Protrusions designs of AFRP to eliminate slippage of bonding adhesive

A presentation of a new innovative smart designs of protrusions in Aramid Fiber Reinforced Polymer (AFRP) which could lead the manufacturing industry of AFRP to a new era. The classic straight AFRP strips has a major disadvantage when externally bonded with other engineering materials using bonding adhesive. When exposed to high temperatures, the bonding adhesive slides causing a weak bondage or a complete debonding in some cases between the AFRP and engineering material surfaces. Thus, the purpose of protrusions in AFRP laminates is to eliminate the slippage of the bonding adhesive between the AFRP strips and other engineering material surfaces. This takes place by eliminating the frictional factor between the surfaces of AFRP laminate and bonded engineering material.

Control of Blood Coagulation by Hemocompatible Material Surfaces—A Review

Hemocompatibility of biomaterials in contact with the blood of patients is a prerequisite for the short- and long-term applications of medical devices such as cardiovascular stents, artificial heart valves, ventricular assist devices, catheters, blood linings and extracorporeal devices such as artificial kidneys (hemodialysis), extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass. Although lower blood compatibility of materials and devices can be handled with systemic anticoagulation, its side effects, such as an increased bleeding risk, make materials that have a better hemocompatibility highly desirable, particularly in long-term applications. This review provides a short overview on the basic mechanisms of blood coagulation including plasmatic coagulation and blood platelets, as well as the activation of the complement system. Furthermore, a survey on concepts for tailoring the blood response of biomaterials to improve the hemocompatibility of medical devices is given which covers different approaches that either inhibit interaction of material surfaces with blood components completely or control the response of the coagulation system, blood platelets and leukocytes.

Editorial: theme issue on coronavirus and surfaces

Since the publication of the headline review on ‘Surface interactions and viability of coronaviruses' in Journal of the Royal Society Interface in January 2021 ( https://doi.org/10.1098/rsif.2020.0798 ), it has been my earnest desire to focus the minds of the scientific community on the role played by surfaces in the spread of COVID-19, especially the input physical sciences and engineering can impart to decelerate the spread of this disease worldwide. In fact, fig. 4 of the above-mentioned review clearly illustrated how persistence and viability of different coronavirus strains were dependent on widely used material surfaces. I thought the best way to achieve this goal on this rather complex and novel scientific issue was to put together a concise theme issue in Interface Focus where we bring together the opinions of a few internationally leading researchers on this important topic to collectively reduce the burden of COVID-19. Coronavirus and surfaces, the theme of this issue, is of utmost importance to many commercially significant industries such as packaging, textiles and metal forming. As the virus mutates and alters its anchoring and survival capabilities, this theme on coronavirus and surfaces will become more important, so we need to focus on this theme scientifically and methodically, with utmost urgency.

Bacterial Adhesion on Prosthetic and Orthotic Material Surfaces

Prosthetic and orthotic parts, such as prosthetic socket and inner sides of orthoses, are often in contact with human skin, giving bacteria the capability to adhere and form biofilms on the materials of those parts which can further cause infections. The purpose of this study was to determine the extent of bacterial adhesion of Staphylococcus aureus and Staphylococcus epidermidis on twelve different prosthetic and orthotic material surfaces and how roughness, hydrophobicity, and surface charge of this materials affect the adhesion. The roughness, contact angle, zeta potential of material surfaces, and adhesion rate of Staphylococcus aureus and Staphylococcus epidermidis were measured on all twelve prosthetic and orthotic materials, i.e., poly(methyl methacrylate), thermoplastic elastomer, three types of ethylene polyvinyl acetates (pure, with low-density polyethylene and with silver nanoparticles), silicone, closed-cell polyethylene foams with and without nanoparticles, thermo and natural cork, and artificial and natural leather. The greatest degree of adhesion was measured on both closed-cell polyethylene foams, followed by artificial thermo cork and leather. The lowest adhesion extent was observed on ethylene-vinyl acetate. The bacterial adhesion extent increases with the increasing surface roughness. Smaller deviations of this rule are the result of the surface’s hydrophobicity and charge.

Bioorthogonal Functionalization of Material Surfaces with Bioactive Molecules

The ability to control and modify the bioactivity of surfaces is pivotal to the success of many medical devices. A biocompatible and bioorthogonal method to functionalize surfaces with a wide variety of bioactive molecules is an important tool for enabling innovative biotechnology and medical applications. We report herein a novel, catecholamine-based surface functionalization method that is chemoselective and free of a metal catalyst. This method utilizes the ligation between a coating formed from the tyrosinase-catalyzed polymerization of a tetrazine-containing catecholamine and one or more strained alkene-containing molecules of interest. The process is achieved under conditions ideal for biological applications. Using this method, we graft surfaces with a variety of active molecules, including a small molecule fluorophore, enzymes, and a cyclic peptide with the RGD motif, and demonstrate the maintenance of their activity on the surface. Additionally, we establish the cytocompatibility of grafted ECM-mimicking surfaces with fibroblasts and show improved cell adhesion and cytoskeletal organization.

A tutorial on radio frequency sheath physics for magnetically confined fusion devices

Radio frequency (RF) sheaths occur under a wide variety of conditions when RF waves, material surfaces and plasma coexist. RF sheaths are of special importance in describing the interaction of ion cyclotron range of frequency (ICRF) waves with the boundary plasma in tokamaks, stellarators and other magnetic confinement devices. In this article the basic physics of RF sheaths is discussed in the context of magnetic fusion research. Techniques for modelling RF sheaths, their interaction with RF wave fields and the resulting consequences are highlighted. The article is intended as a guide for the early-career ICRF researcher, but it may equally well serve to provide an overview of basic RF sheath concepts and modelling directions for any interested fusion scientist.