fuel cells. However, single characterization techniques are usually limited in detecting the ionic dynamics at the full range of environmental conditions. In this report, we probe and uncover the links between the microstructure of nanostructured ceria (NC) and parameters that govern its electrochemical reaction and proton transport, by coupling experimental data obtained with time‐resolved Kelvin probe force microscopy (tr‐KPFM), electrochemical impedance spectroscopy (EIS), and finite element analysis. It is found that surface morphology determines the water splitting rate and proton conductivity at 25°C and wet conditions, when protons are mainly generated and transported within surface physisorbed water layers. However, at higher temperature (i.e., ≥125°C) and dry conditions, when physisorbed water evaporates, grain size, and crystallographic orientation become significant factors. Specifically, the proton generation rate is negatively correlated with the grain size, whereas proton diffusivity is facilitated by surface {111} planes and additional conduction pathways offered by cracks and open pores connected to the surface.     

Optimized Growth of Heteroepitaxial (111) NiFe2O4 Thin Films on (0001) Sapphire with Two In‐Plane Variants via Chemical Solution Deposition

(111)‐oriented epitaxial thin films of nickel ferrite (NFO) are grown on c‐plane sapphire [α‐Al₂O₃(0001)] substrates using a chemical solution deposition technique. The processing conditions, including pyrolysis and annealing temperatures, are varied to achieve a film that shows maximum texture and epitaxy. It is shown that increasing the pyrolysis temperature to 400°C and decreasing the annealing temperature to 750°C for 10 min result in the highest degree of texture in the films. Lower film thickness also leads to a higher degree of texture. Microstructural studies confirm an in‐plane epitaxial relationship between the (111) NFO film and the (0001) Al₂O₃ substrate in two variants, [110]_NFO || or .     

Effect of chemical reagents on the mechanical properties of natural fiber polypropylene composites

Chemical resistance of natural fiber (wood flour, rice hulls, kenaf fiber, and newsprint) polypropylene composites was studied in terms of their weight loss and reduction of mechanical properties after 7 days immersion in chemical reagents. Composites containing 25 and 50% of various natural fibers and polypropylene were prepared and immersed in NaOH (10%), NaClO (bleach solution) (13%), HCl (10%), H₂O₂ (3%), soap solution (1%), and acetone. Results indicated that H₂O₂, soap solution, and acetone had very negligible effects on all composites. On the other hand, the effects of NaClO and HCl were found to be statistically significant. Different fibers exhibited different behaviors regarding their chemical resistance. Rice hulls composites were considerably affected by NaOH, whereas the same chemical reagent was ineffective on other fibers. The effects of bleach solution and HCl on the mechanical performance of the composites were found to be critical. Generally, it was concluded that bleach and acids had the highest effects on natural fiber polypropylene composites. POLYM. COMPOS. 27:563–569, 2006. © 2006 Society of Plastics Engineers